Re: BFD over VXLAN: Trapping BFD Control packet at VTEP

["Joel M. Halpern" <[e-mail]>]

As far as I can tell, the current document we have in front of us is 
explicit that the messages are originated and terminated at the VNI.  If 
you want some other behavior, then we need a document that describes 
that behaviors.

Yours,
Joel

On 9/24/2019 10:39 PM, [e-mail] wrote:
> Hi Santosh,
> 
> 
> With regard to the question whether we should allow multiple BFD 
> sessions for the same VNI or not, IMHO we should allow it, more 
> explanation as follows.
> 
> Below is a figure derived from figure 2 of RFC8014 (An Architecture for 
> Data-Center Network Virtualization over Layer 3 (NVO3)).
> 
>                      |         Data Center Network (IP)        |
>                      |                                         |
>                      +-----------------------------------------+
>                           |                           |
>                           |       Tunnel Overlay      |
>              +------------+---------+       +---------+------------+
>              | +----------+-------+ |       | +-------+----------+ |
>              | |  Overlay Module  | |       | |  Overlay Module  | |
>              | +---------+--------+ |       | +---------+--------+ |
>              |           |          |       |           |          |
>       NVE1   |           |          |       |           |          | NVE2
>              |  +--------+-------+  |       |  +--------+-------+  |
>              |  |VNI1 VNI2  VNI1 |  |       |  | VNI1 VNI2 VNI1 |  |
>              |  +-+-----+----+---+  |       |  +-+-----+-----+--+  |
>              |VAP1| VAP2|    | VAP3 |       |VAP1| VAP2|     | VAP3|
>              +----+-----+----+------+       +----+-----+-----+-----+
>                   |     |    |                   |     |     |
>                   |     |    |                   |     |     |
>                   |     |    |                   |     |     |
>            -------+-----+----+-------------------+-----+-----+-------
>                   |     |    |     Tenant        |     |     |
>              TSI1 | TSI2|    | TSI3          TSI1| TSI2|     |TSI3
>                  +---+ +---+ +---+             +---+ +---+   +---+
>                  |TS1| |TS2| |TS3|             |TS4| |TS5|   |TS6|
>                  +---+ +---+ +---+             +---+ +---+   +---+
> 
> To my understanding, the BFD sessions between NVE1 and NVE2 are actually 
> initiated and terminated at VAP of NVE.
> 
> If the network operator want to set up one BFD session between VAP1 of 
> NVE1 and VAP1of NVE2, at the same time another BFD session between VAP3 
> of NVE1 and VAP3 of NVE2, although the two BFD sessions are for the same 
> VNI1, I believe it's reasonable, so that's why I think we should allow it.
> 
> 
> Of course, in RFC8014 it also says:
> 
> "Note that two different Tenant Systems (and TSIs) attached to a common NVE can share a VAP (e.g., TS1 and TS2 in Figure 2) so long as they connect to the same Virtual Network."
> 
> Some people may argue that all Tenant Systems connecting to the same 
> Virtual Network MUST share one VAP, if that's true, then VAP1 and VAP3 
> should merge into one VAP and my explanation doesn't work. Copying to 
> NVO3 WG to involve more experts, hope for your clarifications and comments.
> 
> 
> Best Regards,
> 
> Xiao Min
> 
> 原始邮件
> *发件人：*SantoshPK <[e-mail]>
> *收件人：*Greg Mirsky <[e-mail]>;
> *抄送人：*[e-mail] 
> <[e-mail]>;Dinesh Dutt <[e-mail]>;rtg-bfd 
> WG <[e-mail]>;Joel M. Halpern <[e-mail]>;T. Sridhar 
> <[e-mail]>;[e-mail] <[e-mail]>;
> *日 期 ：*2019年09月23日 05:39
> *主 题 ：**Re: BFD over VXLAN: Trapping BFD Control packet at VTEP*
> Greg,
>      Please see inline reply tagged [SPK]. I have added text requested.
> 
> Thanks
> Santosh P K
> 
> On Fri, Aug 16, 2019 at 4:59 AM Greg Mirsky <gregimirsky@gmail...com 
> <mailto:[e-mail]>> wrote:
> 
>     Hi Santosh,
>     thank you for your comments. Please find my notes in-lined and
>     tagged GIM>>.
> 
>     Regards,
>     Greg
> 
>     On Tue, Aug 13, 2019 at 10:24 PM Santosh P K
>     <[e-mail] <mailto:[e-mail]>>
>     wrote:
> 
>         Greg,
>             Thanks for updated version of document. Here are few
>         comments on new draft.
> 
>         Section 4:
>         Destination MAC: This MUST NOT be of one of tenant's MAC
>                   addresses.  The MAC address MAY be configured, or it
>         MAY be
>                   learned via a control plane protocol.  The details of
>         how the
>                   MAC address is obtained are outside the scope of this
>         document.
> 
>         I think we may need to give background on why we are saying MAC
>         address MUST not be one of tenant's MAC address. Like in this
>         thread we have discussed one of the tenant could have borrowed
>         the same VTEP mac address and we if we have to use BFD then we
>         need to avoid that conflict to ensure BFD packets get observed
>         in the VTEP itself. Should we add a section before 4 to set that
>         context so that above text makes more sense in that context?
> 
>     GIM>> Certainly. Please share the text you'd like to add. 
> 
> [SPK]  Proposed text for why we should not use VTEP MAX address as 
> tenant MAC address.
> 
> "In some scenarios tenant MAC is borrowed from VTEP MAC address. VXLAN 
> BFD MUST terminate BFD session at VTEP and MUST not forward BFD packets 
> to tenants. To terminate VXLAN BFD packets at VTEP, deployment MUST 
> ensure that there are no tenant VM which barrows VTEP MAC address."
> 
> 
> 
>             IP header:
>                   Destination IP: IP address MUST NOT be of one of
>         tenant's IP
>                   addresses.  IP address MAY be selected from the range
>         127/8 for
>                   IPv4, for IPv6 - from the range 0:0:0:0:0:FFFF:7F00:0/104.
> 
>                   TTL: MUST be set to 1 to ensure that the BFD packet is not
>                   routed within the L3 underlay network.
> 
> 
>         I think we have added some text to address Sridhar comments on
>         why TTL MUST be 1 and dest IP address MUST be 127/8 range. I see
>         that text is missing now.
> 
>     GIM>> My apologies that I've missed to include the text from another
>     discussion thread. I believe the following would be complete:
>                TTL or Hop Limit: MUST be set to 1 to ensure that the BFD
>               packet is not routed within the Layer 3 underlay network. 
>     This
>               addresses the scenario when the inner IP destination
>     address is
>               of VXLAN gateway and there is a router in underlay which
>               removes the VXLAN header, then it is possible to route the
>               packet as VXLAN  gateway address is routable address.
> 
> [SPK] This text looks good.
> 
> 
>         Section 5.1:
>         For such packets, the BFD session MUST be identified
>             using the following three-tuples of fields of the inner
>         header: the
>             source IP, the destination IP, and the source UDP port
>         number present
>             in the IP header carried by the payload of the packet in VXLAN
>             encapsulation.  If BFD packet is received with non-zero Your
>         Discriminator, then BFD session MUST be demultiplexed only with Your
>             Discriminator as the key.
> 
>         Just with 3 tuple we will not be able to demux packet. We need
>         to consider VNI as well if we have multiple BFD session between
>         same pair of VTEP.
> 
>     GIM>> This is one of comments from Carlos we need to address. Your
>     comment have helped me to form the question:
> 
>         What is the goal running multiple BFD sessions between the pair
>         of VTEPs?
> 
> [SPK] The goal of the multiple BFD session is to ensure check liveliness 
> of VXLAN tunnel. There is already a good amount of debate on this topic 
> that do we really need that? As per RFC 5884 we are running BFD per LSP 
> and we might hit scale issues there too. I think it is up to operator to 
> decide how they want to use multiple BFD session per VXLAN tunnel. It 
> could be possible that BFD session with special VNI is run at aggressive 
> interval where as MAY have multiple BFD sessions for different VNI at a 
> sedate interval, for that matter they could be running in demand mode as 
> well (run P/F sequence only when there is no data following for that 
> VNI). As WG if we think running multiple BFD session make sense then we 
> might need to add appropriate text.
> 
>     If the goal is to monitor per VNI, then the following text should
>     describe the demultiplexing of the initial BFD Control packet:
>         Demultiplexing of IP BFD packet has been defined in Section 3 of
>         [RFC5881].  Since multiple BFD sessions may be running between two
>         VTEPs, there needs to be a mechanism for demultiplexing received BFD
>         packets to the proper session.  For demultiplexing packets with Your
>         Discriminator equal to 0, a BFD session MUST be identified using the
>         logical link over which the BFD Control packet is received.  In the
>         case of VXLAN, the VNI number identifies that logical link.  If BFD
>         packet is received with non-zero Your Discriminator, then BFD
>     session
>         MUST be demultiplexed only with Your Discriminator as the key.
> 
> [SPK]  I think this text for multiple BFD session between same pair of 
> VTEPs for multiple VNI makes sense only if as WG we think that could be 
> use case.
> 
>     Would there be need to run multiple BFD sessions with the same VNI
>     number?
> 
> 
> [SPK] IMHO we should not allow multiple BFD session for the same VNI.
> 
> 
> 
> 
>         Thanks
>         Santosh P K
> 
> 
>         On Fri, Aug 9, 2019 at 4:27 AM Greg Mirsky
>         <[e-mail] <mailto:[e-mail]>> wrote:
> 
>             Dinesh, thank you for your help, much appreciated.
>             Hi Joel and Sridhar,
>             could you please check if the updated text on the inner
>             Ethernet frame addressed your concern.
> 
>             On Wed, Aug 7, 2019 at 2:25 PM Dinesh Dutt <[e-mail]
>             <mailto:[e-mail]>> wrote:
> 
>                 Looks god to me Greg. Thank you for your hard work in this,
> 
>                 Dinesh
> 
>                 On Wed, Aug 7, 2019 at 9:25 AM Greg Mirsky
>                 <[e-mail] <mailto:[e-mail]>>
>                 wrote:
> 
>                     Hi Dinesh, Joel, Sridhar, et al.,
>                     much appreciate the help you've given me sharing
>                     your expertise. I hope that the updates you will
>                     find in the attached diff and the working copy of
>                     the draft be closer to the acceptable solution for
>                     VTEP-VTEP BFD. Please note, that I'll shortly start
>                     a new discussion thread to address one of Carlos's
>                     questions on the ambiguity of the text on multiple
>                     concurrent sessions between the same pair of VTEPs.
>                     Please review the changes to Sections 4 and 6 and
>                     share your feedback, suggestions, and questions.
> 
>                     Regards,
>                     Greg
> 
>                     On Mon, Aug 5, 2019 at 6:03 PM Dinesh Dutt
>                     <[e-mail] <mailto:[e-mail]>> wrote:
> 
> 
> 
>                         On Mon, Aug 5, 2019 at 5:56 PM Greg Mirsky
>                         <[e-mail]
>                         <mailto:[e-mail]>> wrote:
> 
>                             Hi Dinesh,
>                             thank you for your expedient detailed response.
>                             I believe that the ability to run BFD
>                             session up to a tenant (VTEP-VTEP-tenant or
>                             tenant-tenant) was never in jeopardy from
>                             this specification.
>                             I'm trying to provide precise specification
>                             on what can be used ad the destination MAC
>                             and IP addresses in the inner frame/packet
>                             as I believe that likely will help to avoid
>                             interoperability issues.
>                             I'm interested to learn some more about the
>                             "martian checking" function. As you know,
>                             martian addresses have been used as
>                             destination IP address in LSP Ping and BFD
>                             over MPLS LSP and PW. I haven't heard that
>                             any silicon feature caused problems for
>                             operators using these tools.
> 
> 
>                         Interesting. I didn't know this aspect of use
>                         with MPLS ping. Did those packets ever go
>                         through a firewall though? In any case, maybe
>                         suggest the use of those addresses with a
>                         statement that this is how LSP does it, but that
>                         other MAC/IP pairs are possible as long as the
>                         conditions of the endpoint owning the MAC/IP was
>                         honored.
> 
>                         Dinesh
> 
> 
>                             Regards,
>                             Greg
> 
>                             On Mon, Aug 5, 2019 at 3:59 PM Dinesh Dutt
>                             <[e-mail] <mailto:[e-mail]>>
>                             wrote:
> 
>                                 Hi Greg,
> 
>                                 That we agree on the problem definition
>                                 is the first step forward. Your original
>                                 document had my cases covered and so I
>                                 was surprised by the track this thread
>                                 took. It doesn't matter, we're back on
>                                 track.
> 
>                                 My recommendation is to not worry about
>                                 specifying the precise MAC/IP address
>                                 used in the inner header. The addresses
>                                 chosen MUST ensure that the packet is
>                                 trapped to the control plane of the VTEP
>                                 and not escape to the tenant if the BFD
>                                 is to the VTEP. Any solution MUST also
>                                 not preclude the use of the BFD by
>                                 tenant systems for that VNI. There are
>                                 many ways an implementer can choose to
>                                 implement this. For example, the inner
>                                 MAC address is whatever the VTEP
>                                 implementer would return if ARP'd for
>                                 the IP address used in the inner header
>                                 in the given VNI. The implementer can
>                                 pick a fixed MAC address, one that they
>                                 own etc. Multiple BFD sessions can be
>                                 run for testing path connectivity on
>                                 more than one VNIs. Limits should be in
>                                 place to avoid overwhelming the receiver
>                                 with BFD messages (you had words about
>                                 this in your currently published
>                                 draft).  If the VNI is irrelevant in the
>                                 test i.e. only the VXLAN pipe at the
>                                 VTEP is being tested. the user can use
>                                 any VNI active on the VTEP on which the
>                                 VTEP owns an IP address.
> 
>                                 I'm concerned about the use of 127/8
>                                 address only because of firewalls or
>                                 implementations that drop packets with
>                                 these addresses as either the source or
>                                 destination. For example, on many
>                                 merchant silicon, I don't believe you
>                                 can turn off martian checking and drops
>                                 *only* for VXLAN-encapsulated BFD
>                                 packets. I don't know what the Linux
>                                 kernel does today on such packets, for
>                                 example (or Hyper-V). I'd like a
>                                 solution that doesn't demand additional
>                                 or new chip functionality or require
>                                 additional middle-box hole punch.
> 
>                                 Why do you feel you MUST to specify the
>                                 MAC/IP address on the inner packet? What
>                                 am I missing here?
> 
>                                 Dinesh
> 
>                                 On Mon, Aug 5, 2019 at 3:04 PM Greg
>                                 Mirsky <[e-mail]
>                                 <mailto:[e-mail]>> wrote:
> 
>                                     Hi Dinesh,
>                                     what do you see as the way forward?
>                                     I agree, that the proposed text
>                                     doesn't work for multi-VNI
>                                     concurrent monitoring because these
>                                     VNIs are tenant's VNIs. And in that
>                                     case, we need to specify another
>                                     mechanism to trap the BFD Control
>                                     packet at VTEP. It seems that VTEP's
>                                     Ethernet address must be used as the
>                                     destination MAC address in the inner
>                                     Ethernet frame. The destination IP
>                                     address may be either VTEP's address
>                                     of martian (I do prefer martian).
>                                     Let me give it  try:
>                                     NEW TEXT:
> 
>                                         To monitor continuity of the
>                                         path between two VTEPs, an
>                                         operator MUST select a VNI
>                                         number to be used as Management
>                                         VNI. Management VNI number MUST
>                                         NOT be one of the tenant's VNIs
>                                         to prevent sending VXLAN packets
>                                         received on Management VNI to a
>                                         tenant. VNI number 1 is
>                                         RECOMMENDED as the default for
>                                         Management VNI. [Ed.note: What
>                                         we set the Destination MAC to?
>                                         Can it be invalid MAC that MUST
>                                         be ignored on receipt?]
> 
>                                         If an implementation supports
>                                         concurrent monitoring of
>                                         multiple VNIs, then the value of
>                                         VNI number MAY be one of
>                                         tenant's VNIs. The destination
>                                         MAC address in the inner
>                                         Ethernet frame encapsulating BFD
>                                         Control packet MUST be MAC
>                                         associated with the remote VTEP.
>                                         The destination IP address of
>                                         the inner IP packet MUST be
>                                         selected from the range 127/8
>                                         for IPv4, and for IPv6 from the
>                                         range 0:0:0:0:0:FFFF:7F00:0/104.
>                                         The TTL value in the inner IP
>                                         header MUST be set to 1.
> 
>                                     Regards,
>                                     Greg
> 
>                                     On Sun, Aug 4, 2019 at 9:07 AM
>                                     Dinesh Dutt <[e-mail]
>                                     <mailto:[e-mail]>> wrote:
> 
>                                         Hi Greg,
> 
>                                         Thanks for your clarifications.
>                                         I agree with your sentiment on
>                                         why you're running BFD over
>                                         VXLAN between VTEPs. I wasn't
>                                         arguing against it at all. All I
>                                         was saying was pointing to the
>                                         limitations of the use of
>                                         management VNI. I spoke to some
>                                         operators who're running EVPN
>                                         and mentioned the discussion on
>                                         this thread. They concur that
>                                         they're using specific VNIs to
>                                         test connectivity over that VNI
>                                         between VTEPs to ensure
>                                         misconfiguration doesn't lead to
>                                         blackholes. My statements are
>                                         based in real world operator
>                                         experience. And I was providing
>                                         language that ensured packets
>                                         didn't leak across to tenants
>                                         when they were destined to VTEPs.
> 
>                                         Dinesh
> 
>                                         On Sat, Aug 3, 2019 at 10:34 AM
>                                         Greg Mirsky
>                                         <[e-mail]
>                                         <mailto:[e-mail]>>
>                                         wrote:
> 
>                                             Hi Dinesh,
>                                             many thanks for your
>                                             detailed updates on how some
>                                             implementations process
>                                             VXLAN header and the inner
>                                             Ethernet frame. These are
>                                             very helpful in achieving
>                                             the workable solution for
>                                             the problem at hand.
>                                             You've noted that a path
>                                             between VTEPs may be
>                                             monitored in the underlay
>                                             network by merely
>                                             establishing a BFD session.
>                                             That is true, but by using
>                                             BFD with VXLAN encapsulation
>                                             between the pair of VTEPs we
>                                             are extending the OAM domain
>                                             by including, to some
>                                             extent, VXLAN forwarding
>                                             engine. Abstract in RFC 5880
>                                             defines the goal and the
>                                             domain in which BFD protocol
>                                             can detect a fault as:
>                                                 This document describes
>                                             a protocol intended to
>                                             detect faults in the
>                                                 bidirectional path
>                                             between two forwarding
>                                             engines, including
>                                                 interfaces, data
>                                             link(s), and to the extent
>                                             possible the forwarding
>                                                 engines themselves, with
>                                             potentially very low latency.
>                                             Thus, BFD in the underlay
>                                             will exercise a part of IP
>                                             forwarding engine while BFD
>                                             with VXLAN encapsulation,
>                                             ran between the same pair of
>                                             VTEPs, extends the OAM
>                                             domain. At the same time,
>                                             defining BFD between tenant
>                                             systems in outside the goal
>                                             of this specification. But
>                                             VXLAN BFD session between
>                                             VTEPs may be useful in
>                                             monitoring e2e path between
>                                             tenants, as described in the
>                                             update to -07:
>                                                 At the same time, a
>                                             service layer BFD session
>                                             may be used between the
>                                                 tenants of VTEPs IP1 and
>                                             IP2 to provide end-to-end
>                                             fault management.
>                                                 In such case, for VTEPs
>                                             BFD control packets of that
>                                             session are
>                                                 indistinguishable from
>                                             data packets.  If end-to-end
>                                             defect detection
>                                                 is realized as the set
>                                             of concatenated OAM domains,
>                                             e.g., VM1-1 - IP1
>                                                 -- IP2 - VM2-1, then the
>                                             BFD session over VXLAN
>                                             between VTEPs SHOULD
>                                                 follow the procedures
>                                             described in Section 6.8.17
>                                             [RFC5880].
>                                             I've attached the current
>                                             working version of the draft.
> 
>                                             Regards,
>                                             Greg
> 
> 
>                                             On Fri, Aug 2, 2019 at 5:43
>                                             PM Dinesh Dutt
>                                             <[e-mail]
>                                             <mailto:[e-mail]>>
>                                             wrote:
> 
>                                                 What I mean is "How do
>                                                 you infer that it
>                                                 excludes the case I'm
>                                                 talking about?".
> 
>                                                 Dinesh
> 
>                                                 On Fri, Aug 2, 2019 at
>                                                 5:41 PM Dinesh Dutt
>                                                 <[e-mail]
>                                                 <mailto:[e-mail]>>
>                                                 wrote:
> 
>                                                     The abstract reads
>                                                     this: "
> 
>                                                     This document describes the use of the Bidirectional Forwarding
>                                                         Detection (BFD) protocol in point-to-point Virtual eXtensible Local
>                                                         Area Network (VXLAN) tunnels forming up an overlay network."
> 
>                                                     How do you infer
>                                                     what you said?
> 
>                                                     Dinesh
> 
> 
>                                                     On Fri, Aug 2, 2019
>                                                     at 5:38 PM Joel M.
>                                                     Halpern
>                                                     <[e-mail]
>                                                     <mailto:[e-mail]>>
>                                                     wrote:
> 
>                                                         I am going by
>                                                         what the draft
>                                                         says its purpose
>                                                         is.  If you
>                                                         (Dinesh) want
>                                                         the draft to
>                                                         fulfill a
>                                                         different
>                                                         purpose, then
>                                                         either ask the
>                                                         chairs to
>                                                         take this draft
>                                                         back to the WG,
>                                                         or write a
>                                                         separate draft.
>                                                         As currently
>                                                         written, the
>                                                         behavior Greg
>                                                         proposed meets
>                                                         the needs, and
>                                                         does so in a way
>                                                         that is
>                                                         consistent with
>                                                         VxLAN.
> 
>                                                         Yours,
>                                                         Joel
> 
>                                                         On 8/2/2019 8:30
>                                                         PM, Dinesh Dutt
>                                                         wrote:
>                                                          > What is the
>                                                         stated purpose
>                                                         of this BFD
>                                                         session? The
>                                                         VTEP
>                                                         reachability is
>                                                          > determined by
>                                                         the underlay, I
>                                                         don't need
>                                                         VXLAN-encaped
>                                                         packet for that.
>                                                          > Do we agree?
>                                                          >
>                                                          > If I want to
>                                                         test the VXLAN
>                                                         encap/decap
>                                                         functionality
>                                                         alone, picking any
>                                                          > single VNI
>                                                         maybe fine. But
>                                                         is this all any
>                                                         network operator
>                                                         wants? Why?
>                                                          > In what
>                                                         situations has
>                                                         this been a
>                                                         problem? I
>                                                         suspect
>                                                         operators also
>                                                          > want to
>                                                         verify path
>                                                         continuity over
>                                                         a specific VNI.
>                                                         If you say this is
>                                                          > not defined
>                                                         by the document,
>                                                         I disagree
>                                                         because the
>                                                         current version
>                                                          > talks about
>                                                         controlling the
>                                                         number of BFD
>                                                         sessions between
>                                                         the VTEPs
>                                                          > (see section
>                                                         3). More
>                                                         importantly,
>                                                         this is a real
>                                                         problem that
>                                                         operators
>                                                          > like to verify.
>                                                          >
>                                                          > Dinesh
>                                                          >
>                                                          > On Fri, Aug
>                                                         2, 2019 at 5:08
>                                                         PM Joel M.
>                                                         Halpern
>                                                         <[e-mail]
>                                                         <mailto:[e-mail]>
> 
>                                                          >
>                                                         <mailto:[e-mail]
>                                                         <mailto:[e-mail]>>>
>                                                         wrote:
>                                                          >
>                                                          >     What is
>                                                         special about
>                                                         the management
>                                                         VNI is precisely
>                                                         that it is NOT a
>                                                          >     tenant
>                                                         VNI.  The VxLAN
>                                                         administration
>                                                         does know how it
>                                                         allocates VNI to
>                                                          >     tenants,
>                                                         and which VNI it
>                                                         has allocated. 
>                                                         In contrast, it
>                                                         does not know
>                                                          >     which IP
>                                                         addresses or MAC
>                                                         adddresses teh
>                                                         tenant is using
>                                                         or may plan
>                                                          >     to use.
>                                                          >
>                                                          >     Yours,
>                                                          >     Joel
>                                                          >
>                                                          >     On
>                                                         8/2/2019 6:41
>                                                         PM, Dinesh Dutt
>                                                         wrote:
>                                                          >      > The
>                                                         assumption of an
>                                                         IP address
>                                                         within any VNI
>                                                         is suspect that way.
>                                                          >      > What's
>                                                         special about a
>                                                         single VNI, the
>                                                         management VNI?
>                                                         The VTEP IP
>                                                          >      >
>                                                         address does not
>                                                         belong in
>                                                         reality in any
>                                                         VNI...
>                                                          >      >
>                                                          >      > Dinesh
>                                                          >      >
>                                                          >      > On
>                                                         Fri, Aug 2, 2019
>                                                         at 3:17 PM Joel
>                                                         M. Halpern
>                                                          >   
>                                                           <[e-mail] <mailto:[e-mail]> <mailto:[e-mail] <mailto:[e-mail]>>
>                                                          >      >
>                                                         <mailto:[e-mail]
>                                                         <mailto:[e-mail]>
>                                                         <mailto:[e-mail]
>                                                         <mailto:[e-mail]>>>>
>                                                         wrote:
>                                                          >      >
>                                                          >      >   
>                                                           Your response
>                                                         seems to miss
>                                                         two points:
>                                                          >      >
>                                                          >      >   
>                                                           First, the
>                                                         problem you
>                                                         describe is not
>                                                         what the
>                                                         document says
>                                                          >     it is
>                                                          >      >   
>                                                           solving.  To
>                                                         the degree it
>                                                         discusses it at
>                                                         all, the document
>                                                          >     says "
>                                                          >      >       In
>                                                          >      >   
>                                                           most cases, a
>                                                         single BFD
>                                                         session is
>                                                         sufficient for
>                                                         the given
>                                                          >     VTEP to
>                                                          >      >   
>                                                           monitor the
>                                                         reachability of
>                                                         a remote VTEP,
>                                                         regardless of the
>                                                          >     number of
>                                                          >      >   
>                                                           VNIs in common. "
>                                                          >      >
>                                                          >      >   
>                                                           Second, you
>                                                         assume the
>                                                         existence of an
>                                                         IP address for a
>                                                         VTEP
>                                                          >     within a
>                                                          >      >   
>                                                           VNI.  As with
>                                                         the MAC address,
>                                                         the VTEP does
>                                                         not have an IP
>                                                          >     address
>                                                          >      >   
>                                                           within the
>                                                         VNI.  Some
>                                                         implementations
>                                                         may have created
>                                                         such a
>                                                          >     thing,
>                                                          >      >     but
>                                                          >      >   
>                                                           the general
>                                                         construct, as
>                                                         defined to date,
>                                                         does not support
>                                                         such.
>                                                          >      >
>                                                          >      >     In
>                                                         short, you are
>                                                         requiring a
>                                                         behavior that
>                                                         violates the
>                                                          >     architectural
>                                                          >      >   
>                                                           structure of
>                                                         overlay /
>                                                         underlay
>                                                         separation, and
>                                                         common
>                                                          >     usage. 
>                                                         And you
>                                                          >      >   
>                                                           are doing so
>                                                         to support a use
>                                                         case that the
>                                                         working group
>                                                         has not
>                                                          >      >   
>                                                           indicated in
>                                                         the document as
>                                                         important.
>                                                          >      >
>                                                          >      >     Yours,
>                                                          >      >     Joel
>                                                          >      >
>                                                          >      >     On
>                                                         8/2/2019 5:01
>                                                         PM, Dinesh Dutt
>                                                         wrote:
>                                                          >      >      >
>                                                         Joel,
>                                                          >      >      >
>                                                          >      >      >
>                                                         You understood
>                                                         correctly.
>                                                          >      >      >
>                                                          >      >      >
>                                                         The VNIs may not
>                                                         share fate due
>                                                         to
>                                                         misconfiguration. And
>                                                         I
>                                                          >     strongly
>                                                          >      >      >
>                                                         suspect someone
>                                                         will want to use
>                                                         BFD for that
>                                                         because its
>                                                          >     about
>                                                          >      >   
>                                                           checking
>                                                          >      >      >
>                                                         path continuity
>                                                         as stated by the
>                                                         draft. As long
>                                                         as there's a
>                                                          >      >   
>                                                           valid IP
>                                                          >      >      >
>                                                         (because it's
>                                                         BFD) owned by
>                                                         the VTEP in that
>                                                         VNI, you can
>                                                          >     use BFD in
>                                                          >      >      >
>                                                         that VNI. Thats
>                                                         all that you
>                                                         need to
>                                                         dictate.  That
>                                                         IP address
>                                                          >      >   
>                                                           has a MAC
>                                                          >      >      >
>                                                         address and you
>                                                         can use that on
>                                                         the inner frame.
>                                                         That is
>                                                          >     all normal
>                                                          >      >      >
>                                                         VXLAN
>                                                         processing. The
>                                                         outer IP is
>                                                         always that of
>                                                         the VTEP.
>                                                          >      >      >
>                                                          >      >      >
>                                                         Dinesh
>                                                          >      >      >
>                                                          >      >      >
>                                                         On Fri, Aug 2,
>                                                         2019 at 11:03 AM
>                                                         Joel M. Halpern
>                                                          >      >   
>                                                           <[e-mail] <mailto:[e-mail]> <mailto:[e-mail] <mailto:[e-mail]>>
>                                                          >   
>                                                           <mailto:[e-mail] <mailto:[e-mail]> <mailto:[e-mail] <mailto:[e-mail]>>>
>                                                          >      >      >
>                                                         <mailto:[e-mail]
>                                                         <mailto:[e-mail]>
>                                                         <mailto:[e-mail]
>                                                         <mailto:[e-mail]>>
>                                                          >   
>                                                           <mailto:[e-mail] <mailto:[e-mail]> <mailto:[e-mail] <mailto:[e-mail]>>>>> wrote:
>                                                          >      >      >
>                                                          >      >     
>                                                          >     If I am
>                                                         reading your
>                                                         various emails
>                                                         correctly Dinesh
>                                                          >     (and I
>                                                          >      >   
>                                                           may have
>                                                          >      >     
>                                                          >     missed
>                                                         something) you
>                                                         are trying to
>                                                         use the MAC address
>                                                          >      >   
>                                                           because you
>                                                          >      >     
>                                                          >     want
>                                                          >      >     
>                                                          >     to be
>                                                         able to send
>                                                         these BFD
>                                                         packets over
>                                                         arbitrary VNI to
>                                                          >      >   
>                                                           monitor the
>                                                          >      >     
>                                                          >     VNI. 
>                                                         That is not a
>                                                         requirement
>                                                         identified in the
>                                                          >     document.
>                                                          >      >     It
>                                                         is not
>                                                          >      >     
>                                                          >     even a
>                                                         problem I
>                                                         understand,
>                                                         since all the
>                                                         VNI between an
>                                                          >      >   
>                                                           ingress and
>                                                          >      >     
>                                                          >     egress
>                                                         VTEP share fate.
>                                                          >      >      >
>                                                          >      >     
>                                                          >     Yours,
>                                                          >      >     
>                                                          >     Joel
>                                                          >      >      >
>                                                          >      >     
>                                                          >     On
>                                                         8/2/2019 1:44
>                                                         PM, Dinesh Dutt
>                                                         wrote:
>                                                          >      >     
>                                                          >      > Thanks
>                                                         for verifying
>                                                         this. On Linux
>                                                         and hardware
>                                                          >     routers
>                                                          >      >   
>                                                           that I'm
>                                                          >      >     
>                                                          >     aware
>                                                          >      >     
>                                                          >      > of
>                                                         (Cisco circa
>                                                         2012 and
>                                                         Cumulus), the
>                                                         physical MAC
>                                                          >     address is
>                                                          >      >     
>                                                          >     reused
>                                                          >      >     
>                                                          >      > across
>                                                         the VNIs on the
>                                                         VTEP. Did you
>                                                         check on a non-VMW
>                                                          >      >   
>                                                           device?
>                                                          >      >     
>                                                          >     This is
>                                                          >      >     
>                                                          >      > more
>                                                         for my own
>                                                         curiosity.
>                                                          >      >     
>                                                          >      >
>                                                          >      >     
>                                                          >      > To
>                                                         address the
>                                                         general case,
>                                                         can we not define a
>                                                          >      >   
>                                                           well-known (or
>                                                          >      >     
>                                                          >     reserve
>                                                          >      >     
>                                                          >      > one)
>                                                         unicast MAC
>                                                         address for use
>                                                         with VTEP? If
>                                                         the MAC
>                                                          >      >   
>                                                           address is
>                                                          >      >     
>                                                          >      >
>                                                         configurable in
>                                                         BFD command,
>                                                         this can be moot.
>                                                          >      >     
>                                                          >      >
>                                                          >      >     
>                                                          >      > Dinesh
>                                                          >      >     
>                                                          >      >
>                                                          >      >     
>                                                          >      > On
>                                                         Fri, Aug 2, 2019
>                                                         at 10:27 AM
>                                                         Santosh P K
>                                                          >      >     
>                                                          >      >
>                                                         <[e-mail]
>                                                         <mailto:[e-mail]>
>                                                          >   
>                                                           <mailto:[e-mail] <mailto:[e-mail]>>
>                                                          >      >   
>                                                           <mailto:santosh.pallagatti@gmail...com <mailto:[e-mail]>
>                                                          >   
>                                                           <mailto:[e-mail] <mailto:[e-mail]>>>
>                                                          >      >     
>                                                          >   
>                                                           <mailto:[e-mail] <mailto:[e-mail]>
>                                                          >   
>                                                           <mailto:[e-mail] <mailto:[e-mail]>>
>                                                          >      >   
>                                                           <mailto:santosh.pallagatti@gmail...com <mailto:[e-mail]>
>                                                          >   
>                                                           <mailto:[e-mail] <mailto:[e-mail]>>>>
>                                                          >      >     
>                                                          >   
>                                                           <mailto:[e-mail] <mailto:[e-mail]>
>                                                          >   
>                                                           <mailto:[e-mail] <mailto:[e-mail]>>
>                                                          >      >   
>                                                           <mailto:santosh.pallagatti@gmail...com <mailto:[e-mail]>
>                                                          >   
>                                                           <mailto:[e-mail] <mailto:[e-mail]>>>
>                                                          >      >     
>                                                          >   
>                                                           <mailto:[e-mail] <mailto:[e-mail]>
>                                                          >   
>                                                           <mailto:[e-mail] <mailto:[e-mail]>>
>                                                          >      >   
>                                                           <mailto:santosh.pallagatti@gmail...com <mailto:[e-mail]>
>                                                          >   
>                                                           <mailto:[e-mail] <mailto:[e-mail]>>>>>> wrote:
>                                                          >      >     
>                                                          >      >
>                                                          >      >     
>                                                          >      >     I
>                                                         have cross
>                                                         checked point
>                                                         raised about MAC
>                                                         address
>                                                          >      >   
>                                                           usage. It is
>                                                          >      >     
>                                                          >      >   
>                                                           possible that
>                                                         tenant could be
>                                                         using physical MAC
>                                                          >      >   
>                                                           address and
>                                                          >      >     
>                                                          >     when a
>                                                          >      >     
>                                                          >      >   
>                                                           packet comes
>                                                         with valid VNI
>                                                         with a MAC address
>                                                          >     that is
>                                                          >      >     being
>                                                          >      >     
>                                                          >     used by
>                                                          >      >     
>                                                          >      >   
>                                                           tenant then
>                                                         packet will be
>                                                         sent to that tenant.
>                                                          >     This rules
>                                                          >      >     
>                                                          >     out the
>                                                          >      >     
>                                                          >      >   
>                                                           fact that we
>                                                         could use
>                                                         physical MAC
>                                                         address as
>                                                          >     inner
>                                                          >      >     MAC to
>                                                          >      >     
>                                                          >     ensure
>                                                          >      >     
>                                                          >      >   
>                                                           packets get
>                                                         terminated at
>                                                         VTEP itself.
>                                                          >      >     
>                                                          >      >
>                                                          >      >     
>                                                          >      >     Thanks
>                                                          >      >     
>                                                          >      >   
>                                                           Santosh P K
>                                                          >      >     
>                                                          >      >
>                                                          >      >     
>                                                          >      >     On
>                                                         Wed, Jul 31,
>                                                         2019 at 11:00 AM
>                                                         Santosh P K
>                                                          >      >     
>                                                          >      >   
>                                                           <[e-mail] <mailto:[e-mail]>
>                                                          >   
>                                                           <mailto:[e-mail] <mailto:[e-mail]>>
>                                                          >      >   
>                                                           <mailto:santosh.pallagatti@gmail...com <mailto:[e-mail]>
>                                                          >   
>                                                           <mailto:[e-mail] <mailto:[e-mail]>>>
>                                                          >      >     
>                                                          >   
>                                                           <mailto:[e-mail] <mailto:[e-mail]>
>                                                          >   
>                                                           <mailto:[e-mail] <mailto:[e-mail]>>
>                                                          >      >   
>                                                           <mailto:santosh.pallagatti@gmail...com <mailto:[e-mail]>
>                                                          >   
>                                                           <mailto:[e-mail] <mailto:[e-mail]>>>>
>                                                          >      >     
>                                                          >   
>                                                           <mailto:[e-mail] <mailto:[e-mail]>
>                                                          >   
>                                                           <mailto:[e-mail] <mailto:[e-mail]>>
>                                                          >      >   
>                                                           <mailto:santosh.pallagatti@gmail...com <mailto:[e-mail]>
>                                                          >   
>                                                           <mailto:[e-mail] <mailto:[e-mail]>>>
>                                                          >      >     
>                                                          >   
>                                                           <mailto:[e-mail] <mailto:[e-mail]>
>                                                          >   
>                                                           <mailto:[e-mail] <mailto:[e-mail]>>
>                                                          >      >   
>                                                           <mailto:santosh.pallagatti@gmail...com <mailto:[e-mail]>
>                                                          >   
>                                                           <mailto:[e-mail] <mailto:[e-mail]>>>>>>
>                                                          >      >     
>                                                          >      >     wrote:
>                                                          >      >     
>                                                          >      >
>                                                          >      >     
>                                                          >      >       
>                                                           Joel,
>                                                          >      >     
>                                                          >      >       
>                                                               Thanks for
>                                                         your inputs. I
>                                                         checked
>                                                          >      >   
>                                                           implementation
>                                                         within
>                                                          >      >     
>                                                          >      >       
>                                                           Vmware.
>                                                         Perhaps I should
>                                                         have been more clear
>                                                          >      >   
>                                                           about MAC
>                                                          >      >     
>                                                          >     address
>                                                          >      >     
>                                                          >      >       
>                                                           space while
>                                                         checking
>                                                         internally. I
>                                                         will cross
>                                                          >      >   
>                                                           check again for
>                                                          >      >     
>                                                          >      >       
>                                                           the same and
>                                                         get back on this
>                                                         list.
>                                                          >      >     
>                                                          >      >
>                                                          >      >     
>                                                          >      >       
>                                                           Thanks
>                                                          >      >     
>                                                          >      >       
>                                                           Santosh P K
>                                                          >      >     
>                                                          >      >
>                                                          >      >     
>                                                          >      >       
>                                                           On Wed, Jul
>                                                         31, 2019 at
>                                                         10:54 AM Joel M.
>                                                          >     Halpern
>                                                          >      >     
>                                                          >      >       
>                                                           <[e-mail] <mailto:jmh@joelhalpern...com>
>                                                          >   
>                                                           <mailto:[e-mail] <mailto:[e-mail]>> <mailto:[e-mail] <mailto:[e-mail]>
>                                                          >   
>                                                           <mailto:[e-mail] <mailto:[e-mail]>>>
>                                                          >      >   
>                                                           <mailto:[e-mail] <mailto:[e-mail]> <mailto:[e-mail] <mailto:[e-mail]>>
>                                                          >   
>                                                           <mailto:[e-mail] <mailto:[e-mail]> <mailto:[e-mail] <mailto:[e-mail]>>>>
>                                                          >      >     
>                                                          >   
>                                                           <mailto:[e-mail] <mailto:[e-mail]>
>                                                          >   
>                                                           <mailto:[e-mail] <mailto:[e-mail]>> <mailto:[e-mail] <mailto:[e-mail]>
>                                                          >   
>                                                           <mailto:[e-mail] <mailto:[e-mail]>>>
>                                                          >      >   
>                                                           <mailto:[e-mail] <mailto:[e-mail]> <mailto:[e-mail] <mailto:[e-mail]>>
>                                                          >   
>                                                           <mailto:[e-mail] <mailto:[e-mail]> <mailto:[e-mail] <mailto:[e-mail]>>>>>> wrote:
>                                                          >      >     
>                                                          >      >
>                                                          >      >     
>                                                          >      >       
>                                                               Sorry to
>                                                         ask a stupid
>                                                         question.  Whose
>                                                          >      >   
>                                                           implementation?
>                                                          >      >     
>                                                          >      >
>                                                          >      >     
>                                                          >      >       
>                                                               The reason
>                                                         I ask is that as
>                                                         far as I
>                                                          >     can tell,
>                                                          >      >   
>                                                           since the
>                                                          >      >     
>                                                          >      >       
>                                                               tenant
>                                                         does not
>                                                          >      >     
>                                                          >      >       
>                                                               have any
>                                                         control access
>                                                         to the VTEP,
>                                                          >     there is no
>                                                          >      >     
>                                                          >     reason for
>                                                          >      >     
>                                                          >      >       
>                                                               the VTEP to
>                                                          >      >     
>                                                          >      >       
>                                                               have a MAC
>                                                         address in the
>                                                         tenant
>                                                          >     space. 
>                                                         Yes, the
>                                                          >      >     
>                                                          >     device has
>                                                          >      >     
>                                                          >      >       
>                                                               a physical
>                                                          >      >     
>                                                          >      >       
>                                                               MAC
>                                                         address.  But
>                                                         the tenant could
>                                                         well be
>                                                          >      >   
>                                                           using that MAC
>                                                          >      >     
>                                                          >      >       
>                                                               address.  Yes,
>                                                          >      >     
>                                                          >      >       
>                                                               they would
>                                                         be violating the
>                                                         Ethernet spec.
>                                                          >      >   
>                                                           But the whole
>                                                          >      >     
>                                                          >      >       
>                                                               point of
>                                                          >      >     
>                                                          >      >       
>                                                             
>                                                           segregation is
>                                                         not to care
>                                                         about such
>                                                          >     issues.
>                                                          >      >     
>                                                          >      >
>                                                          >      >     
>                                                          >      >       
>                                                               On the
>                                                         other hand, if
>                                                         you tell me that
>                                                          >     the VMWare
>                                                          >      >     
>                                                          >      >       
>                                                             
>                                                           implementation
>                                                         has an
>                                                          >      >     
>                                                          >      >       
>                                                               Ethernet
>                                                         address that is
>                                                         part of the tenant
>                                                          >      >   
>                                                           space, well,
>                                                          >      >     
>                                                          >      >       
>                                                               they made up
>                                                          >      >     
>                                                          >      >       
>                                                               this
>                                                         particular game.
>                                                          >      >     
>                                                          >      >
>                                                          >      >     
>                                                          >      >       
>                                                               Yours,
>                                                          >      >     
>                                                          >      >       
>                                                               Joel
>                                                          >      >     
>                                                          >      >
>                                                          >      >     
>                                                          >      >       
>                                                               On
>                                                         7/31/2019 1:44
>                                                         PM, Santosh P K
>                                                         wrote:
>                                                          >      >     
>                                                          >      >       
>                                                                > I have
>                                                         checked with
>                                                         implementation
>                                                          >     in data
>                                                          >      >     path.
>                                                          >      >     
>                                                          >     When we
>                                                          >      >     
>                                                          >      >       
>                                                               receive a
>                                                          >      >     
>                                                          >      >       
>                                                                > packet
>                                                         with valid VNI
>                                                         then lookup
>                                                          >     for MAC will
>                                                          >      >     
>                                                          >     happen and
>                                                          >      >     
>                                                          >      >       
>                                                               it is VTEP own
>                                                          >      >     
>                                                          >      >       
>                                                                > MAC
>                                                         then it will be
>                                                         trapped to control
>                                                          >      >   
>                                                           plane for
>                                                          >      >     
>                                                          >      >       
>                                                             
>                                                           processing. I
>                                                         think we
>                                                          >      >     
>                                                          >      >       
>                                                                > can
>                                                         have following
>                                                         options
>                                                          >      >     
>                                                          >      >       
>                                                                > 1.
>                                                         Optional
>                                                         managment VNI
>                                                          >      >     
>                                                          >      >       
>                                                                > 2.
>                                                         Mandatory inner
>                                                         MAC set to VTEP mac
>                                                          >      >     
>                                                          >      >       
>                                                                > 3.
>                                                         Inner IP TTL set
>                                                         to 1 to avoid
>                                                          >      >   
>                                                           forwarding of
>                                                         packet
>                                                          >      >     
>                                                          >      >       
>                                                               via inner IP
>                                                          >      >     
>                                                          >      >       
>                                                                > address.
>                                                          >      >     
>                                                          >      >       
>                                                                >
>                                                          >      >     
>                                                          >      >       
>                                                                >
>                                                          >      >     
>                                                          >      >       
>                                                                > Thoughts?
>                                                          >      >     
>                                                          >      >       
>                                                                >
>                                                          >      >     
>                                                          >      >       
>                                                                > Thansk
>                                                          >      >     
>                                                          >      >       
>                                                                > Santosh P K
>                                                          >      >     
>                                                          >      >       
>                                                                >
>                                                          >      >     
>                                                          >      >       
>                                                                > On Wed,
>                                                         Jul 31, 2019 at
>                                                         9:20 AM Greg
>                                                          >     Mirsky
>                                                          >      >     
>                                                          >      >       
>                                                             
>                                                           <[e-mail] <mailto:[e-mail]>
>                                                          >   
>                                                           <mailto:[e-mail] <mailto:[e-mail]>>
>                                                          >      >   
>                                                           <mailto:[e-mail] <mailto:[e-mail]> <mailto:[e-mail] <mailto:[e-mail]>>>
>                                                          >   
>                                                           <mailto:[e-mail] <mailto:[e-mail]> <mailto:[e-mail] <mailto:[e-mail]>>
>                                                          >      >   
>                                                           <mailto:[e-mail] <mailto:[e-mail]> <mailto:[e-mail] <mailto:[e-mail]>>>>
>                                                          >      >     
>                                                          >   
>                                                           <mailto:[e-mail] <mailto:[e-mail]>
>                                                          >   
>                                                           <mailto:[e-mail] <mailto:[e-mail]>> <mailto:[e-mail] <mailto:[e-mail]>
>                                                          >   
>                                                           <mailto:[e-mail] <mailto:[e-mail]>>>
>                                                          >      >   
>                                                           <mailto:[e-mail] <mailto:[e-mail]> <mailto:[e-mail] <mailto:[e-mail]>>
>                                                          >   
>                                                           <mailto:[e-mail] <mailto:[e-mail]> <mailto:[e-mail] <mailto:[e-mail]>>>>>
>                                                          >      >     
>                                                          >      >       
>                                                                >
>                                                         <mailto:[e-mail]
>                                                         <mailto:[e-mail]>
>                                                          >   
>                                                           <mailto:[e-mail] <mailto:[e-mail]>>
>                                                          >      >   
>                                                           <mailto:[e-mail] <mailto:[e-mail]> <mailto:[e-mail] <mailto:[e-mail]>>>
>                                                          >      >     
>                                                          >   
>                                                           <mailto:[e-mail] <mailto:[e-mail]>
>                                                          >   
>                                                           <mailto:[e-mail] <mailto:[e-mail]>> <mailto:[e-mail] <mailto:[e-mail]>
>                                                          >   
>                                                           <mailto:[e-mail] <mailto:[e-mail]>>>>
>                                                          >      >     
>                                                          >      >       
>                                                             
>                                                           <mailto:[e-mail] <mailto:[e-mail]>
>                                                          >   
>                                                           <mailto:[e-mail] <mailto:[e-mail]>>
>                                                          >      >   
>                                                           <mailto:[e-mail] <mailto:[e-mail]> <mailto:[e-mail] <mailto:[e-mail]>>>
>                                                          >      >     
>                                                          >   
>                                                           <mailto:[e-mail] <mailto:[e-mail]>
>                                                          >   
>                                                           <mailto:[e-mail] <mailto:[e-mail]>>
>                                                          >      >   
>                                                           <mailto:[e-mail] <mailto:[e-mail]>
>                                                          >   
>                                                           <mailto:[e-mail] <mailto:[e-mail]>>>>>>> wrote:
>                                                          >      >     
>                                                          >      >       
>                                                                >
>                                                          >      >     
>                                                          >      >       
>                                                                >     Hi
>                                                         Dinesh,
>                                                          >      >     
>                                                          >      >       
>                                                                >   
>                                                           thank you for
>                                                         your consideration
>                                                          >     of the
>                                                          >      >     
>                                                          >     proposal and
>                                                          >      >     
>                                                          >      >       
>                                                               questions.
>                                                         What
>                                                          >      >     
>                                                          >      >       
>                                                                >   
>                                                           would you see
>                                                         as the scope of
>                                                          >     testing the
>                                                          >      >     
>                                                          >      >       
>                                                             
>                                                           connectivity
>                                                         for the
>                                                          >      >     
>                                                          >      >       
>                                                                >   
>                                                           specific VNI?
>                                                         If it is
>                                                          >      >   
>                                                           tenant-to-tenant, then
>                                                          >      >     
>                                                          >     VTEPs
>                                                          >      >     
>                                                          >      >       
>                                                               will treat
>                                                         these
>                                                          >      >     
>                                                          >      >       
>                                                                >   
>                                                           packets as
>                                                         regular user
>                                                         frames. More
>                                                          >      >   
>                                                           likely, these
>                                                          >      >     
>                                                          >      >       
>                                                               could be
>                                                         Layer 2
>                                                          >      >     
>                                                          >      >       
>                                                                >   
>                                                           OAM, e.g. CCM
>                                                         frames. The reason
>                                                          >     to use
>                                                          >      >   
>                                                           127/8 for
>                                                          >      >     
>                                                          >      >       
>                                                               IPv4, and
>                                                          >      >     
>                                                          >      >       
>                                                                >   
>                                                           0:0:0:0:0:FFFF:7F00:0/104 for
>                                                          >     IPv6 is
>                                                          >      >     to
>                                                         safeguard
>                                                          >      >     
>                                                          >      >       
>                                                               from leaking
>                                                          >      >     
>                                                          >      >       
>                                                                >   
>                                                           Ethernet
>                                                         frames with BFD
>                                                         Control
>                                                          >     packet
>                                                          >      >     to a
>                                                          >      >     
>                                                          >     tenant.
>                                                          >      >     
>                                                          >      >       
>                                                                >   
>                                                           You've
>                                                         suggested using
>                                                         a MAC
>                                                          >     address to
>                                                          >      >   
>                                                           trap the
>                                                          >      >     
>                                                          >      >       
>                                                               control
>                                                         packet at
>                                                          >      >     
>                                                          >      >       
>                                                                >   
>                                                           VTEP. What
>                                                         that address
>                                                         could be? We
>                                                          >      >   
>                                                           had proposed
>                                                          >      >     
>                                                          >      >       
>                                                               using the
>                                                          >      >     
>                                                          >      >       
>                                                                >   
>                                                           dedicated MAC
>                                                         and VTEP's MAC and
>                                                          >     both
>                                                          >      >     raised
>                                                          >      >     
>                                                          >     concerns
>                                                          >      >     
>                                                          >      >       
>                                                               among VXLAN
>                                                          >      >     
>                                                          >      >       
>                                                                >   
>                                                           experts. The
>                                                         idea of using
>                                                          >     Management
>                                                          >      >   
>                                                           VNI may
>                                                          >      >     
>                                                          >     be more
>                                                          >      >     
>                                                          >      >       
>                                                               acceptable
>                                                          >      >     
>                                                          >      >       
>                                                                >   
>                                                           based on its
>                                                         similarity to the
>                                                          >     practice
>                                                          >      >     of
>                                                         using
>                                                          >      >     
>                                                          >      >       
>                                                               Management
>                                                         VLAN.
>                                                          >      >     
>                                                          >      >       
>                                                                >
>                                                          >      >     
>                                                          >      >       
>                                                                >   
>                                                           Regards,
>                                                          >      >     
>                                                          >      >       
>                                                                >     Greg
>                                                          >      >     
>                                                          >      >       
>                                                                >
>                                                          >      >     
>                                                          >      >       
>                                                                >     On
>                                                         Wed, Jul 31,
>                                                         2019 at 12:03 PM
>                                                          >     Dinesh
>                                                          >      >     Dutt
>                                                          >      >     
>                                                          >      >       
>                                                             
>                                                           <[e-mail] <mailto:[e-mail]>
>                                                          >   
>                                                           <mailto:[e-mail] <mailto:[e-mail]>> <mailto:[e-mail] <mailto:[e-mail]>
>                                                          >   
>                                                           <mailto:[e-mail] <mailto:[e-mail]>>>
>                                                          >      >   
>                                                           <mailto:[e-mail] <mailto:[e-mail]> <mailto:[e-mail] <mailto:[e-mail]>>
>                                                          >   
>                                                           <mailto:[e-mail] <mailto:[e-mail]> <mailto:[e-mail] <mailto:[e-mail]>>>>
>                                                          >      >     
>                                                          >   
>                                                           <mailto:[e-mail] <mailto:[e-mail]> <mailto:[e-mail] <mailto:[e-mail]>>
>                                                          >   
>                                                           <mailto:[e-mail] <mailto:[e-mail]> <mailto:[e-mail] <mailto:[e-mail]>>>
>                                                          >      >   
>                                                           <mailto:[e-mail] <mailto:[e-mail]> <mailto:[e-mail] <mailto:[e-mail]>>
>                                                          >   
>                                                           <mailto:[e-mail] <mailto:[e-mail]> <mailto:[e-mail] <mailto:[e-mail]>>>>>
>                                                          >      >     
>                                                          >      >       
>                                                                >   
>                                                           <mailto:[e-mail] <mailto:[e-mail]>
>                                                          >   
>                                                           <mailto:[e-mail] <mailto:[e-mail]>>
>                                                          >      >   
>                                                           <mailto:[e-mail] <mailto:[e-mail]> <mailto:[e-mail] <mailto:[e-mail]>>>
>                                                          >      >     
>                                                          >   
>                                                           <mailto:[e-mail] <mailto:[e-mail]> <mailto:[e-mail] <mailto:[e-mail]>>
>                                                          >   
>                                                           <mailto:[e-mail] <mailto:[e-mail]> <mailto:[e-mail] <mailto:[e-mail]>>>>
>                                                          >      >   
>                                                           <mailto:[e-mail] <mailto:[e-mail]> <mailto:[e-mail] <mailto:[e-mail]>>
>                                                          >   
>                                                           <mailto:[e-mail] <mailto:[e-mail]> <mailto:[e-mail] <mailto:[e-mail]>>>
>                                                          >      >     
>                                                          >   
>                                                           <mailto:[e-mail] <mailto:[e-mail]> <mailto:[e-mail] <mailto:[e-mail]>>
>                                                          >   
>                                                           <mailto:[e-mail] <mailto:[e-mail]> <mailto:[e-mail] <mailto:[e-mail]>>>>>>>
>                                                          >      >     
>                                                          >      >       
>                                                               wrote:
>                                                          >      >     
>                                                          >      >       
>                                                                >
>                                                          >      >     
>                                                          >      >       
>                                                                >       
>                                                           Hi Greg,
>                                                          >      >     
>                                                          >      >       
>                                                                >
>                                                          >      >     
>                                                          >      >       
>                                                                >       
>                                                           As long as the
>                                                         inner MAC
>                                                          >     address is
>                                                          >      >     such
>                                                          >      >     
>                                                          >     that the
>                                                          >      >     
>                                                          >      >       
>                                                               packet is
>                                                          >      >     
>                                                          >      >       
>                                                                >       
>                                                           trapped to the
>                                                         CPU, it should be
>                                                          >      >   
>                                                           fine for
>                                                          >      >     
>                                                          >     use as
>                                                          >      >     
>                                                          >      >       
>                                                               an inner
>                                                         MAC is
>                                                          >      >     
>                                                          >      >       
>                                                                >       
>                                                           it not?
>                                                         Stating that is
>                                                          >     better than
>                                                          >      >   
>                                                           trying to
>                                                          >      >     
>                                                          >      >       
>                                                               force a
>                                                         management
>                                                          >      >     
>                                                          >      >       
>                                                                >       
>                                                           VNI. What if
>                                                         someone wants
>                                                          >     to test
>                                                          >      >     
>                                                          >     connectivity
>                                                          >      >     
>                                                          >      >       
>                                                               on a specific
>                                                          >      >     
>                                                          >      >       
>                                                                >       
>                                                           VNI? I would
>                                                         not pick a
>                                                          >     loopback IP
>                                                          >      >     
>                                                          >     address for
>                                                          >      >     
>                                                          >      >       
>                                                               this since
>                                                         that
>                                                          >      >     
>                                                          >      >       
>                                                                >       
>                                                           address range
>                                                         is host/node local
>                                                          >      >   
>                                                           only. Is
>                                                          >      >     
>                                                          >     there a
>                                                          >      >     
>                                                          >      >       
>                                                               reason you're
>                                                          >      >     
>                                                          >      >       
>                                                                >       
>                                                           not using the
>                                                         VTEP IP as the
>                                                          >     inner IP
>                                                          >      >     
>                                                          >     address ?
>                                                          >      >     
>                                                          >      >       
>                                                                >
>                                                          >      >     
>                                                          >      >       
>                                                                >       
>                                                           Dinesh
>                                                          >      >     
>                                                          >      >       
>                                                                >
>                                                          >      >     
>                                                          >      >       
>                                                                >       
>                                                           On Wed, Jul
>                                                         31, 2019 at 5:48 AM
>                                                          >      >   
>                                                           Greg Mirsky
>                                                          >      >     
>                                                          >      >       
>                                                                >       
>                                                           <[e-mail] <mailto:[e-mail]>
>                                                          >   
>                                                           <mailto:[e-mail] <mailto:[e-mail]>>
>                                                          >      >   
>                                                           <mailto:[e-mail] <mailto:[e-mail]> <mailto:[e-mail] <mailto:[e-mail]>>>
>                                                          >      >     
>                                                          >   
>                                                           <mailto:[e-mail] <mailto:[e-mail]>
>                                                          >   
>                                                           <mailto:[e-mail] <mailto:[e-mail]>> <mailto:[e-mail] <mailto:[e-mail]>
>                                                          >   
>                                                           <mailto:[e-mail] <mailto:[e-mail]>>>>
>                                                          >      >     
>                                                          >      >       
>                                                             
>                                                           <mailto:[e-mail] <mailto:[e-mail]>
>                                                          >   
>                                                           <mailto:[e-mail] <mailto:[e-mail]>>
>                                                          >      >   
>                                                           <mailto:[e-mail] <mailto:[e-mail]> <mailto:[e-mail] <mailto:[e-mail]>>>
>                                                          >      >     
>                                                          >   
>                                                           <mailto:[e-mail] <mailto:[e-mail]>
>                                                          >   
>                                                           <mailto:[e-mail] <mailto:[e-mail]>>
>                                                          >      >   
>                                                           <mailto:[e-mail] <mailto:[e-mail]>
>                                                          >   
>                                                           <mailto:[e-mail] <mailto:[e-mail]>>>>> <mailto:[e-mail] <mailto:[e-mail]>
>                                                          >   
>                                                           <mailto:[e-mail] <mailto:[e-mail]>>
>                                                          >      >   
>                                                           <mailto:[e-mail] <mailto:[e-mail]> <mailto:[e-mail] <mailto:[e-mail]>>>
>                                                          >      >     
>                                                          >   
>                                                           <mailto:[e-mail] <mailto:[e-mail]>
>                                                          >   
>                                                           <mailto:[e-mail] <mailto:[e-mail]>> <mailto:[e-mail] <mailto:[e-mail]>
>                                                          >   
>                                                           <mailto:[e-mail] <mailto:[e-mail]>>>>
>                                                          >      >     
>                                                          >      >       
>                                                             
>                                                           <mailto:[e-mail] <mailto:[e-mail]>
>                                                          >   
>                                                           <mailto:[e-mail] <mailto:[e-mail]>>
>                                                          >      >   
>                                                           <mailto:[e-mail] <mailto:[e-mail]> <mailto:[e-mail] <mailto:[e-mail]>>>
>                                                          >      >     
>                                                          >   
>                                                           <mailto:[e-mail] <mailto:[e-mail]>
>                                                          >   
>                                                           <mailto:[e-mail] <mailto:[e-mail]>>
>                                                          >      >   
>                                                           <mailto:[e-mail] <mailto:[e-mail]>
>                                                          >   
>                                                           <mailto:[e-mail] <mailto:[e-mail]>>>>>>> wrote:
>                                                          >      >     
>                                                          >      >       
>                                                                >
>                                                          >      >     
>                                                          >      >       
>                                                                >       
>                                                               Dear All,
>                                                          >      >     
>                                                          >      >       
>                                                                >       
>                                                               thank you
>                                                         for your comments,
>                                                          >      >     
>                                                          >   
>                                                           suggestions on
>                                                          >      >     
>                                                          >      >       
>                                                               this issue,
>                                                          >      >     
>                                                          >      >       
>                                                                >       
>                                                               probably
>                                                         the most
>                                                          >     challenging
>                                                          >      >   
>                                                           for this
>                                                          >      >     
>                                                          >      >       
>                                                             
>                                                           specification.
>                                                         In the
>                                                          >      >     
>                                                          >      >       
>                                                                >       
>                                                               course of
>                                                         our discussions,
>                                                          >      >   
>                                                           we've agreed to
>                                                          >      >     
>                                                          >      >       
>                                                               abandon the
>                                                          >      >     
>                                                          >      >       
>                                                                >       
>                                                               request to
>                                                         allocate the
>                                                          >      >   
>                                                           dedicated MAC
>                                                          >      >     
>                                                          >     address
>                                                          >      >     
>                                                          >      >       
>                                                               to be used as
>                                                          >      >     
>                                                          >      >       
>                                                                >       
>                                                               the
>                                                         destination MAC
>                                                          >     address in
>                                                          >      >   
>                                                           the inner
>                                                          >      >     
>                                                          >      >       
>                                                               Ethernet
>                                                         frame.
>                                                          >      >     
>                                                          >      >       
>                                                                >       
>                                                               Also,
>                                                         earlier using VNI
>                                                          >     0 was
>                                                          >      >   
>                                                           changed from
>                                                          >      >     
>                                                          >      >       
>                                                               mandatory
>                                                         to one
>                                                          >      >     
>                                                          >      >       
>                                                                >       
>                                                               of the
>                                                         options an
>                                                          >      >   
>                                                           implementation may
>                                                          >      >     
>                                                          >     offer to
>                                                          >      >     
>                                                          >      >       
>                                                               an operator.
>                                                          >      >     
>                                                          >      >       
>                                                                >       
>                                                               The most
>                                                         recent
>                                                          >   
>                                                           discussion was
>                                                          >      >   
>                                                           whether
>                                                          >      >     
>                                                          >     VTEP's
>                                                          >      >     
>                                                          >      >       
>                                                               MAC address
>                                                          >      >     
>                                                          >      >       
>                                                                >       
>                                                               might be
>                                                         used as the
>                                                          >      >   
>                                                           destination MAC
>                                                          >      >     
>                                                          >     address
>                                                          >      >     
>                                                          >      >       
>                                                               in the inner
>                                                          >      >     
>                                                          >      >       
>                                                                >       
>                                                               Ethernet
>                                                         frame. As I
>                                                          >     recall
>                                                         it, the
>                                                          >      >     
>                                                          >     comments
>                                                          >      >     
>                                                          >      >       
>                                                               from VXLAN
>                                                          >      >     
>                                                          >      >       
>                                                                >       
>                                                               experts
>                                                         equally split
>                                                          >     with one
>                                                          >      >     for it
>                                                          >      >     
>                                                          >     and one
>                                                          >      >     
>                                                          >      >       
>                                                               against. Hence
>                                                          >      >     
>                                                          >      >       
>                                                                >       
>                                                               I would
>                                                         like to propose
>                                                          >     a new
>                                                          >      >   
>                                                           text to
>                                                          >      >     
>                                                          >     resolve
>                                                          >      >     
>                                                          >      >       
>                                                               the issue. The
>                                                          >      >     
>                                                          >      >       
>                                                                >       
>                                                               idea is to
>                                                         let an
>                                                          >     operator
>                                                         select
>                                                          >      >     
>                                                          >     Management
>                                                          >      >     
>                                                          >      >       
>                                                               VNI and use
>                                                          >      >     
>                                                          >      >       
>                                                                >       
>                                                               that VNI
>                                                         in VXLAN
>                                                          >     encapsulation
>                                                          >      >     of BFD
>                                                          >      >     
>                                                          >      >       
>                                                               Control
>                                                         packets:
>                                                          >      >     
>                                                          >      >       
>                                                                >       
>                                                               NEW TEXT:
>                                                          >      >     
>                                                          >      >       
>                                                                >
>                                                          >      >     
>                                                          >      >       
>                                                                >       
>                                                                   An
>                                                         operator MUST
>                                                          >     select a VNI
>                                                          >      >     
>                                                          >     number to
>                                                          >      >     
>                                                          >      >       
>                                                               be used as
>                                                          >      >     
>                                                          >      >       
>                                                                >       
>                                                                 
>                                                           Management
>                                                         VNI. VXLAN
>                                                          >      >   
>                                                           packet for
>                                                          >      >     
>                                                          >      >       
>                                                               Management
>                                                         VNI MUST NOT
>                                                          >      >     
>                                                          >      >       
>                                                                >       
>                                                                   be
>                                                         sent to a
>                                                         tenant. VNI
>                                                          >      >   
>                                                           number 1 is
>                                                          >      >     
>                                                          >      >       
>                                                             
>                                                           RECOMMENDED as the
>                                                          >      >     
>                                                          >      >       
>                                                                >       
>                                                                 
>                                                           default for
>                                                          >   
>                                                           Management VNI.
>                                                          >      >     
>                                                          >      >       
>                                                                >
>                                                          >      >     
>                                                          >      >       
>                                                                >       
>                                                               With that
>                                                         new text, what
>                                                          >     can be the
>                                                          >      >     
>                                                          >     value of
>                                                          >      >     
>                                                          >      >       
>                                                               the
>                                                         destination
>                                                          >      >     
>                                                          >      >       
>                                                                >       
>                                                               MAC in the
>                                                         inner Ethernet? I
>                                                          >      >   
>                                                           tend to
>                                                          >      >     
>                                                          >     believe
>                                                          >      >     
>                                                          >      >       
>                                                               that it can be
>                                                          >      >     
>                                                          >      >       
>                                                                >       
>                                                               anything
>                                                         and ignored by the
>                                                          >      >   
>                                                           reciever VTEP.
>                                                          >      >     
>                                                          >      >       
>                                                               Also, if the
>                                                          >      >     
>                                                          >      >       
>                                                                >       
>                                                               trapping
>                                                         is based on VNI
>                                                          >      >   
>                                                           number, the
>                                                          >      >     
>                                                          >      >       
>                                                             
>                                                           destination IP
>                                                         address
>                                                          >      >     
>                                                          >      >       
>                                                                >       
>                                                               of the
>                                                         inner IP packet
>                                                          >     can from
>                                                          >      >   
>                                                           the range
>                                                          >      >     
>                                                          >      >       
>                                                               127/8 for
>                                                         IPv4,
>                                                          >      >     
>                                                          >      >       
>                                                                >       
>                                                               and for
>                                                         IPv6 from the range
>                                                          >      >     
>                                                          >      >       
>                                                             
>                                                           0:0:0:0:0:FFFF:7F00:0/104. And
>                                                          >      >     
>                                                          >      >       
>                                                                >       
>                                                               lastly,
>                                                         the TTL to be
>                                                          >     set to 1 (no
>                                                          >      >     
>                                                          >     change here).
>                                                          >      >     
>                                                          >      >       
>                                                                >
>                                                          >      >     
>                                                          >      >       
>                                                                >       
>                                                               Much
>                                                         appreciate your
>                                                          >     comments,
>                                                          >      >     
>                                                          >   
>                                                           questions, and
>                                                          >      >     
>                                                          >      >       
>                                                               suggestions.
>                                                          >      >     
>                                                          >      >       
>                                                                >
>                                                          >      >     
>                                                          >      >       
>                                                                >       
>                                                               Best regards,
>                                                          >      >     
>                                                          >      >       
>                                                                >       
>                                                               Greg
>                                                          >      >     
>                                                          >      >       
>                                                                >
>                                                          >      >     
>                                                          >      >
>                                                          >      >      >
>                                                          >      >
>                                                          >
> 
>