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

[Greg Mirsky <[e-mail]>]

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]> 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]> 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]>
>> 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]>> 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]>>>
>>> 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]>>>> 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:[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:
>>> >      >      >      >
>>> >      >      >      >     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:[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:
>>> >      >      >      >
>>> >      >      >      >         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:[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]>>>>>> 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]>>>>>>
>>> >      >      >      >             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]>>>>>> 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
>>> >      >      >      >              >
>>> >      >      >      >
>>> >      >      >
>>> >      >
>>> >
>>>
>>