Re: [nvo3] BFD over VXLAN: Trapping BFD Control packet at VTEP

[Greg Mirsky <[e-mail]>]

Dear All,
thank you for your comments, suggestions that have made the discussion the
most helpful to the Editors. I've tried to reflect your comments in the
updates listed below:

   - on the inner destination IP address:

OLD TEXT:
         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.
NEW TEXT:
         Destination IP: IP address MUST NOT be of one of tenant's IP
         addresses.  The IP address SHOULD be selected from the range 127/8
         for IPv4, for IPv6 - from the range 0:0:0:0:0:FFFF:7F00:0/104.
         Alternatively, the destination IP address MAY be set to VTEP's
         IP address.

   - firewall. Appended Section 3 Deployment with the following paragraph:

   As per Section 4, the inner destination IP address SHOULD be set to
   one of the loopback addresses (127/8 range for IPv4 and
   0:0:0:0:0:FFFF:7F00:0/104 range for IPv6).  There could be a firewall
   configured on VTEP to block loopback addresses if set as the
   destination IP in the inner IP header.  It is RECOMMENDED to allow
   addresses from the loopback range through a firewall only if it is
   used as the destination IP address in the inner IP header, and the
   destination UDP port is set to 3784 [RFC5881].

Regarding the use of VNI 0 as the Management VNI. In Section 6 has been
noted:
   An implementation MAY support the use of the Management
   VNI as control and management channel between VTEPs.  The selection
   of the VNI number of the Management VNI MUST be controlled through
   management plane.  An implementation MAY use VNI number 1 as the
   default value for the Management VNI.

Attached, please find the updated working version and the diff to -07.
Editors much appreciate your comments, suggestions, abd help to have the
new version uploaded before the cut-off deadline.

Regards,
Greg

On Wed, Oct 30, 2019 at 4:46 AM Dinesh Dutt <[e-mail]> wrote:

>
>
> On Wed, Oct 30, 2019 at 11:40 AM, Anoop Ghanwani <[e-mail]>
> wrote:
>
> Hi Dinesh,
>
> Your earlier comment was about silicon, that's why I discussed only the
> trapping issue.  As far as software goes, IP stacks would typically discard
> packets received from a non-loopback interface if the packet's address is
> in 127/8.  I am not sure a traditional IP stack can play here because even
> on Tx, we have the same MAC for reaching all remote VTEPs.  It seems to me
> the BFD module would have to be working directly with L2 frames coming off
> the tunnel.  Kind of like if we were running LLDP between the VTEPs.
>
>
> Hi Anoop,
>
> My earlier comment was indeed about silicon, but the packet has to go
> through the software stack as well once it gets to the CPU. Linux-based
> solutions such as Linux servers or Cumulus Linux or maybe even SONIC will
> need to have a valid IP address to process the packet. Given that 127/8 is
> already mandated by MPLS BFD, sticking with that is better than ignoring
> the IP address. This is why I agreed with Jeffrey Haas' comment about
> SHOULD be set.
>
> Dinesh
>
>
> Thanks,
> Anoop
>
> On Tue, Oct 29, 2019 at 10:02 PM Dinesh Dutt <[e-mail]> wrote:
>
>> Trapping to the CPU would be fine based on MAC DA. But once there, a
>> self-respecting network stack would look at the IP header to decide what to
>> do. Ignoring it on receive may not be an option,
>>
>> Dinesh
>> On Oct 30, 2019, 10:26 AM +0530, Anoop Ghanwani <[e-mail]>,
>> wrote:
>>
>> Hi Dinesh,
>>
>> What would break?  If messages are trapped to CPU based on the MAC DA,
>> what is the problem?
>>
>> On the flip side, there are implementations running BFD today which use
>> different addresses as specified here:
>> http://www.openvswitch.org/support/dist-docs/vtep.5.html
>> >>>
>>
>>        *b**f**d**_**c**o**n**f**i**g**_**l**o**c**a**l* *:* *b**f**d**_**d**s**t**_**i**p*: optional string
>>               Set to an IPv4 address to set the IP address that is expected as
>>               destination   for   received   BFD   packets.   The  default  is
>>               *1**6**9**.**2**5**4**.**1**.**0*.
>>
>> >>>
>>
>> Thanks,
>> Anoop
>>
>> On Tue, Oct 29, 2019 at 7:01 PM Dinesh Dutt <[e-mail]> wrote:
>>
>>> I suspect silicon implementations will have a problem with saying that
>>> they can be set to anything and MUST be ignored on reception. Your logic is
>>> sound, it's just that I fear you'll break many existing implementations. I
>>> recommend sticking with the 127/8 address for this case.
>>>
>>> Dinesh
>>>
>>> On Tue, Oct 29, 2019 at 9:15 PM, Joel M. Halpern <[e-mail]>
>>> wrote:
>>>
>>> In all the discussion about what VNI to use and multiple VNI support, I
>>> lsot track. Sorry. Still, the earlier documents did not specify the IP to
>>> use. That does NOT mean that we are required in later revisions of the
>>> document to allow anything the client wants. Having said that, we could add
>>> text saying that since the IP address in the BFD request in VNI 0 is
>>> effectively meaningless, it can be set to any value on transmission and
>>> must be ignored on reception. As far as I can tell, it is definitional that
>>> the VtEP does not have any assigned IP address for VNI 0, so we can't
>>> expect that address. Yours, Joel On 10/29/2019 11:10 AM, Anoop Ghanwani
>>> wrote:
>>>
>>> Hi Joel, Yes, existing implementations use VNI 0 for BFD over VXLAN.
>>> Here are a couple of references:
>>> https://www.juniper.net/documentation/en_US/junos/topics/concept/sdn-ovsdb-bfd-nsx.html
>>> https://www.cisco.com/c/en/us/products/collateral/switches/nexus-9000-series-switches/white-paper-c11-740091.html#_Toc18013665
>>> I guess this document has been evolving and I have not kept up with it. The
>>> version I had reviewed and commented on originally allowed for VNI 0.  The
>>> -04 version of the draft has this:
>>> https://tools.ietf.org/html/draft-ietf-bfd-vxlan-04#section-7 What
>>> version are you referring to? Thanks, Anoop On Mon, Oct 28, 2019 at 12:55
>>> PM Joel M. Halpern <[e-mail] <mailto:[e-mail]
>>> <[e-mail]>>> wrote: You are saying that there are existing
>>> implementations using VNI 0 for this?  Given that previous versions of the
>>> spec explicitly disallowed VNI 0, I am having trouble with your objecting
>>> that a spec for how to run over VNI 0 breask existing implementations. Note
>>> that when there is a good technical reason, the IETF does change Internet
>>> Drafts in ways that break early implementations.  That is the price of
>>> standardization. Yours, Joel On 10/28/2019 2:30 PM, Anoop Ghanwani wrote: >
>>> Hi Joel, > > Writing the spec in that way would make the current,
>>> inter-operable > implementation of multiple vendors non-compliant with the
>>> spec. > > Thanks, > Anoop > > On Mon, Oct 28, 2019 at 11:07 AM Joel M.
>>> Halpern <[e-mail] <mailto:[e-mail]
>>> <[e-mail]>> > <mailto:[e-mail]
>>> <[e-mail]> <mailto:[e-mail] <[e-mail]>>>>
>>> wrote: > >     I assumed this was only for the case where a tenant VNI was
>>> being used. > >     For the 0 VNI (which is what I prefer), always (MUST)
>>> use the loopback >     address.  There are no addresses assigned to the
>>> VTEP in that space. >     There is no IRB in that space. > >     Yours, >
>>>    Joel > >     On 10/28/2019 1:58 PM, Anoop Ghanwani wrote: >      > Joel,
>>> >      > >      > Are we going to qualify this by VNI?  There's a bunch of
>>> >     implementations >      > out there that don't use a tenant IP or a
>>> loopback with VNI 0--they >      > simply repeat the underlay IP in the
>>> inner IPDA. >      > >      > Thanks, >      > Anoop >      > >      > On
>>> Mon, Oct 28, 2019 at 10:46 AM Joel M. Halpern >     <[e-mail]
>>> <mailto:[e-mail] <[e-mail]>> <
>>> mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>>> >      > <
>>> mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>> <
>>> mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>>>>> wrote: >      > >
>>>     >     I can live with saying that you SHOULD use loopback, and MAY >
>>>  instead >      >     use >      >     an IP address in the customer space
>>> known to be owned by the VTEP >      >     device >      >     when such
>>> exists. >      > >      >     Yours, >      >     Joel >      > >      >
>>>  On 10/28/2019 1:32 PM, Anoop Ghanwani wrote: >      >      > Hi Joel, >
>>>   >      > >      >      > Perhaps we need to say use of an address owned
>>> by the device >      >     containing >      >      > the VTEP. >      >
>>>   > >      >      > Or are you suggesting that the use of the loopback
>>> address >     space >      >     is a MUST? >      >      > >      >      >
>>> Anoop >      >      > >      >      > On Mon, Oct 28, 2019 at 10:22 AM Joel
>>> M. Halpern >      >     <[e-mail] <mailto:[e-mail]
>>> <[e-mail]>> <mailto:[e-mail] <[e-mail]>
>>> <mailto:[e-mail] <[e-mail]>>> >     <
>>> mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>> <
>>> mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>>>> >      >      > <
>>> mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>> <
>>> mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>>> >     <
>>> mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>> <
>>> mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>>>>>> wrote: >      >
>>>     > >      >      >     There is something I am missing in your
>>> assumption >     about IRB. >      >      > >      >      >     As I
>>> understand VxLAN, the VTEP is under the control >     of the >      >
>>>  operator. >      >      >     As such, it is a pure bridge.  If you run
>>> IRB behind >     it, that >      >     is fine. >      >      >     Yes, an
>>> operator may offer IRB.  But as I understand it, >      >     conceptually,
>>> >      >      >     in terms of the VxLAN architecture the IRB is an entity
>>> >      >     behind the >      >      >     VTEP, >      >      >     not
>>> part of the VTEP. >      >      > >      >      >     Yours, >      >
>>> >     Joel >      >      > >      >      >     On 10/28/2019 12:23 PM,
>>> Anoop Ghanwani wrote: >      >      >      > Santosh, >      >      >
>>> > >      >      >      > Does it have to be a MUST?  What if I am running
>>> >     IRB and there >      >      >     are IP >      >      >      >
>>> addresses per VNI assigned to the VTEPs? Why can the >      >     operator
>>> not >      >      >      > choose to use those? >      >      >      > >
>>>   >      >      > Anoop >      >      >      > >      >      >      > On
>>> Mon, Oct 28, 2019 at 7:51 AM Santosh P K >      >      >      > <
>>> [e-mail] <mailto:[e-mail]
>>> <[e-mail]>> >     <
>>> mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>>> >
>>>     >     <mailto:[e-mail]
>>> <[e-mail]> <mailto:[e-mail]
>>> <[e-mail]>> >     <
>>> mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>>>>
>>> >      >      >     <mailto:[e-mail]
>>> <[e-mail]> <mailto:[e-mail]
>>> <[e-mail]>> >     <
>>> mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>>> >
>>>     >     <mailto:[e-mail]
>>> <[e-mail]> <mailto:[e-mail]
>>> <[e-mail]>> >     <
>>> mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>>>>>
>>> >      >      >     <mailto:[e-mail]
>>> <[e-mail]> <mailto:[e-mail]
>>> <[e-mail]>> >     <
>>> mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>>> >
>>>     >     <mailto:[e-mail]
>>> <[e-mail]> <mailto:[e-mail]
>>> <[e-mail]>> >     <
>>> mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>>>>
>>> >      >      >     <mailto:[e-mail]
>>> <[e-mail]> <mailto:[e-mail]
>>> <[e-mail]>> >     <
>>> mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>>> >
>>>     >     <mailto:[e-mail]
>>> <[e-mail]> <mailto:[e-mail]
>>> <[e-mail]>> >     <
>>> mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>>>>>>>
>>> wrote: >      >      >      > >      >      >      >     Dinesh, Anoop et
>>> all, >      >      >      >           Lets us know if this text works for
>>> 127/8 >      >     address range? >      >      >      > >      >      >
>>>   >     [proposed text for firewall] >      >      >      > >      >
>>> >      >     "As per section 4 inner destination IP address >     MUST be
>>> >      >     set to >      >      >     127/8 >      >      >      >
>>>  address. There may be firewall configured on >     VTEP to >      >
>>>  block 127/8 >      >      >      >     address range if set as destination
>>> IP in inner IP >      >     header. It is >      >      >      >
>>>  recommended to allow 127/8 range address through >      >     firewall
>>> only if >      >      >      >     127/8 IP address is set as destination
>>> address >     in inner IP >      >      >     header." >      >      >
>>> > >      >      >      > >      >      >      >     In section 4 we are
>>> talking about using 127/8 >     and not >      >     really >      >
>>> >     giving >      >      >      >     reason why. I think we should have
>>> text as RFC 5884 >      >     has mentioned >      >      >      >     with
>>> below text. >      >      >      > >      >      >      >     [From RFC
>>> 5884] >      >      >      >     "The motivation for using the address
>>> range >     127/8 is >      >     the same as >      >      >      >
>>>  specified in Section 2.1 of [RFC4379] >      >      >      >  <
>>> https://tools.ietf.org/html/rfc4379#section-2.1>. >      >     This is
>>> an >      >      >      >     exception to the behavior defined in [RFC1122
>>> >      >      >      >     <https://tools.ietf.org/html/rfc1122>]." >
>>>     >      >      > >      >      >      > >      >      >      > >      >
>>>     >      >     Thanks >      >      >      >     Santosh P K >      >
>>>   >      > >      >      >      > >      >      >      > >      >      >
>>>   >     On Thu, Oct 24, 2019 at 1:24 AM Dinesh Dutt >      >     <
>>> [e-mail] <mailto:[e-mail] <[e-mail]>> <
>>> mailto:[e-mail] <[e-mail]> <mailto:[e-mail]
>>> <[e-mail]>>> >     <mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>> <mailto:[e-mail]
>>> <[e-mail]> <mailto:[e-mail] <[e-mail]>>>> >
>>>   >      >     <mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>> <mailto:[e-mail]
>>> <[e-mail]> <mailto:[e-mail] <[e-mail]>>> >     <
>>> mailto:[e-mail] <[e-mail]> <mailto:[e-mail]
>>> <[e-mail]>> <mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>>>>> >      >      >      >
>>>    <mailto:[e-mail] <[e-mail]> <mailto:[e-mail]
>>> <[e-mail]>> >     <mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>>> <mailto:[e-mail]
>>> <[e-mail]> <mailto:[e-mail] <[e-mail]>> >     <
>>> mailto:[e-mail] <[e-mail]> <mailto:[e-mail]
>>> <[e-mail]>>>> >      >     <mailto:[e-mail]
>>> <[e-mail]> <mailto:[e-mail] <[e-mail]>> <
>>> mailto:[e-mail] <[e-mail]> <mailto:[e-mail]
>>> <[e-mail]>>> >     <mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>> <mailto:[e-mail]
>>> <[e-mail]> <mailto:[e-mail] <[e-mail]>>>>>>>
>>> wrote: >      >      >      > >      >      >      >         Looks good to
>>> me Greg. I see that the text >     around >      >     the use >      >
>>>   >     of the >      >      >      >         inner IP address as also
>>> quite acceptable. Will >      >     you add any >      >      >      >
>>>    words about the firewall? >      >      >      > >      >      >      >
>>>        Dinesh >      >      >      > >      >      >      >         On Wed,
>>> Oct 23, 2019 at 8:36 PM, Greg Mirsky >      >      >      >         <
>>> [e-mail] <mailto:[e-mail]
>>> <[e-mail]>> >     <mailto:[e-mail]
>>> <[e-mail]> <mailto:[e-mail]
>>> <[e-mail]>>> >      >     <mailto:[e-mail]
>>> <[e-mail]> <mailto:[e-mail]
>>> <[e-mail]>> <mailto:[e-mail]
>>> <[e-mail]> <mailto:[e-mail]
>>> <[e-mail]>>>> >     <mailto:[e-mail]
>>> <[e-mail]> <mailto:[e-mail]
>>> <[e-mail]>> <mailto:[e-mail]
>>> <[e-mail]> <mailto:[e-mail]
>>> <[e-mail]>>> >      >     <mailto:[e-mail]
>>> <[e-mail]> <mailto:[e-mail]
>>> <[e-mail]>> <mailto:[e-mail]
>>> <[e-mail]> <mailto:[e-mail]
>>> <[e-mail]>>>>> >      >      >     <
>>> mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>> >     <
>>> mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>>> <
>>> mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>> >     <
>>> mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>>>> >      >     <
>>> mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>> <
>>> mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>>> >     <
>>> mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>> <
>>> mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>>>>>>> wrote: >
>>>   >      >      >>         Hi Dinesh, et al., >      >      >      >>
>>>    please check the updated version that >     removed the >      >      >
>>>    reference to >      >      >      >>         Hypervisor in the text and
>>> Figure 1. >      >      >      >> >      >      >      >>         Regards,
>>> >      >      >      >>         Greg >      >      >      >> >      >
>>> >      >>         On Wed, Oct 23, 2019 at 10:47 AM Santosh P K >      >
>>>   >      >>         <[e-mail] <
>>> mailto:[e-mail] <[e-mail]>> >
>>>    <mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>>> >
>>>     >     <mailto:[e-mail]
>>> <[e-mail]> <mailto:[e-mail]
>>> <[e-mail]>> >     <
>>> mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>>>>
>>> >      >      >     <mailto:[e-mail]
>>> <[e-mail]> <mailto:[e-mail]
>>> <[e-mail]>> >     <
>>> mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>>> >
>>>     >     <mailto:[e-mail]
>>> <[e-mail]> <mailto:[e-mail]
>>> <[e-mail]>> >     <
>>> mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>>>>>
>>> >      >      >      >>  <mailto:[e-mail]
>>> <[e-mail]> <mailto:[e-mail]
>>> <[e-mail]>> >     <
>>> mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>>> >
>>>     >     <mailto:[e-mail]
>>> <[e-mail]> <mailto:[e-mail]
>>> <[e-mail]>> >     <
>>> mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>>>>
>>> >      >      >     <mailto:[e-mail]
>>> <[e-mail]> <mailto:[e-mail]
>>> <[e-mail]>> >     <
>>> mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>>> >
>>>     >     <mailto:[e-mail]
>>> <[e-mail]> <mailto:[e-mail]
>>> <[e-mail]>> >     <
>>> mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>>>>>>>
>>> wrote: >      >      >      >> >      >      >      >>             Dinesh,
>>> >      >      >      >>                  Please see my inline comments
>>> [SPK] >      >      >      >> >      >      >      >> >      >      >
>>> >>                 - In section 3, there's a sentence >     that >      >
>>>    is: "BFD >      >      >      >>                 packets intended for a
>>> Hypervisor >     VTEP MUST >      >      >     NOT..". I >      >      >
>>>   >>                 recommend getting rid of the word >      >
>>>  "Hypervisor" ashe >      >      >      >>                 logic applies to
>>> any VTEP. >      >      >      >> >      >      >      >>             [SPK]
>>> Thanks for comments. We will >     change this. >      >      >      >> >
>>>     >      >      >>                 - You already explained the >
>>>  precedence of >      >     the use of >      >      >      >>
>>>    127/8 address in the inner header in >      >     MPLS. I have no >
>>> >      >      >>                 specific comments in that area. I have >
>>>     >     only two >      >      >      >>                 questions: >
>>>   >      >      >>                    - Has anybody verified that the >
>>>  use of >      >     127/8 >      >      >      >>                 address
>>> (and the right MAC) works with >      >     existing >      >      >
>>> >>                 implementations, including the silicon >      >
>>>  ones? If this >      >      >      >>                 doesn't work there,
>>> is it worth >     adding the >      >      >     possibilit >      >
>>> >      >>                 y of another address, one that is >     owned >
>>>     >     by the >      >      >     VTEP node? >      >      >      >> >
>>>     >      >      >>                    - Do we know if Firewalls stop >
>>>  such VXLAN >      >      >     packets? >      >      >      >>
>>>      I ask this because VXLAN has an IP >     header >      >     and I >
>>>     >      >     don't >      >      >      >>                 know if
>>> firewalls stop packets >     with 127/8 >      >     in the >      >
>>> >     inner >      >      >      >>                 header. If not, is it
>>> worth adding a >      >     sentence to say >      >      >      >>
>>>          that firewalls  allow such >     packets? The >      >     use of
>>> a >      >      >      >>                 non-127/8 address may alleviate
>>> >     this case >      >     as well. >      >      >      >> >      >
>>> >      >>             [SPK] I think we may need to add the text >      >
>>>  about firewall >      >      >      >>             as some checks in
>>> firewall will be >     there if >      >     they are not >      >      >
>>>     >>             already using MPLS OAM which has inner IP >      >
>>>  header with >      >      >      >>             127/8 address range. >
>>>   >      >      >> >      >      >      >> >      >      >      >>
>>>        The rest of the draft looks good >     to me, >      >      >
>>> >> >      >      >      >>                 Dinesh >      >      >      >>
>>> >      >      >      >>                 On Wed, Oct 23, 2019 at 7:58 AM, >
>>>    Greg Mirsky >      >      >      >>                 <
>>> [e-mail] <mailto:[e-mail]
>>> <[e-mail]>> >     <mailto:[e-mail]
>>> <[e-mail]> <mailto:[e-mail]
>>> <[e-mail]>>> >      >     <mailto:[e-mail]
>>> <[e-mail]> <mailto:[e-mail]
>>> <[e-mail]>> <mailto:[e-mail]
>>> <[e-mail]> <mailto:[e-mail]
>>> <[e-mail]>>>> >      >      >     <
>>> mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>> >     <
>>> mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>>> <
>>> mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>> >     <
>>> mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>>>>> >      >     <
>>> mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>> <
>>> mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>>> >     <
>>> mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>> <
>>> mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>>>> >      >
>>> >     <mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>> >     <
>>> mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>>> <
>>> mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>> >     <
>>> mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>>>>>>> >      >
>>>   >      >>                 wrote: >      >      >      >>>
>>>  Hi Dinesh, >      >      >      >>>                 I greatly appreciate
>>> your comments. >      >     Please heave a >      >      >      >>>
>>>          look at the attached copy of the >     working >      >      >
>>>  version and >      >      >      >>>                 its diff to -07
>>> (latest in the >     datatracker). >      >      >      >>> >      >
>>> >      >>>                 Regards, >      >      >      >>>
>>>  Greg >      >      >      >>> >      >      >      >>>                 On
>>> Tue, Oct 22, 2019 at 9:52 PM >     Dinesh Dutt >      >      >      >>>
>>>              <[e-mail] <mailto:[e-mail]
>>> <[e-mail]>> >     <mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>>> >      >     <
>>> mailto:[e-mail] <[e-mail]> <mailto:[e-mail]
>>> <[e-mail]>> <mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>>>> >     <
>>> mailto:[e-mail] <[e-mail]> <mailto:[e-mail]
>>> <[e-mail]>> <mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>>> >      >     <
>>> mailto:[e-mail] <[e-mail]> <mailto:[e-mail]
>>> <[e-mail]>> <mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>>>>> >      >      >     <
>>> mailto:[e-mail] <[e-mail]> <mailto:[e-mail]
>>> <[e-mail]>> <mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>>> >     <
>>> mailto:[e-mail] <[e-mail]> <mailto:[e-mail]
>>> <[e-mail]>> <mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>>>> >      >     <
>>> mailto:[e-mail] <[e-mail]> <mailto:[e-mail]
>>> <[e-mail]>> <mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>>> >     <
>>> mailto:[e-mail] <[e-mail]> <mailto:[e-mail]
>>> <[e-mail]>> <mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>>>>>>> wrote: >      >
>>> >      >>> >      >      >      >>>                     I have the same
>>> feeling as Anoop. >      >     Greg, can you >      >      >      >>>
>>>                please point me to the latest >     draft >      >     so
>>> that >      >      >     I can >      >      >      >>>
>>>  quickly glance through it to be >      >     doubly sure, >      >      >
>>>     >>> >      >      >      >>>                     Dinesh >      >
>>> >      >>> >      >      >      >>>                     On Wed, Oct 23,
>>> 2019 at 4:35 AM, >      >     Anoop Ghanwani >      >      >      >>>
>>>                <[e-mail] <mailto:[e-mail]
>>> <[e-mail]>> >     <mailto:[e-mail]
>>> <[e-mail]> <mailto:[e-mail]
>>> <[e-mail]>>> >      >     <mailto:[e-mail]
>>> <[e-mail]> <mailto:[e-mail]
>>> <[e-mail]>> <mailto:[e-mail]
>>> <[e-mail]> <mailto:[e-mail]
>>> <[e-mail]>>>> >      >      >     <
>>> mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>> >     <
>>> mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>>> <
>>> mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>> >     <
>>> mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>>>>> >      >
>>> >      >>>  <mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>> >     <
>>> mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>>> >      >     <
>>> mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>> <
>>> mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>>>> >      >
>>> >     <mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>> >     <
>>> mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>>> >      >     <
>>> mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>> >     <
>>> mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>>>>>>> wrote: >
>>>   >      >      >>>>                     Greg, >      >      >      >>>> >
>>>     >      >      >>>>                     I think the draft is fine as is.
>>> >      >      >      >>>> >      >      >      >>>>                     I
>>> discussion with Xiao Min was >      >     about #3 and I >      >      >
>>>   >>>>                     see that as unnecessary until we >      >
>>>  have a draft >      >      >      >>>>                     that explains
>>> why that is >     needed in the >      >      >     context >      >
>>> >      >>>>                     of the NVO3 architecture. >      >      >
>>>     >>>> >      >      >      >>>>                     Anoop >      >
>>> >      >>>> >      >      >      >>>>                     On Tue, Oct 22,
>>> 2019 at 11:17 AM >      >     Greg Mirsky >      >      >      >>>>  <
>>> [e-mail] <mailto:[e-mail]
>>> <[e-mail]>> >     <mailto:[e-mail]
>>> <[e-mail]> <mailto:[e-mail]
>>> <[e-mail]>>> >      >     <mailto:[e-mail]
>>> <[e-mail]> <mailto:[e-mail]
>>> <[e-mail]>> <mailto:[e-mail]
>>> <[e-mail]> <mailto:[e-mail]
>>> <[e-mail]>>>> >      >      >     <
>>> mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>> >     <
>>> mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>>> <
>>> mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>> >     <
>>> mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>>>>> >      >
>>> >      >>>> >       <mailto:[e-mail]
>>> <[e-mail]> <mailto:[e-mail]
>>> <[e-mail]>> <mailto:[e-mail]
>>> <[e-mail]> <mailto:[e-mail]
>>> <[e-mail]>>> >      >     <mailto:[e-mail]
>>> <[e-mail]> <mailto:[e-mail]
>>> <[e-mail]>> <mailto:[e-mail]
>>> <[e-mail]> <mailto:[e-mail]
>>> <[e-mail]>>>> >      >      >     <
>>> mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>> >     <
>>> mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>>> >      >     <
>>> mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>> >     <
>>> mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>>>>>>> wrote: >
>>>   >      >      >>>> >      >      >      >>>>                         Hi
>>> Anoop, et al., >      >      >      >>>>                         I agree
>>> with your >     understanding >      >     of what is >      >      >
>>> >>>>                         being defined in the current >      >
>>>  version >      >      >     of the >      >      >      >>>>
>>>            BFD over VxLAN >     specification. >      >     But, as I >
>>>   >      >      >>>>                         understand, the WG is >
>>> >     discussing the scope >      >      >      >>>>
>>>  before the WGLC is closed. I >      >     believe there >      >      >
>>>   >>>>                         are three options: >      >      >      >>>>
>>> >      >      >      >>>>                          1. single BFD session >
>>>    between >      >     two VTEPs >      >      >      >>>>
>>>           2. single BFD session >     per VNI >      >     between >
>>> >      >     two VTEPs >      >      >      >>>>
>>> 3. multiple BFD >     sessions per >      >     VNI between >      >
>>> >      >>>>                             two VTEPs >      >      >      >>>>
>>> >      >      >      >>>>                         The current text >
>>>  reflects #2. Is WG >      >      >     accepts >      >      >      >>>>
>>>                        this scope? If not, which >      >     option WG
>>> would >      >      >      >>>>                         accept? >      >
>>>   >      >>>> >      >      >      >>>>                         Regards, >
>>>     >      >      >>>>                         Greg >      >      >
>>> >>>> >      >      >      >>>>                         On Tue, Oct 22, 2019
>>> at >     2:09 PM >      >     Anoop >      >      >      >>>>
>>>            Ghanwani >     <[e-mail] <
>>> mailto:[e-mail] <[e-mail]>> <
>>> mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>>> >      >     <
>>> mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>> <
>>> mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>>>> >      >
>>> >     <mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>> >     <
>>> mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>>> <
>>> mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>> >     <
>>> mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>>>>> >      >
>>> >      >>>> >       <mailto:[e-mail]
>>> <[e-mail]> <mailto:[e-mail]
>>> <[e-mail]>> <mailto:[e-mail]
>>> <[e-mail]> <mailto:[e-mail]
>>> <[e-mail]>>> >      >     <mailto:[e-mail]
>>> <[e-mail]> <mailto:[e-mail]
>>> <[e-mail]>> <mailto:[e-mail]
>>> <[e-mail]> <mailto:[e-mail]
>>> <[e-mail]>>>> >      >      >     <
>>> mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>> >     <
>>> mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>>> >      >     <
>>> mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>> >     <
>>> mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>>>>>>> wrote: >
>>>   >      >      >>>> >      >      >      >>>>
>>>  I concur with Joel's >     assessment >      >      >     with the >
>>> >      >      >>>>                             following >
>>>  clarifications. >      >      >      >>>> >      >      >      >>>>
>>>                      The current document >     is already >      >      >
>>>    capable >      >      >      >>>>                             of
>>> monitoring >     multiple VNIs >      >      >     between VTEPs. >      >
>>>     >      >>>> >      >      >      >>>>                             The
>>> issue under >     discussion >      >     was how >      >      >     do we
>>> >      >      >      >>>>                             use BFD to monitor >
>>>    multiple >      >     VAPs that >      >      >      >>>>
>>>              use the same VNI >     between a >      >     pair of >
>>> >      >      >>>>                             VTEPs.  The use case for >
>>>     >     this is not >      >      >      >>>>
>>>  clear to me, as from my >      >     understanding, >      >      >
>>> >>>>                             we cannot have a >     situation with >
>>>   >      >     multiple >      >      >      >>>>
>>>    VAPs using the same >      >     VNI--there is 1:1 >      >      >
>>> >>>>                             mapping between VAP >     and VNI. >
>>> >      >      >>>> >      >      >      >>>>
>>>  Anoop >      >      >      >>>> >      >      >      >>>>
>>>            On Tue, Oct 22, 2019 >     at 6:06 AM >      >      >     Joel
>>> M. >      >      >      >>>>                             Halpern >      >
>>>    <[e-mail] <mailto:[e-mail]
>>> <[e-mail]>> <mailto:[e-mail] <[e-mail]>
>>> <mailto:[e-mail] <[e-mail]>>> >     <
>>> mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>> <
>>> mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>>>> >      >      >
>>>  <mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>> >     <
>>> mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>>> <
>>> mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>> >     <
>>> mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>>>>> >      >      >
>>>   >>>> >       <mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>> <
>>> mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>>> >      >     <
>>> mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>> <
>>> mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>>>> >      >      >
>>>  <mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>> >     <
>>> mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>>> <
>>> mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>> >     <
>>> mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>>>>>>> >      >
>>>  wrote: >      >      >      >>>> >      >      >      >>>>
>>>                   From what I can >     tell, >      >     there >      >
>>>     >     are two >      >      >      >>>>
>>>  separate problems. >      >      >      >>>>
>>>    The document we >     have is a >      >      >     VTEP-VTEP >      >
>>>     >      >>>>                                 monitoring >     document.
>>> >      >     There is no >      >      >      >>>>
>>>        need for that >     document to >      >      >     handle the >
>>>   >      >      >>>>                                 multiple VNI case. >
>>>     >      >      >>>>                                 If folks want a >
>>>   >     protocol for doing >      >      >      >>>>
>>>          BFD monitoring >     of things >      >      >     behind the >
>>>   >      >      >>>>                                 VTEPs (multiple >
>>>  VNIs), >      >     then do >      >      >     that >      >      >
>>> >>>>                                 as a separate >      >     document.
>>>  The >      >      >      >>>>                                 encoding
>>> will be >     a tenant >      >      >     encoding, >      >      >
>>> >>>>                                 and thus >     sesparate from >
>>> >     what is >      >      >      >>>>
>>>  defined in this >     document. >      >      >      >>>> >      >      >
>>>     >>>>                                 Yours, >      >      >      >>>>
>>>                                Joel >      >      >      >>>> >      >
>>> >      >>>>                                 On 10/21/2019 >     5:07 PM, >
>>>     >     Jeffrey >      >      >     Haas >      >      >      >>>>
>>>                          wrote: >      >      >      >>>>
>>>                > Santosh and >     others, >      >      >      >>>>
>>>                          > >      >      >      >>>>
>>>          > On Thu, Oct >     03, 2019 at >      >      >     07:50:20PM >
>>>     >      >      >>>>                                 +0530, Santosh P >
>>>    K wrote: >      >      >      >>>>                                 >>
>>>  Thanks >     for your >      >      >     explanation. >      >      >
>>>   >>>>                                 This helps a lot. I >      >
>>>  would wait >      >      >     for more >      >      >      >>>>
>>>                        >> comments from >     others >      >     to see if
>>> >      >      >      >>>>                                 this what we >
>>>  need in this >      >      >     draft to be >      >      >      >>>>
>>>                              >> supported >     based on >      >     that
>>> we can >      >      >      >>>>                                 provide
>>> appropriate >      >     sections >      >      >     in the >      >
>>> >      >>>>                                 draft. >      >      >
>>> >>>>                                 > >      >      >      >>>>
>>>                      > The threads on the >      >     list have >      >
>>>     >      >>>>                                 spidered to the >     point
>>> >      >     where it is >      >      >      >>>>
>>>        challenging >      >      >      >>>>
>>>  > to follow what the >      >     current >      >      >     status >
>>>   >      >      >>>>                                 of the draft is, >
>>>  or should >      >      >     be.  :-) >      >      >      >>>>
>>>                        > >      >      >      >>>>
>>>        > However, if I've >      >     followed things >      >      >
>>> >>>>                                 properly, the >     question >      >
>>>    below is >      >      >      >>>>
>>>  really the >      >      >      >>>>                                 >
>>> hinge point on >     what our >      >      >      >>>>
>>>              encapsulation >     for BFD >      >     over vxlan >      >
>>>     >      >>>>                                 should look like. >      >
>>>     >      >>>>                                 > Correct? >      >      >
>>>     >>>>                                 > >      >      >      >>>>
>>>                          > Essentially, >     do we or >      >     do we
>>> not >      >      >      >>>>                                 require the
>>> >     ability to >      >     permit >      >      >      >>>>
>>>                    multiple BFD >      >      >      >>>>
>>>                > sessions between >      >     distinct VAPs? >      >
>>> >      >>>>                                 > >      >      >      >>>>
>>>                              > If this is so, >     do we >      >     have
>>> a >      >      >     sense >      >      >      >>>>
>>>            as to how we should >      >     proceed? >      >      >
>>> >>>>                                 > >      >      >      >>>>
>>>                      > -- Jeff >      >      >      >>>>
>>>              > >      >      >      >>>>                                 >
>>> [context preserved >      >     below...] >      >      >      >>>>
>>>                          > >      >      >      >>>>
>>>          >> Santosh P K >      >      >      >>>>
>>>        >> >      >      >      >>>>                                 >> On
>>> Wed, Sep >     25, 2019 >      >     at 8:10 AM >      >      >      >>>>
>>> >       <[e-mail] <mailto:[e-mail]
>>> <[e-mail]>> <mailto:[e-mail]
>>> <[e-mail]> <mailto:[e-mail]
>>> <[e-mail]>>> >      >     <mailto:[e-mail]
>>> <[e-mail]> <mailto:[e-mail]
>>> <[e-mail]>> <mailto:[e-mail]
>>> <[e-mail]> <mailto:[e-mail]
>>> <[e-mail]>>>> >      >      >     <
>>> mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>> >     <
>>> mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>>> <
>>> mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>> >     <
>>> mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>>>>> >      >      >
>>>     >>>> >      >       <mailto:[e-mail]
>>> <[e-mail]> <mailto:[e-mail]
>>> <[e-mail]>> <mailto:[e-mail]
>>> <[e-mail]> <mailto:[e-mail]
>>> <[e-mail]>>> >     <mailto:[e-mail]
>>> <[e-mail]> <mailto:[e-mail]
>>> <[e-mail]>> <mailto:[e-mail]
>>> <[e-mail]> <mailto:[e-mail]
>>> <[e-mail]>>>> >      >      >     <
>>> mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>> >     <
>>> mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>>> <
>>> mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>> >     <
>>> mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[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 >      >      >      >>>> >      >      >
>>> >>>> >      >      >       _______________________________________________
>>> >      >      >      >>>>                                 nvo3 mailing list
>>> >      >      >      >>>> [e-mail] <mailto:[e-mail]
>>> <[e-mail]>> <mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>>> >     <mailto:[e-mail]
>>> <[e-mail]> <mailto:[e-mail] <[e-mail]>> <
>>> mailto:[e-mail] <[e-mail]> <mailto:[e-mail]
>>> <[e-mail]>>>> >      >     <mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>> <mailto:[e-mail]
>>> <[e-mail]> <mailto:[e-mail] <[e-mail]>>> >     <
>>> mailto:[e-mail] <[e-mail]> <mailto:[e-mail]
>>> <[e-mail]>> <mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>>>>> <mailto:[e-mail]
>>> <[e-mail]> <mailto:[e-mail] <[e-mail]>> >     <
>>> mailto:[e-mail] <[e-mail]> <mailto:[e-mail]
>>> <[e-mail]>>> >      >     <mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>> <mailto:[e-mail]
>>> <[e-mail]> <mailto:[e-mail] <[e-mail]>>>> >      >
>>> >     <mailto:[e-mail] <[e-mail]> <mailto:[e-mail]
>>> <[e-mail]>> <mailto:[e-mail] <[e-mail]> <
>>> mailto:[e-mail] <[e-mail]>>> >     <mailto:[e-mail]
>>> <[e-mail]> <mailto:[e-mail] <[e-mail]>> <
>>> mailto:[e-mail] <[e-mail]> <mailto:[e-mail]
>>> <[e-mail]>>>>>> >      >      >      >>>>
>>> https://www.ietf.org/mailman/listinfo/nvo3 >      >      >      >>>> >
>>>     >      > >      > >
>>>
>>>