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

Hi Joel,
if the underlay may balance VXLAN between two VTEPs using VNI in addition
to other fields, then Option 2 has a certain value in my opinion.

Regards,
Greg

On Tue, Oct 22, 2019 at 3:06 PM Joel M. Halpern <jmh@joelhalpern.com> wrote:

> I do not understand the value of option 2.
> Which is why I asked in my initial review to move to option 1.
>
> And option 2 requires stealing MAC addresses from the users, which seems
> to me to be a very bad thing that option 1 avoids.
>
> Yours,
> Joel
>
> On 10/22/2019 2:17 PM, Greg Mirsky 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 <anoop@alumni.duke.edu
> > <mailto:anoop@alumni.duke.edu>> 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 <jmh@joelhalpern.com
> >     <mailto:jmh@joelhalpern.com>> 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 <xiao.min2@zte.com.cn
> >         <mailto:xiao.min2@zte.com.cn>> 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
> >
> >         _______________________________________________
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> >         nvo3@ietf.org <mailto:nvo3@ietf.org>
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> >
>