Re: [nvo3] New Version Notification for draft-ietf-bfd-vxlan-08.txt

[Anoop Ghanwani <[e-mail]>]

Hi Santosh,

I'm not aware of any implementation that uses a multicast MAC for this.
The closest thing that I'm aware of that helps alleviate the need for
knowing the MAC of the remote VTEP is what's done in open vswitch:
http://www.openvswitch.org/support/dist-docs/vtep.5.html

   *b**f**d**_**c**o**n**f**i**g**_**r**e**m**o**t**e* *:*
*b**f**d**_**d**s**t**_**m**a**c*: optional string
              Set  to an Ethernet address in the form
*x**x*:*x**x*:*x**x*:*x**x*:*x**x*:*x**x* to set
              the destination MAC to be used for transmitted BFD packets.  The
              default is *0**0**:**2**3**:**2**0**:**0**0**:**0**0**:**0**1*.

That OUI belongs to Nicira/VMware.  An IANA assigned unicast MAC would be
the equivalent.

Anoop

On Mon, Nov 4, 2019 at 5:14 AM Santosh P K <[e-mail]>
wrote:

> Anoop,
>    Thanks for your comments. For non-managment VNI why do we need to have
> multicast MAC address for backward compatibility for existing
> implementation or there are any use cases such that we can avoid learning
> of remote end VTEP?
>
> Thanks
> Santosh P K
>
> On Mon, Nov 4, 2019 at 10:41 AM Anoop Ghanwani <[e-mail]>
> wrote:
>
>> Hi Joel,
>>
>> In that case I would propose the following text:
>>
>> "Destination MAC: If the BFD session is not using the Management VNI,
>> the destination MAC address MUST be the address
>> associated with the destination VTEP.  If the BFD session uses
>> the Management VNI, it may use any MAC address, since use of the
>> Management VNI ensures that these packets will never be forwarded to a VM.
>> The MAC address may be configured, or it may be learned via
>> a control plane protocol. The details of how the MAC address
>> to be used is obtained are outside the scope of this document."
>>
>> That said, for non-Management VNI, do we want to allow for flexibility
>> for an implementation to use a multicast MAC of their choosing?  If so, we
>> should probably add a sentence for that too.
>>
>> Thanks,
>> Anoop
>>
>>
>> On Sun, Nov 3, 2019 at 7:52 PM Joel M. Halpern <[e-mail]>
>> wrote:
>>
>>> Anoop, I think I at least am misunderstanding you.
>>> If one is using the management VNI, as I understand it there is no
>>> tenant.  So there are no tenant MAC addresses.  (This is one of the
>>> reasons I like using the management VNI.)
>>>
>>>
>>> Yours,
>>> Joel
>>>
>>> On 11/3/2019 10:32 PM, Anoop Ghanwani wrote:
>>> > Hi Greg,
>>> >
>>> > In the case of the management VNI, are we trying to say that we would
>>> > allow any MAC address other than a tenant MAC address?  I would
>>> suggest
>>> > some more text be added to clarify what is permitted on the management
>>> > VLAN.  Assuming that we want to allow any MAC other than a tenant MAC,
>>> > how does this get enforced?  In other words, what can be done for the
>>> > network to protect itself if a sender violates this?
>>> >
>>> > One possible answer is to restrict the MAC address that may be used to
>>> > one that is owned by the VTEP or a "agreed on" multicast MAC address.
>>> > That means the receiver only needs to validate for those, and just
>>> > treats everything else as data.
>>> >
>>> > Also, for interoperability purposes, it would be best to specify that
>>> a
>>> > receiver MUST be able to handle any valid MAC address for the BFD
>>> > session, while a sender MAY pick any of them.
>>> >
>>> > Thanks,
>>> > Anoop
>>> >
>>> > On Sun, Nov 3, 2019 at 6:50 PM Greg Mirsky <[e-mail]
>>> > <mailto:[e-mail]>> wrote:
>>> >
>>> >     Hi Anoop,
>>> >     thank you for your comments and questions. Please find my notes
>>> >     in-line tagged GIM>>.
>>> >
>>> >     Regards,
>>> >     Greg
>>> >
>>> >     On Fri, Nov 1, 2019 at 4:24 PM Anoop Ghanwani <
>>> [e-mail]..edu <[e-mail]>
>>> >     <mailto:[e-mail]>> wrote:
>>> >
>>> >         Hi Greg,
>>> >
>>> >         A few comments.
>>> >
>>> >         The draft has nits, specifically around the way the IPv6
>>> address
>>> >         is written.
>>> >
>>> >         In section 4:
>>> >
>>> >         BFD packet MUST be encapsulated ->
>>> >
>>> >         BFD packets MUST be encapsulated
>>> >
>>> >     GIM>> Thanks, will do.
>>> >
>>> >
>>> >          >>>
>>> >
>>> >         Destination MAC: This MUST NOT be of one of tenant's MAC
>>> >                   addresses.  The destination MAC address MAY be the
>>> address
>>> >                   associated with the destination VTEP.  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.
>>> >
>>> >          >>>
>>> >         It looks like we have removed the option of using a well-known
>>> >         IANA assigned MAC.  If so, why is the above a MAY and not a
>>> >         MUST?  What else can it be?  One interpretation is that it can
>>> >         be anything unicast, or multicast, as long as it's not a tenant
>>> >         MAC.  Is that the intent?  If so, it would be better to state
>>> it
>>> >         that way.  Also (and this is purely editorial), I think it
>>> would
>>> >         be better if the first sentence above were moved to the end of
>>> >         the paragraph.
>>> >
>>> >     GIM>> Yes, you're right, we've removed that option and have removed
>>> >     the request to IANA. I also agree that " MAY be the address
>>> >     associated with the destination VTEP" is not the right choice of
>>> >     normative language. On the other hand, MUST might be too
>>> restrictive
>>> >     if BFD session is using the Management VNI. Would the following
>>> >     update address your concern:
>>> >     OLD TEXT:
>>> >               Destination MAC: This MUST NOT be of one of tenant's MAC
>>> >               addresses.  The destination MAC address MAY be the
>>> address
>>> >               associated with the destination VTEP.  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.
>>> >     NEW TEXT:
>>> >               Destination MAC: If the BFD session is not using the
>>> >     Management VNI,
>>> >               the destination MAC address MUST be the address
>>> >               associated with the destination VTEP.  The Destination
>>> MAC
>>> >               MUST NOT be one of the 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.
>>> >
>>> >
>>> >         "The inner Ethernet frame carrying the BFD
>>> >             Control packet- has the following format:"
>>> >
>>> >         Extraneous '-' after packet.
>>> >
>>> >     GIM>> Thanks, will do that too.
>>> >
>>> >
>>> >         Thanks,
>>> >         Anoop
>>> >
>>> >         On Fri, Nov 1, 2019 at 10:53 AM Greg Mirsky
>>> >         <[e-mail] <mailto:[e-mail]>> wrote:
>>> >
>>> >             Dear All,
>>> >             the new version includes updates resulting from the
>>> >             discussions of Joel's comments in the RtrDir review of BFD
>>> >             over VXLAN draft, comments from Anoop, and Dinesh. On
>>> behalf
>>> >             of editors, thank you for your constructive comments and
>>> for
>>> >             sharing your expertise, all much appreciated.
>>> >             I hope we've addressed all your comments, and the draft can
>>> >             proceed further.
>>> >
>>> >             Regards,
>>> >             Greg
>>> >
>>> >             ---------- Forwarded message ---------
>>> >             From: <[e-mail]
>>> >             <mailto:[e-mail]>>
>>> >             Date: Fri, Nov 1, 2019 at 10:45 AM
>>> >             Subject: New Version Notification for
>>> >             draft-ietf-bfd-vxlan-08..txt
>>> >             To: Gregory Mirsky <[e-mail]
>>> >             <mailto:[e-mail]>>, Mallik Mudigonda
>>> >             <[e-mail] <mailto:[e-mail]>>, Sudarsan
>>> >             Paragiri <[e-mail]
>>> >             <mailto:[e-mail]>>, Vengada Prasad Govindan
>>> >             <[e-mail] <mailto:[e-mail]>>, Santosh
>>> >             Pallagatti <[e-mail]
>>> >             <mailto:[e-mail]>>
>>> >
>>> >
>>> >
>>> >             A new version of I-D, draft-ietf-bfd-vxlan-08.txt
>>> >             has been successfully submitted by Greg Mirsky and posted
>>> to the
>>> >             IETF repository.
>>> >
>>> >             Name:           draft-ietf-bfd-vxlan
>>> >             Revision:       08
>>> >             Title:          BFD for VXLAN
>>> >             Document date:  2019-11-01
>>> >             Group:          bfd
>>> >             Pages:          11
>>> >             URL:
>>> >
>>> https://www.ietf.org/internet-drafts/draft-ietf-bfd-vxlan-08.txt
>>> >             Status:
>>> https://datatracker.ietf.org/doc/draft-ietf-bfd-vxlan/
>>> >             Htmlized:
>>> https://tools.ietf.org/html/draft-ietf-bfd-vxlan-08
>>> >             Htmlized:
>>> >             https://datatracker.ietf.org/doc/html/draft-ietf-bfd-vxlan
>>> >             Diff:
>>> https://www.ietf.org/rfcdiff?url2=draft-ietf-bfd-vxlan-08
>>> >
>>> >             Abstract:
>>> >                 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.
>>> >
>>> >
>>> >
>>> >
>>> >             Please note that it may take a couple of minutes from the
>>> >             time of submission
>>> >             until the htmlized version and diff are available at
>>> >             tools.ietf.org <http://tools..ietf.org> <
>>> http://tools.ietf.org>.
>>> >
>>> >             The IETF Secretariat
>>> >
>>>
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