Re: [mpls] Two new drafts on (micro-)BFD over MC-LAG interfaces

[Jeffrey Haas <[e-mail]>]

Greg,

This is more of a general comment on discussions from the development from
RFC 7130 than any specific comment on your draft.  

On Fri, Apr 08, 2016 at 11:43:18AM -0700, Greg Mirsky wrote:
> yes, link local multicast may be used in MC-LAG scenario. The draft states
> that it MAY be used while the broadcast has SHOULD normative. But we are
> all open to the discussion.

During our discussions across multiple vendors, including some hardware
vendors, it was determined that attempts to exercise the layer 3 mechanisms
would vary significantly across implementations depending on how packets
were encapsulated.  Multicast in particular provided some problematic issues
for us beyond the initial bootstrapping phase of LAG for BFD wherein we
might not have ARP completed.  

My recommendation is to proceed with your drafts with similar caution.  Try
to stay as true to pure IP as possible to best insure the L3 data paths are
exercised across implementations from various vendors.

-- Jeff (speaking as an individual contributor)