Re: WG LC: draft-ietf-l3vpn-2547bis-mcast

[Eric Rosen <[e-mail]>]

> Indeed there is no valid semantic for S-PMSI Join packets received from
> a CE.  But a wrong semantic can very easily be given to such packets by
> a implementation not having been carefully written in this respect,

Implementation  errors which cause  packets to  be processed  with incorrect
semantics can  cause a variety of  problems.  However, we  cannot expect the
security   considerations  section   to  list   all  the   things   that  an
implementation could possibly get wrong.

However, if it makes you happy, I suppose we could replace:

   If one uses the UDP-based protocol for switching to S-PMSI (as
   specified in Section 7.2.1), then by default each PE router MUST
   install packet filters that would result in discarding all UDP
   packets with the destination port 3232 that the PE router receives
   from the CE routers connected to the PE router.

with

   The S-PMSI  Join messages  defined in section  7.4.2 are valid  only when
   received over a PMSI, and MUST NOT be processed in other contexts.