Re: draft-ietf-idmr-igmp-mrdisc-10.txt

[Randy Bush <randy@psg.com>]

further comment on this from ops-dir reviewer.

randy

---

- the document does not conform to editorial guidelines (use of some '¡' 
instead of '-')

- I dislike IPv6 sections being only waved off in one section
even though the rest; also, the technical solution needs justification, as 
it was stated that:

--8<--
   The following are justifications for inventing another router
   discovery protocol:
 
           ¡ Using ICMP router discovery is not an appropriate solution
              for multicast router discovery because: 1.) It may confuse
              hosts listening to ICMP router advertisements; unicast and
              multicast topologies may not be congruent.  2.) There is 
              no way to tell from an ICMP router advertisement if a    
              router is running a multicast routing protocol. 
[...]
--8<--

.. it appears to me that (ab)using NDP falls within this category (at 
least sub-item 1).

- Also, this consumes 2 precious bits from IPv6 router advertisement 
messages; if this is really the approach that seems best, at least it 
needs a round of review in e.g. IPv6 w.g. or the like..

- as an operational/security aspect, security considerations lists the
possibility of rogue nodes masquarading as multicast routers to get all
data.  This should be expanded a bit.  The reason for this seems to be
that snooping switches would mark the incoming port of such advertisements
as "router port" and push all the multicast there.  Additionally, one
might explicitly say something to the extent of "Therefore,
administratively disabling Multicast Router Advertisement processing
SHOULD be possible."  (or MAY).