Re: multicast and IPv6 over ETHCS (was: [16NG] FW: Review on v6ops 802.16 deployment scenario (J Kim of AT&TLabs))

Hi, sorry for following-up on my own email...

Alexandru Petrescu wrote:
> gabriel montenegro wrote:
>> GARP/GMRP is not widely deployed, and seems to be obsoleted at the
>>  IEEE already.
> 
> Thanks for clarification.  Maybe IEEE proposes something else 
> instead, in order to have link-layer multicast?
> 
>> RFC 4541 (MLD snooping) is the deployed solution, as Max already 
>> discussed in the November meeting:
>> 
>> http://www3.ietf.org/proceedings/06nov/slides/16ng-4/sld7.htm

Absent GARP/GMRP I think a thing to write in the future version of
IPv6-over-ETHCS draft with respect to multicast is about the multicast
features of the 802.16 MAC and ETHCS?  More than the current section 4.3
saying just that 802.16 MAC dl is mc while ul is not mc
(download/upload/multicast).

It's clear that IPv6 ND needs a link-layer that is multicast capable,
and in both directions.  802.16 MAC seems to be mc-capable (CID for
multiple links, MCA-REQ/RSP, etc).  However, it's not clear to me from
IEEE spec whether (1) both directions are mc capable and (2) the ETHCS
(_over_ 802.16MAC) offers a multicast capable link interface to IP.

Ie the questions are: (1) will a multicasted NS sent by SS get delivered
to that mc group?  or just the RA sent by BS? (is 802.16 MAC mc-capable
in both directions)? and (2) will an IPv6 RA sent to all-nodes IP and
all-nodes MAC address get delivered as such, when it's put on ETHCS (not
on 802.16MAC SAP)?  (will the ETHCS classifiers understand MAC multicast
dst addresses.)

If ETHCS is link-layer multicast capable then it is enough to say in the
document that ETHCS is link-layer multicast capable, with an example.
If ETHCS is not link-layer multicast capable, bidirectionally, I think
the draft should say that ETHCS should be link-layer multicast capable,
bidirectionally, otherwise IPv6 doesn't work on it.  I don't think the
draft should develop a technique to make ETHCS link-layer multicast
capable, bidirectionally.

If there is agreement or incentive I can provide text as I suggested above.

Alex

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