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

Hi Alex,

Let me jump into discussion.
1) 802.16/16e MAC has no capability to do uplink multicast. In DL,
802.16provides multicast CIDs which is initiated by DSA messages. In
UL, however,
there is no way for an MS to access others' UL data fundamentally, in
802.16PHY/MAC. In case of ETH over
802.16, the ETH(bridge) may cover this (an MS sends multicast data in UL,
and then a bridge forwards it back). But, there is still a difficulty in
multicasting data back except for the source MS.

Best regards,
Jihoon Lee

==============================================================

Jihoon(Brandon) Lee (jhlee@mmlab.snu.ac.kr, brandon.jihoon@gmail.com)
Multimedia  and Mobile Communication Laboratory, Seoul National University.

2007/1/12, Alexandru Petrescu <alexandru.petrescu@motorola.com>om>:
>
> 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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