I do not think we can ignore the rest of the network. The SGSN needs a
mechanism to populate its forwarding table with mcast addresses -
that is where MLD snooping comes in.
Is the following a good representation of a cellular network ?
IPL1 IPR1
Mobile 1--------(SGSN)------\
(GGSN)-->
Mobile 2--------(SGSN)------/
IPL2 IPR2
I am saying IPR1 = IPR2 , hence IPL1, IPL2, IPR1 all are on the same
link as SGSN are L2 devices. So if Mobile 1 subscribes to a link-local
group and so does Mobile 2, then we need mcast forwarding between
them. Next question would be what are IPL1, IPL2, and IPRx - global,
site-scope,link-local unicat addresses ?
Subrata.
-----Original Message-----
From: Hesham Soliman (ERA) [mailto:[EMAIL PROTECTED]]
Sent: Friday, May 24, 2002 11:28 AM
To: 'Dr. Subrata Goswami'; Hesham Soliman (ERA)
Subject: RE: MLD comments on cellular host drafts - seeking feedback
> Are you sure that the BTS does not terminate the radio link
> - physically
=> Yes. I'm assuming you're still talking about WCDMA.
> that looks like the spot for termination. Okay, if the IP
> stack sees a L3
> p2p link, then the IP address on the GGSN interface is same
> for a number of
> mobile hosts - right ? So the GGSN has to know which of the mobiles
> connected to it need mcast group traffic, right ?
=> But we're not talking about mcast addresses in general,
we're talking about link-local mcast addresses. For those
addresses you don't need to join on a p2p link.
Similarly
> the SGSN also
> needs to know which links it needs to copy an mcast group packet to.
=> No. The SGSN is not involved in any routing. The
_only_ node that does routing is the GGSN. We can
ignore the rest of the network as far as the IETF
is concerned. Or at least as far this WG is concerned.
Hesham
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