Someone may need to correct this, but, I think the misunderstanding comes from the nature of the link between the mobile and the GGSN. Conceptually it is more like the device making a phone call to the ggsn: it doesn't matter how many phone switches are between the endpoints, they don't come into play in the packet forwarding, only the GGSN does. However, in this case the "phone calls" are called pdp contexts and pass through the SGSN.
In that case I think the answer to your question about scope is that the addresses of the SGSN can be any scope, but they are conceptually below the point to point relationship that exists between the device and GGSN. Craig. -----Original Message----- From: Dr. Subrata Goswami [mailto:[EMAIL PROTECTED]] Sent: May 24, 2002 2:58 PM To: [EMAIL PROTECTED] Subject: RE: MLD comments on cellular host drafts - seeking feedback 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. -------------------------------------------------------------------- IETF IPng Working Group Mailing List IPng Home Page: http://playground.sun.com/ipng FTP archive: ftp://playground.sun.com/pub/ipng Direct all administrative requests to [EMAIL PROTECTED] --------------------------------------------------------------------
