SSM vs ASM and IGMPv3 reports
John Zwiebel <[email protected]>
| Newsgroups | gmane.ietf.magma |
|---|---|
| Message-ID | <[email protected]> |
This was my last statement in an email I sent in the thread: Subject: Re: mboned: RE: [magma] suggestion for simplifying IGMPV3/MLDV2 to discard EXCLUDEmode I figure it needs a thread of its own... ONE LAST POINT: (hmmm... I'll put this into a separate email, please don't respond on this thread.) The v3-lite spec discusses ASM and SSM. Like Dino, I think SSM is well defined, but ASM is not. But reading the spec, I need to ask how an SSM group range is allocated. We know that currently it defaults to 232/8, but that routers can configure locally it for any range. Routers specifically reject (*,G) IGMP host reports for groups in the SSM range. AND routers -reject- (S,G) IGMP host reports for ASM groups. The spec combines ASM and SSM in a way that suggests to me that at least some of you would be "surprised" to see this. You would expect an ALLOW (224.1.1.1,1.1.1.1) to create an IGMP cache entry and trigger a (S,G) join even though the router is specifically configured to treat this as a PIM-sparse group (Note, can't say ASM since -- in some circles -- that includes Bi-dir, and I certainly don't want to send (S,G) joins for a bidir group). John Zwiebel