Subject: Comments on draft-ietf-pim-v2-dm-01.txt

From: Sangeeta Mukherjee <[email-masked]>
Date: Mon, 14 Dec 1998 15:18:50 -0800 (PST)

I had a couple of comments regarding draft-ietf-pim-v2-dm-01.txt.

Firstly, it would be nice if all the PIM control message formats
specific to PIM-dm was in this spec itself rather than being
referenced to PIM-sm spec. We want to make sure this is a standalone
draft.

The second one is more of a clarification. Section 5.3 states:

Routers with no group state do nothing on  receipt  of  IGMP  reports,
since   dense-mode   PIM  will  deliver  multicast  datagrams  to  all
interfaces when creating state for a group

From an implementation point of view, is this exactly correct? When a router
receives IGMP join request from a directly connected ( say on interface 1)
host for group X, and has no (S,G) state for group X, 
it needs to record the request somehow that there is a
membership request on interface 1 for group X. Then when the router gets a 
datagram packet for group X, it would create and (S,G) entry and create
a outgoing interface list containing interface 1. 

Should this be stated in the draft in some form?

Sangeeta

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From: [email-masked] (Ravi Shekhar)
Date: Mon, 14 Dec 1998 18:50:34 -0500 (EST)

>a outgoing interface list containing interface 1. 
    
    Isnt it the responsibility of the IGMP running on the router to keep
    this state?

    How a multicast protocol gets that information from IGMP would depend 
    on the router implementation. For eg: PIM-DM might be started after
    IGMP has already been started. In which case there has to be a separate
    mechanism to inform PIM-DM about the group memberships which were 
    expressed by hosts before PIM-DM was started.

	- Ravi Shekhar.

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From: Bill Fenner <[email-masked]>
Date: Mon, 14 Dec 1998 15:57:03 PST

Actually, I think the draft shouldn't mention IGMP at all, other
than describing it as one way of determining group membership on
an interface.  PIM's actions can then be described with respect to
group memberships on interfaces.

  Bill