Subject: Re: Doubts PIM

From: Bill Fenner <[email-masked]>
Date: Tue, 21 Mar 2000 08:02:24 -0800

>   I dont understand the the second condition in 1 b? How it helps in 
>sending Periodic Join Message.

It allows a "downstream" DR with no downstream group members (so it
has an empty OIF list) to still send Joins to get traffic to the
network it's the DR for.  Bad ASCII art:

        RP
        |
        R1
        |
        R2
        |
    -----------------------------------
                 |                   |
                 H                   DR

In this case,it's the DR's job to get the traffic from the RP since H
is interested, but the DR has an empty oiflist so the first half of
1b would prevent it from sending a join to R2.

>2)   With what Version of IGMP does PIM can operate?

Any.

>      And if Querier in IGMP v2 is diiferent from DR on the LAN, then how
>does the DR knows about Group Information.

That's how IGMP works; non-Queriers know group membership also.

  Bill