Re: Question about IGMPv3 state machine

Hi Kunal,

    In section 6.4, RFC 3376 has defined the meaning of roles the two source list in EXCLUDE( A, B) plays. Sources available in A are those sources for which a host has asked for data to be forwarded and sources in B has been explicitly asked to be excluded.

    In section 6.3, RFC 3376 has defined the forwarding rules. Now if its exclude mode, and source timer is running [i.e. the sources in list 'A'], it should forward the data and if it is not in exclude list [i.e. it is not in source list B], it should forward the traffic.

    In the first example, source '2' exist in list of sources whose source timer will be running and so will get forwarded and now (B-A) in this case will be 0 and so sources 1 and 3 will get forwarded.

    Similarly in the second example, source '3' will get forwarded as its source timer will be running and all sources except source 4 will get forwarded as only source 4 needs to be excluded.

    I hope this helps.

Thanks,
Bharat
________________________________________
From: [email protected] [[email protected]] On Behalf Of Kunal Shah [[email protected]]
Sent: Wednesday, March 25, 2009 4:27 AM
To: [email protected]
Subject: [magma] Question about IGMPv3 state machine

Hi,

This is Kunal. I am trying to understand IGMPv3 router side functionality and have the following questions about the RFC 3776:

In section 6.4.1

INCLUDE (A)    TO_EX (B)    EXCLUDE (A*B,B-A)       (B-A)=0
                                                    Delete (A-B)
                                                    Send Q(G,A*B)
                                                    Group Timer=GMI

If A=1,2,3 and B=2, A*B=2. How does the host that has requested sources 1 and 3 still get them?? And If we delete A-B=2 in this case, how does the host interested in 2 get traffic from it??

And similarly for

EXCLUDE (X,Y)  TO_EX (A)    EXCLUDE (A-Y,Y*A)       (A-X-Y)=Group Timer

                                                    Delete (X-A)

                                                    Delete (Y-A)

                                                    Send Q(G,A-Y)

                                                    Group Timer=GMI

If X=1,2,3, Y=4,5,6, and A=3,4 the A-Y=3 and Y*A=4 What about hosts that want 1,2 sources. If X-A=1,2 is deleted how will the hosts get traffic from 1,2 .

I will really appreciate if you can answer these two questions. I have contacted a lot of people to get these two questions answered but have not heard from any one yet.

Thanks
Kunal


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