Re: IGMP Router Group Membership state

Raja,

        When the To_Ex(A) is received, router will change its mode to EXCLUDE. In exclude mode, it maintains two list. Following rule will apply:


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

         Now when router generates group-source specific query and it gets a response with IS_INC(A). Following rule will apply:

         EXCLUDE (X,Y)  IS_IN (A)     EXCLUDE (X+A,Y-A)        (A)=GMI

        The state as per this will be EXCLUDE mode with source 'A' in Include list and exclude list will now be empty.

        Now if the response does not come, state will be EXCLUDE (A*B,B-A) which is an empty include list and source 'A' in exclude list.

Thanks,
Bharat
________________________________________
From: [email protected] [[email protected]] On Behalf Of rajasekar bonthala [[email protected]]
Sent: Monday, January 18, 2010 4:30 PM
To: [email protected]; [email protected]
Subject: [magma] IGMP Router Group Membership state

Hi All,

Section 6.4.2 of RFC 3376 talks about on how should IGMP routers respond on receiving Filter Mode Change and Source List Change records.

I do not get about what should be the action of the IGMP router in the following scenario.

Router is in "INCLUDE A"  state. It receives a report "TO EXCLUDE A". Here, IGMP Router sends a Group and Source specific query for the source A group B.

Let us say that IGMP Router receives a response "IS INCLUDE A".

What should be the state of the IGMP Router before and after receiving response?
What should be the state of the IGMP Router if it doesn't receive any response before the last member query time expires?

In my IGMP Router I could see the state as below :

BEFORE RESPONSE :

atca-f120#show ip igmp groups detail
Interface:      ge45
Group:          224.0.6.130
Uptime:         00:00:20
Group mode:     Exclude (Expires: 00:06:22)
Last reporter:  192.168.1.8
Group source list: (R - Remote, M - SSM Mapping, S - Static)
Include Source List :
  Source Address  Uptime    v3 Exp    Fwd  Flags
  10.10.10.10     00:00:20  00:00:27  Yes  R




NO RESPONSE :

atca-f120#show ip igmp groups detail
Interface:      ge45
Group:          224.0.6.130
Uptime:         00:00:49
Group mode:     Exclude (Expires: 00:05:53)
Last reporter:  192.168.1.8
Group source list: (R - Remote, M - SSM Mapping, S - Static)
Exclude Source List :
  Source Address  Uptime    v3 Exp    Fwd  Flags
  10.10.10.10     00:00:49  stopped   No   R


But could not interpret the above outputs. Can anyone help me.

Thanks,
RajaSekhar