Re: [magma] IGMP Router Group Membership state

[Bharat Joshi <[e-mail]>]

RajaSekhar,

         I am not sure what you exactly mean by 'please explain on what is "EXCLUDE (A*B,B-A)". I understand that this does not look straight forward but if you do the calculation with a list of source and group address, you will see that this is just perfect. Same is true with the other rule. Please use a specific group-address and source address to check them out.

        The sources in the include list are those which has been explicitly asked to be allowed. This is maintained so that a router can move from Exclude to Include mode as and when group-timer fires. Source in exclude list are simply not forwarded and is explicitly asked to be excluded by someone on LAN.

Thanks,
Bharat
________________________________________
From: rajasekar bonthala [[e-mail]]
Sent: Monday, January 18, 2010 6:01 PM
To: Bharat Joshi
Cc: [e-mail]; [e-mail]
Subject: Re: [magma] IGMP Router Group Membership state

Bharat,

Thanks a lot for the reply.
In the first rule can you please explain on what is "EXCLUDE (A*B,B-A)" and what is the meaning of action of the router i.e :-

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

In the seconds rule can you explain me the meaning of "EXCLUDE (X+A,Y-A)" and "(A)=GMI
"

You said that in the exclude mode, it maintains two lists, one is the exclude list and the other is the include list. Is it that Exclude list to inform about the blocked sources and Include list to inform the sources from which the multicast packets are allowed. Am i correct.

Thanks,
RajaSekhar

On Mon, Jan 18, 2010 at 5:31 PM, Bharat Joshi <[e-mail]<mailto:[e-mail]>> wrote:
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: [e-mail]<mailto:[e-mail]> [[e-mail]<mailto:[e-mail]>] On Behalf Of rajasekar bonthala [[e-mail]<mailto:[e-mail]>]
Sent: Monday, January 18, 2010 4:30 PM
To: [e-mail]<mailto:[e-mail]>; [e-mail]<mailto:[e-mail]>
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


**************** CAUTION - Disclaimer *****************
This e-mail contains PRIVILEGED AND CONFIDENTIAL INFORMATION intended solely
for the use of the addressee(s). If you are not the intended recipient, please
notify the sender by e-mail and delete the original message. Further, you are not
to copy, disclose, or distribute this e-mail or its contents to any other person and
any such actions are unlawful. This e-mail may contain viruses. Infosys has taken
every reasonable precaution to minimize this risk, but is not liable for any damage
you may sustain as a result of any virus in this e-mail. You should carry out your
own virus checks before opening the e-mail or attachment. Infosys reserves the
right to monitor and review the content of all messages sent to or from this e-mail
address. Messages sent to or from this e-mail address may be stored on the
Infosys e-mail system.
***INFOSYS******** End of Disclaimer ********INFOSYS***