Re: [magma] Question about IGMPv3 state change

Kunal Shah <kunal.shah@ericsson.com> Mon, 07 March 2011 13:09 UTC

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From: Kunal Shah <kunal.shah@ericsson.com>
To: Indranil Bhattacharya <myselfindranil@gmail.com>
Date: Mon, 07 Mar 2011 08:10:51 -0500
Thread-Topic: [magma] Question about IGMPv3 state change
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Subject: Re: [magma] Question about IGMPv3 state change
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Hi Indranil,

>From the RFC "

When a router filter-mode for a group is EXCLUDE, the source record
   list contains two types of sources.  The first type is the set which
   represents conflicts in the desired reception state; this set must be
   forwarded by some router on the network.

"
This means that a source can be in X only if it is being requested for being blocked as well as for being forwarded. In my example below s5 is not being requested to be blocked by any host. So what is the reason for keeping it in X??

Kunal

________________________________
From: Indranil Bhattacharya [mailto:myselfindranil@gmail.com]
Sent: Monday, March 07, 2011 6:33 PM
To: Kunal Shah
Cc: magma@ietf.org
Subject: Re: [magma] Question about IGMPv3 state change

Hi Kunal,
             X is for all INCLUDE mode sources. A is TO_IN report. So, s5 should be there in X. Why should s5 be blocked? Somebody wants data from this source.

Thanks,
Indranil

On Mon, Mar 7, 2011 at 5:52 PM, Kunal Shah <kunal.shah@ericsson.com<mailto:kunal.shah@ericsson.com>> wrote:
Hi Indranil,

Consider this,

X= s1,s2
Y= s3,s4

A=s4,s5

Then X+A= s1,s2,s4,s5
Y-A=s3

s5 is in X even when it is not being blocked ??

Kunal

________________________________
From: Indranil Bhattacharya [mailto:myselfindranil@gmail.com<mailto:myselfindranil@gmail.com>]
Sent: Monday, February 28, 2011 6:57 PM
To: Kunal Shah
Cc: magma@ietf.org<mailto:magma@ietf.org>
Subject: Re: [magma] Question about IGMPv3 state change

Hi Kunal,


x = s1,s2
y= s3,s4
a=s2,s3

x+a = s1,s2,s3
y-a = s4
Does it answer your question?

Thanks,
Indranil


On Tue, Feb 15, 2011 at 1:28 AM, Kunal Shah <kunal.shah@ericsson.com<mailto:kunal.shah@ericsson.com>> wrote:
Hi all,

I have a question about IGMPv3 state machine. If a group is in EX(X,Y) and a TO_IN(A) is received, the new state according to the RFC is EX (X+A, Y-A). I think this mean remove all the elements of A from Y and add all elements of A to X. This also implies that sources not removed from Y will still end up being added to X. My question is why cant we add only those elemets of A to X which are removed from Y as opposed to adding all the elements of A to X ??

If only the elements that are removed from Y are added to X, the new state would look like EX (X+(Y*A), Y-A).

Am I missing something here??

Kunal


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