rajasekar bonthala | 2 Jun 13:13 2010
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IGMP Basics and Advanced

Hello,
 
I had gone through the IGMP RFC and understood the IGMP to a basic level.
If any one can suggest me any book it would help me to understand better.
If you have any interview topics to be covered in IGMP also, please share with me.
 
Thanks,
Raj
 
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magma <at> ietf.org
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Kudachi, Deepak S | 2 Jun 14:20 2010
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Igmp Group-Source specific Retransmission

Hi All,

 

I was going through the IGMPv3 RFC 3376  and was not clear on the below

Mentioned section.

 

/*---------------------------------------------------------------------------------------------------------*/

6.6.3.2. Building and Sending Group and Source Specific Queries

 

   When a table action "Send Q(G,X)" is encountered by a querier in the

   table in section 6.4.2, the following actions must be performed for

   each of the sources in X of group G, with source timer larger than

   LMQT:

 

   o Set number of retransmissions for each source to [Last Member Query

     Count].

 

   o Lower source timer to LMQT.

 

   The router must then immediately send a group and source specific

   query as well as schedule [Last Member Query Count - 1] query

   retransmissions to be sent every [Last Member Query Interval] over

   [Last Member Query Time].  The contents of these queries are

   calculated as follows.

/*-----------------------------------------------------------------*/

 

 

This section talks about how the group-source specific queries are build and

Send out.

 

Suppose our robustness variable is set to 2(default value).

And Last Member Query Interval is 10 Sec.

 

Any group-source specific query need to be transmitted robustness number of times

That is 2 times in our case and separated by LMQI which 10 sec.

So 2 queries has to be sent across Last Member Query Time which is 20 sec.

 

 

Now suppose we already sent Q(G,X) query for a group at T1 with set of sources. And we received

A report which causes new Q(G,(X+Y)) needs to be sent and T2( before T1+LMQI). Where Y is new set of sources to be

Queried. New Query will be sent with all sources merged from previous and new(x + y).

 

So the sources x already two queries will be sent and not separated by LMQI in this scenario.

 

My question is whether we need to send one more query after LMQI ( at T1+LMQI) for x

Set of sources for this group?

 

If we need to then we will be sending 3 queries for x set of sources as follows.

 

Time interval T1

Time interval T2

Time interval T1+LMQI

 

Which is not correct.

 

Let me know whether we should send query for x set of sources for this group

At T1+LMQI interval.

 

Thanks and Regards

Deepak

 

 

 

 

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magma mailing list
magma <at> ietf.org
https://www.ietf.org/mailman/listinfo/magma
Bharat Joshi | 2 Jun 14:37 2010

Re: Igmp Group-Source specific Retransmission

Deepak,

      It would be better if you handle the example with IP addresses. Also consider how the state in the hosts are
and what final state should be there after things stabilize.

      For the below example, I think you should attach the robustness count as query count with the source
addresses and then as and when timer fires, you prepare a group-source specific query, send it out and
reduce the query count for each source address you include in the query. Once the query count for a source
address reaches zero, it is removed from the list and when all sources are removed from the list, we do not
restart the timer.

      So we will end up sending three queries. But all the three queries will carry different sources in the list.

      I hope this helps.

Regards,
Bharat
________________________________________
From: magma-bounces <at> ietf.org [magma-bounces <at> ietf.org] On Behalf Of Kudachi, Deepak S [deepak.kudachi <at> hp.com]
Sent: Wednesday, June 02, 2010 5:50 PM
To: magma <at> core3.amsl.com; magma <at> ietf.org
Subject: [magma]  Igmp Group-Source specific Retransmission

Hi All,

I was going through the IGMPv3 RFC 3376  and was not clear on the below
Mentioned section.

/*---------------------------------------------------------------------------------------------------------*/
6.6.3.2. Building and Sending Group and Source Specific Queries

   When a table action "Send Q(G,X)" is encountered by a querier in the
   table in section 6.4.2, the following actions must be performed for
   each of the sources in X of group G, with source timer larger than
   LMQT:

   o Set number of retransmissions for each source to [Last Member Query
     Count].

   o Lower source timer to LMQT.

   The router must then immediately send a group and source specific
   query as well as schedule [Last Member Query Count - 1] query
   retransmissions to be sent every [Last Member Query Interval] over
   [Last Member Query Time].  The contents of these queries are
   calculated as follows.
/*-----------------------------------------------------------------*/

This section talks about how the group-source specific queries are build and
Send out.

Suppose our robustness variable is set to 2(default value).
And Last Member Query Interval is 10 Sec.

Any group-source specific query need to be transmitted robustness number of times
That is 2 times in our case and separated by LMQI which 10 sec.
So 2 queries has to be sent across Last Member Query Time which is 20 sec.

Now suppose we already sent Q(G,X) query for a group at T1 with set of sources. And we received
A report which causes new Q(G,(X+Y)) needs to be sent and T2( before T1+LMQI). Where Y is new set of sources to be
Queried. New Query will be sent with all sources merged from previous and new(x + y).

So the sources x already two queries will be sent and not separated by LMQI in this scenario.

My question is whether we need to send one more query after LMQI ( at T1+LMQI) for x
Set of sources for this group?

If we need to then we will be sending 3 queries for x set of sources as follows.

Time interval T1
Time interval T2
Time interval T1+LMQI

Which is not correct.

Let me know whether we should send query for x set of sources for this group
At T1+LMQI interval.

Thanks and Regards
Deepak
Kudachi, Deepak S | 3 Jun 11:45 2010
Picon

Re: Igmp Group-Source specific Retransmission

Hi Bharat,

I am still not clear on the part that you said all the queries have different src addresses.

May be I can give an example for this case.

Let us assume following values.

Robustness = 2
LMQI = 10 sec

Group = G1 = 224.0.2.1
Srouces
        S1 = 10.10.10.10
        S2 = 10.10.10.20
        S3 = 10.10.10.30
        S4 = 10.10.10.40
        S5 = 10.10.10.50

Our interface's current state is INCLUDE for group G1.

So 
INCLUDE{S1,S2,S3,S4} for G1

Now we received Block message for the same group on same interface

Consider the message received is 
BLOCK {S3}.

now according to RFC 3376 sec 6.4.2
INCLUDE (A)    BLOCK (B)    INCLUDE (A)             Send Q(G,A*B)

We need to send a group-source specific query for A*B 
which is nothing but send a query for source S3.

So query will be sent at Time = T1
Send Q(G1, S3) 
We have started the timer (LMQI)10 sec with repeat 1 so that 
When timer expires we need to send one more query for this G1,S3. 
( query is send out for group G1= 224.0.1.2 ,S3 = 10.10.10.30.)

now at time  interval T2 < (T1+LMQI)
we received TO_EXC{ S1 , S2, S5 } on same interface for the same group G1.

Now according to RFC following function need to be performed.
INCLUDE (A)    TO_EX (B)    EXCLUDE (A*B,B-A)       (B-A)=0
                                                    Delete (A-B)
                                                    Send Q(G,A*B)
                                                    Group Timer=GMI

Interface moves to exclude mode 
EXCLUDE { (S1,S2),(S5)} for group G1.

Now immediate query has to be sent for S1,S2.

Since S3 retransmission is still pending we need to merge S3 with S1,S3 in this query.
Now Q(G1,S1,S2,S3) will be sent at interval T2.

Now for S3 we have sent two queries and its query count is set to 0 and will be
removed from retransmission list.

For S3 we sent out second query much before T1+LMQI and no more queries will be sent for S3.

This is what we infer from the RFC and just want to know others view on this.

(please Note: I am only considering router side processing).

Thanks and Regards
Deepak

-----Original Message-----
From: Bharat Joshi [mailto:bharat_joshi <at> infosys.com] 
Sent: Wednesday, June 02, 2010 6:07 PM
To: Kudachi, Deepak S; magma <at> core3.amsl.com; magma <at> ietf.org
Subject: RE: [magma] Igmp Group-Source specific Retransmission

Deepak,

      It would be better if you handle the example with IP addresses. Also consider how the state in the hosts are
and what final state should be there after things stabilize.

      For the below example, I think you should attach the robustness count as query count with the source
addresses and then as and when timer fires, you prepare a group-source specific query, send it out and
reduce the query count for each source address you include in the query. Once the query count for a source
address reaches zero, it is removed from the list and when all sources are removed from the list, we do not
restart the timer.

      So we will end up sending three queries. But all the three queries will carry different sources in the list.

      I hope this helps.

Regards,
Bharat
________________________________________
From: magma-bounces <at> ietf.org [magma-bounces <at> ietf.org] On Behalf Of Kudachi, Deepak S [deepak.kudachi <at> hp.com]
Sent: Wednesday, June 02, 2010 5:50 PM
To: magma <at> core3.amsl.com; magma <at> ietf.org
Subject: [magma]  Igmp Group-Source specific Retransmission

Hi All,

I was going through the IGMPv3 RFC 3376  and was not clear on the below
Mentioned section.

/*---------------------------------------------------------------------------------------------------------*/
6.6.3.2. Building and Sending Group and Source Specific Queries

   When a table action "Send Q(G,X)" is encountered by a querier in the
   table in section 6.4.2, the following actions must be performed for
   each of the sources in X of group G, with source timer larger than
   LMQT:

   o Set number of retransmissions for each source to [Last Member Query
     Count].

   o Lower source timer to LMQT.

   The router must then immediately send a group and source specific
   query as well as schedule [Last Member Query Count - 1] query
   retransmissions to be sent every [Last Member Query Interval] over
   [Last Member Query Time].  The contents of these queries are
   calculated as follows.
/*-----------------------------------------------------------------*/

This section talks about how the group-source specific queries are build and
Send out.

Suppose our robustness variable is set to 2(default value).
And Last Member Query Interval is 10 Sec.

Any group-source specific query need to be transmitted robustness number of times
That is 2 times in our case and separated by LMQI which 10 sec.
So 2 queries has to be sent across Last Member Query Time which is 20 sec.

Now suppose we already sent Q(G,X) query for a group at T1 with set of sources. And we received
A report which causes new Q(G,(X+Y)) needs to be sent and T2( before T1+LMQI). Where Y is new set of sources to be
Queried. New Query will be sent with all sources merged from previous and new(x + y).

So the sources x already two queries will be sent and not separated by LMQI in this scenario.

My question is whether we need to send one more query after LMQI ( at T1+LMQI) for x
Set of sources for this group?

If we need to then we will be sending 3 queries for x set of sources as follows.

Time interval T1
Time interval T2
Time interval T1+LMQI

Which is not correct.

Let me know whether we should send query for x set of sources for this group
At T1+LMQI interval.

Thanks and Regards
Deepak
Bharat Joshi | 3 Jun 12:01 2010

Re: Igmp Group-Source specific Retransmission

Deepak,

     I think your interpretation is perfect and I think that is exactly how one should implement it on router side.

     BTW, Just one question. Do you see any issue with this?

Thanks,
Bharat
________________________________________
From: Kudachi, Deepak S [deepak.kudachi <at> hp.com]
Sent: Thursday, June 03, 2010 3:15 PM
To: Bharat Joshi; magma <at> core3.amsl.com; magma <at> ietf.org
Cc: Sankaran, Balaji (HP Procurve)
Subject: RE: [magma]  Igmp Group-Source specific Retransmission

Hi Bharat,

I am still not clear on the part that you said all the queries have different src addresses.

May be I can give an example for this case.

Let us assume following values.

Robustness = 2
LMQI = 10 sec

Group = G1 = 224.0.2.1
Srouces
        S1 = 10.10.10.10
        S2 = 10.10.10.20
        S3 = 10.10.10.30
        S4 = 10.10.10.40
        S5 = 10.10.10.50

Our interface's current state is INCLUDE for group G1.

So
INCLUDE{S1,S2,S3,S4} for G1

Now we received Block message for the same group on same interface

Consider the message received is
BLOCK {S3}.

now according to RFC 3376 sec 6.4.2
INCLUDE (A)    BLOCK (B)    INCLUDE (A)             Send Q(G,A*B)

We need to send a group-source specific query for A*B
which is nothing but send a query for source S3.

So query will be sent at Time = T1
Send Q(G1, S3)
We have started the timer (LMQI)10 sec with repeat 1 so that
When timer expires we need to send one more query for this G1,S3.
( query is send out for group G1= 224.0.1.2 ,S3 = 10.10.10.30.)

now at time  interval T2 < (T1+LMQI)
we received TO_EXC{ S1 , S2, S5 } on same interface for the same group G1.

Now according to RFC following function need to be performed.
INCLUDE (A)    TO_EX (B)    EXCLUDE (A*B,B-A)       (B-A)=0
                                                    Delete (A-B)
                                                    Send Q(G,A*B)
                                                    Group Timer=GMI

Interface moves to exclude mode
EXCLUDE { (S1,S2),(S5)} for group G1.

Now immediate query has to be sent for S1,S2.

Since S3 retransmission is still pending we need to merge S3 with S1,S3 in this query.
Now Q(G1,S1,S2,S3) will be sent at interval T2.

Now for S3 we have sent two queries and its query count is set to 0 and will be
removed from retransmission list.

For S3 we sent out second query much before T1+LMQI and no more queries will be sent for S3.

This is what we infer from the RFC and just want to know others view on this.

(please Note: I am only considering router side processing).

Thanks and Regards
Deepak

-----Original Message-----
From: Bharat Joshi [mailto:bharat_joshi <at> infosys.com]
Sent: Wednesday, June 02, 2010 6:07 PM
To: Kudachi, Deepak S; magma <at> core3.amsl.com; magma <at> ietf.org
Subject: RE: [magma] Igmp Group-Source specific Retransmission

Deepak,

      It would be better if you handle the example with IP addresses. Also consider how the state in the hosts are
and what final state should be there after things stabilize.

      For the below example, I think you should attach the robustness count as query count with the source
addresses and then as and when timer fires, you prepare a group-source specific query, send it out and
reduce the query count for each source address you include in the query. Once the query count for a source
address reaches zero, it is removed from the list and when all sources are removed from the list, we do not
restart the timer.

      So we will end up sending three queries. But all the three queries will carry different sources in the list.

      I hope this helps.

Regards,
Bharat
________________________________________
From: magma-bounces <at> ietf.org [magma-bounces <at> ietf.org] On Behalf Of Kudachi, Deepak S [deepak.kudachi <at> hp.com]
Sent: Wednesday, June 02, 2010 5:50 PM
To: magma <at> core3.amsl.com; magma <at> ietf.org
Subject: [magma]  Igmp Group-Source specific Retransmission

Hi All,

I was going through the IGMPv3 RFC 3376  and was not clear on the below
Mentioned section.

/*---------------------------------------------------------------------------------------------------------*/
6.6.3.2. Building and Sending Group and Source Specific Queries

   When a table action "Send Q(G,X)" is encountered by a querier in the
   table in section 6.4.2, the following actions must be performed for
   each of the sources in X of group G, with source timer larger than
   LMQT:

   o Set number of retransmissions for each source to [Last Member Query
     Count].

   o Lower source timer to LMQT.

   The router must then immediately send a group and source specific
   query as well as schedule [Last Member Query Count - 1] query
   retransmissions to be sent every [Last Member Query Interval] over
   [Last Member Query Time].  The contents of these queries are
   calculated as follows.
/*-----------------------------------------------------------------*/

This section talks about how the group-source specific queries are build and
Send out.

Suppose our robustness variable is set to 2(default value).
And Last Member Query Interval is 10 Sec.

Any group-source specific query need to be transmitted robustness number of times
That is 2 times in our case and separated by LMQI which 10 sec.
So 2 queries has to be sent across Last Member Query Time which is 20 sec.

Now suppose we already sent Q(G,X) query for a group at T1 with set of sources. And we received
A report which causes new Q(G,(X+Y)) needs to be sent and T2( before T1+LMQI). Where Y is new set of sources to be
Queried. New Query will be sent with all sources merged from previous and new(x + y).

So the sources x already two queries will be sent and not separated by LMQI in this scenario.

My question is whether we need to send one more query after LMQI ( at T1+LMQI) for x
Set of sources for this group?

If we need to then we will be sending 3 queries for x set of sources as follows.

Time interval T1
Time interval T2
Time interval T1+LMQI

Which is not correct.

Let me know whether we should send query for x set of sources for this group
At T1+LMQI interval.

Thanks and Regards
Deepak
K.Kawaguchi | 4 Jun 02:22 2010
Picon

Re: Igmp Group-Source specific Retransmission

Hi Deepak-san,

I comment only one point.
Please observe S flag. (RFC3376 4.1.5.)

""Kudachi, Deepak S" <deepak.kudachi <at> hp.com>" wrote:

> Hi Bharat,
> 
> I am still not clear on the part that you said all the queries have different src addresses.
> 
> May be I can give an example for this case.
> 
> Let us assume following values.
> 
> 
> Robustness = 2
> LMQI = 10 sec
> 
> Group = G1 = 224.0.2.1
> Srouces
>         S1 = 10.10.10.10
>         S2 = 10.10.10.20
>         S3 = 10.10.10.30
>         S4 = 10.10.10.40
>         S5 = 10.10.10.50
> 
> Our interface's current state is INCLUDE for group G1.
> 
> So 
> INCLUDE{S1,S2,S3,S4} for G1
> 
> Now we received Block message for the same group on same interface
> 
> Consider the message received is 
> BLOCK {S3}.
> 
> now according to RFC 3376 sec 6.4.2
> INCLUDE (A)    BLOCK (B)    INCLUDE (A)             Send Q(G,A*B)
> 
> We need to send a group-source specific query for A*B 
> which is nothing but send a query for source S3.
> 
> So query will be sent at Time = T1
> Send Q(G1, S3) 
> We have started the timer (LMQI)10 sec with repeat 1 so that 
> When timer expires we need to send one more query for this G1,S3. 
> ( query is send out for group G1= 224.0.1.2 ,S3 = 10.10.10.30.)
> 
> now at time  interval T2 < (T1+LMQI)
> we received TO_EXC{ S1 , S2, S5 } on same interface for the same group G1.
> 
> Now according to RFC following function need to be performed.
> INCLUDE (A)    TO_EX (B)    EXCLUDE (A*B,B-A)       (B-A)=0
>                                                     Delete (A-B)
>                                                     Send Q(G,A*B)
>                                                     Group Timer=GMI
> 
> 
> Interface moves to exclude mode 
> EXCLUDE { (S1,S2),(S5)} for group G1.
> 
> Now immediate query has to be sent for S1,S2.
> 
> Since S3 retransmission is still pending we need to merge S3 with S1,S3 in this query.
> Now Q(G1,S1,S2,S3) will be sent at interval T2.

Q(G1,S1,S2)w/SFlag=0 and Q(G1,S3)w/S Flag=1

> 
> Now for S3 we have sent two queries and its query count is set to 0 and will be
> removed from retransmission list.
> 
> For S3 we sent out second query much before T1+LMQI and no more queries will be sent for S3.
> 
> This is what we infer from the RFC and just want to know others view on this.
> 
> (please Note: I am only considering router side processing).
> 
> 
> Thanks and Regards
> Deepak
> 
> -----Original Message-----
> From: Bharat Joshi [mailto:bharat_joshi <at> infosys.com] 
> Sent: Wednesday, June 02, 2010 6:07 PM
> To: Kudachi, Deepak S; magma <at> core3.amsl.com; magma <at> ietf.org
> Subject: RE: [magma] Igmp Group-Source specific Retransmission
> 
> Deepak,
> 
>       It would be better if you handle the example with IP addresses. Also consider how the state in the hosts are
and what final state should be there after things stabilize.
> 
>       For the below example, I think you should attach the robustness count as query count with the source
addresses and then as and when timer fires, you prepare a group-source specific query, send it out and
reduce the query count for each source address you include in the query. Once the query count for a source
address reaches zero, it is removed from the list and when all sources are removed from the list, we do not
restart the timer.
> 
>       So we will end up sending three queries. But all the three queries will carry different sources in the list.
> 
>       I hope this helps.
> 
> Regards,
> Bharat
> ________________________________________
> From: magma-bounces <at> ietf.org [magma-bounces <at> ietf.org] On Behalf Of Kudachi, Deepak S [deepak.kudachi <at> hp.com]
> Sent: Wednesday, June 02, 2010 5:50 PM
> To: magma <at> core3.amsl.com; magma <at> ietf.org
> Subject: [magma]  Igmp Group-Source specific Retransmission
> 
> Hi All,
> 
> I was going through the IGMPv3 RFC 3376  and was not clear on the below
> Mentioned section.
> 
> /*---------------------------------------------------------------------------------------------------------*/
> 6.6.3.2. Building and Sending Group and Source Specific Queries
> 
>    When a table action "Send Q(G,X)" is encountered by a querier in the
>    table in section 6.4.2, the following actions must be performed for
>    each of the sources in X of group G, with source timer larger than
>    LMQT:
> 
>    o Set number of retransmissions for each source to [Last Member Query
>      Count].
> 
>    o Lower source timer to LMQT.
> 
>    The router must then immediately send a group and source specific
>    query as well as schedule [Last Member Query Count - 1] query
>    retransmissions to be sent every [Last Member Query Interval] over
>    [Last Member Query Time].  The contents of these queries are
>    calculated as follows.
> /*-----------------------------------------------------------------*/
> 
> 
> This section talks about how the group-source specific queries are build and
> Send out.
> 
> Suppose our robustness variable is set to 2(default value).
> And Last Member Query Interval is 10 Sec.
> 
> Any group-source specific query need to be transmitted robustness number of times
> That is 2 times in our case and separated by LMQI which 10 sec.
> So 2 queries has to be sent across Last Member Query Time which is 20 sec.
> 
> 
> Now suppose we already sent Q(G,X) query for a group at T1 with set of sources. And we received
> A report which causes new Q(G,(X+Y)) needs to be sent and T2( before T1+LMQI). Where Y is new set of sources
to be
> Queried. New Query will be sent with all sources merged from previous and new(x + y).
> 
> So the sources x already two queries will be sent and not separated by LMQI in this scenario.
> 
> My question is whether we need to send one more query after LMQI ( at T1+LMQI) for x
> Set of sources for this group?
> 
> If we need to then we will be sending 3 queries for x set of sources as follows.
> 
> Time interval T1
> Time interval T2
> Time interval T1+LMQI
> 
> Which is not correct.
> 
> Let me know whether we should send query for x set of sources for this group
> At T1+LMQI interval.
> 
> Thanks and Regards
> Deepak
> 
> 
> 
> 
> _______________________________________________
> magma mailing list
> magma <at> ietf.org
> https://www.ietf.org/mailman/listinfo/magma

Best Regards
--
Kiyoaki Kawaguchi
Bharat Joshi | 4 Jun 03:44 2010

Re: Igmp Group-Source specific Retransmission

Hi,

       I am not sure if I understand this correctly. 'S' bit flag needs to be set only when a querier wants to tell
non-querier to not-to-update their timer. It is set when someone replies to the first query saying that he
still wants that source and a source timer is updated. In this case, 'S3' will not be available in the final
include source list so why should the 'S' flag be set for this source?

Thanks,
Bharat
________________________________________
From: K.Kawaguchi [kawaguti <at> ysknet.co.jp]
Sent: Friday, June 04, 2010 5:52 AM
To: deepak.kudachi <at> hp.com
Cc: sankaran.balaji <at> hp.com; Bharat Joshi; magma <at> core3.amsl.com; magma <at> ietf.org
Subject: Re: [magma] Igmp Group-Source specific Retransmission

Hi Deepak-san,

I comment only one point.
Please observe S flag. (RFC3376 4.1.5.)

""Kudachi, Deepak S" <deepak.kudachi <at> hp.com>" wrote:

> Hi Bharat,
>
> I am still not clear on the part that you said all the queries have different src addresses.
>
> May be I can give an example for this case.
>
> Let us assume following values.
>
>
> Robustness = 2
> LMQI = 10 sec
>
> Group = G1 = 224.0.2.1
> Srouces
>         S1 = 10.10.10.10
>         S2 = 10.10.10.20
>         S3 = 10.10.10.30
>         S4 = 10.10.10.40
>         S5 = 10.10.10.50
>
> Our interface's current state is INCLUDE for group G1.
>
> So
> INCLUDE{S1,S2,S3,S4} for G1
>
> Now we received Block message for the same group on same interface
>
> Consider the message received is
> BLOCK {S3}.
>
> now according to RFC 3376 sec 6.4.2
> INCLUDE (A)    BLOCK (B)    INCLUDE (A)             Send Q(G,A*B)
>
> We need to send a group-source specific query for A*B
> which is nothing but send a query for source S3.
>
> So query will be sent at Time = T1
> Send Q(G1, S3)
> We have started the timer (LMQI)10 sec with repeat 1 so that
> When timer expires we need to send one more query for this G1,S3.
> ( query is send out for group G1= 224.0.1.2 ,S3 = 10.10.10.30.)
>
> now at time  interval T2 < (T1+LMQI)
> we received TO_EXC{ S1 , S2, S5 } on same interface for the same group G1.
>
> Now according to RFC following function need to be performed.
> INCLUDE (A)    TO_EX (B)    EXCLUDE (A*B,B-A)       (B-A)=0
>                                                     Delete (A-B)
>                                                     Send Q(G,A*B)
>                                                     Group Timer=GMI
>
>
> Interface moves to exclude mode
> EXCLUDE { (S1,S2),(S5)} for group G1.
>
> Now immediate query has to be sent for S1,S2.
>
> Since S3 retransmission is still pending we need to merge S3 with S1,S3 in this query.
> Now Q(G1,S1,S2,S3) will be sent at interval T2.

Q(G1,S1,S2)w/SFlag=0 and Q(G1,S3)w/S Flag=1

>
> Now for S3 we have sent two queries and its query count is set to 0 and will be
> removed from retransmission list.
>
> For S3 we sent out second query much before T1+LMQI and no more queries will be sent for S3.
>
> This is what we infer from the RFC and just want to know others view on this.
>
> (please Note: I am only considering router side processing).
>
>
> Thanks and Regards
> Deepak
>
> -----Original Message-----
> From: Bharat Joshi [mailto:bharat_joshi <at> infosys.com]
> Sent: Wednesday, June 02, 2010 6:07 PM
> To: Kudachi, Deepak S; magma <at> core3.amsl.com; magma <at> ietf.org
> Subject: RE: [magma] Igmp Group-Source specific Retransmission
>
> Deepak,
>
>       It would be better if you handle the example with IP addresses. Also consider how the state in the hosts are
and what final state should be there after things stabilize.
>
>       For the below example, I think you should attach the robustness count as query count with the source
addresses and then as and when timer fires, you prepare a group-source specific query, send it out and
reduce the query count for each source address you include in the query. Once the query count for a source
address reaches zero, it is removed from the list and when all sources are removed from the list, we do not
restart the timer.
>
>       So we will end up sending three queries. But all the three queries will carry different sources in the list.
>
>       I hope this helps.
>
> Regards,
> Bharat
> ________________________________________
> From: magma-bounces <at> ietf.org [magma-bounces <at> ietf.org] On Behalf Of Kudachi, Deepak S [deepak.kudachi <at> hp.com]
> Sent: Wednesday, June 02, 2010 5:50 PM
> To: magma <at> core3.amsl.com; magma <at> ietf.org
> Subject: [magma]  Igmp Group-Source specific Retransmission
>
> Hi All,
>
> I was going through the IGMPv3 RFC 3376  and was not clear on the below
> Mentioned section.
>
> /*---------------------------------------------------------------------------------------------------------*/
> 6.6.3.2. Building and Sending Group and Source Specific Queries
>
>    When a table action "Send Q(G,X)" is encountered by a querier in the
>    table in section 6.4.2, the following actions must be performed for
>    each of the sources in X of group G, with source timer larger than
>    LMQT:
>
>    o Set number of retransmissions for each source to [Last Member Query
>      Count].
>
>    o Lower source timer to LMQT.
>
>    The router must then immediately send a group and source specific
>    query as well as schedule [Last Member Query Count - 1] query
>    retransmissions to be sent every [Last Member Query Interval] over
>    [Last Member Query Time].  The contents of these queries are
>    calculated as follows.
> /*-----------------------------------------------------------------*/
>
>
> This section talks about how the group-source specific queries are build and
> Send out.
>
> Suppose our robustness variable is set to 2(default value).
> And Last Member Query Interval is 10 Sec.
>
> Any group-source specific query need to be transmitted robustness number of times
> That is 2 times in our case and separated by LMQI which 10 sec.
> So 2 queries has to be sent across Last Member Query Time which is 20 sec.
>
>
> Now suppose we already sent Q(G,X) query for a group at T1 with set of sources. And we received
> A report which causes new Q(G,(X+Y)) needs to be sent and T2( before T1+LMQI). Where Y is new set of sources
to be
> Queried. New Query will be sent with all sources merged from previous and new(x + y).
>
> So the sources x already two queries will be sent and not separated by LMQI in this scenario.
>
> My question is whether we need to send one more query after LMQI ( at T1+LMQI) for x
> Set of sources for this group?
>
> If we need to then we will be sending 3 queries for x set of sources as follows.
>
> Time interval T1
> Time interval T2
> Time interval T1+LMQI
>
> Which is not correct.
>
> Let me know whether we should send query for x set of sources for this group
> At T1+LMQI interval.
>
> Thanks and Regards
> Deepak
>
>
>
>
> _______________________________________________
> magma mailing list
> magma <at> ietf.org
> https://www.ietf.org/mailman/listinfo/magma

Best Regards
--
Kiyoaki Kawaguchi
K.Kawaguchi | 4 Jun 04:06 2010
Picon

Re: Igmp Group-Source specific Retransmission

Hi Bharat-san,

> now at time  interval T2 < (T1+LMQI)
> we received TO_EXC{ S1 , S2, S5 } on same interface for the same group G1.

This report desires source 'S3'.

Best Regards
--
Kiyoaki Kawaguchi

"Bharat Joshi <bharat_joshi <at> infosys.com>" wrote:

> Hi,
> 
>        I am not sure if I understand this correctly. 'S' bit flag needs to be set only when a querier wants to tell
non-querier to not-to-update their timer. It is set when someone replies to the first query saying that he
still wants that source and a source timer is updated. In this case, 'S3' will not be available in the final
include source list so why should the 'S' flag be set for this source?
> 
> Thanks,
> Bharat
> ________________________________________
> From: K.Kawaguchi [kawaguti <at> ysknet.co.jp]
> Sent: Friday, June 04, 2010 5:52 AM
> To: deepak.kudachi <at> hp.com
> Cc: sankaran.balaji <at> hp.com; Bharat Joshi; magma <at> core3.amsl.com; magma <at> ietf.org
> Subject: Re: [magma] Igmp Group-Source specific Retransmission
> 
> Hi Deepak-san,
> 
> I comment only one point.
> Please observe S flag. (RFC3376 4.1.5.)
> 
> 
> ""Kudachi, Deepak S" <deepak.kudachi <at> hp.com>" wrote:
> 
> > Hi Bharat,
> >
> > I am still not clear on the part that you said all the queries have different src addresses.
> >
> > May be I can give an example for this case.
> >
> > Let us assume following values.
> >
> >
> > Robustness = 2
> > LMQI = 10 sec
> >
> > Group = G1 = 224.0.2.1
> > Srouces
> >         S1 = 10.10.10.10
> >         S2 = 10.10.10.20
> >         S3 = 10.10.10.30
> >         S4 = 10.10.10.40
> >         S5 = 10.10.10.50
> >
> > Our interface's current state is INCLUDE for group G1.
> >
> > So
> > INCLUDE{S1,S2,S3,S4} for G1
> >
> > Now we received Block message for the same group on same interface
> >
> > Consider the message received is
> > BLOCK {S3}.
> >
> > now according to RFC 3376 sec 6.4.2
> > INCLUDE (A)    BLOCK (B)    INCLUDE (A)             Send Q(G,A*B)
> >
> > We need to send a group-source specific query for A*B
> > which is nothing but send a query for source S3.
> >
> > So query will be sent at Time = T1
> > Send Q(G1, S3)
> > We have started the timer (LMQI)10 sec with repeat 1 so that
> > When timer expires we need to send one more query for this G1,S3.
> > ( query is send out for group G1= 224.0.1.2 ,S3 = 10.10.10.30.)
> >
> > now at time  interval T2 < (T1+LMQI)
> > we received TO_EXC{ S1 , S2, S5 } on same interface for the same group G1.
> >
> > Now according to RFC following function need to be performed.
> > INCLUDE (A)    TO_EX (B)    EXCLUDE (A*B,B-A)       (B-A)=0
> >                                                     Delete (A-B)
> >                                                     Send Q(G,A*B)
> >                                                     Group Timer=GMI
> >
> >
> > Interface moves to exclude mode
> > EXCLUDE { (S1,S2),(S5)} for group G1.
> >
> > Now immediate query has to be sent for S1,S2.
> >
> > Since S3 retransmission is still pending we need to merge S3 with S1,S3 in this query.
> > Now Q(G1,S1,S2,S3) will be sent at interval T2.
> 
> Q(G1,S1,S2)w/SFlag=0 and Q(G1,S3)w/S Flag=1
> 
> 
> >
> > Now for S3 we have sent two queries and its query count is set to 0 and will be
> > removed from retransmission list.
> >
> > For S3 we sent out second query much before T1+LMQI and no more queries will be sent for S3.
> >
> > This is what we infer from the RFC and just want to know others view on this.
> >
> > (please Note: I am only considering router side processing).
> >
> >
> > Thanks and Regards
> > Deepak
> >
> > -----Original Message-----
> > From: Bharat Joshi [mailto:bharat_joshi <at> infosys.com]
> > Sent: Wednesday, June 02, 2010 6:07 PM
> > To: Kudachi, Deepak S; magma <at> core3.amsl.com; magma <at> ietf.org
> > Subject: RE: [magma] Igmp Group-Source specific Retransmission
> >
> > Deepak,
> >
> >       It would be better if you handle the example with IP addresses. Also consider how the state in the hosts are
and what final state should be there after things stabilize.
> >
> >       For the below example, I think you should attach the robustness count as query count with the source
addresses and then as and when timer fires, you prepare a group-source specific query, send it out and
reduce the query count for each source address you include in the query. Once the query count for a source
address reaches zero, it is removed from the list and when all sources are removed from the list, we do not
restart the timer.
> >
> >       So we will end up sending three queries. But all the three queries will carry different sources in the list.
> >
> >       I hope this helps.
> >
> > Regards,
> > Bharat
> > ________________________________________
> > From: magma-bounces <at> ietf.org [magma-bounces <at> ietf.org] On Behalf Of Kudachi, Deepak S [deepak.kudachi <at> hp.com]
> > Sent: Wednesday, June 02, 2010 5:50 PM
> > To: magma <at> core3.amsl.com; magma <at> ietf.org
> > Subject: [magma]  Igmp Group-Source specific Retransmission
> >
> > Hi All,
> >
> > I was going through the IGMPv3 RFC 3376  and was not clear on the below
> > Mentioned section.
> >
> > /*---------------------------------------------------------------------------------------------------------*/
> > 6.6.3.2. Building and Sending Group and Source Specific Queries
> >
> >    When a table action "Send Q(G,X)" is encountered by a querier in the
> >    table in section 6.4.2, the following actions must be performed for
> >    each of the sources in X of group G, with source timer larger than
> >    LMQT:
> >
> >    o Set number of retransmissions for each source to [Last Member Query
> >      Count].
> >
> >    o Lower source timer to LMQT.
> >
> >    The router must then immediately send a group and source specific
> >    query as well as schedule [Last Member Query Count - 1] query
> >    retransmissions to be sent every [Last Member Query Interval] over
> >    [Last Member Query Time].  The contents of these queries are
> >    calculated as follows.
> > /*-----------------------------------------------------------------*/
> >
> >
> > This section talks about how the group-source specific queries are build and
> > Send out.
> >
> > Suppose our robustness variable is set to 2(default value).
> > And Last Member Query Interval is 10 Sec.
> >
> > Any group-source specific query need to be transmitted robustness number of times
> > That is 2 times in our case and separated by LMQI which 10 sec.
> > So 2 queries has to be sent across Last Member Query Time which is 20 sec.
> >
> >
> > Now suppose we already sent Q(G,X) query for a group at T1 with set of sources. And we received
> > A report which causes new Q(G,(X+Y)) needs to be sent and T2( before T1+LMQI). Where Y is new set of sources
to be
> > Queried. New Query will be sent with all sources merged from previous and new(x + y).
> >
> > So the sources x already two queries will be sent and not separated by LMQI in this scenario.
> >
> > My question is whether we need to send one more query after LMQI ( at T1+LMQI) for x
> > Set of sources for this group?
> >
> > If we need to then we will be sending 3 queries for x set of sources as follows.
> >
> > Time interval T1
> > Time interval T2
> > Time interval T1+LMQI
> >
> > Which is not correct.
> >
> > Let me know whether we should send query for x set of sources for this group
> > At T1+LMQI interval.
> >
> > Thanks and Regards
> > Deepak
> >
> >
> >
> >
> > _______________________________________________
> > magma mailing list
> > magma <at> ietf.org
> > https://www.ietf.org/mailman/listinfo/magma
> 
> 
> Best Regards
> --
> Kiyoaki Kawaguchi
> 
> 
> 
Bharat Joshi | 4 Jun 04:23 2010

Re: Igmp Group-Source specific Retransmission

Hi,

Yes. I agree that this report desires S3 but neither querier nor non-querier has state for S3 so what is the
point in setting the 'S' flag.

From implementation perspective, while setting 'S' flag at querier, would not an implementation be
checking if the source timer has been updated or not? and because the querier won't even have state for
that, would it really set 'S' flag?

Thanks,
Bharat
________________________________________
From: K.Kawaguchi [kawaguti <at> ysknet.co.jp]
Sent: Friday, June 04, 2010 7:36 AM
To: Bharat Joshi; deepak.kudachi <at> hp.com
Cc: sankaran.balaji <at> hp.com; magma <at> ietf.org
Subject: Re: [magma] Igmp Group-Source specific Retransmission

Hi Bharat-san,

> now at time  interval T2 < (T1+LMQI)
> we received TO_EXC{ S1 , S2, S5 } on same interface for the same group G1.

This report desires source 'S3'.

Best Regards
--
Kiyoaki Kawaguchi

"Bharat Joshi <bharat_joshi <at> infosys.com>" wrote:

> Hi,
>
>        I am not sure if I understand this correctly. 'S' bit flag needs to be set only when a querier wants to tell
non-querier to not-to-update their timer. It is set when someone replies to the first query saying that he
still wants that source and a source timer is updated. In this case, 'S3' will not be available in the final
include source list so why should the 'S' flag be set for this source?
>
> Thanks,
> Bharat
> ________________________________________
> From: K.Kawaguchi [kawaguti <at> ysknet.co.jp]
> Sent: Friday, June 04, 2010 5:52 AM
> To: deepak.kudachi <at> hp.com
> Cc: sankaran.balaji <at> hp.com; Bharat Joshi; magma <at> core3.amsl.com; magma <at> ietf.org
> Subject: Re: [magma] Igmp Group-Source specific Retransmission
>
> Hi Deepak-san,
>
> I comment only one point.
> Please observe S flag. (RFC3376 4.1.5.)
>
>
> ""Kudachi, Deepak S" <deepak.kudachi <at> hp.com>" wrote:
>
> > Hi Bharat,
> >
> > I am still not clear on the part that you said all the queries have different src addresses.
> >
> > May be I can give an example for this case.
> >
> > Let us assume following values.
> >
> >
> > Robustness = 2
> > LMQI = 10 sec
> >
> > Group = G1 = 224.0.2.1
> > Srouces
> >         S1 = 10.10.10.10
> >         S2 = 10.10.10.20
> >         S3 = 10.10.10.30
> >         S4 = 10.10.10.40
> >         S5 = 10.10.10.50
> >
> > Our interface's current state is INCLUDE for group G1.
> >
> > So
> > INCLUDE{S1,S2,S3,S4} for G1
> >
> > Now we received Block message for the same group on same interface
> >
> > Consider the message received is
> > BLOCK {S3}.
> >
> > now according to RFC 3376 sec 6.4.2
> > INCLUDE (A)    BLOCK (B)    INCLUDE (A)             Send Q(G,A*B)
> >
> > We need to send a group-source specific query for A*B
> > which is nothing but send a query for source S3.
> >
> > So query will be sent at Time = T1
> > Send Q(G1, S3)
> > We have started the timer (LMQI)10 sec with repeat 1 so that
> > When timer expires we need to send one more query for this G1,S3.
> > ( query is send out for group G1= 224.0.1.2 ,S3 = 10.10.10.30.)
> >
> > now at time  interval T2 < (T1+LMQI)
> > we received TO_EXC{ S1 , S2, S5 } on same interface for the same group G1.
> >
> > Now according to RFC following function need to be performed.
> > INCLUDE (A)    TO_EX (B)    EXCLUDE (A*B,B-A)       (B-A)=0
> >                                                     Delete (A-B)
> >                                                     Send Q(G,A*B)
> >                                                     Group Timer=GMI
> >
> >
> > Interface moves to exclude mode
> > EXCLUDE { (S1,S2),(S5)} for group G1.
> >
> > Now immediate query has to be sent for S1,S2.
> >
> > Since S3 retransmission is still pending we need to merge S3 with S1,S3 in this query.
> > Now Q(G1,S1,S2,S3) will be sent at interval T2.
>
> Q(G1,S1,S2)w/SFlag=0 and Q(G1,S3)w/S Flag=1
>
>
> >
> > Now for S3 we have sent two queries and its query count is set to 0 and will be
> > removed from retransmission list.
> >
> > For S3 we sent out second query much before T1+LMQI and no more queries will be sent for S3.
> >
> > This is what we infer from the RFC and just want to know others view on this.
> >
> > (please Note: I am only considering router side processing).
> >
> >
> > Thanks and Regards
> > Deepak
> >
> > -----Original Message-----
> > From: Bharat Joshi [mailto:bharat_joshi <at> infosys.com]
> > Sent: Wednesday, June 02, 2010 6:07 PM
> > To: Kudachi, Deepak S; magma <at> core3.amsl.com; magma <at> ietf.org
> > Subject: RE: [magma] Igmp Group-Source specific Retransmission
> >
> > Deepak,
> >
> >       It would be better if you handle the example with IP addresses. Also consider how the state in the hosts are
and what final state should be there after things stabilize.
> >
> >       For the below example, I think you should attach the robustness count as query count with the source
addresses and then as and when timer fires, you prepare a group-source specific query, send it out and
reduce the query count for each source address you include in the query. Once the query count for a source
address reaches zero, it is removed from the list and when all sources are removed from the list, we do not
restart the timer.
> >
> >       So we will end up sending three queries. But all the three queries will carry different sources in the list.
> >
> >       I hope this helps.
> >
> > Regards,
> > Bharat
> > ________________________________________
> > From: magma-bounces <at> ietf.org [magma-bounces <at> ietf.org] On Behalf Of Kudachi, Deepak S [deepak.kudachi <at> hp.com]
> > Sent: Wednesday, June 02, 2010 5:50 PM
> > To: magma <at> core3.amsl.com; magma <at> ietf.org
> > Subject: [magma]  Igmp Group-Source specific Retransmission
> >
> > Hi All,
> >
> > I was going through the IGMPv3 RFC 3376  and was not clear on the below
> > Mentioned section.
> >
> > /*---------------------------------------------------------------------------------------------------------*/
> > 6.6.3.2. Building and Sending Group and Source Specific Queries
> >
> >    When a table action "Send Q(G,X)" is encountered by a querier in the
> >    table in section 6.4.2, the following actions must be performed for
> >    each of the sources in X of group G, with source timer larger than
> >    LMQT:
> >
> >    o Set number of retransmissions for each source to [Last Member Query
> >      Count].
> >
> >    o Lower source timer to LMQT.
> >
> >    The router must then immediately send a group and source specific
> >    query as well as schedule [Last Member Query Count - 1] query
> >    retransmissions to be sent every [Last Member Query Interval] over
> >    [Last Member Query Time].  The contents of these queries are
> >    calculated as follows.
> > /*-----------------------------------------------------------------*/
> >
> >
> > This section talks about how the group-source specific queries are build and
> > Send out.
> >
> > Suppose our robustness variable is set to 2(default value).
> > And Last Member Query Interval is 10 Sec.
> >
> > Any group-source specific query need to be transmitted robustness number of times
> > That is 2 times in our case and separated by LMQI which 10 sec.
> > So 2 queries has to be sent across Last Member Query Time which is 20 sec.
> >
> >
> > Now suppose we already sent Q(G,X) query for a group at T1 with set of sources. And we received
> > A report which causes new Q(G,(X+Y)) needs to be sent and T2( before T1+LMQI). Where Y is new set of sources
to be
> > Queried. New Query will be sent with all sources merged from previous and new(x + y).
> >
> > So the sources x already two queries will be sent and not separated by LMQI in this scenario.
> >
> > My question is whether we need to send one more query after LMQI ( at T1+LMQI) for x
> > Set of sources for this group?
> >
> > If we need to then we will be sending 3 queries for x set of sources as follows.
> >
> > Time interval T1
> > Time interval T2
> > Time interval T1+LMQI
> >
> > Which is not correct.
> >
> > Let me know whether we should send query for x set of sources for this group
> > At T1+LMQI interval.
> >
> > Thanks and Regards
> > Deepak
> >
> >
> >
> >
> > _______________________________________________
> > magma mailing list
> > magma <at> ietf.org
> > https://www.ietf.org/mailman/listinfo/magma
>
>
> Best Regards
> --
> Kiyoaki Kawaguchi
>
>
>
K.Kawaguchi | 4 Jun 05:13 2010
Picon

Re: Igmp Group-Source specific Retransmission

Hi,

It is just an matter of the implementation method.
Although I am not related to it, I know the implementation
which sets S Flag correctly. (For example, Xorp)

Best Regards
--
Kiyoaki Kawaguchi

"Bharat Joshi <bharat_joshi <at> infosys.com>" wrote:

> Hi,
> 
> Yes. I agree that this report desires S3 but neither querier nor non-querier has state for S3 so what is the
point in setting the 'S' flag.
> 
> From implementation perspective, while setting 'S' flag at querier, would not an implementation be
checking if the source timer has been updated or not? and because the querier won't even have state for
that, would it really set 'S' flag?
> 
> Thanks,
> Bharat
> ________________________________________
> From: K.Kawaguchi [kawaguti <at> ysknet.co.jp]
> Sent: Friday, June 04, 2010 7:36 AM
> To: Bharat Joshi; deepak.kudachi <at> hp.com
> Cc: sankaran.balaji <at> hp.com; magma <at> ietf.org
> Subject: Re: [magma] Igmp Group-Source specific Retransmission
> 
> Hi Bharat-san,
> 
> > now at time  interval T2 < (T1+LMQI)
> > we received TO_EXC{ S1 , S2, S5 } on same interface for the same group G1.
> 
> This report desires source 'S3'.
> 
> Best Regards
> --
> Kiyoaki Kawaguchi
> 
> 
> "Bharat Joshi <bharat_joshi <at> infosys.com>" wrote:
> 
> > Hi,
> >
> >        I am not sure if I understand this correctly. 'S' bit flag needs to be set only when a querier wants to tell
non-querier to not-to-update their timer. It is set when someone replies to the first query saying that he
still wants that source and a source timer is updated. In this case, 'S3' will not be available in the final
include source list so why should the 'S' flag be set for this source?
> >
> > Thanks,
> > Bharat
> > ________________________________________
> > From: K.Kawaguchi [kawaguti <at> ysknet.co.jp]
> > Sent: Friday, June 04, 2010 5:52 AM
> > To: deepak.kudachi <at> hp.com
> > Cc: sankaran.balaji <at> hp.com; Bharat Joshi; magma <at> core3.amsl.com; magma <at> ietf.org
> > Subject: Re: [magma] Igmp Group-Source specific Retransmission
> >
> > Hi Deepak-san,
> >
> > I comment only one point.
> > Please observe S flag. (RFC3376 4.1.5.)
> >
> >
> > ""Kudachi, Deepak S" <deepak.kudachi <at> hp.com>" wrote:
> >
> > > Hi Bharat,
> > >
> > > I am still not clear on the part that you said all the queries have different src addresses.
> > >
> > > May be I can give an example for this case.
> > >
> > > Let us assume following values.
> > >
> > >
> > > Robustness = 2
> > > LMQI = 10 sec
> > >
> > > Group = G1 = 224.0.2.1
> > > Srouces
> > >         S1 = 10.10.10.10
> > >         S2 = 10.10.10.20
> > >         S3 = 10.10.10.30
> > >         S4 = 10.10.10.40
> > >         S5 = 10.10.10.50
> > >
> > > Our interface's current state is INCLUDE for group G1.
> > >
> > > So
> > > INCLUDE{S1,S2,S3,S4} for G1
> > >
> > > Now we received Block message for the same group on same interface
> > >
> > > Consider the message received is
> > > BLOCK {S3}.
> > >
> > > now according to RFC 3376 sec 6.4.2
> > > INCLUDE (A)    BLOCK (B)    INCLUDE (A)             Send Q(G,A*B)
> > >
> > > We need to send a group-source specific query for A*B
> > > which is nothing but send a query for source S3.
> > >
> > > So query will be sent at Time = T1
> > > Send Q(G1, S3)
> > > We have started the timer (LMQI)10 sec with repeat 1 so that
> > > When timer expires we need to send one more query for this G1,S3.
> > > ( query is send out for group G1= 224.0.1.2 ,S3 = 10.10.10.30.)
> > >
> > > now at time  interval T2 < (T1+LMQI)
> > > we received TO_EXC{ S1 , S2, S5 } on same interface for the same group G1.
> > >
> > > Now according to RFC following function need to be performed.
> > > INCLUDE (A)    TO_EX (B)    EXCLUDE (A*B,B-A)       (B-A)=0
> > >                                                     Delete (A-B)
> > >                                                     Send Q(G,A*B)
> > >                                                     Group Timer=GMI
> > >
> > >
> > > Interface moves to exclude mode
> > > EXCLUDE { (S1,S2),(S5)} for group G1.
> > >
> > > Now immediate query has to be sent for S1,S2.
> > >
> > > Since S3 retransmission is still pending we need to merge S3 with S1,S3 in this query.
> > > Now Q(G1,S1,S2,S3) will be sent at interval T2.
> >
> > Q(G1,S1,S2)w/SFlag=0 and Q(G1,S3)w/S Flag=1
> >
> >
> > >
> > > Now for S3 we have sent two queries and its query count is set to 0 and will be
> > > removed from retransmission list.
> > >
> > > For S3 we sent out second query much before T1+LMQI and no more queries will be sent for S3.
> > >
> > > This is what we infer from the RFC and just want to know others view on this.
> > >
> > > (please Note: I am only considering router side processing).
> > >
> > >
> > > Thanks and Regards
> > > Deepak
> > >
> > > -----Original Message-----
> > > From: Bharat Joshi [mailto:bharat_joshi <at> infosys.com]
> > > Sent: Wednesday, June 02, 2010 6:07 PM
> > > To: Kudachi, Deepak S; magma <at> core3.amsl.com; magma <at> ietf.org
> > > Subject: RE: [magma] Igmp Group-Source specific Retransmission
> > >
> > > Deepak,
> > >
> > >       It would be better if you handle the example with IP addresses. Also consider how the state in the hosts
are and what final state should be there after things stabilize.
> > >
> > >       For the below example, I think you should attach the robustness count as query count with the source
addresses and then as and when timer fires, you prepare a group-source specific query, send it out and
reduce the query count for each source address you include in the query. Once the query count for a source
address reaches zero, it is removed from the list and when all sources are removed from the list, we do not
restart the timer.
> > >
> > >       So we will end up sending three queries. But all the three queries will carry different sources in the list.
> > >
> > >       I hope this helps.
> > >
> > > Regards,
> > > Bharat
> > > ________________________________________
> > > From: magma-bounces <at> ietf.org [magma-bounces <at> ietf.org] On Behalf Of Kudachi, Deepak S [deepak.kudachi <at> hp.com]
> > > Sent: Wednesday, June 02, 2010 5:50 PM
> > > To: magma <at> core3.amsl.com; magma <at> ietf.org
> > > Subject: [magma]  Igmp Group-Source specific Retransmission
> > >
> > > Hi All,
> > >
> > > I was going through the IGMPv3 RFC 3376  and was not clear on the below
> > > Mentioned section.
> > >
> > > /*---------------------------------------------------------------------------------------------------------*/
> > > 6.6.3.2. Building and Sending Group and Source Specific Queries
> > >
> > >    When a table action "Send Q(G,X)" is encountered by a querier in the
> > >    table in section 6.4.2, the following actions must be performed for
> > >    each of the sources in X of group G, with source timer larger than
> > >    LMQT:
> > >
> > >    o Set number of retransmissions for each source to [Last Member Query
> > >      Count].
> > >
> > >    o Lower source timer to LMQT.
> > >
> > >    The router must then immediately send a group and source specific
> > >    query as well as schedule [Last Member Query Count - 1] query
> > >    retransmissions to be sent every [Last Member Query Interval] over
> > >    [Last Member Query Time].  The contents of these queries are
> > >    calculated as follows.
> > > /*-----------------------------------------------------------------*/
> > >
> > >
> > > This section talks about how the group-source specific queries are build and
> > > Send out.
> > >
> > > Suppose our robustness variable is set to 2(default value).
> > > And Last Member Query Interval is 10 Sec.
> > >
> > > Any group-source specific query need to be transmitted robustness number of times
> > > That is 2 times in our case and separated by LMQI which 10 sec.
> > > So 2 queries has to be sent across Last Member Query Time which is 20 sec.
> > >
> > >
> > > Now suppose we already sent Q(G,X) query for a group at T1 with set of sources. And we received
> > > A report which causes new Q(G,(X+Y)) needs to be sent and T2( before T1+LMQI). Where Y is new set of
sources to be
> > > Queried. New Query will be sent with all sources merged from previous and new(x + y).
> > >
> > > So the sources x already two queries will be sent and not separated by LMQI in this scenario.
> > >
> > > My question is whether we need to send one more query after LMQI ( at T1+LMQI) for x
> > > Set of sources for this group?
> > >
> > > If we need to then we will be sending 3 queries for x set of sources as follows.
> > >
> > > Time interval T1
> > > Time interval T2
> > > Time interval T1+LMQI
> > >
> > > Which is not correct.
> > >
> > > Let me know whether we should send query for x set of sources for this group
> > > At T1+LMQI interval.
> > >
> > > Thanks and Regards
> > > Deepak
> > >
> > >
> > >
> > >
> > > _______________________________________________
> > > magma mailing list
> > > magma <at> ietf.org
> > > https://www.ietf.org/mailman/listinfo/magma
> >
> >
> > Best Regards
> > --
> > Kiyoaki Kawaguchi
> >
> >
> >
> 
> 
> 

Gmane