Subject: Re: [magma] Igmp snooping querier recommendations

From: "Kimball, Karen E" <[email-masked]>
Date: Wed, 26 Aug 2009 17:58:51 +0000

For IGMP-snooping, several scenarios apply:

1) Snooping only, with existing network Querier - just forward the Queries as directed by the standard.

2) Snooping with NO existing network Querier - assume Querier function (for both General and Group-Specific Queries), and use the snooping device's real IP address on that network interface.

2a) IF a router comes up on the network, it is required to send out "Announcement Queries" so that if IT should be the network Querier (lowest IP address), then this happens quickly. When such a Query is received, the IGMP snooping device can give up being Querier and let the other device take over.

As a general rule of thumb, if a device is simply IGMP-snooping and not a full router, it can maintain clean behavior by:

        A) NOT sending the "Announcement Queries" itself until it has waited long enough for a true Querier to speak (see the information on the length of Querier Timers).

        B) GIVING UP being Querier any time a General Query is received from another device (assume that this is an "Announcement Query," and that an election will result).

        C) Always use a real IP address when the snooping device is itself Querier. Many IGMP hosts will not respond to Queries with the 0.0.0.0 IP Address, which means that the protocol will not fully work on that portion of the network if the 0.0.0.0 IP Address is used.

Regards,
     Karen Kimball

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Subject: magma Digest, Vol 60, Issue 2

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Today's Topics:

   1. Re: igmp snooping querier recommendations (Prashanth Badabagni)
   2. Re: igmp snooping querier recommendations (V, Magesh (Magesh))
   3. Re: igmp snooping querier recommendations (V, Magesh (Magesh))
   4. Re: igmp snooping querier recommendations (Prashanth Badabagni)

----------------------------------------------------------------------

Message: 1
Date: Wed, 19 Aug 2009 20:35:40 -0600
From: Prashanth Badabagni <[email-masked]>
Subject: Re: [magma] igmp snooping querier recommendations
To: "Prashant Jhingran (pjhingra)" <[email-masked]>
Cc: "[email-masked]" <[email-masked]>
Message-ID:
        <[email-masked]>

Content-Type: text/plain; charset="us-ascii"

Are there any ways to avoid the problem mentioned in point 2 in the original post? The only way I see is using a source ip address 0.0.0.0; But vendors like cisco generate the queries with a valid ip address configured on the vlan on which snooping querier is enabled.

thanks

-----Original Message-----
From: Prashant Jhingran (pjhingra) [mailto:[email-masked]]
Sent: Tuesday, August 18, 2009 7:04 PM
To: Prashanth Badabagni
Cc: [email-masked]
Subject: RE: [magma] igmp snooping querier recommendations

Hi Prashanth,

Refer rfc 4541 & 4605, these would clarify your doubts.

Regards,
Prashant Jhingran

Phone:   +91-80-442 61800

-----Original Message-----
From: [email-masked] [mailto:[email-masked]] On Behalf Of Prashanth Badabagni
Sent: Tuesday, August 18, 2009 4:49 PM
To: [email-masked]
Subject: [magma] igmp snooping querier recommendations

Hi,

I've the following questions regarding igmp snooping querier implementation.
Please provide your thoughts on this.

1. Are there any recommendations for implementation igmp snooping querier.

2. what should be the ip address of the queries sent. Should it always be 0.0.0.0 or valid ip address should be allowed. There can be a problem if the general queries are sent with valid ip address, if an l3 router comes up in the vlan, by listening to the query message, it might assume that there is another querier present, which can potentially make the l3 querier a non-querier on that interface.

3. what kinds of queries should be sent, only general queries, or group specific queries should also be allowed.

4. what should be the behavior, if the switch listens to igmp activity in the vlan on which snooping querier is enabled.

Thanks

_______________________________________________
magma mailing list
[email-masked]
https://www.ietf.org/mailman/listinfo/magma

------------------------------

Message: 2
Date: Fri, 21 Aug 2009 16:21:26 +0530
From: "V, Magesh (Magesh)" <[email-masked]>
Subject: Re: [magma] igmp snooping querier recommendations
To: Prashanth Badabagni <[email-masked]>, "Prashant Jhingran
        (pjhingra)"     <[email-masked]>
Cc: "[email-masked]" <[email-masked]>
Message-ID:
        <[email-masked]>

Content-Type: text/plain; charset="us-ascii"

The idea of sending GenQuery w/ valid srcIp is indeed to take care of the scenario mentioned in 2) below. That is, whenever a igmp interface in a router receives a general query from someone else then it MUST run querier election on that LAN to decide the ultimate querier.

Thanks,
Magesh.

-----Original Message-----
From: [email-masked] [mailto:[email-masked]] On Behalf Of Prashanth Badabagni
Sent: Thursday, August 20, 2009 8:06 AM
To: Prashant Jhingran (pjhingra)
Cc: [email-masked]
Subject: Re: [magma] igmp snooping querier recommendations

Are there any ways to avoid the problem mentioned in point 2 in the original post? The only way I see is using a source ip address 0.0.0.0; But vendors like cisco generate the queries with a valid ip address configured on the vlan on which snooping querier is enabled.

thanks

-----Original Message-----
From: Prashant Jhingran (pjhingra) [mailto:[email-masked]]
Sent: Tuesday, August 18, 2009 7:04 PM
To: Prashanth Badabagni
Cc: [email-masked]
Subject: RE: [magma] igmp snooping querier recommendations

Hi Prashanth,

Refer rfc 4541 & 4605, these would clarify your doubts.

Regards,
Prashant Jhingran

Phone:   +91-80-442 61800

-----Original Message-----
From: [email-masked] [mailto:[email-masked]] On Behalf Of Prashanth Badabagni
Sent: Tuesday, August 18, 2009 4:49 PM
To: [email-masked]
Subject: [magma] igmp snooping querier recommendations

Hi,

I've the following questions regarding igmp snooping querier implementation.
Please provide your thoughts on this.

1. Are there any recommendations for implementation igmp snooping querier.

2. what should be the ip address of the queries sent. Should it always be 0.0.0.0 or valid ip address should be allowed. There can be a problem if the general queries are sent with valid ip address, if an l3 router comes up in the vlan, by listening to the query message, it might assume that there is another querier present, which can potentially make the l3 querier a non-querier on that interface.

3. what kinds of queries should be sent, only general queries, or group specific queries should also be allowed.

4. what should be the behavior, if the switch listens to igmp activity in the vlan on which snooping querier is enabled.

Thanks

_______________________________________________
magma mailing list
[email-masked]
https://www.ietf.org/mailman/listinfo/magma
_______________________________________________
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[email-masked]
https://www.ietf.org/mailman/listinfo/magma

------------------------------

Message: 3
Date: Fri, 21 Aug 2009 17:32:55 +0530
From: "V, Magesh (Magesh)" <[email-masked]>
Subject: Re: [magma] igmp snooping querier recommendations
To: "V, Magesh (Magesh)" <[email-masked]>, Prashanth
        Badabagni       <[email-masked]>, "Prashant Jhingran (pjhingra)"
        <[email-masked]>
Cc: "[email-masked]" <[email-masked]>
Message-ID:
        <[email-masked]>

Content-Type: text/plain; charset="us-ascii"

Okay, wait a minute. I might be slightly out of context.
For Snooping querier; the way to avoid scenario 2) is to send queries w/ zero srcip.
By default it can send w/ 0.0.0.0. It can also give a simple configuration option to specify an ip-address (a real ip interface w/ that address need not exist). If it is so, then it becomes the responsibility of the administrator to ensure the ip address he chooses is inferior to that of the IGMP router.

Thanks,
Magesh.

-----Original Message-----
From: [email-masked] [mailto:[email-masked]] On Behalf Of V, Magesh (Magesh)
Sent: Friday, August 21, 2009 4:21 PM
To: Prashanth Badabagni; Prashant Jhingran (pjhingra)
Cc: [email-masked]
Subject: Re: [magma] igmp snooping querier recommendations

The idea of sending GenQuery w/ valid srcIp is indeed to take care of the scenario mentioned in 2) below. That is, whenever a igmp interface in a router receives a general query from someone else then it MUST run querier election on that LAN to decide the ultimate querier.

Thanks,
Magesh.

-----Original Message-----
From: [email-masked] [mailto:[email-masked]] On Behalf Of Prashanth Badabagni
Sent: Thursday, August 20, 2009 8:06 AM
To: Prashant Jhingran (pjhingra)
Cc: [email-masked]
Subject: Re: [magma] igmp snooping querier recommendations

Are there any ways to avoid the problem mentioned in point 2 in the original post? The only way I see is using a source ip address 0.0.0.0; But vendors like cisco generate the queries with a valid ip address configured on the vlan on which snooping querier is enabled.

thanks

-----Original Message-----
From: Prashant Jhingran (pjhingra) [mailto:[email-masked]]
Sent: Tuesday, August 18, 2009 7:04 PM
To: Prashanth Badabagni
Cc: [email-masked]
Subject: RE: [magma] igmp snooping querier recommendations

Hi Prashanth,

Refer rfc 4541 & 4605, these would clarify your doubts.

Regards,
Prashant Jhingran

Phone:   +91-80-442 61800

-----Original Message-----
From: [email-masked] [mailto:[email-masked]] On Behalf Of Prashanth Badabagni
Sent: Tuesday, August 18, 2009 4:49 PM
To: [email-masked]
Subject: [magma] igmp snooping querier recommendations

Hi,

I've the following questions regarding igmp snooping querier implementation.
Please provide your thoughts on this.

1. Are there any recommendations for implementation igmp snooping querier.

2. what should be the ip address of the queries sent. Should it always be 0.0.0.0 or valid ip address should be allowed. There can be a problem if the general queries are sent with valid ip address, if an l3 router comes up in the vlan, by listening to the query message, it might assume that there is another querier present, which can potentially make the l3 querier a non-querier on that interface.

3. what kinds of queries should be sent, only general queries, or group specific queries should also be allowed.

4. what should be the behavior, if the switch listens to igmp activity in the vlan on which snooping querier is enabled.

Thanks

_______________________________________________
magma mailing list
[email-masked]
https://www.ietf.org/mailman/listinfo/magma
_______________________________________________
magma mailing list
[email-masked]
https://www.ietf.org/mailman/listinfo/magma
_______________________________________________
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------------------------------

Message: 4
Date: Fri, 21 Aug 2009 06:11:36 -0600
From: Prashanth Badabagni <[email-masked]>
Subject: Re: [magma] igmp snooping querier recommendations
To: "V, Magesh (Magesh)" <[email-masked]>, "Prashant
        Jhingran        (pjhingra)" <[email-masked]>
Cc: "[email-masked]" <[email-masked]>
Message-ID:
        <[email-masked]>

Content-Type: text/plain; charset="us-ascii"

Is it not simple to use the source address 0.0.0.0 always?
Are there any other problems of using source ip as 0.0.0.0

thanks
-----Original Message-----
From: V, Magesh (Magesh) [mailto:[email-masked]]
Sent: Friday, August 21, 2009 5:33 PM
To: V, Magesh (Magesh); Prashanth Badabagni; Prashant Jhingran (pjhingra)
Cc: [email-masked]
Subject: RE: [magma] igmp snooping querier recommendations

Okay, wait a minute. I might be slightly out of context.
For Snooping querier; the way to avoid scenario 2) is to send queries w/ zero srcip.
By default it can send w/ 0.0.0.0. It can also give a simple configuration option to specify an ip-address (a real ip interface w/ that address need not exist). If it is so, then it becomes the responsibility of the administrator to ensure the ip address he chooses is inferior to that of the IGMP router.

Thanks,
Magesh.

-----Original Message-----
From: [email-masked] [mailto:[email-masked]] On Behalf Of V, Magesh (Magesh)
Sent: Friday, August 21, 2009 4:21 PM
To: Prashanth Badabagni; Prashant Jhingran (pjhingra)
Cc: [email-masked]
Subject: Re: [magma] igmp snooping querier recommendations

The idea of sending GenQuery w/ valid srcIp is indeed to take care of the scenario mentioned in 2) below. That is, whenever a igmp interface in a router receives a general query from someone else then it MUST run querier election on that LAN to decide the ultimate querier.

Thanks,
Magesh.

-----Original Message-----
From: [email-masked] [mailto:[email-masked]] On Behalf Of Prashanth Badabagni
Sent: Thursday, August 20, 2009 8:06 AM
To: Prashant Jhingran (pjhingra)
Cc: [email-masked]
Subject: Re: [magma] igmp snooping querier recommendations

Are there any ways to avoid the problem mentioned in point 2 in the original post? The only way I see is using a source ip address 0.0.0.0; But vendors like cisco generate the queries with a valid ip address configured on the vlan on which snooping querier is enabled.

thanks

-----Original Message-----
From: Prashant Jhingran (pjhingra) [mailto:[email-masked]]
Sent: Tuesday, August 18, 2009 7:04 PM
To: Prashanth Badabagni
Cc: [email-masked]
Subject: RE: [magma] igmp snooping querier recommendations

Hi Prashanth,

Refer rfc 4541 & 4605, these would clarify your doubts.

Regards,
Prashant Jhingran

Phone:   +91-80-442 61800

-----Original Message-----
From: [email-masked] [mailto:[email-masked]] On Behalf Of Prashanth Badabagni
Sent: Tuesday, August 18, 2009 4:49 PM
To: [email-masked]
Subject: [magma] igmp snooping querier recommendations

Hi,

I've the following questions regarding igmp snooping querier implementation.
Please provide your thoughts on this.

1. Are there any recommendations for implementation igmp snooping querier.

2. what should be the ip address of the queries sent. Should it always be 0.0.0.0 or valid ip address should be allowed. There can be a problem if the general queries are sent with valid ip address, if an l3 router comes up in the vlan, by listening to the query message, it might assume that there is another querier present, which can potentially make the l3 querier a non-querier on that interface.

3. what kinds of queries should be sent, only general queries, or group specific queries should also be allowed.

4. what should be the behavior, if the switch listens to igmp activity in the vlan on which snooping querier is enabled.

Thanks

_______________________________________________
magma mailing list
[email-masked]
https://www.ietf.org/mailman/listinfo/magma
_______________________________________________
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[email-masked]
https://www.ietf.org/mailman/listinfo/magma
_______________________________________________
magma mailing list
[email-masked]
https://www.ietf.org/mailman/listinfo/magma

------------------------------

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End of magma Digest, Vol 60, Issue 2
************************************