Re: IGMP Snooping proxy

Hi Magesh,

     You are right. I was thinking that I have read this somewhere.

     From RFC 4541, it is clear that a switch can generate a join message with 0.0.0.0 source address. Now if your router is IGMPv2 and follow RFC to the word, it will discard this packet. But if your router can interoperate with switches that supports RFC 4541, it must not discard this packet.

     Alternatively, you can check if switch provides some mean to configure an IP address that can be used as source address for these messages but then the same IP address can not be used in the general queries generated on downstream ports.

Thanks,
Bharat

________________________________________
From: V, Magesh (Magesh) [[email protected]]
Sent: Monday, April 13, 2009 12:21 PM
To: Bharat Joshi
Cc: [email protected]
Subject: RE: IGMP Snooping proxy

Hi Bharat,
4541 talks about a switch receiving/sending reports with src-ip 0.0.0.0. My question was w.r.t the upstream igmp router that receives this report. Hence, I was referring 2236. However, I got a reference in 3376 (IgmpV3 - section 4.2.13) that mandates to accept reports w/ source-ip 0.0.0.0

However, my igmp router is v2.

Thanks,
Magesh.

-----Original Message-----
From: Bharat Joshi [mailto:[email protected]]
Sent: Monday, April 13, 2009 11:09 AM
To: V, Magesh (Magesh)
Cc: [email protected]
Subject: RE: IGMP Snooping proxy

Hi Magesh,

      Please see my response in line.

Thanks,
Bharat

>
> *        Can you please elaborate as to what the igmp router can be configured with; is it to explicitly specify to process reports with src-ip 0.0.0.0?
>
> *        I referred in 2236 (mine is a v2 router) where, I couldn't find a reference for this?

Please look at point 2 of section 2.1.1 of RFC 4541. It mention this. Just read through this RFC, consideration of source address as 0.0.0.0 is mentioned at couple of places.

> *        Lastly, regarding valid source-ip; I agree that a part of aggregation will be defeated but the switch may send just ONE report per mc group per vlan in addition to the aggregated report. The switch can use the source-ip of the report which it last heard to refresh its group membership expiry timer for than LAN.

Yes. Switch can surely do that and with this you do not need to send multiple join/leave requests upstream.

> *        OR it must be made possible in the proxy-snooping implementation to configure an ip-address per mrouter port which, can be used as the source-ip for the aggregates.

You can do this as well. It is similar to the above one but more granular.
**************** 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***