How to forward IGMP join message?

[Lingfeng Xiong]

Hi all,

The network topology is illustrated below:

WAN ------ Router ------ L3 Switch ------ Client

PIM-SD are configured on both L3 Switch and Router. The Client is going to join a multicast group, for example 239.42.1.1. This join message is received by L3 Switch and then converted to a PIM message to Router. After that, we can see such item in Router's mroute table. However, when Router insert such item into its mrouter table, it will not send the corresponding IGMP join message to WAN port. Without this join message, the Router cannot receive UDP multicast packets from the server in WAN.

So how can I configure my Router to send such IGMP join message?

[Joseph W. Doherty]

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Posting

Why do you want to send an IGMP join to the "WAN"?  Normally, your WAN connected router would forward your PIM message to the next "upsteam" multicast router.

It might be helpful if you could further identify your topology and what form of PIM you're using.

[Lingfeng Xiong]

Hi Joseph,

The "WAN" I put in the diagram is actually a link to my ISP which does not support PIM. It needs normal IGMP join messages.

[Joseph W. Doherty]

Disclaimer

The Author of this posting offers the information contained within this posting without consideration and with the reader's understanding that there's no implied or expressed suitability or fitness for any purpose. Information provided is for informational purposes only and should not be construed as rendering professional advice of any kind. Usage of this posting's information is solely at reader's own risk.

Liability Disclaimer

In no event shall Author be liable for any damages whatsoever (including, without limitation, damages for loss of use, data or profit) arising out of the use or inability to use the posting's information even if Author has been advised of the possibility of such damage.

Posting

On your WAN interface, you might use a static IGMP membership command.  Then the router interface will appear as a host wanting that multicast stream.  Once it obtains it, it can then forward the stream to any downstream requesting multicast clients.

[Lingfeng Xiong]

Hi Joseph,

The static-join will put the Router to announce itself as a host forever. There are nearly 300 multicast streams needs to be forwarded. It is impracticable to join all of them at the same time.

Is there anyway to join the multicast streams "on-demand"? I mean, when a host in network sends a join message, the router forward (or proxy) that message to ISP?

A daemon called igmproxy (http://sourceforge.net/projects/igmpproxy/) implemented the functionality I required. I just need a equivalent function on Cisco router.

[Joseph W. Doherty]

Disclaimer

The Author of this posting offers the information contained within this posting without consideration and with the reader's understanding that there's no implied or expressed suitability or fitness for any purpose. Information provided is for informational purposes only and should not be construed as rendering professional advice of any kind. Usage of this posting's information is solely at reader's own risk.

Liability Disclaimer

In no event shall Author be liable for any damages whatsoever (including, without limitation, damages for loss of use, data or profit) arising out of the use or inability to use the posting's information even if Author has been advised of the possibility of such damage.

Posting

I'm unaware of a similar IGMP proxy feature for a "typical" Cisco switch.

The only other alternative that comes to mind, can you create a GRE tunnel to another router you control (doing multicast PIM across it)?