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New Member

Moh Multicast issue

L2 mutlicast moh is not working, i have setup RP and Gre tunnel, L3 multicast moh works fine for internal calls, PSTN phone calls hear only dead air.

cucm version 7.1.2  gateway : mgcp, gateway 2851

appreciate your comments

  • IP Telephony
7 REPLIES

Moh Multicast issue

There is no L2 multicast it is a L 3 technology however cisco L 2 switch support a feature called muticast snooping

If you don't Spanish a L 3 interfaces then multicast snooping required only

HTH

New Member

Moh Multicast issue

Oppsss.... didnt knwo much about mutlicasting ? anyways the post shoudl be have been like we want to use mutlicast moh over mpls, sicne mpls has limiataiton [ not go to into details] we need to build GRE tunnel to realy multicast moh, so far the  tuneel is created we can ping to pub inside tunnel, multicast moh only work for internal calls , i.e. abc ext. 123 calls def ext 456  place call on hold receive moh stream fantastic so all Layers are working... otherwise when abc and def  receive pstn calls and palce call on hold, its dead air no moh stream, since the call setup is L2 its isdn pri...le tme know if these was helpful,

New Member

Re: Moh Multicast issue

Hi,   Check out this link http://www.cisco.com/en/US/docs/ios/12_2/ip/configuration/guide/1cfmulti.html#wp1002274. Even though your tunnel is established, the multicast subscribe messages won't make it through the tunnel to create the mroute entry.  Best luck! 

New Member

Re: Moh Multicast issue

Ryan, thanks for the link, im trying to route moh over mpls circuit [ its mgcp gateway pub is configured with multicast], gre tunnel between sites is configured and active, my  mroute shows the multicast streams, upto access switch  im able to see 239.1.1.40 join request, for some reason phone doesnt send igmp join request to moh streasm 239.1.1.1 239.1.1.2,

thanks

New Member

Re: Moh Multicast issue

Does the gateway have a device pool that includes a MRGL that has the MMOH server? Is the gateway in the same regoin as the phones? By default only G711 is supported for MOH unless it is changed in service parameters.

New Member

Re: Moh Multicast issue

Hi m.ateeque,

   There are lots of variables here, but I think you can break them down into at least two groups, the network configuration and the UCS configuration.

On the network side, while the GRE tunnel is established, that doens't mean that the multicast traffic will automatically flow across that path. In the document I pointed out: http://www.cisco.com/en/US/docs/ios/12_2/ip/configuration/guide/1cfmulti.html#wp1002274, they mention the RPF check that multicast does before establishing the flow. The static mroute establishes the reachability of the endpoints across the tunnel. If your tunnel is configured properly, you should be able to use a tool like ifperf to pass multicast traffic across it from a sender to a listener.

http://webfolder.wirelessleiden.nl/iperf/

If the iperf test works properly then you might have a configuration issue as mathewlouis pointed out above. Make sure that the device pool of the gateway does have the MMOH server in the MRGL and if it crosses a region boundary, that the change doesn't require some transcoding that is breaking the stream.

Another consideration is whether the bandwidth that you are saving is really worth the complication. The last time I passed multicast traffic in a GRE tunnel was for some security camera streams that traversed a pix firewall. The stream was about 1.2Mb/s and the processing overhead to terminate the GRE tunnel was sufficient to bring the RSM on a 5509 to 99% utilization.   If you have the bandwidth on the link to accommodate the additional traffic (number of concurrent connections to MOH X bandwidth of MOH stream) why not just give the gateway a MRGL with a MOH server in it that is unicast?  This might serve you well in other cases also. It has been a little while since I was actively working on UCS, but I do recall running into applications that did not support MMOH.

Best of Luck!

New Member

Re: Moh Multicast issue

Ryan / Matthew, thanks much for replying to my post, copyign moh-file to flash and realying stream from router has crossed my mind, it will be easier, i have opened TAC case, technicans are working from last week, we are yet to get reslution, its a great learning process for me,[ im aspring for CCIE voice, mutlicast moh, over mpls is punch on my face, material im using for study  has proven solution over frame....]  i haven't really worked with multicast much, im hoping TAC folks will find resolution, i will keep you all update,   after adding the static mroute i was able to see 239.1.1.40 stream, i will defintely verify your suggestion.

thanks again for help..

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