troubleshooting Question

music on hold not working in multicast mode

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nabeel92 asked on
RoutersVoice Over IPIP Telephony
3 Comments2 Solutions2644 ViewsLast Modified:
Hi there,

I'm getting tone-on-hold instead of music-on-hold with multicast enabled between 2 Cisco IP phones on same LAN. CUCM version is 7.1.3. CUCM MOH Server is configured with multicast I.P and has max-hops set to 30. MRG uses this MOH server and has 'Enable multicast MOH' ticked. This MRG is in use by MRGL and eventually by the device pool that the phone is assigned to. Music-on-hold audio source is 1 and it is a .wav file. When uploading it, CUCM converts it into its right ulaw and alaw format. I restarted IPVMA service after uploading this too.

On LAN is a a Cisco Router (2821) where multicast routing and PIM Sparse-mode is enabled. Commands I've used are below

// To enable Multicast routing
Router(config)# ip multicast-routing

// Enabling PIM on the LAN interface
Router(config-if)#ip pim sparse-mode

//Specifying RP Address on router
ip pim rp-address

Switch by default has IGMP snooping enabled so don't need to configure anything there, do i ?

In CUCM Fall-back mode, I've got the following
moh port 16384 (and this is the same multicast I.P as configured in MOH server).
Note the gateway itself does not have any MGCP, CCM running as all I'm doing is trying to source MOH using multicast. I restared IPVMS and CUCM Service but still no good and I contiue get tone on hold instead.

Wireshark shows what looks like a broadcast storm with lot of packets from CUCM MOH server to the multicast I.P when tone-on-hold plays. 'show ip mroute' also shows multicast path established but all i get is TOH. SDI traces show no media resources available which shouldn't be the case as phone is using the right MRGL --> MRG --> MOH Server --> MOH source.

Any help would be greately appreciated. If you need snapshots of config or router config, please let me know.

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