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VIP Advisor

Multicast Music on Hold (MOH) Issue

I have an issue with multicast MOH, that seems to be related to the voicegateway. I am running a 2951 c2951-universalk9-mz.SPA.153-3.M6. in conjunction with CUCM 10.0.  I can see that when a phone is being put in hold, the correct multicast address is used (see debug below) but the MOH file is never played out.  


voicegateway connected to layer 3 switch, phone connected to same Layer 3switch, but different subnet.


Voicegateway configuration, MOH related

interface GigabitEthernet0/0
 ip address
 ip pim sparse-mode
 ip multicast boundary 2
 duplex auto
 speed auto

 max-conferences 8 gain -6
 transfer-system full-consult
 moh "CaribbeanBlue.wav"
 multicast moh port 16384 route

ccm-manager music-on-hold bind GigabitEthernet0/0

ip multicast-routing 

on SW1:

interface Vlan11    (voicegateway, MOH, connected to this L3 interface)
 ip address
 ip helper-address
 no ip redirects
 ip pim sparse-mode

interface Vlan40   (Phone, being put on hold, connected to this L3 interface)
 ip address
 ip helper-address
 no ip redirects
 ip pim sparse-mode

debug ip mrouting, when putting a phone on hold:

Oct 26 23:57:11: MRT(0): Update (*,, RPF  /
Oct 26 23:57:11: MRT(0): Set the C-flag for (*,
Oct 26 23:57:11: MRT(0): WAVL Insert interface: Vlan40 in (* , Successful
Oct 26 23:57:11: MRT(0): set min mtu for (, 18010->1500
Oct 26 23:57:11: MRT(0): Add Vlan40/ to the olist of (*,, Forward state - MAC not built

Oct 26 23:55:35: PIM(0): Building Triggered (*,G) Join / (S,G,RP-bit) Prune message for


Above shows a join request on interface vlan40, where the phone is L3 connected.


sw1#sh ip mroute
IP Multicast Routing Table
Flags: D - Dense, S - Sparse, B - Bidir Group, s - SSM Group, C - Connected,
       L - Local, P - Pruned, R - RP-bit set, F - Register flag,
       T - SPT-bit set, J - Join SPT, M - MSDP created entry,
       X - Proxy Join Timer Running, A - Candidate for MSDP Advertisement,
       U - URD, I - Received Source Specific Host Report, 
       Z - Multicast Tunnel, z - MDT-data group sender, 
       Y - Joined MDT-data group, y - Sending to MDT-data group
       V - RD & Vector, v - Vector
Outgoing interface flags: H - Hardware switched, A - Assert winner
 Timers: Uptime/Expires
 Interface state: Interface, Next-Hop or VCD, State/Mode

(*,, 00:02:34/00:02:23, RP, flags: SJC  <------------------------------------------ is what is configured on the VGW, and the                                                                                                                                                              phone is using the right multicast address
  Incoming interface: Null, RPF nbr
  Outgoing interface list:
    Vlan40, Forward/Sparse, 00:00:57/00:02:23

(*,, 19:37:40/00:02:17, RP, flags: SP
  Incoming interface: Null, RPF nbr
  Outgoing interface list: Null


No where can I see that the IP address (VGW) has actually joined the multicast group as the source.


I have removed the call-manager-fallback config in its entirety and performed a reboot, but cannnot get the VGW to become the source for and until then, MOH will not play out.   


one interesting thing i noticed is:

voipgw#sh ephone summ

Max 0, Registered 0, Unregistered 0, Deceased 0 High Water Mark 0, Sockets 0
ephone_send_packet process switched 0

Max Conferences 77 with 0 active (8 allowed)

Skinny Music On Hold Status - group 0
 Active MOH clients 0 (max 1300), Media Clients 0, B-ACD Clients 0
 No MOH file loaded         <-----------------------------------------------------------------??


as it definitely loaded into flash:


   5  -rw-    41992652  Apr 29 2014 10:35:42 +10:00  CaribbeanBlue.wav

Before I TAC this, any ideas?


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Everyone's tags (2)

You can try couple of things

You can try couple of things:

1) Remove the call-manager fallback and re-add it back

2) add the max-ephone and max-dn commands

3) You can also try to upload the file again (may not be required if it was working before, refer to below note in that case)

4) If it is a working router and has stopped suddenly, then it may be memory leak. I came across that, and a reboot fixed the issue. IOS upgrade stabilized that. I remember the output of sh ephone summ was similar to yours.


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Sorry didnt realise you have

Sorry didnt realise you have already tried pretty much all of that :)

VIP Advisor

Yeah cheers Terry, I will

Yeah cheers Terry,


I will upgrade the IOS and give it another shot, otherwise I will  go and TAC it


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Try adding the IP Address 10

Try adding the IP Address to the multicast command under call-manager fallback.

multicast moh port 16384 route


And just so we are clear, you are playing G711ulaw from MoH Source Number 2 in CUCM? Unless you have configured your MoH Server to play from Source 1?


See how you go.



VIP Advisor

Ben, I am playing, source 5,



I am playing, source 5, g711ulaw from cucm. my debugs show is invoked by the phone, this is why i concluded cucm is not the reason it is not working, but I could be wrong

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