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Multicast MOH Question

Hi Guys,

I am recieving silence when placing users on hold. MOH is multicast using CUCM 7.1 and file stored locally on router. Config is as follows:

ccm-manager music-on-hold
moh moh.ulaw.wav
multicast moh port 16544

#sh ephone summ        

Max 30, Registered 0, Unregistered 0, Deceased 0, Sockets 0
ephone_send_packet process switched 0

Max Conferences 8 with 0 active (8 allowed)
Skinny Music On Hold Status
Active MOH clients 0 (max 196), Media Clients 0, B-ACD Clients 0
File NZOct2010.ulaw.wav type WAVE Media_Payload_G711Ulaw64k  160 bytes
Moh multicast on port 16544 via

#show ccm-manager music-on-hold
Current active multicast sessions : 1
Multicast       RTP port   Packets       Call   Codec    Incoming
Address         number     in/out        id              Interface
===================================================================         16544   0/0          42   G.711ulaw

The packets do not increment while the call is on hold.

Can anyone assist? Thanks


Re: Multicast MOH Question


you have NOT activated SRST function yet, add the following commands to the router to start the SRST process required to support MOH on the router:


ephone-dn 1

ephone 1

ip source-address X.X.X.X <--an ip address of the router to bind the SRST app to.

this should fix you problem.




Re: Multicast MOH Question


Yes, call-manager-fallback has been enabled:

secondary-dialtone 0
max-conferences 8 gain -6
transfer-system full-consult
timeouts interdigit 5
ip source-address port 2000
max-ephones 30
max-dn 48
transfer-pattern 3...
transfer-pattern 91..
keepalive 10
default-destination 9199
no huntstop
call-forward pattern .T
moh moh.ulaw.wav
multicast moh port 16544
time-format 24
date-format dd-mm-yy


Re: Multicast MOH Question


I see from the show ephone output that the current active MoH file is NZOct2010.ulaw.wav whereas the file specified under call-manager-fallback is moh moh.ulaw.wav. Please change the filename to match exactly the one which you are streaming from the router flash.

moh NZOct2010.ulaw.wav ----->use this instead

Have you enabled multicast routing in your router? You should have the following two commands

ip multicast-routing------>global config mode

ip pim sparse-dense-mode------->under all the exit interfaces through which the MoH has to be streamed.

Also in multicast moh port 16544 add the route command also.

multicast moh port 16544 route

What is the MoH server configuration at the CUCM? Is it increment by IP address or port number? Which multicast MoH source id are you trying to play from the CUCM since the IP and port at the router and the CUCM should match for the MoH to work properly.

For PSTN users to listen to MoH you will have to stream it out the loopback interface.

Take a look at the following doc which may help you



Do a debug ephone moh and check if router is streaming MOH:

R2#deb ephone moh

Jun 28 23:07:43.299: MoH route If Loopback0 46 via
Jun 28 23:07:43.299: MoH route If Vlan240 ETHERNET via ARP
Jun 28 23:07:48.747: MoH route If Loopback0 46 via
Jun 28 23:07:48.747: MoH route If Vlan240 ETHERNET via ARP
Jun 28 23:07:50.551: ifs_read end of file at 490557 read 5964 = 496521
Jun 28 23:07:50.555: moh tail fill from 24 at 0x4A73816C length 2036

Also you can check the multicast Interface status by using following command:

R2#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

(*,, 00:01:01/00:01:59, RP, flags: DCL
Incoming interface: Null, RPF nbr
Outgoing interface list:
Vlan240, Forward/Sparse-Dense, 00:01:01/00:00:00

Hope that helps



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Cisco Employee

Re: Multicast MOH Question

Why multicast moh port 16544? port 16544?

What codec is this?. Which audio source?


Cisco Employee

Re: Multicast MOH Question

Does the file-name "NZOct2010.ulaw.wav"  really matter?

How does the phone know whats the filename?

All it knows is what is the Multicast address it needs to listen to.


PS: Rate useful posts


Re: Multicast MOH Question

Shouldn't the router need to know what MoH file to stream? If the router has multiple audio files in its flash and we want to enable only 1 file for multicast MoH, shouldn't we specify the exact filename in that command?

Not too sure on that though. Never tried using a wrong filename. Can check that up




Re: Multicast MOH Question

Sorry, the filename is a typo on my behalf - they are the same.

However, this router has no loopback interface. I was under the impression if there was no loopback, it would use the configuerd ip source under the callmanager-fallback?

When I debug ephone moh I only get the gig interface with MoH IF response.

And when I do sh ip mroute, there is no entry for


Re: Multicast MOH Question

Is multicasting enabled in you router? post a show run of your router. also attach a scrrenshot of the moh server config in the cucm. which audio source are you trying to use? incrementing by port or ip address?



P.S:rate helpful posts


Did you fix this issue, if

Did you fix this issue, if yes could you please tell me how?



Cisco Employee

Re: Multicast MOH Question

I read your post too fast :)... Yeah..i was under the impression that

CUCM File name and Router File name has to be the same :). That is not

the case here.

anyways... Check the port numbers?. What codec?. What Source Number on

the CUCM?.

I would say

multicast moh port X route

Whats the codec between the Phone and the MOH server?.

Usually MOH server region to any other region usually is configured as

G711. There's Then if its the first source on the CUCM then

just use

multicast moh port 16384 route

if is my Voice VLAN interface on the Router.

Just follow this table...Table 1


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