SRST Music On Hold

• Multicast MOH from branch router flash
• Router does not have to be in SRST mode for this feature to operate, just need to configure SRST
• SRST router can stream only one file and use one multicast address and port
• Multicast branch MOH supports only G.711
• G.711 must also be used for the stream generated by CUCM MOH server
• Saving WAN bandwidth by sourcing MOH from remote router
• Only works with multicast MOH
• CUCM and IP phone is not aware that SRST gateway is involved
  • Use max-hop 1 on CUCM to stop multicast stream from reaching remote router. It will be dropped at WAN router bcos of TTL 1
  • CUCM and branch router use same multicast IP and port

• When remote phone is put on hold, CUCM signals phone to listen to DA 239.1.1.1, DP 16384, and played the received stream.

• CCM Increments multicast or port for different codecs as follow

• Need to enable multicast everywhere in the network
• Enable network for multicast routing globally
• Enable multicast routing on LAN and WAN interfaces

ip multicast routing
!
interface FastEthernet0/0
  ip pim dense-mode
!
interface Serial0/1
  ip pim dense-mode

• Must be configure with mutlicast MOH
• Configure MOH audio sources for multicast

• Configure MOH audio server for multicast

• Assuming we are not using the ACL or disable multicast routing on the router, block multicast by
  • Configure multicast MOH but with TTL = 1 to prevent multicast MOH streams from being sent over the IPWAN
  • Setting to zero means multicast will remain in the same subnet and will not even propagate across a single router.

• Put CUCM MOH server into a dedicated region
• Allow G.711 between the region of the MOH server and the region of the remote branch phones
• Limit all other intersite calls to G.729

• Make sure multicast is enabled? Not sure if needed
• Configure SRST as usual
  • Must include source-address, max-ephones, max-dn (min for SRST to work)
• Make sure moh file exist in flash and codec must match CUCM
• Configure moh multicast IP and port to match CUCM
  • <ip1> <ip2> - interface in which multicast will be flooded out
  • If you ever have to change the multicast moh commands, remove using “no” first and reapply. Do not just retype the commands as it won't work

ip multicast-routing
!
! *** Without this, multicast moh will not stream to PSTN
ccm-manager music-on-hold
!
call-manager-fallback
  ip source-address <srst-ip>
  max-ephones 1
  max-dn 1
  moh moh-file.au
  multicast moh 239.1.1.1 port 16384 route <ip1> <ip2>
  create cnf

• If MGCP
  • Disable mgcp receive-rtcp timer
  • RTCP will monitor if any RTP traffic is being streamed. Because the RTP is source from the local router instead of CUCM, RTCP will terminate the PRI connection after 30s.

no mgcp timer receive-rtcp 

• Three options are available
  • Configure CUCM Multicast Max Hops (TTL) to 1
  • Disable multicast on interface
  • Apply ACL to drop multicast on interface

• To retrieve MOH file from CCME

! *** On CCME Router
tftp-server flash:music-on-hold.au

! *** On SRST Router
SRST# copy tftp flash

• To retrieve MOH file from Call Manager
• SSH to Call Manager

admin: file list activelog /mohprep

CiscoMOHSourceReport.xml                SampleAudioSource.alaw.wav
SampleAudioSource.g729.wav              SampleAudioSource.ulaw.wav
SampleAudioSource.wb.wav                SampleAudioSource.xml
dir count = 0, file count = 6

admin: file get activelog mohprep/SampleAudioSource.g729.wav

Please wait while the system is gathering files info ...done.
Sub-directories were not traversed.
Number of files affected: 1
Total size in Bytes: 332600
Total size in Kbytes: 324.8047
Would you like to proceed [y/n]? y
SFTP server IP: 192.168.100.101
SFTP server port [22]: 
User ID: cisco
Password: *****

Download directory: /moh

.
Transfer completed.

admin:

Router# debug ephone moh

• Show active moh

Router# show ccm-manager music-on-hold