====== 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.
{{cucm-srst-moh1.png|}}

  * CCM Increments multicast or port for different codecs as follow

^  ^  ^ **Inc Multicast on IP Address** ^^ **Inc Multicast on Port Number** ^^
^ **Audio Stream** ^ **Codec** ^ **Multicast IP** ^ **Port** ^ **Multicast IP** ^ **Port** ^ 
|  1  | G.711 ulaw |  239.1.1.1  |  16384  |  239.1.1.1  |  16384  |
|  1  | G.711 alaw |  239.1.1.2  |  16384  |  239.1.1.1  |  16386  |
|  1  |  G.729  |  239.1.1.3  |  16384  |  239.1.1.1  |  16388  |
|  1  |  Wideband  |  239.1.1.4  |  16384  |  239.1.1.1  |  16390  |
|  2  | G.711 ulaw  |  239.1.1.5  |  16384  |  239.1.1.1  |  16392  |
|  2  | G.711 alaw  |  239.1.1.6  |  16384  |  239.1.1.1  |  16394  |
|  2  |  G.729  |  239.1.1.7  |  16384  |  239.1.1.1  |  16396  |
|  2  |  Wideband  |  239.1.1.8  |  16384  |  239.1.1.1  |  16398  |

===== Configuration =====

==== IOS Mutlicast Routing ====
  * Need to enable multicast everywhere in the network
  * Enable network for multicast routing globally
  * Enable multicast routing on LAN and WAN interfaces
<code>
ip multicast routing
!
interface FastEthernet0/0
  ip pim dense-mode
!
interface Serial0/1
  ip pim dense-mode
</code>

==== CUCM Audio Source ====
  * Must be configure with mutlicast MOH
  * Configure MOH audio sources for multicast
{{cucm-srst-moh3.png|}}

==== CUCM Audio Server ====
  * Configure MOH audio server for multicast
{{cucm-srst-moh4.png|}}

  * 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.
{{cucm-srst-moh5.png|}}

  * 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

==== IOS SRST ====
  * 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
<code>
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
</code>

  * 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.
<code>
no mgcp timer receive-rtcp 
</code>

==== BLOCK CUCM MOH ====
  * Three options are available
    * Configure CUCM Multicast Max Hops (TTL) to 1
    * Disable multicast on interface
    * Apply ACL to drop multicast on interface
{{cucm-srst-moh2.png|}}

===== Moh File =====
  * To retrieve MOH file from CCME
<code>
! *** On CCME Router
tftp-server flash:music-on-hold.au

! *** On SRST Router
SRST# copy tftp flash
</code>

  * To retrieve MOH file from Call Manager
  * SSH to Call Manager
<code>
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:
</code>

===== Debug =====
<code>
Router# debug ephone moh
</code>

  * Show active moh
<code>
Router# show ccm-manager music-on-hold
</code>