Information About Using Cisco Unified Srst Gateways As A Multicast Moh Resource; Cisco Unified Srst Gateways And Cisco Unified Communications Manager - Cisco CP-7911G-CH1 System Administrator Manual

Appendix B: Integrating Cisco Unified Communications Manager and Cisco Unified SRST to Use Cisco Unified SRST
Information About Using Cisco Unified SRST Gateways as a
Multicast MOH Resource
To configure Cisco Unified SRST gateways as an MOH resource, you should understand the following
concepts:
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Cisco Unified SRST Gateways and Cisco Unified Communications Manager

Cisco Unified SRST gateways can be configured to multicast Real-Time Transport Protocol (RTP)
packets from flash memory during fallback and normal Cisco Unified CM operation. To make this
happen, Cisco Unified Communications Manager must be configured for multicast MOH so that the
audio packets do not cross the WAN. Instead, audio packets are broadcast from the flash memory of
Cisco Unified SRST gateways to the same multicast MOH IP address and port number configured for
Cisco Unified Communications Manager multicast MOH. IP phones at remote sites are able to pick up
RTP packets that are multicast from the local branch gateways instead of from the central Cisco Unified
CM.
Multicast MOH for PSTN callers is supported when the Cisco Unified SRST router is used as the
Cisco IOS voice gateway for Cisco Unified CM. In this state the Cisco Unified SRST function of the
router remains in standby mode (no phones registered) with call control of the phones and gateway
provided by Cisco Unified Communications Manager. This feature does not apply when the Cisco
Unified SRST router is in fallback mode (phones are registered to Cisco Unified SRST). Instead, MOH
is provided to PSTN callers via a direct internal path rather than through the multicast loopback
interface.
Figure 1
Communications Manager to receive multicast MOH through port number 16384 and IP address
239.1.1.1. Cisco Unified CM is configured so that multicast MOH cannot reach the WAN, and local
Cisco Unified SRST gateways are configured to send audio packets from their flash files to port number
16384 and IP address 239.1.1.1. Cisco Unified CM and the IP phones are spoofed and behave as if Cisco
Unified CM were originating the multicast MOH.
Phone users at the central site would use multicast MOH from the central site.
Note
OL-13143-04
Cisco Unified SRST Gateways and Cisco Unified Communications Manager, page 283
Codecs, Port Numbers, and IP Addresses, page 284
Multicast MOH Transmission, page 286
MOH from a Live Feed, page 286
MOH from Flash Files, page 287
shows a sample configuration in which all phones are configured by Cisco Unified

Information About Using Cisco Unified SRST Gateways as a Multicast MOH Resource

Cisco Unified SCCP and SIP SRST System Administrator Guide
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