Why is multicast MoH not heard across WAN links or to external users?
• Verify that the multicast stream makes it to the network of the endpoint that needs to hear it. It could be that the infrastructure devices, such as routers and switches, no longer forward this multicast stream. A sniffer is the easiest way to verify that the multicast stream has made it to the subnet of the Cisco IP phone. Also, if it is a gateway, ensure that it is multicast-capable for voice. • Increase the hop count on the MoH source file in the MoH Server configuration page. Note: In most environments it is recommended to increment multicast based on the IP address instead of the port. When the IP address is used, a different multicast IP address is used for each codec that has been configured. When the port is used, all codecs are sent to all phones on different ports. This can result in unnecessary network saturation.
• Verify that the multicast stream makes it to the network of the endpoint that needs to hear it. It could be that the infrastructure devices, such as routers and switches, no longer forward this multicast stream. A sniffer is the easiest way to verify that the multicast stream has made it to the subnet of the Cisco IP phone. Also, if it is a gateway, ensure that it is multicast-capable for voice. • Increase the hop count on the MoH source file in the MoH Server configuration page. • Note: In most environments it is recommended to increment multicast based on the IP address instead of the port. When the IP address is used, a different multicast IP address is used for each codec that has been configured. When the port is used, all codecs are sent to all phones on different ports. This can result in unnecessary network saturation.
