Cisco Systems 78-11741-02 manual Controlling the Transmission Rate to a Multicast Group, IPC-430

Configuring IP Multicast Routing

Controlling the Transmission Rate to a Multicast Group

A multicast static route allows you to use the configuration in Figure 68 by configuring a static multicast source. The Cisco IOS software uses the configuration information instead of the unicast routing table. Therefore, multicast packets can use the tunnel without having unicast packets use the tunnel. Static mroutes are local to the router they are configured on and not advertised or redistributed in any way to any other router.

To configure a multicast static route, use the following command in global configuration mode:

Command	Purpose
Router(config)# ip mroute source-address mask	Configures an IP multicast static route.
[protocol as-number]{rpf-address type number}
[distance]

Controlling the Transmission Rate to a Multicast Group

By default, there is no limit as to how fast a sender can send packets to a multicast group. To control the rate that the sender from the source list can send to a multicast group in the group list, use the following command in interface configuration mode:

Command		Purpose
Router(config-if)#ip multicast rate-limit {in		Controls transmission rate to a multicast group.
out} [video whiteboard]	[group-list access-list]
[source-list access-list]	kbps

Configuring RTP Header Compression

Real-Time Transport Protocol (RTP) is a protocol used for carrying packetized audio and video traffic over an IP network. RTP, described in RFC 1889, is not intended for data traffic, which uses TCP or UDP. RTP provides end-to-end network transport functions intended for applications with real-time requirements (such as audio, video, or simulation data over multicast or unicast network services).

The minimal 12 bytes of the RTP header, combined with 20 bytes of IP header and 8 bytes of UDP header, create a 40-byte IP/UDP/RTP header, as shown in Figure 70. The RTP packet has a payload of approximately 20 to 150 bytes for audio applications that use compressed payloads. It is very inefficient to send the IP/UDP/RTP header without compressing it.

Cisco IOS IP Configuration Guide

IPC-430