Cisco Systems 78-11741-02 manual Verifying the Load Splitting, IPC-445, Tunnel0, Serial1

Configuring IP Multicast Routing

Monitoring and Maintaining IP Multicast Routing Configuration Task List

Verifying the Load Splitting

Load splitting works for both fast switching and process switching, but splitting the traffic among the physical interfaces is performed differently for each case. Fast switching occurs if both the incoming and outgoing interfaces are configured with the ip mroute-cacheinterface configuration command. IP multicast fast switching is enabled by default. Note the following properties of load splitting:

•With process switching, load splitting occurs on a per-packet basis by round robin on the equal-cost links. To verify that load splitting is working, look at the interface statistics using the show interfaces accounting EXEC command, and verify that the packet count is about equal for the underlying interfaces that provide the equal-cost paths.

•With fast switching, load splitting occurs on a per-flow basis. A flow is a set of traffic with the same source and destination. Once the cache is populated for the (S, G) pair, that flow is pinned to the physical interface assigned on the cache (the outgoing interface used by the first packet of the flow). If the cached interface goes down, the cache entry for the (S, G) pair is torn down and the flow is automatically switched to a different physical interface.

In the case of fast switching, you can verify that load splitting is occurring by viewing the multicast fast-switched cache by using the show ip mcache EXEC command. The flows should be split among the underlying interfaces, as shown in the following example:

Router# show ip mcache

IP Multicast Fast-Switching Cache
(100.1.1.6/32, 224.1.1.1), Ethernet0,		Last used: 00:00:00
Tunnel0	MAC Header: 0F000800	(Serial1)
(100.1.1.6/32, 224.1.1.2), Ethernet0,		Last used: 00:00:00
Tunnel0	MAC Header: 0F000800	(Serial1)
(100.1.1.5/32, 224.1.1.3), Ethernet0,		Last used: 00:00:00
Tunnel0	MAC Header: 0F000800	(Serial0)
(100.1.1.5/32, 224.1.1.4), Ethernet0,		Last used: 00:00:00
Tunnel0	MAC Header: 0F000800	(Serial0)

For an example of load splitting IP multicast traffic across equal-cost paths, see the section “Load Splitting IP Multicast Traffic Across Equal-Cost Paths Example” later in this chapter.

Monitoring and Maintaining IP Multicast Routing Configuration Task List

To monitor and maintain IP multicast routing, perform the optional tasks described in the following sections.

•Clearing Caches, Tables, and Databases (Optional)

•Displaying System and Network Statistics (Optional)

•Using IP Multicast Heartbeat (Optional)

Note For information about Multicast Routing Monitor (MRM) and commands that monitor IP multicast information, see the chapter “Using IP Multicast Tools.”

Cisco IOS IP Configuration Guide

IPC-445