Cisco 2821 high CPU with Multicast

Tshi M · ‎09-09-2008

I have two Cisco 2821 that I tried to use for MCAST but once MCAST traffic is enabled, the CPU goes to 98% and the HSRP process starts to flip flop between both routers. Could the 2821 routers be used for MCAST?

romccallum · ‎09-09-2008

on your interfaces do you have ip mroute-cache? if not try adding that - also make sure CEF is enabled.

Tshi M · ‎09-09-2008

yes, I do.

romccallum · ‎09-09-2008

what is the bandwidth of the stream?

Tshi M · ‎09-09-2008

the problem seems to be with over subscriptions. We are dropping a significant number of packets once we turn on MCAST.

romccallum · ‎09-09-2008

so all you are doing is configuring pim? No multicast flows? If you have a flow how much is the pps total? The reason i ask is i have destroyed a 7200-npe-g1 with a 1-10mb flow of multicast.

Tshi M · ‎09-09-2008

If I understand your question. Yes, I only have ip pim rp address and ip pim sparse-mode configured on the device.

Below is part of the sh int output after clearing the counters.

Last clearing of "show interface" counters 00:03:48

Input queue: 4/75/35053/0 (size/max/drops/flushes); Total output drops: 0

Queueing strategy: fifo

Output queue: 0/40 (size/max)

5 minute input rate 3767000 bits/sec, 3667 packets/sec

5 minute output rate 0 bits/sec, 0 packets/sec

1300612 packets input, 172618718 bytes, 0 no buffer

Received 1300319 broadcasts, 0 runts, 0 giants, 7825 throttles

Tshi M · ‎10-13-2008

I resolved the problem. The routers' CPU were clearly not able to handle multicast so I redesign the network to use the 3750G switches.