7600 High CPU interupt

Unanswered Question
Jun 19th, 2009

Dear all,

I am seeing an intermittent 90% CPU load on a 7600 SUP720-3BXL / 12.2(18)SXF6.

The above is traffic punted to CPU, which I spanned. it is mainly multicast traffic (with good ttl) but with a zero checksum.

I also ran a netdr debug and got below output as a sample:

------- dump of incoming inband packet -------

interface Te2/4, routine draco2_process_rx_packet_inline

dbus info: src_vlan 0x3FF(1023), src_indx 0x43(67), len 0x552(1362)

bpdu 0, index_dir 0, flood 1, dont_lrn 0, dest_indx 0x43FF(17407)

BC020400 03FF0400 00430005 52000000 00110030 02000040 00000008 43FF0000

mistral hdr: req_token 0x0(0), src_index 0x43(67), rx_offset 0x76(118)

requeue 0, obl_pkt 0, vlan 0x3FF(1023)

destmac 01.00.5E.0B.35.70, srcmac 00.15.2B.1A.D4.64, protocol 0800

protocol ip: version 0x04, hlen 0x05, tos 0x80, totlen 1344, identifier 73

df 1, mf 0, fo 0, ttl 26, src, dst

udp src 5501, dst 5501 len 1324 checksum 0x0

I am running Copp and can see that ACL match any any increments in matches rapidly when CPU fires up.

Any thoughts would be appreciated !



I have this problem too.
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cisco_lad2004 Fri, 06/19/2009 - 03:16

Thanks Giuseppe

I found out what teh problem is, someone added "igmp join group" under a loopback.

so instead of traffic being switched out it was hotting the CPU

Oddly enough, the ERSPAN I set up did not show these packets.


Giuseppe Larosa Fri, 06/19/2009 - 03:56

Hello Sam,

>> someone added "igmp join group" under a loopback.

it looks like so innocent so lightweigth..

Best Regards


cisco_lad2004 Fri, 06/19/2009 - 05:29

indeed ! but with severe consequences :-)

It actually acted as a time bob as the IPTV provider were only streaming this particular group during testing...so the config layed there waiting to be triggered.



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