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571
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7600 High CPU interupt

cisco_lad2004
Level 5
Level 5

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 172.16.10.2, dst 233.139.53.112

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 !

TIA

Sam

4 Replies 4

Giuseppe Larosa
Hall of Fame
Hall of Fame

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.

Sam

Hello Sam,

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

it looks like so innocent so lightweigth..

Best Regards

Giuseppe

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.

Sam

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