[c-nsp] Intermittent 100% backplane utilisation on Cisco 6500

[Patrick Wu]

Hi,



I'm currently having issues with one of the Cisco 6506 in the network, it is
running HSRP with another 6506 and also running OSPF/BGP. Recently, I this
6506 is having intermittent 100% backplane utilisation, which caused
everything to stop responding for a couple of seconds.



As a result, spanning tree recalculation and HSRP failover kicked in, and
caused interruptions in many parts of the network.



What I don't understand is what caused the 100% utilisation, googling
reveals that it could be caused by spanning tree loops and broadcast storms.
But I have already tuned down the storm-control on broadcast on all ports
into the 6506, and I don't think there are any loops in the network.



Unlike an DDoS attack where the 100% utilisation is continuous, it just
peaks at 100% for 1 or 2 seconds and comes back down... the logs don't seem
to show much



Any one have similar experience or is able to point me in the right
direction would be greatly appreciated! Thanks.



Here's the show version and show module:



show version

Cisco Internetwork Operating System Software

IOS (tm) c6sup1_rp Software (c6sup1_rp-PSV-M), Version 12.1(22)E1, EARLY
DEPLOYMENT RELEASE SOFTWARE (fc1)

Technical Support:
http://www.cisco.com/techsupport<http://www.cisco.com/techsupport%5B/url%5D>

Copyright (c) 1986-2004 by cisco Systems, Inc.

Compiled Fri 16-Apr-04 10:13 by pwade

Image text-base: 0x60020F90, data-base: 0x616EA000



ROM: System Bootstrap, Version 12.0(3)XE, RELEASE SOFTWARE

BOOTLDR: MSFC Software (C6MSFC-BOOT-M), Version 12.1(3a)E4, EARLY DEPLOYMENT
RELEASE SOFTWARE (fc1)



xxxxxxxx uptime is 23 weeks, 5 days, 27 minutes

Time since xxxxxxxx switched to active is 23 weeks, 5 days, 29 minutes

System returned to ROM by power-on (SP by reload)

System restarted at 09:34:31 AEST Sat May 31 2008

System image file is "slot0:c6sup11-psv-mz.121-22.E1"



cisco WS-C6506 (R5000) processor (revision 3.0) with 114688K/16384K bytes of
memory.

Processor board ID TBA05290886

R5000 CPU at 200Mhz, Implementation 35, Rev 2.1

Last reset from power-on

X.25 software, Version 3.0.0.

Bridging software.

146 Virtual Ethernet/IEEE 802.3  interface(s)

48 FastEthernet/IEEE 802.3 interface(s)

10 Gigabit Ethernet/IEEE 802.3 interface(s)

381K bytes of non-volatile configuration memory.

4096K bytes of packet SRAM memory.



16384K bytes of Flash internal SIMM (Sector size 256K).

Configuration register is 0x2102





show module

Mod Ports Card Type                              Model              Serial
No.

--- ----- -------------------------------------- ------------------
-----------

  1    2  Cat 6k sup 1 Enhanced QoS (Active)     WS-X6K-SUP1A-2GE
SAD03414219

  3   48  48 port 10/100 mb RJ-45 ethernet       WS-X6248-RJ-45
SAD03430896

  5    8  8 port 1000mb GBIC Enhanced QoS        WS-X6408A-GBIC
SAD05040L5K



Mod MAC addresses                       Hw    Fw           Sw
Status

--- ---------------------------------- ------ ------------ ------------
-------

  1  00d0.bcee.59a8 to 00d0.bcee.59a9   3.2   5.3(1)       12.1(22)E1   Ok

  3  0030.9613.f314 to 0030.9613.f343   1.1   4.2(0.24)VAI 8.3(0.111)TF Ok

  5  0002.fc25.3224 to 0002.fc25.322b   1.6   5.4(2)       8.3(0.111)TF Ok



Mod Sub-Module                  Model           Serial           Hw
Status

--- --------------------------- --------------- --------------- -------
-------

  1 Policy Feature Card         WS-F6K-PFC      SAD03424981      1.0    Ok

  1 MSFC Cat6k daughterboard    WS-F6K-MSFC     SAD03427635      1.4    Ok



Mod Online Diag Status

--- -------------------