8600 Switch Fabric Questions 1

[SFSRJSTW]

We are running an 8610 with release 3.3 at my work, which is a college of about 2200 students. We have, from top to bottom, 2 8 port gig cards, 2 100 mb fiber cards, 2 switch fabrics. I have a couple questions.

First, on the master switch fabric in slot 5, the master light is blinking. I don't recall seeing it do this before. Has anyone ever seen this, or know what it means?

Second, for the past week or so, the switch utiliztion has been hovering right around 100%, and we have made no major network changes aside from a switch or two, but I have ruled those out. I know this question is vague, but any direction to start looking at would be helpful.

Third and finally, I would assume that the 8600 has some sort of self preservation features that could cause it to automatically shut off a port. That is what I think happened last night, but am not sure what would cause it to happen. Does anyone know what triggers it to occur, or have a paper about it from Nortel's site? I looked, but haven't seen any.

Thanks for the help...

 

[leedsit]

Hi,

the flashing master light means that that unit is running in Master, if you have another processor card in slot 6 this light should be out.

The high utilisation could be caused by a high amount of packets caused by numerous sources, loops in your network, or broadcast storms.

The 8600`s do protect their ports if the feature is active ( beleive it it by default ) and will shut down a port if a threshold is reached.

If you do have high utilisation and ports are shutting down, I would suspect you do have a broadcast store, nerwork loop or possible a virus causing this.

Check the stats on the port that shut down ...

LEEroy
MCNE6,CCNA2,CWNA, Project+

 

[anthonyanderberg]

The 3.3 code branch is pretty old, you might want to consider upgrading to a 3.5 or 3.7 branch, be sure to check how much RAM you've got since some of the newer versions require more than shipped with older CPUs (especially the 8690.)

Is it switch utilization or CPU utilization that has reached 100%? Is the switch utilization maxed out on both switch fabrics?

I've seen ports disable themselves when the CP-Limit value gets triggered, as leedsit noted a loop could cause this.

 

[mucka]

Above are all correct & you may want to try this :
telnet to passport
and type "show log file tail"
this will print most recent entries on your log file.
you will probably see the message " multicast packets exeeded NNNNN shutting port x/x down"

you can disable and then re-enable to bring the port back up
remember to fix the loop first.
Good luck
Mucka

 

[Jynxx]

I have seen a few things cause high CPU load on the 8600's.

1 - a loop in the network
2 - a mis-configured MLT group
3 - something hammering the switch with SNMP

There is something that you can do, though with extremem caution.

Do a CPU trace.

From the CLI type:

trace
off
clear
trace level 9 3
***wait 5 seconds - this should be more than sufficient if it is pegged***
off
info

Then when done looking at it:
clear

Trace level 9 turns on IP tracing as well as OSPF and RIP
Trace level 3 turns on verbose to give you as much info as possible.

Either post your trace results here or let us know what the most common typ= is.