Processor load on 7609 SUP720 PFC3BXL peering platform

Unanswered Question
Sep 26th, 2007
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Hi all!

I was wondering if anyone could share with me their opinion on what is still considered a safe processor load for a

7600 SUP720 PFC3BXL router as main BGP peering router.

We are currently running about 30% average load. Lots of peaks towards 90%-100%.

BGP Router process takes up most as far as I can tell.

Any thoughts would be appreciated!!!


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Overall Rating: 3.5 (2 ratings)
avmabe Wed, 09/26/2007 - 11:19
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I have two 7600 SUP720 PFC3BXL routers that take the full BGP table and one runs at 6% and the other at 9% consistently with little to no spikes in CPU.

reinier.hamstra... Wed, 09/26/2007 - 13:14
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Thanks, that's very helpful!

Four questions if you wouldn't mind...

1.Do you have BGP route-dampening configured on these two?

2.I'm not entirely worried about the spikes. Firstly I see them only in the show proc cpu hist output, not in my 5min interval snmp graphs. Secondly, I would explain them as the inevitable and frequent route recalculations that happen whilst carying the full table. Would you agree?

3.I currently terminate two separate sessions per machine that advertise full routes. Would this cause a significantly or even proportionally higher load compared to a single session setup?

4.Is the show proc cpu hist/sh proc cpu readout a readout of the MFC processor?

Thanks again for your response, it is much appreciated!!!

Joseph W. Doherty Wed, 09/26/2007 - 19:45
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If you see the spikes in show proc cpu history every 60 seconds, probably the BGP scanner.

Believe work load does increase with number of peers.

If the 90 to 100% cpu spikes are short duration and average is about 30%, I would think you're still okay.

balajitvk Wed, 09/26/2007 - 20:22
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Common symptoms of high CPU utilization

Slow performance

Services on the router fail to respond, for instance:

Slow response in Telnet or unable to Telnet to the router

Slow response on the console

Slow or no response to ping

Router does not send routing updates to other routers

But 90 to 100% cpu spikes are short duration and average is about 30%,it seems to be fine and more over this processor is highly capable of handling these spikes.

Rate if it does,



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