High Processor Rates on Routers.

Petri Helenius pete at he.iki.fi
Wed Nov 6 20:31:52 UTC 2002


If you happen NOT to run CEF on your boxes which see large number of 
prefixes,
you'll see CPU jump every 60 seconds when the box does cache cleaning. 
This is not
an option 12xxx's.

Pete

internetguy205 at hotmail.com wrote:

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>Ladies & Gentleman.
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>Was wondering if it is common for processor rates on higher end Crisco boxes to race from 1 or 2 % show on the 5 second processor rate interval, to anywhere from 70 to 90 %, instanteously, then drop back down to 1 or 2 % after 10 seconds.
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>The above mentioned scenario would happen every 30 seconds.
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>The higher end boxes are very lightly loaded, with total traffic throughput of maybe 100 Meg, in some cases.
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>Think that if these boxes are loaded more, to the point where the aggragated throughtput approaches a Gig, this will cause the processors to run at high levels constantly, driving the CPU rates indicators on the box for 1 & 5 minute intervals up to the values mentioned above. ( 70 to 90 % ).
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>Higher end devices would be something like 7200, 7500, 12xxx series routers.
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>This scenerio would be in a large ( very large network, atleast a tier 2 OR tier 1 provider )...  possible rebutals to the fact that processors could race like mentioned above on lightly loaded devices of a higher end nature would be that BGP scanner is causing the problem, Telnet to the devices, show config when on the devices...
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>So what happens to the processor rates when the devices are more heavily loaded ( 1 G aggragated throughput opposed to 100 Meg throughtput )?  Will the devices work worrectly AND would a large internet be stable ?
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>Is it also common for BGP Routing tables to be changing version every 1/2 second ?  Same high end routers, lightly loaded, large Autonomous System.
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>Thank-you for your time on this query.
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