RE: [nsp] how counters get updated

From: Casassa, Nathan (ncasassa@gnilink.net)
Date: Sat May 12 2001 - 14:12:20 EDT


>Actually the problem is that I cannot get accurate line rate at short
>intervals (not even 30 seconds) and this is very nasty.

The reason behind your counters not appearing accurate on 30 second
intervals is normal. An exponentially decaying algorithm is used to
calculate the input/output bps rate.

Nathan

-----Original Message-----
From: George Boulescu [mailto:george@roedu.net]
Sent: Saturday, May 12, 2001 3:37 AM
To: cisco-nsp@puck.nether.net
Subject: [nsp] how counters get updated

Hi.

I'am using a bunch of 75xx running IOS 12.0S and 12.1E series.
Every router has at least a VIP2-40 with FastSerial PA's or E3 PA's on it.

I have this strange problem : sometimes when issuing a 'show interface' on
an E3 interface for example, I get output that shows something like
38Mbits/sec input rate, anyway something bigger then 34Mbits/sec.

The encapsulation is HDLC. I have 'load-interval 30' on the interface.
I've noticed that the type of queueing doen't influence this problem.
Also, the input bytes counter is wrong too, if pooled at less than a
minute.

Acctually the problem is that I cannot get accurate line rate at short
intervals (not even 30 seconds) and this is very nasty.

If I pool the counters at 5 minutes, the output is somehow ok, because the
error is very small.

I belive that this is a VIP related problem. Probably the counters don't
get updated at a regular period of time.

Anyway, any ideas ?

-- 

George Boulescu Senior Network Engineer RoEduNet Bucharest NOC



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