Thanks for the information. Do the routers maintain a timestamp of when they last updated their MIB. The time difference between the updates will give me a good indication of the average traffic being observed by the router.
Thanks, -Proveen -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of mack Sent: Tuesday, March 25, 2008 5:42 PM To: cisco-nsp@puck.nether.net Subject: Re: [c-nsp] SNMP MIB update interval on CISCO? On the 6500/7600 platform you can set: service counters max age 5 Obviously this is platform specific. On high CPU load SNMP counters may be updated at a longer interval. At extreme levels SNMP may stop updating completely until the load goes down. Most platforms have a best-effort interval of 10 seconds. As for the accuracy: % Accuracy~=update interval*100/sample interval So with a 60 second sample interval and a ten second update interval you can have a variance of ~17%. With a 5 minute sample interval the variance is ~3%. The accuracy is an approximation as the update interval is best-effort. To sum it up you can sample slower and get more accurate readings or faster and get less accurate readings. -- LR Mack McBride Network Administrator Alpha Red, Inc. > Message: 9 > Date: Tue, 25 Mar 2008 20:02:23 -0000 > From: "Dean Smith" <[EMAIL PROTECTED]> > Subject: Re: [c-nsp] SNMP MIB update interval on CISCO? > To: <cisco-nsp@puck.nether.net> > Message-ID: <[EMAIL PROTECTED]> > Content-Type: text/plain; charset="us-ascii" > > Basically - No. > > Counters like those are really only valid for polling every minute at a > minimum and even then you can occasionally see strange affects due to > the > internal updates happening out of sync. > > If you essentially need granularity of a second or so sampling you > probably > need an external tool. > > Dean > > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of Gurung, Provin > Sent: 25 March 2008 17:02 > To: cisco-nsp@puck.nether.net > Subject: [c-nsp] SNMP MIB update interval on CISCO? > > I have a question about how to get the cisco routers updates rate of > one > of the snmp mib entries. > > > > Background: > > > > I am using a cisco 3640 series router running ios 12.4. > > I am cyclically doing snmpwalks to get the number of bytes transmitted > on an output interface for a particular Diff serv code point. The > actually snmpwalk call is for cbQosMatchPrePolicyByte > (enterprises.9.9.166.1.16.1.1.5) in the CISCO-CLASS-BASED-QOS-MIB mib. > > > > My problem. > > > > I would like to compute the number of bytes sent per second as quickly > and accurately as possible. However I found that the above mib entry > can be updated anywhere from 6 to 10 seconds. Sometimes if I poll this > snmp entry every 8 seconds the entry hasn't had a chance to change yet > and my message rate incorrectly is 0 kbs. > > > > My question: > > > > 1) Is there somewhere in the mib or cisco's command line interface > where I can get the cyclic rate that is being used? Or the timestamp > when the MIB entries are being updated? > > > > 2) Is it possible to set this rate via snmp or the cisco command > line interface and make the router update at a fixed interval of my > choosing? > > 3) Alternatively, Is there a way to generate SNMP traps when > router > updates its traffic statistics for some DSCP value? > > > > Thanks for any inputs, > > -Proveen > > > > > > _______________________________________________ > cisco-nsp mailing list cisco-nsp@puck.nether.net > https://puck.nether.net/mailman/listinfo/cisco-nsp > archive at http://puck.nether.net/pipermail/cisco-nsp/ > > > _______________________________________________ cisco-nsp mailing list cisco-nsp@puck.nether.net https://puck.nether.net/mailman/listinfo/cisco-nsp archive at http://puck.nether.net/pipermail/cisco-nsp/ _______________________________________________ cisco-nsp mailing list cisco-nsp@puck.nether.net https://puck.nether.net/mailman/listinfo/cisco-nsp archive at http://puck.nether.net/pipermail/cisco-nsp/
