OpenView Network Node Manager: Designing and Implementing an Enterprise Solution

Estimating SNMP Data Sample Rates

When you ask five network managers “what is a sensible sampling rate for SNMP data?” you will get six different answers. There are many conflicting issues responsible for this. Let’s review some of them.

NNM itself allows SNMP sampling intervals as small as one second. SNMP agents running on 8-bit hardware as low-priority processes may be unable to respond to an SNMP request for multiple objects in such a short interval. They will often time-out and become unresponsive when pressed too hard. Recall that NNM is configured by default to try an SNMP request three extra times with a 0.8-second exponential time-out (0.8, 1.6, 3.2, and 6.4 seconds for four time-outs totalling 12 seconds). The retries will just serve ...