SNMPstats.pl is a moderately simple and quick perl SNMP poller for simple
interface traffic and other counters. It's written with flexible and easy
hacking in mind, and is commented appropriately.

It requires Net::SNMP version 2, available from CPAN.

For the sake of simplicity, device names, IPs, and SNMP read strings are
hard coded, but this can be easily substituted with something more
dynamic. Structure for the devices hash is:

$devices{<Canonical device name>}{'ip_address'} = <target ip address>
				 {'snmp_read'}  = <SNMP read community>

SNMP objects are stored in %oids. SNMP objects polled during device sweeps
are stored in @poll_int, using named references to the object names used
as key variables in %oids.

Interface stats are only collected for interfaces that have an
ifAdminStatus of 1. This cuts down on SNMP load quite a bit, given devices
are properly managed. Your mileage will vary based on device policies.

RRDs are only created for interfaces with ifAdminStatus of 1. This gives
you some amount of scale control. Interfaces are checked for an existing
RRD on each collection pass, and RRDs created as needed. They are NOT
removed if you admin down an interface, so stale RRD cleanup is your
problem.

One caveat to note is that RRDs are created with upper limits based on
ifSpeed. For autosensing 10/100 switches, this is a problem. In an effort
to keep this utility simple, I formally declare it to be 'your
problem'.

This utility runs as a recurring loop, so it's meant to be run in the
background like a daemon. You can strip the while/sleep sets and stuff it
in cron, if you're so inclined. YMMV. 

The script itself is heavily commented, explaining what I do as I go. Be a
good user, read the code before you run it. It's simple and
straightforward, and it's a good idea to understand how it works,
especially if you're a novice user.

Bill Nash
billn@billn.net / billn@gblx.net