You'll need to do a MIB walk on your 7600 and find the number ARP requests OID. Then you can create an Universal Device Poller, add the OID and poll your device for that OID.
To add a UnDP, consult Chapter 16 of the Orion NPM Administrator Guide or see the online guide at:
Thanks. I'll take a look at that too. I don't necessarily need to know the size of the arp table, but the number of requests per second. We have some DSL modems that are flooding the network with ARP requests and are theoretically causing issues with other services due to contention for CPU cycles. In the end I set up a poller to graph broadcast traffic. Not the same thing but about as close as I could really get and should give us a general picture of whether the changes we are making to the modems is having any effect.
The posted branch of the tree also has some goodies in it though. Thanks for that.