Onesixtyone is a simple SNMP scanner which sends SNMP requests for the sysDescr value asynchronously with user-adjustable sending times and then logs the responses which gives the description of the software running on the device.

Running onesixtyone on a class B network (switched 100Mbs with 1Gbs backbone) with -w 10 gives a performance of 3 seconds per class C, with no dropped packets, and all 65536 IP addresses were scanned in less than 13 minutes.