This plugin uses SNMPv2 to check CDP neighbor status. You can also use this script to list the neighbors to make writing the Nagios services easier. The "neighbor name" argument is not case sensitive.
./check_snmp_cdp-neighbor.sh [snmp community] [device hostname/IP] [neighbor name or 'list'] (count)
The list argument is used list all cdp neighbors. The optional count
parameters specifies how many physical links should exist between
the host and the neighbor.