Start the daemon monitor by running ./throughput.rb
 * You can change the port the daemon runs on by changing the "port" settings at the top of the file.  This file will run continuously.

 Use the "check_throughput" file as the Nagios checker.  In the Nagios commands file, put the following:

  define command {
          command_name    check_throughput
          command_line    /usr/lib/nagios/plugins/check_throughput $HOSTADDRESS$ $ARG5$ $ARG4$ $ARG1$ $ARG2$ $ARG3$
          }

  define service{
          use                             standard
          host_name                       my-rtr
          service_description             IN THROUGHPUT
          check_command                   check_throughput!10!2400:-1!2800:-1!in!public
          notifications_enabled           0
          }

 Where the following arguments are the settings:

HOSTADDRESS = ip address of the router / switch
ARG1        = SNMP device number -- get this with snmpwalk 
ARG2        = the "OKAY" range, outside this range will generate a warning
ARG3        = the "warning" range, outside this range will be critical
ARG4        = the direction of traffic (in|out) 
ARG5        = SNMP community string (usually default to "public")