Ruby Snmp Interface Bandwidth

snmp.rb

#!/usr/bin/ruby
require 'rubygems'
require 'snmp'
include SNMP

@results = Array.new
# Interface speed in mbps
interface_speed = 10000

def get_snmp
#interface index for WS-C3750E Te1/0/1 running Cisco IOS 15.0(2)SE4
interface_index = 10201
#SNMP OID values for IF-MIB::ifHCOutOctets and IF-MIB::ifHCInOctets
lookup_values = [ "1.3.6.1.2.1.31.1.1.1.10", "1.3.6.1.2.1.31.1.1.1.6" ]

        Manager.open(:Host => 'localhost', :Version => :SNMPv2c, :Community => 'Public') do |manager|
                manager.walk(lookup_values) do |row|
                        row.each { |vb|
                                if vb.name.to_s == "IF-MIB::ifHCOutOctets.#{interface_index.to_s}" || vb.name.to_s == "IF-MIB::ifHCInOctets.#{interface_index.to_s}"
                                        @results.push(vb.value.to_i)
                                end}
                        end
        end
end

get_snmp; sleep(10); get_snmp; out_delta = @results[2] - @results[0];  in_delta = @results[3] - @results[1];
out_mbps = out_delta / 10 * 8 / 1024 / 1024; in_mbps = in_delta / 10 * 8 / 1024 / 1024 ;
out_percent = out_mbps.to_f / interface_speed * 100; in_percent = in_mbps.to_f / interface_speed * 100;


puts "out traffic mbps = #{out_mbps}\nin traffic mbps = #{in_mbps}\nout traffic % = #{out_percent}\nin traffic % = #{in_percent}\n"