With IPHost Network Monitor you can run simple snmp requests against a Cisco device in your network.
cnatAddrPortBindSessionCount
cnat Address Port Bind Session Count
1.3.6.1.4.1.9.10.77.1.2.4.1.10
Number of sessions currently using this BIND.
Back to CISCO-IETF-NAT-MIB MIB page.
IPHost Network monitor allows you to monitor cnatAddrPortBindSessionCount on Cisco device via the SNMP protocol. Download IPHost Network Monitor (500 monitors for 30 days, 50 monitors free forever) to start monitoring Cisco optical switches right now.