With IPHost Network Monitor you can run simple snmp requests against a Cisco device in your network.
cagwProcessedSignalingPkts
Cisco's ASN Gateway Processed Signaling Packets
1.3.6.1.4.1.9.9.638.1.3.1.1.1.13
The total number of signaling packets processed by this ASN-GW.
Back to CISCO-ASN-GATEWAY-MIB MIB page.
IPHost Network monitor allows you to monitor cagwProcessedSignalingPkts on Cisco device via the SNMP protocol. Download IPHost Network Monitor (500 monitors for 30 days, 50 monitors free forever) to start monitoring Cisco firewalls right now.