With IPHost Network Monitor you can run simple snmp requests against a Cisco device in your network.
cvpdnSessionSentZLB
cvpdn Session Sent ZLB
1.3.6.1.4.1.9.10.51.1.2.1.1.10
This object returns the total number of Zero Length Body acknowledgement packets transmitted on this session.
Back to CISCO-VPDN-MGMT-EXT-MIB MIB page.
IPHost Network monitor allows you to monitor cvpdnSessionSentZLB on Cisco device via the SNMP protocol. Download IPHost Network Monitor (500 monitors for 30 days, 50 monitors free forever) to start monitoring Cisco switches right now.