With IPHost Network Monitor you can run simple snmp requests against a Cisco device in your network.
cvForwNeighborAge
Cisco Voice Forw Neighbor Age
1.3.6.1.4.1.9.9.17.1.2.4.1.7
The age of the entry, in seconds. The value -1 indicates not applicable, for RTP Version 0 neighbors on WAN interfaces, when the interface is configured for delta-only updates.
Back to CISCO-VINES-MIB MIB page.
IPHost Network monitor allows you to monitor cvForwNeighborAge on Cisco device via the SNMP protocol. Download IPHost Network Monitor (500 monitors for 30 days, 50 monitors free forever) to start monitoring Cisco multiplexers right now.