With IPHost Network Monitor you can run simple snmp requests against a Cisco device in your network.
ccmPhoneFailedInetAddressIPv6
Cisco Call Manager Phone Failed Inet Address I Pv6
1.3.6.1.4.1.9.9.156.1.2.3.1.9
This object identifies the last known primary IPv6 address of the phone experiencing a communication failure. This object contains value zero if IPV6 address is not available.
Back to CISCO-CCM-MIB MIB page.
IPHost Network monitor allows you to monitor ccmPhoneFailedInetAddressIPv6 on Cisco device via the SNMP protocol. Download IPHost Network Monitor (500 monitors for 30 days, 50 monitors free forever) to start monitoring Cisco routers right now.