With IPHost Network Monitor you can run simple snmp requests against a Cisco device in your network.
cdpInterfaceExtTable
Cisco Discovery Protocol Interface Ext Table
1.3.6.1.4.1.9.9.23.1.1.2
This table contains the additional CDP configuration on the device's interfaces.
Back to CISCO-CDP-MIB MIB page.
IPHost Network monitor allows you to monitor cdpInterfaceExtTable 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.