With IPHost Network Monitor you can run simple snmp requests against a Cisco device in your network.
dmAreaAssignedPortIdList
Cisco Domain Management Area Assigned Port Id List
1.3.6.1.4.1.9.9.302.1.2.1.1.2
The list of Port IDs which have been assigned in this Area and VSAN, formatted as an array of octets in ascending order. There could be zero or more Port IDs assigned on this Area and VSAN. Port ID is an 8-bit value. And therefore, each octet represents one Port ID. So, the list containing the Port IDs 23, 45, 235 and 56 would be formatted as the 4-octet string x'172d38eb'.
Back to CISCO-DM-MIB MIB page.
IPHost Network monitor allows you to monitor dmAreaAssignedPortIdList 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.