With IPHost Network Monitor you can run simple snmp requests against a Cisco device in your network.
serialNumber
serial Number
1.3.6.1.4.1.52.259.10.3.2.2.2.1.2
Unique value assigned to each DPA device.
Back to CALISTA-DPA-MIB MIB page.
IPHost Network monitor allows you to monitor serialNumber 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.