Cisco Prime Collaboration requests network devices to send SNMP notifications (Traps and InformRequests). By definition and in Cisco Prime Collaboration Assurance configuration, these unsolicited SNMP messages are delivered to the manager over UDP port 162. Prime must therefore listen on UDP/162 to receive the notifications it solicits.

A. UDP 161 – Used for SNMP polling (Get, Get-Next, Set), not for traps/informs.
B. TCP 161 – TCP transport is optional and for polling; traps/informs still default to UDP 162.
D. TCP 80 – Standard port for HTTP web traffic, unrelated to SNMP or Prime notification delivery.

1. Cisco Prime Collaboration Assurance and Analytics Administration Guide, Release 12.1, “Configuring SNMP,” p. 18: “PCA listens for SNMP traps and inform requests on UDP port 162.”

2. Cisco Prime Collaboration 11.x Quick Start Guide, Appendix B “Port Utilization,” p. B-4: “SNMP Traps/Informs – UDP 162 inbound to Prime.”

3. Cisco Systems, “Simple Network Management Protocol (SNMP) Overview,” Technical Note, 2019, p. 2: “Managers receive traps and inform requests on UDP port 162.”

4. Case, J. et al., RFC 3412 – SNMP Message Processing and Dispatching, §5: “All SNMP engines use UDP/162 as the well-known port for traps and informs.”