Any SNMP trap is logged, only simple traps like link state change or cold start are decoded. The source IP address is used to try and add the device if it has not already been discovered.
To configure a Cisco switch or router for SNMP the configuration needs to be modified to conatin lines similar to the following.
To respond to SNMP requests from the NMS:
snmp-server community public ro 1 access-list 1 permit 10.1.1.1
To send SNMP traps from the router or switch to the NMS:
snmp-server host 10.1.1.1 public snmp-server enable traps
In control panel, add or remove programs, add/remove windows components, management and monitoring tools, details. Check Simple Network Management Protocol, click OK, and install from the disk.
To configure it go to Control panel, Administrative Tools, Services, double click SNMP service. Configure under traps and security tabs.