Cisco - Sending Syslog Messages As SNMP Traps and Informs
The following is an extract from the book Cisco IOS Cookbook,2nd edition (available online)
You want to send syslog messages as SNMP traps or informs.
You can configure the router to forward syslog messages to your network management server as SNMP traps instead of syslog packets with the following configuration commands:
To forward syslog messages as SNMP informs, use the following configuration commands:
Cisco routers normally forward syslog messages via the syslog facility by using UDP port 514. However, in networks that support SNMP traffic only, Cisco routers can encapsulate their syslog messages into SNMP traps before sending them.
This feature is most useful if your network management software doesn’t support the syslog protocol. However, since routers can produce many more syslog messages than SNMP traps, we recommend using syslog when possible.