check this link for SNMP trap configs
http://www.cisco.com/en/US/partner/products/sw/iosswrel/ps1834/products_feature_guide09186a008008026f.html
SNMP uses a data structure called MIB - Management Information Base, which is a collection of all the objects that are to be managed. An example of an object would be the Number of incoming packets at an interface. The objects are organized in a tree structure and each object is given an ID, which is the OID- Object Identifier. OID is a sequence of integers that uniquely identifies an object from the root of the tree to the leaf, ie. the object itself.
Hope that helps.
