Routers MUST be manageable by SNMP [MGT:3]. The SNMP MUST operate using UDP/IP as its transport and network protocols. Others MAY be supported (e.g., see [MGT:25, MGT:26, MGT:27, and MGT:28]). SNMP management operations MUST operate as if the SNMP was implemented on the router itself. Specifically, management operations MUST be effected by sending SNMP management requests to any of the IP addresses assigned to any of the router's interfaces. The actual management operation may be performed either by the router or by a proxy for the router.
This wording is intended to allow management either by proxy, where the proxy device responds to SNMP packets that have one of the router's IP addresses in the packets destination address field, or the SNMP is implemented directly in the router itself and receives packets and responds to them in the proper manner.
It is important that management operations can be sent to one of the router's IP Addresses. In diagnosing network problems the only thing identifying the router that is available may be one of the router's IP address; obtained perhaps by looking through another router's routing table.
All SNMP operations (get, get-next, get-response, set, and trap) MUST be implemented.
Routers MUST provide a mechanism for rate-limiting the generation of SNMP trap messages. Routers MAY provide this mechanism through the algorithms for asynchronous alert management described in [MGT:5].
Although there is general agreement about the need to rate-limit traps, there is not yet consensus on how this is best achieved. The reference cited is considered experimental.