RFC 2092 (rfc2092) - Page 2 of 6
Protocol Analysis for Triggered RIP
Alternative Format: Original Text Document
RFC 2092 Triggered RIP Protocol Analysis January 1997 o Point-to-point links supporting PPP link quality monitoring or echo request to determine link failure. A triggered RIP implementation runs standard RIP on Local Area Networks (LANs) allowing them to interoperate transparently with implementations adhering to the original specifications. 3. Key Features The proposal shares the same basic algorithms as RIP or RIP-2 when running on LANs; Packet formats, broadcast frequency, triggered update operation and database timeouts are all unmodified. The new features operate on WANs which use switched circuits on demand to achieve intermittent connectivity; Or on permanent WAN connections where there is a desire to keep routing packet overhead to a minimum. Instead of using periodic 'broadcasts', information is only sent as triggered updates. The proposal makes use of features of the underlying connection oriented service to provide feedback on connectivity. 3.1 Triggered Updates Updates are only sent on the WAN when an event changes the routing database. Each update is retransmitted until acknowledged. Information received in an update is not timed out. The packet format of a RIP response is modified (with a different unique command field) to include sequence number information. An acknowledgement packet is also defined. 3.2 Circuit Manager The circuit manager running below the IP network layer is responsible for establishing a circuit to the next hop router whenever there is data (or a routing update) to transfer. After a period of inactivity the circuit will be closed by the circuit manager. If the circuit manager fails to make a connection a circuit down indication is sent to the routing application. The circuit manager will then attempt at (increasing) intervals to establish a connection. When successful a circuit up indication is sent to the routing application. Sherry & Meyer Informational
