Chapter 4: Ospf And Rip Fundamentals; Routing Information Protocol - Avaya 8800 Configuration Manual

Chapter 4: OSPF and RIP fundamentals

Use the information in these sections to help you understand Routing Information Protocol (RIP) and Open
Shortest Path First (OSPF).
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Routing Information Protocol

• Open Shortest Path First
• Border Gateway Protocol
Routing Information Protocol
In routed environments, routers communicate with one another to track available routes.
Routers can dynamically learn about available routes using the Routing Information Protocol
(RIP). The Avaya Ethernet Routing Switch 8800/8600 software implements standard RIP to
exchange Transmission Control Protocol (TCP)/IP route information with other routers.
RIP uses broadcast User Datagram Protocol (UDP) data packets to exchange routing
information. Each router advertises routing information by sending a routing information update
every 30 seconds (one interval). If a router does not receive an update from another router
within 90 seconds (three intervals), it marks the routes served by the nonupdating router as
unusable. If no update is received within 180 seconds (six intervals), the router removes all
routing table entries for the nonupdating router.
RIP is known as a distance vector protocol. The vector is the network number and next hop,
and the distance is the cost associated with the network number. RIP identifies network
reachability based on cost, and cost is defined as hop count. One hop is the distance from one
router to the next. This cost or hop count is known as the metric (see the following figure).
Configuration — OSPF and RIP
on page 31
on page 33
on page 55
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