1. Routing Information Protocol (RIP) Josh Timmons, CCNA Datacom II February 15, 2000

2. RIP -- What is it? b RIP is a routing protocol for exchanging routing table information between routers. Routing updates must be passed between routers so that they can make the proper choice on how to route a packet.Routing updates must be passed between routers so that they can make the proper choice on how to route a packet.

3. RIP Characteristics b Distance vector routing protocol. b Uses hop count as a path selection metric. b Three types of timers. b Multiple stability features.

4. Distance Vector Routing Protocol b Each router sends all or part of its routing table in routing updates. However, the updates are only sent to neighboring routers. Cisco Systems Inc.

5. Hop Count -- Fifteen Hop Limit b Hop count is the sum of all the legs in a route. –After 15 hops, the packet is discarded Lucent Technologies

6. Timers b Routing-update timer By default, routers send updates every 30 seconds.By default, routers send updates every 30 seconds. A small random number is added to prevent collisions.A small random number is added to prevent collisions. b Route timeout A route timeout timer is associated with a route. When it expires, the route is marked invalid.A route timeout timer is associated with a route. When it expires, the route is marked invalid. b Route-flush timer After the route timeout expires, the route-flush timer eventually expires, deleting the route from the table.After the route timeout expires, the route-flush timer eventually expires, deleting the route from the table.

7. Multiple Stability Features b Split Horizon –Information learned about a route is not sent back out the interface it was learned from. b Hold-down mechanisms –When a link in a route fails, that route is put in a hold-down state, where routers neither send or receive updates about that route.

8. Rip Packet b A -- Command - request or response. b B -- Version # - specifies version of RIP. b C -- Zero - Not used. b D -- Address Family Identifier (AFI) - Indicates type of address being specified (IP, IPX, etc) b E -- Address - Specifies IP address of entry. b F -- Metric - # of hops traversed from source to destination

9. Drawbacks b RIP version 1 does not recognize subnets. –This feature was added in RIP version 2. b Because RIP only uses hop count as a metric, packets may be forced to take a slower route with less hops over a faster route with more hops. –Other routing protocols use a combination of different metrics to calculate a route.

10. FHSU Percussion Ensemble b Where: –Beach/Schmidt PAC b When: –Thursday 2-17-2000 –8:00 PM b Cost: Adults -- $6.00 Senior Citizens & Students Over 12 -- $4.00 FHSU Students -- Free w/ ID