3com 10014299 Betriebsanweisung

This chapter covers the following topics:

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The Routing Information Protocol (RIP) is an interior gateway and dynamic routing 
protocol based on the Distance-Vector (D-V) routing algorithm. RIP uses User 
Datagram Protocol (UDP) packets to exchange routing information and adopts 
hop count to measure the distance from the destination, called the routing cost. In 
RIP, a hop count that is equal to or larger than 16 is defined as infinity (the 
destination network or host is unreachable) so RIP is generally applied to 
medium-sized networks, such as a campus network. RIP is not designed for 
complicated and large-sized networks.

RIP has two versions, RIP-1 and RIP-2. RIP-2 supports simple text authentication 
and MD5 authentication, as well as the variable-length sub-net masks.

To improve performance and prevent route loops, RIP supports split-horizon, 
poisoned reverse using triggered update. This allows the importation of routes 
that are obtained by other routing protocols.

Each router that runs RIP manages a database that includes route items of all 
reachable routers on the network. A route item includes the following 
information.

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Destination address: The address of the host or network.

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Next-hop address: The address of the next router through which this route 
passes to get to the destination.

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Interface: The interface where messages are forwarded.

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Metric value: The overhead for the router to get to the destination. It is an 
integer ranging from 0 to16.

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Timer: The last time the route item was modified.

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Route tag: The tag indicates whether it is an internal routing protocol route or 
an external routing protocol route.