IP Routing Features
Configuring RIP
Configuring RIP
This section describes how to configure RIP using the CLI interface.
To display RIP configuration information and statistics, see “Displaying RIP
Information” on page 11-27.
Overview of RIP
Routing Information Protocol (RIP) is an IP route exchange protocol that uses
a distance vector (a number representing distance) to measure the cost of
a given route. The cost is a distance vector because the cost often is equivalent
to the number of router hops between the HP routing switch and the destina-
tion network.
An HP routing switch can receive multiple paths to a destination. The software
evaluates the paths, selects the best path, and saves the path in the IP route
table as the route to the destination. Typically, the best path is the path with
the fewest hops. A hop is another router through which packets must travel
to reach the destination. If the HP routing switch receives a RIP update from
another router that contains a path with fewer hops than the path stored in
the HP routing switch's route table, the routing switch replaces the older route
with the newer one. The routing switch then includes the new path in the
updates it sends to other RIP routers, including HP routing switches.
RIP routers, including HP routing switches, also can modify a route's cost,
generally by adding to it, to bias the selection of a route for a given destination.
In this case, the actual number of router hops may be the same, but the route
has an administratively higher cost and is thus less likely to be used than other,
lower-cost routes. A RIP route can have a maximum cost of 15. Any destination
with a higher cost is considered unreachable. Although limiting to larger
networks, the low maximum hop count prevents endless loops in the network.
The switches covered in this guide support the following RIP types:
■ Version 1
■ V1 compatible with V2
■ Version 2 (the default)
Note ICMP Host Unreachable Message for Undeliverable ARPs. If the
routing switch receives an ARP request packet that it is unable to deliver to
the final destination because of the ARP timeout and no ARP response is
received (the routing switch knows of no route to the destination address),
the routing switch sends an ICMP Host Unreachable message to the source.
11-21
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