Chapter 34
Configuring IP Unicast Routing
Enabling IP Unicast Routing
By default, the switch is in Layer 2 switching mode and IP routing is disabled. To use the Layer 3
capabilities of the switch, you must enable IP routing.
Beginning in privileged EXEC mode, follow these steps to enable IP routing:
Command
Step 1
configure terminal
Step 2
ip routing
Step 3
router ip_routing_protocol
Step 4
end
Step 5
show running-config
Step 6
copy running-config startup-config
Use the no ip routing global configuration command to disable routing.
This example shows how to enable IP routing using RIP as the routing protocol:
Switch# configure terminal
Enter configuration commands, one per line.
Switch(config)# ip routing
Switch(config)# router rip
Switch(config-router)# network 10.0.0.0
Switch(config-router)# end
Configuring RIP
The Routing Information Protocol (RIP) is an interior gateway protocol (IGP) created for use in small,
homogeneous networks. It is a distance-vector routing protocol that uses broadcast User Datagram
Protocol (UDP) data packets to exchange routing information. The protocol is documented in RFC 1058.
You can find detailed information about RIP in IP Routing Fundamentals, published by Cisco Press.
RIP is the only routing protocol supported by the switch.
Note
Using RIP, the switch sends routing information updates (advertisements) every 30 seconds. If a router
does not receive an update from another router for 180 seconds or more, it marks the routes served by
that router as unusable. If there is still no update after 240 seconds, the router removes all routing table
entries for the non-updating router.
RIP uses hop counts to rate the value of different routes. The hop count is the number of routers that can
be traversed in a route. A directly connected network has a hop count of zero; a network with a hop count
of 16 is unreachable. This small range (0 to 15) makes RIP unsuitable for large networks.
OL-8915-03
Purpose
Enter global configuration mode.
Enable IP routing.
Specify an IP routing protocol. This step might include other
commands, such as specifying the networks to route with the
network (RIP) router configuration command. For information on
specific protocols, see sections later in this chapter and the Cisco IOS
IP Configuration Guide, Release 12.2.
The IP base image supports only RIP as a routing protocol
Note
Return to privileged EXEC mode.
Verify your entries.
(Optional) Save your entries in the configuration file.
End with CNTL/Z.
Cisco Catalyst Blade Switch 3020 for HP Software Configuration Guide
Enabling IP Unicast Routing
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