Chapter 34
Configuring IP Unicast Routing
To restore clear text authentication, use the no ip rip authentication mode interface configuration
command. To prevent authentication, use the no ip rip authentication key-chain interface
configuration command.
Configuring Summary Addresses and Split Horizon
Routers connected to broadcast-type IP networks and using distance-vector routing protocols normally
use the split-horizon mechanism to reduce the possibility of routing loops. Split horizon blocks
information about routes from being advertised by a router on any interface from which that information
originated. This feature usually optimizes communication among multiple routers, especially when links
are broken.
Note
In general, disabling split horizon is not recommended unless you are certain that your application
requires it to properly advertise routes.
If you want to configure an interface running RIP to advertise a summarized local IP address pool on a
network access server for dial-up clients, use the ip summary-address rip interface configuration
command.
If split horizon is enabled, neither autosummary nor interface IP summary addresses are advertised.
Note
Beginning in privileged EXEC mode, follow these steps to set an interface to advertise a summarized
local IP address and to disable split horizon on the interface:
Command
Step 1
configure terminal
Step 2
interface interface-id
Step 3
ip address ip-address subnet-mask
Step 4
ip summary-address rip ip address ip-network mask Configure the IP address to be summarized and the IP
Step 5
no ip split horizon
Step 6
end
Step 7
show ip interface interface-id
Step 8
copy running-config startup-config
To disable IP summarization, use the no ip summary-address rip router configuration command.
In this example, the major net is 10.0.0.0. The summary address 10.2.0.0 overrides the autosummary
address of 10.0.0.0 so that 10.2.0.0 is advertised out interface Gigabit Ethernet port 2, and 10.0.0.0 is
not advertised. In the example, if the interface is still in Layer 2 mode (the default), you must enter a no
switchport interface configuration command before entering the ip address interface configuration
command.
OL-8915-03
Purpose
Enter global configuration mode.
Enter interface configuration mode, and specify the Layer 3
interface to configure.
Configure the IP address and IP subnet.
network mask.
Disable split horizon on the interface.
Return to privileged EXEC mode.
Verify your entries.
(Optional) Save your entries in the configuration file.
Cisco Catalyst Blade Switch 3020 for HP Software Configuration Guide
Configuring RIP
34-21