Cisco Systems 3750E Manual De Usuario
38-24
Catalyst 3750-E and 3560-E Switch Software Configuration Guide
OL-9775-02
Chapter 38 Configuring IP Unicast Routing
Configuring RIP
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:
local IP address and to disable split horizon on the interface:
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.
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.
Note
If split horizon is enabled, neither autosummary nor interface summary addresses (those configured with
the ip summary-address rip router configuration command) are advertised.
the ip summary-address rip router configuration command) are advertised.
Switch(config)# router rip
Switch(config-router)# interface gi1/0/2
Switch(config-if)# ip address 10.1.5.1 255.255.255.0
Switch(config-if)# ip summary-address rip 10.2.0.0 255.255.0.0
Switch(config-if)# no ip split-horizon
Switch(config-if)# exit
Switch(config)# router rip
Switch(config-router)# network 10.0.0.0
Switch(config-router)# neighbor 2.2.2.2 peer-group mygroup
Switch(config-router)# end
Configuring 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 can optimize communication among multiple routers, especially when links are
broken.
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 can optimize communication among multiple routers, especially when links are
broken.
Note
In general, we do not recommend disabling split horizon unless you are certain that your application
requires it to properly advertise routes.
requires it to properly advertise routes.
Command
Purpose
Step 1
configure terminal
Enter global configuration mode.
Step 2
interface interface-id
Enter interface configuration mode, and specify the Layer 3
interface to configure.
interface to configure.
Step 3
ip address ip-address subnet-mask
Configure the IP address and IP subnet.
Step 4
ip summary-address rip ip address ip-network mask Configure the IP address to be summarized and the IP
network mask.
Step 5
no ip split horizon
Disable split horizon on the interface.
Step 6
end
Return to privileged EXEC mode.
Step 7
show ip interface interface-id
Verify your entries.
Step 8
copy running-config startup-config
(Optional) Save your entries in the configuration file.