interfaces <interface> ip rip split-horizon
Enables split-horizon or split-horizon poison-reverse on an interface that is running RIP.
Split-horizon and split-horizon poison-reverse are disabled.
- interface
- Mandatory. A type of interface. For detailed keywords and arguments that can be specified as an interface, refer to Supported Interface Types.
- disable
- Disables split-horizon on the interface.
- poison-reverse
- Enables split-horizon poison-reverse on the interface.
Configuration mode
interfaces interface {
ip {
rip {
split-horizon {
disable
poison-reverse
}
}
}
}Use this command to enable split-horizon or split-horizon poison-reverse on an interface that is running RIP.
Split-horizon is a stability feature that reduces the possibility of network loops, particularly when links become disconnected. It stops an interface from including in its network updates of any routes that it learned from that interface. Split-horizon is effective at preventing loops between routers that are directly connected to each another and speeds convergence when network conditions change; it is the default setting in RIP.
Poison-reverse is a variation of split-horizon. When an interface that has poison-reverse enabled detects that a link is down, it increases the metric for that route to 16 and propagates that information in its next update. Because 15 is the largest number of hops that are considered reachable on a RIP network, increasing the metric to 16 renders the route unreachable as far as downstream RIP routers are concerned. This is called “poisoning” the route. Poison-reverse can be used to propagate information about bad routes to routers that are downstream but not immediate neighbors, where split-horizon is ineffective.
When this option is enabled, the router includes the route in announcements to the neighbor from which it was learned. When this option is disabled, the router omits the route in announcements to the neighbor from which it was learned.
Use the set form of this command to configure split-horizon and split-horizon poison-reverse on an interface that is running RIP.
Use the delete form of this command to restore the default configuration, that is, split-horizon and split-horizon poison-reverse are disabled.
Use the show form of this command to display whether split-horizon and split-horizon poison-reverse are enabled or disabled.