Configuring Split Horizon And Poison Reverse - HP VSR1000 Configuration Manual

Suppress timer—Specifies how long a RIP route stays in suppressed state. When the metric of a
•
route is 16, the route enters the suppressed state. A suppressed route can be replaced by an
updated route that is received from the same neighbor before the suppress timer expires and has a
metric less than 16.
• Garbage-collect timer—Specifies the interval from when the metric of a route becomes 16 to when
it is deleted from the routing table. RIP advertises the route with a metric of 16. If no update is
announced for that route before the garbage-collect timer expires, the route is deleted from the
routing table.
IMPORTANT:
To avoid unnecessary traffic or route flapping, configure identical RIP timer settings on RIP routers.
To configure RIP timers:
Step
1. Enter system view.
2. Enter RIP view.
3. Configure RIP timers.

Configuring split horizon and poison reverse

The split horizon and poison reverse functions can prevent routing loops.
If both split horizon and poison reverse are configured, only the poison reverse function takes effect.
Enabling split horizon
Split horizon disables RIP from sending routes through the interface where the routes were learned to
prevent routing loops between adjacent routers.
To enable split horizon:
Step
1. Enter system view.
2. Enter interface view.
3. Enable split horizon.
Enabling poison reverse
Poison reverse allows RIP to send routes through the interface where the routes were learned, but the
metric of these routes is always set to 16 (unreachable) to avoid routing loops between neighbors.
To enable poison reverse:
Command
system-view
rip [ process-id ] [ vpn-instance
vpn-instance-name ]
timers { garbage-collect
garbage-collect-value | suppress
suppress-value | timeout
timeout-value | update
update-value } *
Command
system-view
interface interface-type
interface-number
rip split-horizon
31
Remarks
N/A
N/A
By default:
•
The garbage-collect timer is 120
seconds.
•
The suppress timer is 120 seconds.
•
The timeout timer is 180 seconds.
•
The update timer is 30 seconds.
Remarks
N/A
N/A
By default, split horizon is enabled.