UMN:CLI
User Manual
V8102
720
12.5.11
RIP Network Timer
Routing protocols use several timers that determine such variables as the frequency of
routing updates, the length of time before a route becomes invalid, and other parameters.
You can adjust these timers to tune routing protocol performance to better your internet
needs. The default settings for the timers are as follows.
•
Update
The routing information is updated once every 30 seconds. This is the fundamental
timing parameter of the routing protocol. Every update timer seconds, the RIP proc-
ess is supposed to send the routing table to all neighboring RIP routers.
•
Timeout
The default is 180 seconds. It
’s the interval of time in seconds after which a route is
declared invalid. However, this information will be still written in routing table until the
neighbor routers are notified that this route is removed from the routing table.
•
Garbage
The invalid information of route is deleted on the routing table every 120 seconds.
Once the information of route is classified as
“invalid”, it’s eventually removed from
the routing table after 120 seconds.
To adjust the timers, use the following command.
Command
Mode
Description
timers basic
UPDATE TIMEOUT
GARBAGE
Router
Adjusts RIP network timers.
UPDATE: routing table update timer value in second
(5-2147483647, default: 30 seconds)
TIMEOUT: routing information timeout timer value in
second (5-2147483647, default: 180 seconds)
GARBAGE: garbage collection timer value in second
(5-2147483647, default: 120 seconds)
no timers basic
Restores the default timers.
12.5.12
Split Horizon
Normally, routers that are connected to broadcast type IP networks and that use distance-
vector routing protocols employ the split horizon mechanism to reduce the possibility of
routing loops. Split horizon blocks information about routes from being advertised by a
router out any interface from which that information originated. This behavior usually op-
timizes communications among multiple routers, particularly when links are broken. How-
ever, with non-broadcast networks, such as Frame Relay, situations can arise for which
this behavior is less than ideal. For these situations, you might want to disable split hori-
zon. If the interface is configured with secondary IP address and split horizon is enabled,
updates might not be sourced by every secondary address. One routing update is
sourced per network number unless split horizon is disabled.
To enable or disable split horizon mechanism, use the following command in
Interface
Configuration
mode.
