Apply Offsets to Routing Metrics
An offset list is the mechanism for increasing incoming and outgoing metrics to routes learned via RIP. You can limit the offset list with an access list. To increase the value of routing metrics, perform the following task in router configuration mode.
Command | Purpose |
| Apply an offset to routing metrics. |
5.4.9 Adjust Timers
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. These timers can be adjusted to fine- tune the routing protocol performance to better suit the
The default settings for the various timers are as follows:
•The update timer is 30 seconds. During every update, the RIP process sends an unsolicited response message containing the complete routing table to all neighboring RIP routers
•The timeout timer is 180 seconds. Upon expiration of the timeout, an unresponsive route becomes invalid; however, it is retained in the routing table for a short time so that neighbors can be notified that the route has been dropped
•The garbage collect timer is 120 seconds. Upon expiration of the
To adjust the timers, use the following command in router configuration mode.
Command | Purpose |
timers basic update timeout garbage | Adjust routing protocol timers. |
5.4.10 Enable or Disable Split-horizon
Normally, routers that are connected to
The split horizon with poison reverse mechanism blocks information about routes from being advertised by a router out any interface from which that information originated. This behavior usually optimizes communications among multiple routers, particularly when links are broken. However, with
To enable or disable split horizon, perform the following tasks in interface configuration mode.
Command | Purpose |
ip rip poison reverse | Enable split horizon with |
| poison reverse. |
no ip rip poison reverse | Disable split horizon with |
| poison reverse. |
5.4.11 Manage Authentication Keys
If you are sending and receiving RIP Version 2 packets, you can enable RIP authentication on an interface. RIP Version 1 does not support authentication.
The IC35516 software supports two modes of authentication on an interface for which RIP authentication is enabled: plain text authentication and MD5 authentication. The default authentication in every RIP Version 2 packet is plain text authentication.
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