Alteon Application Switch Operating System Application Guide
Routing Information Protocol
Document ID: RDWR-ALOS-V2900_AG1302
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RIP Features
Alteon provides the following features to support RIPv1 and RIPv2:
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Poison
Simple split horizon in the RIP scheme omits routes learned from one neighbor in updates sent to
that neighbor. That is the most common configuration used in RIP network topology. Split horizon
with poisoned reverse includes such routes in updates, but sets their metrics to 16. The
disadvantage of using this feature is the increase of size in the routing updates. Therefore, Radware
recommends disabling split horizon with poisoned reverse.
Triggered Updates
Triggered updates are an attempt to speed up convergence. When triggered updates are enabled,
whenever a router changes the metric for a route, it sends update messages almost immediately
without waiting for the regular update interval. Radware recommends enabling triggered updates.
Multicast
RIPv2 messages use the IP multicast address (224.0.0.9) for periodic broadcasts. Multicast RIPv2
announcements are not processed by RIPv1 routers.
To configure RIPv2 in RIPv1 compatibility mode, set multicast to disable.
Default
The RIP router can listen and supply a default route, usually represented as 0.0.0.0 in the routing
table. When a router does not have an explicit route to a destination network in its routing table, it
uses the default route to forward those packets.
Metric
The metric field contains a configurable value between 1 and 15 which specifies the current metric
for the interface. The metric value typically indicates the total number of hops to the destination.
The metric value of 16 represents an unreachable destination.
Authentication
RIPv2 authentication uses clear text passwords for authentication. If configured using an
authentication password, then it is necessary to enter an authentication key value.
The following method is used to authenticate a RIP message:
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If the router is not configured to authenticate RIPv2 messages, then RIPv1 and unauthenticated
RIPv2 messages are accepted. Authenticated RIPv2 messages are discarded.
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If the router is configured to authenticate RIPv2 messages, then RIPv1 messages and RIPv2
messages which pass authentication testing are accepted. Unauthenticated and failed
authentication RIPv2 messages are discarded.
