Cisco 500 series Administration Manual page 464

RIP
How RIP Operates on the Device
Cisco 500 Series Stackable Managed Switch Administration Guide
Filtering Routing Updates
You can filter incoming and outgoing routes for a given IP interface using two
Standard Access Lists - one for input and one for output.
The Standard Access List is a named, ordered list of pairs of IP prefix (IP address
and IP mask length) and action. The action can be deny or permit.
If an access list is defined, each route from the RIP message is checked against
the list starting from the first pair: if it matches the first pair and the action is permit,
the route is passed; if the action is deny, the route is not passed. If the route does
not match, the following pair is considered.
If there is no pair that the route matches, the deny action is applied.
Advertising Default Route Entries on IP Interfaces
The special address 0.0.0.0 is used for describing a default route. A default route is
used to avoid listing every possible network in the routing updates, when one or
more closely-connected routers in the system are prepared to transfer traffic to
the networks that are not listed explicitly. These routers create RIP entries for the
address 0.0.0.0, just as if it were a network to which they are connected.
You can enable the default route advertisement and configures it with a given
metric.
Redistributing Static Route Configuration
You can determine whether static routes are redistributed or not by RIP by
configuring the Redistribute Static Metric feature. This feature is disabled by
default and can be enabled globally.
If this feature is enabled, rejected routes are advertised by routes with a metric of
16.
The static route configuration can be propagated using one of the following
options:
• Default Metric
Causes RIP to use the predefined default metric value for the propagated
static route configuration.
• Transparent (default)
Causes RIP to use the routing table metric as the RIP metric for the
propagated static route configuration.
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