Black Box LGB6026A, Management Manual

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21 | Unicast Routing
Configuring the Routing Information Protocol
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Metric – Metric assigned to all external routes for the specified
protocol. (Range: 0-16; Default: the default metric as described under
"Configuring General Protocol Settings" on page 519 .)
A route metric must be used to resolve the problem of redistributing
external routes with incompatible metrics.
When a metric value has not been configured on this page, the default-
metric determines the metric value to be used for all imported external
routes.
It is advisable to use a low metric when redistributing routes from
another protocol into RIP. Using a high metric limits the usefulness of
external routes redistributed into RIP. For example, if a metric of 10 is
defined for redistributed routes, these routes can only be advertised to
routers up to 5 hops away, at which point the metric exceeds the
maximum hop count of 15. By defining a low metric of 1, traffic can
follow an imported route the maximum number of hops allowed within
a RIP domain. However, using a low metric can increase the possibility
of routing loops For example, this can occur if there are multiple
redistribution points and the router learns about the same external
network with a better metric from a redistribution point other than that
derived from the original source.
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To import external routing information from other routing domains:
1. Click Routing Protocol, RIP, Redistribute.
2. Select Add from the Action list.
3. Specify the protocol types (directly connected, OSPF or static) from
which to import external routes, and the metric to assign to these
routes.
4. Click Apply.
Figure 333: Redistributing External Routes into RIP
To show external routes imported into RIP:
1. Click Routing Protocol, RIP, Redistribute.
2. Select Show from the Action list.