Controlling The Cost Of Individual Network Segments - Juniper J2300 User Manual

J-series™ Services Router User Guide
Table 120: Controlling Route Selection in the Forwarding Table by Setting Preferences
Task
Navigate to the Ospf level in the
configuration hierarchy.
Set the external and internal route
preferences.

Controlling the Cost of Individual Network Segments

When evaluating the cost of individual network segments, OSPF evaluates
the reference bandwidth. For any link faster than 100 Mbps, the default cost
metric is 1. When OSPF calculates the SPF algorithm, it sums the metrics
of all interfaces along a path to determine the overall cost of the path. The
path with the lowest metric is selected for the forwarding table.
To control the cost of the network segment, you can modify the metric value on an
individual interface. Suppose all routers in the OSPF network use default metric
values. If you increase the metric on an interface to
interface have a calculated metric higher than the default and are not preferred.
To manually set the cost of a network segment on the stub area's Fast
Ethernet interface by modifying the interface metric:
1.
2.
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Tuning an OSPF Network for Efficient Operation
J-Web Configuration Editor
In the configuration editor hierarchy,
select Protocols>Ospf.
1. In the External preference box,
type an external preference
value—for example, 7.
2.
In the Preference box, type an
internal preference value—for
example, 130.
3. Click OK.
Navigate to the top of the configuration hierarchy in either the J-Web or the CLI
configuration editor.
Perform the configuration tasks described in Table 121.
CLI Configuration Editor
From the top of the configuration
hierarchy, enter
edit protocols ospf
1. Set the internal preference. For
example:
set preference 7
2.
Set the external preference. For
example:
set external-preference 130
Changes in the CLI are applied
automatically when you execute
the set command.
, all paths through this
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