Alcatel-Lucent 7750 SR OS Service Manual page 1097

A route can be learned by the router from different protocols in which case the costs are not
comparable, when this occurs the preference is used to decide to which route will be used.
Different protocols should not be configured with the same preference, if this occurs the tiebreaker is
per the default preference table as defined in
preference using the same protocol, the lowest cost route is used.
If multiple routes are learned with an identical preference using the same protocol and the costs
(metrics) are equal, then the decision of what route to use is determined by the configuration of the
ecmp in the config>router context.
The no form of the command reverts to the default value.
Default
preference 10 — OSPF internal routes have a preference of 10.
Parameters
preference — The preference for internal routes expressed as a decimal integer. Defaults for different
Table 7: Route Preference Defaults by Route Type
reference-bandwidth
Syntax reference-bandwidth reference-bandwidth
no reference-bandwidth
Context config>service>vprn>ospf
Description
This command configures the reference bandwidth in kilobits per second (Kbps) that provides the
reference for the default costing of interfaces based on their underlying link speed.
7750 SR OS Services Guide
route types are listed in
Route Type
Direct attached
Static routes
OSPF internal
IS-IS level 1 internal
IS-IS level 2 internal
RIP
OSPF external
IS-IS level 1 external
IS-IS level 2 external
BGP
a. Preference for OSPF internal routes is configured with the preference
command.
Values
1 — 255
Virtual Private Routed Network Services
Table 7. If multiple routes are learned with an identical
Table 7.
Preference Configurable
0 No
5 Yes
10
Yes
15 Yes
18 Yes
100 Yes
150 Yes
160 Yes
165 Yes
170 Yes
a
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