Alcatel-Lucent OmniAccess 5740 - Page 619

OSPF Configuration
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Alcatel-Lucent
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OmniAccess 5740 Unified Services Gateway CLI Configuration Guide
TO CONFIGURE OSPF ADMINISTRATIVE DISTANCES
An administrative distance is an integer from 1 to 255. ‘0’ administrative distance
is used for connected routes to give a high preference to these routes. In general,
the higher the value, the lower the trust rating. An administrative distance of 255
means the routing information source cannot be trusted at all and should be
ignored.
OSPF uses three different administrative distances: intra-area, inter-area, and
external. Routes within an area are intra-area; routes to another area are inter-
area; and routes from another routing domain learned via redistribution are
external. The default distance for each type of route is 110. To change any of the
OSPF distance values, enter the following command:
‘Distance ospf’ command is used when we have multiple OSPF instance and we
want prefer routes of one OSPF instance over routes of other instance.
E
XAMPLE
ALU(config-router ospf 1)# distance 60 10.0.0.0/8
ALU(config-router ospf 1)# distance ospf external 10
Command (in RCM) Description
distance {<1-255> [<ip-address
subnet-mask|<ip-address/prefix-
length>][<1-99>] [<1300-1999>]}
This command is used to change
the administrative distance for a
given network.
distance ospf { external|inter-area|
intra-area} <1-255>}}
This command performs the same
function as the distance command
used with an access list. However,
the ‘distance ospf’ command
allows you to set a distance for an
entire group of routes, rather than
a specific route that passes an
access list.