Motorola BSR 2000, Configuration And Management Manual

Page: 546 / 650

BSR 2000 Configuration and Management Guide Release 1.0
12-28 MGBI 526360-001-00 Rev. B
Configuring BGP Administrative Weights
You can assign a weight to a neighbor connection if more than one route exists for the
same destination. A weight indicates a preference for a particular route; a higher
weight indicates a preferred route. Initially, all routes learned from the neighbor have
the assigned weight. The BSR chooses the route with the highest weight as the
preferred route if multiple routes exist for a particular network.
In Figure 12-10 , Routers Boston and New York learn about network 160.80.0.0 from
AS200. Router Boston and New York propagate the update to Router Los Angeles.
Router Los Angeles has two routes for reaching 160.80.0.0 and must determine the
appropriate route. On Router Los Angeles, if you set the weight of updates coming
from Router Boston to be higher than the updates coming from Router New York,
Router Los Angeles uses Router Boston as the next hop to reach network 160.80.0.0.
Use the following commands to assign a weight to a neighbor connection:
■
neighbor weight
■
route-map
■
access-list
The weights assigned with the match as-path and set weight route map commands
override the weights assigned using the neighbor weight and neighbor filter-list
commands.
Use the neighbor weight command in Router Configuration mode to change the
weight attribute of all route updates received from a specific AS:
MOT(config-bgp)#
neighbor {<
A.B.C.D
> | <
WORD
>} weight <
0-65535>
where:
A.B.C.D
is the IP address of the neighbor.
WORD
is the name of the BGP peer group.
0-65535
is the assigned weight.