User Manual
UMN:CLI
V5824G
397
During the best-path selection process, use the
bgp always-compare-med
command in
case of comparing MED values regardless of AS-path. Otherwise, use the
bgp
deterministic-med
command if it compares MED values of lots of paths contained same
AS-path information.
10.1.2.6
Choosing Best Path
There are a lot of path parameters BGP protocol, which are IP address, AS, MED value
and router ID. Even if two paths look same under the condition of IP address, they are
actually different when other parameters are compared with each other.
To ignore AS-path for selecting the best path, use the following command.
Command
Mode
Description
bgp bestpath as-path ignore
Router
Ignores the information of AS-path as a factor in the
algorithm for choosing the best route.
no bgp bestpath as-path ignore
Considers the information of AS-path as a factor in the
algorithm for choosing the best route.
If you would like to configure to select the best route by considering AS-path length of
Confederation, you should configure the router first to ignore AS-path for choosing the
best route using the
bgp bestpath as-path ignore
command before implementing the
following command.
To consider AS-path length of Confederation during the best-path selection process, use
the following command.
Command
Mode
Description
bgp bestpath compare-confed-
aspath
Router
Considers the information of AS-path length of
confederation as a factor in the algorithm for choosing
the best route.
no
bgp
bestpath
compare-
confed-aspath
Ignores AS-path length of confederation as a factor in
the algorithm for choosing the best route.
When comparing similar routes from more than 2 peers the BGP router does not consider
router ID of the routes. It selects the first received route. The V5824G uses router ID in
the selection process; similar routes are compared and the route with lowest router ID is
selected as the best route. Router ID can be manually set by using the following
command.
To select the best path by comparing router ID, use the following command. However, the
default condition is that BGP receives routes with identical eBGP paths from eBGP peers.
Command
Mode
Description
bgp bestpath compare-routerid
Router
Selects the best path using the router ID for identical
eBGP paths.
no
bgp
bestpath
compare-
routerid
Disables selecting the best path using the router ID.
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