bestroute med-confederation (BGP-IPv6 unicast address family view)

Function

The bestroute med-confederation command enables BGP to compare the Multi Exit Discriminator (MED) values of routes in a confederation when BGP selects the optimal route.

The undo bestroute med-confederation command restores the default settings.

By default, BGP compares the MED values of only the routes that are learned from peers in the same AS.

Format

bestroute med-confederation

undo bestroute med-confederation

Parameters

None

Views

BGP-IPv6 unicast address family view

Default Level

2: Configuration level

Task Name and Operations

Task Name	Operations
bgp	write

Usage Guidelines

Usage Scenario

By default, BGP compares the MED values of only the routes that are learned from peers in the same AS (excluding confederation sub-ASs). To enable BGP to compare MED values of routes in a confederation when selecting the optimal route, run the bestroute med-confederation command.

Configuration Impact

After the bestroute med-confederation command is configured, BGP compares MED values only when AS_Path does not contain any external AS (AS that is not in the confederation) numbers.

For example, ASs 65000, 65001, 65002, and 65004 belong to the same confederation. Routes to the same destination are listed as follows:

path1: AS_Path=65000 65004, med=2
path2: AS_Path=65001 65004, med=3
path3: AS_Path=65002 65004, med=4
path4: AS_Path=65003 65004, med=1
After the bestroute med-confederation command is run, the AS_Path attributes of paths 1, 2, and 3 does not contain external AS numbers. Therefore, when selecting routes based on MED values, BGP compares the MED values of paths 1, 2, and 3 only.

Example

# Configure BGP to compare the MED values of routes only in the confederation when selecting the optimal route.

<HUAWEI> system-view
[~HUAWEI] bgp 100
[*HUAWEI-bgp] ipv6-family unicast
[*HUAWEI-bgp-af-ipv6] bestroute med-confederation