bestroute med-confederation (BGP-IPv4 multicast address family view)

Function

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

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

By default, MBGP compares the MED values of the routes that are from the same AS.

Format

bestroute med-confederation

undo bestroute med-confederation

Parameters

None

Views

BGP-IPv4 multicast address family view

Default Level

2: Configuration level

Task Name and Operations

Task Name	Operations
bgp	write

Usage Guidelines

Usage Scenario

MBGP AS_Path records the number of each AS from the local Router to the destination according to a certain order. After the bestroute med-confederation command is configured, MBGP compares MED values only when AS_Path does not contain the external AS (AS that is not in the confederation) number. Otherwise, MBGP does not compare MED values.

For example, ASs 65000, 65001, 65002, and 65004 belong to the same confederation. The rules for selecting the optimal route from the four routes are 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 1, med=1
After the bestroute med-confederation command is used, MBGP selects path1. Although the MED value of path4 is smaller, the MED value cannot be compared. This is because AS_Path contains the external AS number.

Example

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

<HUAWEI> system-view
[~HUAWEI] bgp 100
[*HUAWEI-bgp] ipv4-family multicast
[*HUAWEI-bgp-af-multicast] bestroute med-confederation