Command:

bgp bestpath med confed


Mode:

Router(config-router)#


Syntax:

bgp bestpath med confed
no bgp bestpath med confed

 

Syntax Description:

This command has no arguments or keywords.

 

Command Description:

To enable Multi Exit Discriminator (MED) comparison among paths learned from confederation peers, use the bgp bestpath med confed command in router configuration mode. To prevent the software from considering the MED attribute in comparing paths, use the no form of this command.

By default, the software does not consider the MED attribute when choosing among paths learned from confederation peers.

The comparison between MEDs is made only if no external autonomous systems are in the path (an external autonomous system is an autonomous system that is not within the confederation). If an external autonomous system in the path, then the external MED is passed transparently through the confederation, and the comparison is not made.

For example, assume that autonomous system 65000, 65001, 65002, and 65004 are part of the confederation; autonomous system 1 is not; and we are comparing route A with four paths. If the bgp bestpath med confed command is enabled, path 1 would be chosen. The fourth path has a lower MED, but it is not involved in the MED comparison because there is an external autonomous system in this path. The following list displays the MED for each autonomous system.

path = 65000 65004, med = 2

path = 65001 65004, med = 3

path = 65002 65004, med = 4

path = 65003 1, med = 1


Example:

The following command enables the BGP router to compare MED values for paths learned from confederation peers:

Router(config-router)# bgp bestpath med confed


Misconceptions:

None


Related Commands:

show ip bgp
show ip bgp ipv4

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