3Com MSR 30, MSR 50 Confederation id, Syntax confederation id as-number Undo confederation id

958CHAPTER 72: BGP CONFIGURATION COMMANDS

Description Use the compare-different-as-medcommand to enable the comparison of the MED for paths from peers in different ASs.

Use the undo compare-different-as-medcommand to disable the comparison.

The comparison is disabled by default.

If there are several paths for one destination available, the path with the smallest

MED is selected.

Do not use this command unless associated ASs adopt the same IGP protocol and routing selection method.

Examples # In BGP view, enable to compare the MED for paths from peers in different ASs.

<Sysname> system-view

[Sysname] bgp 100

[Sysname-bgp] compare-different-as-med

#In BGP-VPN instance view, enable to compare the MED for paths from peers in different ASs (The VPN has been created).

<Sysname> system-view [Sysname] bgp 100

[Sysname-bgp] ipv4-family vpn-instance vpn1 [Sysname-bgp-vpn1] compare-different-as-med

confederation id

Syntax confederation id as-number

undo confederation id

View BGP view

Parameters as-number: Number of the AS that contains multiple sub-ASs, in the range 1 to 65535.

Description Use the confederation id command to configure a confederation ID.

Use the undo confederation id command to remove a specified confederation.

By default, no confederation ID is configured.

Configuring a confederation can reduce IBGP connections in a large AS. You can split the AS into several sub-ASs, and each sub-AS remains fully meshed. These sub-ASs form a confederation. Key IGP attributes of a route, such as the next hop, MED, local preference, are not discarded when crossing each sub-AS. The sub-ASs still look like a whole from the perspective of other ASs. This can ensure the integrity of the former AS, and solve the problem of too many IBGP connections in the AS.