Allied Telesis VERSION 5.4.3-2.6 manual Bgp bestpath med BGP and BGP4+, Missing-as-worst

BGP and BGP4+ Commands

bgp bestpath med (BGP and BGP4+)

This command controls how the Multi Exit Discriminator (MED) attribute comparison is performed.

Use the no variant of this command to prevent BGP from considering the MED attribute when comparing paths.

Syntax bgp bestpath med {[confed] [missing-as-worst]}

Parameter	Description
confed	Compares MED among confederation paths.
missing-as-worst	Treats missing MED as the least preferred one.

Mode Router Configuration

Usage The confed parameter enables MED comparison among paths learned from confederation peers. The MED attributes are compared only if there is no external AS (Autonomous System), where an external AS is one that is not within the confederation. If there is an external AS in the path, then the MED comparison is not made.

For example, in the following paths the MED value is not compared with Path3 since it is not in the confederation. MED is compared for Path1 and Path2 only.

Path1 = 32000 32004, med=4

Path2 = 32001 32004, med=2

Path3 = 32003 1, med=1

The effect of the missing-as-worstparameter is to treat a missing MED attribute in a path as having a value of infinity, making the path without a MED value the least desirable path. If the missing-as-worstparameter is not configured, the missing MED attribute is assigned the value of 0, making the path with the missing MED attribute the best path.

Examples

awplus#	configure terminal
awplus(config)#	router bgp 100
awplus(config-router)#bgp bestpath med missing-as-worst
awplus#	configure terminal
awplus(config)#	router bgp 100
awplus(config-router)# bgp bestpath med confed
awplus#	configure terminal
awplus(config)#	router bgp 100
awplus(config-router)#	bgp bestpath med confed missing-as-worst

Related Commands bgp always-compare-med (BGP and BGP4+) bgp bestpath as-path ignore (BGP and BGP4+) bgp deterministic-med (BGP and BGP4+)

	Software Reference Supplement for SwitchBlade® x8112, x908, x900 and x610 Series Switches
C613-50032-01 REV D	AlliedWare PlusTM Operating System - Software Version 5.4.3-2.6	3.17