B Commands

This chapter describes the Cisco NX-OS unicast routing commands that begin with the letter B.

bestpath

To change the default bestpath selection algorithm, use the bestpath router bgp configuration mode command. To return the BGP routing process to the default operation, use the no form of this command.

bestpath { always-compare-med | as-path multipath-relax | c ompare-routerid | cost-community ignore | med { confed | missing-as-worst | non-deterministic }}

no bestpath { always-compare-med | as-path multipath-relax | c ompare-routerid | cost-community ignore | med { confed | missing-as-worst | non-deterministic }}

 
Syntax Description

always-compare-med

Compares the multi-exit discriminator MED on paths from different autonomous systems.

as-path multipath-relax

Allows load sharing across providers with different (but equal- length) autonomous system paths. Without this option, the AS paths must be identical for load sharing.

compare-routerid

Compares the router IDs for identical eBGP paths.

cost-community ignore

Ignores the cost community for BGP best-path calculations. For more information on the BGP cost community, see the “Configuring MLPS Layer 3 VPN Load Balancing” chapter of the Cisco Nexus 7000 Series NX-OS MPLS Configuration Guide.

med confed

Forces bestpath to do a MED comparison only between paths originated within a confederation.

med missing-as-worst

Treats a missing MED as the highest MED.

med non-deterministic

Does not always pick the best MED path from among the paths from the same autonomous system.

None

 
Command Modes

Router BGP configuration
Neighbor configuration
VRF configuration

 
Supported User Roles

network-admin
vdc-admin

 
Command History

Release
Modification

4.0(1)

This command was introduced.

 
Usage Guidelines

You must ensure that BGP is enabled prior to entering this command for this command to be supported. You can enter the feature bgp global configuration mode command to enable BGP.

To enable the comparison of the MED for paths from neighbors in different autonomous systems, use the bgp always-compare-med command.

This command requires the Enterprise Services license.

Examples

This example shows how to change the default bestpath selection algorithm to compare the MED on paths from different AS:

switch(config)# router bgp 64496
switch(config-router)# bestpath always-compare-med

 
Related Commands

Command
Description

feature bgp

Enables BGP globally.