Tuning The Bgp Best-Path Calculation - Cisco ASR 9000 Series Routing Configuration Manual

Tuning the BGP Best-Path Calculation

Tuning the BGP Best-Path Calculation
Perform this task to change the default BGP best-path calculation behavior.
SUMMARY STEPS
1. configure
2. router bgp as-number
3. bgp bestpath med missing-as-worst
4. bgp bestpath med always
5. bgp bestpath med confed
6. bgp bestpath as-path ignore
7. bgp bestpath compare-routerid
8. commit
DETAILED STEPS
Command or Action
Step 1 configure
Step 2 router bgp as-number
Example:
RP/0/RSP0/CPU0:router(config)# router bgp 126
Step 3 bgp bestpath med missing-as-worst
Example:
RP/0/RSP0/CPU0:router(config-bgp)# bgp
bestpath med missing-as-worst
Step 4 bgp bestpath med always
Example:
RP/0/RSP0/CPU0:router(config-bgp)# bgp
bestpath med always
Step 5 bgp bestpath med confed
Example:
RP/0/RSP0/CPU0:router(config-bgp)# bgp
bestpath med confed
Cisco ASR 9000 Series Aggregation Services Router Routing Configuration Guide, Release 5.3.x
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Purpose
Specifies the autonomous system number and enters the BGP
configuration mode, allowing you to configure the BGP
routing process.
Directs the BGP software to consider a missing MED attribute
in a path as having a value of infinity, making this path the
least desirable path.
Configures the BGP speaker in the specified autonomous
system to compare MEDs among all the paths for the prefix,
regardless of the autonomous system from which the paths
are received.
Enables BGP software to compare MED values for paths
learned from confederation peers.
Implementing BGP