Indicating Bgp Back-Door Routes - Cisco ASR 9000 Series Configuration Manual

Implementing BGP
Command or Action
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
Step 6 bgp bestpath as-path ignore
Example:
RP/0/RSP0/CPU0:router(config-bgp)# bgp
bestpath as-path ignore
Step 7 bgp bestpath compare-routerid
Example:
RP/0/RSP0/CPU0:router(config-bgp)# bgp
bestpath compare-routerid
Step 8 commit

Indicating BGP Back-door Routes

Perform this task to set the administrative distance on an external Border Gateway Protocol (eBGP) route to
that of a locally sourced BGP route, causing it to be less preferred than an Interior Gateway Protocol (IGP)
route.
SUMMARY STEPS
1. configure
2. router bgp as-number
3. address-family { ipv4 | ipv6 } unicast
4. network { ip-address / prefix-length | ip-address mask } backdoor
5. commit
OL-30423-03
Cisco ASR 9000 Series Aggregation Services Router Routing Configuration Guide, Release 5.1.x
Indicating BGP Back-door Routes
Purpose
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.
Configures the BGP software to ignore the autonomous system
length when performing best-path selection.
Configure the BGP speaker in the autonomous system to
compare the router IDs of similar paths.
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