Posted on May 31, 2019 5:01 pm
 |  Asked by James Greig
Print Friendly, PDF & Email


Could anyone explain what the state ‘Unusable’ is on best path selection in BGP. I’ve pasted some output below but removed some of the IP’s. RIB-in route-maps are applied for both as-path and ip prefixes but the prefix and as paths should be permitted (i’ve checked and look correct as far as I can tell). The next hop is also reachable. If it is as a result of a RIB-in filter, is there any way to confirm this or see which?

router(config)#show ip bgp nei X.X.X.X received-routes
Origin codes: i - IGP, e - EGP, ? - incomplete
AS Path Attributes: Or-ID - Originator ID, C-LST - Cluster List, LL Nexthop - Link Local Nexthop

Network Next Hop Metric LocPref Weight Path
BGP routing table entry for
Paths: 1 available
6939 4826 38803 56203
X.X.X.X from X.X.X.X (X.X.X.X)
Origin IGP, metric 0, localpref -, weight 0, invalid, external
Not best: Unusable



Post your Answer

You must be logged in to post an answer.