cancel
Showing results for 
Search instead for 
Did you mean: 
cancel
410
Views
0
Helpful
1
Replies

BGP Selection .. Why Path #2 is better ! ?

I have a question please. For below output why 2nd output is considered best

According to my topology this is the right behavior however I am just curious why it is considered the best

Many Thanks

||||||||||||||

R9#show ip bgp vpnv4 vrf ABC 172.9.0.5
BGP routing table entry for 1009:9:172.9.0.5/32, version 142
Paths: (2 available, best #2, table ABC, RIB-failure(17) - next-hop mismatch)
  Not advertised to any peer
  Local
    172.9.195.15 from 0.0.0.0 (9.9.0.9)
      Origin incomplete, metric 2560077056, localpref 100, weight 32768, valid, sourced
      Extended Community: SoO:109:109 RT:1009:9
        Cost:pre-bestpath:129:2560077056 (default+412593409) 0x8800:0:9
        0x8801:100:77056 0x8802:259:2560000000 0x8803:257:1
        0x8804:1009:2886270986 0x8805:9:0
      mpls labels in/out 31/nolabel
  9, imported path from 9:9:172.9.0.5/32
    9.9.0.8 (metric 30) from 9.9.0.8 (9.9.0.8)
      Origin IGP, metric 4125934090, localpref 100, valid, internal, best
      Extended Community: RT:9:9 OSPF DOMAIN ID:0x0005:0x0000006D0200
        OSPF RT:0.0.0.0:2:0 OSPF ROUTER ID:172.9.0.5:36783
      mpls labels in/out 31/62
R9#

1 Reply 1

bhnegi
Cisco Employee
Cisco Employee

The BGP cost community modifies the BGP path selection process.

the "pre-bestpath" point of insertion was introduced in the BGP Cost Community feature. This POI is applied automatically to EIGRP routes that are redistributed into BGP and carries the EIGRP route type and metric. This POI influences the best path calculation process by influencing BGP to consider this POI before any other comparison step effectivefly forcing BGP to use IGP-like selection rules.

 

https://supportforums.cisco.com/document/58226/dual-ce-pe-connection-and-eigrp

http://www.cisco.com/c/en/us/td/docs/ios/12_0s/feature/guide/s_bgpcc.html

http://www.cisco.com/c/en/us/support/docs/ip/border-gateway-protocol-bgp/13753-25.html#custom

 

Best Regards,

Bheem

 

 

 

Getting Started

Find answers to your questions by entering keywords or phrases in the Search bar above. New here? Use these resources to familiarize yourself with the community: