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New Member

BGB Best path selection

Hi,

Could someone tell me why second path remains as best?

 

MPLS_CORE#show ip bgp 192.168.1.0
BGP routing table entry for 192.168.1.0/24, version 27
Paths: (2 available, best #2, table default)
  Advertised to update-groups:
     1         
  Refresh Epoch 1
  64513
    2.2.2.1 from 2.2.2.1 (10.201.240.2)
      Origin incomplete, metric 156160, localpref 100, valid, external
      rx pathid: 0, tx pathid: 0
  Refresh Epoch 1
  64512
    1.1.1.1 from 1.1.1.1 (192.168.4.253)
      Origin incomplete, metric 1415680, localpref 100, valid, external, best
      rx pathid: 0, tx pathid: 0x0

 

 

Regards

 

Michal 

 

 

 

 

 

 

 

2 ACCEPTED SOLUTIONS

Accepted Solutions
Cisco Employee

Hi Michal, Please refer below

Hi Michal,

 

Please refer below CCO document for BGP best path selection criteria on cisco routers

 

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

 

If everything attribute is same then it comes to router-id and lowest router-id is preferred.

 

11. Prefer the route that comes from the BGP router with the lowest router ID.

The router ID is the highest IP address on the router, with preference given to loopback addresses. Also, you can use the bgp router-id command to manually set the router ID.

 

In your case, second route is having lowest router-id (1.1.1.1)

 

--Pls dont forget to rate helpful posts--

Regards,

Akash

Cisco Employee

 If you have control on MPLS

 

If you have control on MPLS_CORE node, you can change local preference to prefer a route. I see both routes are coming from different autonomous system (64512 and 64513). If you have control on both node 1.1.1.1 and 2.2.2.1 then you can do as-path prepend while advertising to MPLS_CORE.

 

3 REPLIES
Cisco Employee

Hi Michal, Please refer below

Hi Michal,

 

Please refer below CCO document for BGP best path selection criteria on cisco routers

 

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

 

If everything attribute is same then it comes to router-id and lowest router-id is preferred.

 

11. Prefer the route that comes from the BGP router with the lowest router ID.

The router ID is the highest IP address on the router, with preference given to loopback addresses. Also, you can use the bgp router-id command to manually set the router ID.

 

In your case, second route is having lowest router-id (1.1.1.1)

 

--Pls dont forget to rate helpful posts--

Regards,

Akash

New Member

Hi Akash,Thanks for that

Hi Akash,

Thanks for that.

Assuming I dont have control over router that makes decision on that route. How can i influence route decision on it with basic route redistribution from EIGRP (redistribute eigrp 1000) ?

 

Cisco Employee

 If you have control on MPLS

 

If you have control on MPLS_CORE node, you can change local preference to prefer a route. I see both routes are coming from different autonomous system (64512 and 64513). If you have control on both node 1.1.1.1 and 2.2.2.1 then you can do as-path prepend while advertising to MPLS_CORE.

 

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