09-30-2014 09:18 AM - edited 03-05-2019 06:53 AM
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
Solved! Go to Solution.
09-30-2014 11:15 AM
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
09-30-2014 09:15 PM
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.
09-30-2014 11:15 AM
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
09-30-2014 12:29 PM
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) ?
09-30-2014 09:15 PM
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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