DX ECMP from on-prem to aws

0

Dear Team - As per https://aws.amazon.com/blogs/networking-and-content-delivery/creating-active-passive-bgp-connections-over-aws-direct-connect/, we can use Local Pref to select the preferred path from on-prem to AWS VPC. However, example given there are for two datacenter. If both the DX links are terminated on same CISCO router, how can we ensure it ECMPed both the outbound path to AWS VPC.

For exam,

DX link -1 from Mumbai PoP terminating to CISCO Router-A interface-0 DX link -2 from Banglore PoP terminating to CISCO Router-A interface-1

When i do show ip bgp neighbor x.x.x.x advertised-route command, i see that destination for AWS VPC showing only DX-link-1. i wants to see both the DX links as destination on both the neighbors for outbound traffic. i used example from https://www.rogerperkin.co.uk/bgp/bgp-local-preference/ but did not work. Let me know if anyone has done such config ?

JD
已提問 2 個月前檢視次數 139 次
1 個回答
2
已接受的答案

You are only seeing the information for DX-1 because you are only specifying that neighbor in your show command. If you want to see all BGP routes to the remote site, use the command: show ip bgp

This will list all BGP peers and routes, and also show and values for weight, local pref and the AS Path. There should be a > symbol that shows the preferred path, but as long as the number of hops (AS Path) is equal along with the other values mentioned, both circuits will be leveraged. Take a look at this cisco article: https://www.cisco.com/c/en/us/support/docs/ip/border-gateway-protocol-bgp/13762-40.html#toc-hId--255936387

AWS
Jason
已回答 2 個月前
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專家
已審閱 2 個月前
  • This is my show ip bgp

    • 10.20.0.0/16 169.254.96.10 150 0 65005 i *> 169.254.96.20 150 0 65005 i
    • 10.21.0.0/16 169.254.96.10 150 0 65005 i *> 169.254.96.20 150 0 65005 i

    10.20.0.0/16 is towards region-A and 10.21.0.0/16 towards region-B but still outbound from CISCO router takes only 169.254.96.20 neighbor....

  • i think you nailed it...i was missing maximum-paths command. Now i see below entry..m multipath..thanks a lot for quick solution and ref doc

    *m 10.20.0.0/16 169.254.96.10 150 0 65005 i *> 169.254.96.20 150 0 65005 i *m 10.21.0.0/16 169.254.96.10 150 0 65005 i *> 169.254.96.20 150 0 65005 i

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