Consider the cost community. IOS-XR implements the pre-bestpath and the after IGP-nexthop-cost point of insertion. https://datatracker.ietf.org/doc/html/draft-ietf-idr-custom-decision https://www.cisco.com/c/en/us/td/docs/routers/asr9000/software/asr9k-r7-6/routing/command/reference/b-routing-cr-asr9000-76x/routing-policy-language-commands.html#wp3193927332 https://www.cisco.com/c/en/us/td/docs/routers/asr9000/software/asr9k-r7-6/routing/configuration/guide/b-routing-cg-asr9000-76x/implementing-bgp.html#con_1390979
Regards, Jakob. -----Original Message----- From: Nick Hilliard <[email protected]> Drew Weaver wrote on 03/06/2022 16:48: > Would it be better to adjust MED? MED tends to be a better idea because it will accumulate the IGP metric with the BGP metric, which means you can fine-tune your routing in a dynamic basis in a way that you can't do with just localpref. If you use MED, then you probably want: router bgp xxxx bgp bestpath med always Otherwise the best path selection algorithm will select the oldest route in favour of a MED. The selection algorithm is documented here: > https://www.cisco.com/c/en/us/support/docs/ip/border-gateway-protocol-bgp/13753-25.html Worth reading. Localpref overrides as-path length. MEDs don't. If you're a leaf network, you may also want to normalise the origin type to either IGP or EGP. Some transit providers change theirs to IGP, which will cause traffic to unnaturally swing over to them, so higher sales for them. Nick _______________________________________________ cisco-nsp mailing list [email protected] https://puck.nether.net/mailman/listinfo/cisco-nsp archive at http://puck.nether.net/pipermail/cisco-nsp/
