I am trying to split inbound traffic 70/30 (more or less!) for our 188.8.131.52/16 network, with two providers, AS701 (Verizon) and AS13385 (Comcast). Since Verizon is originating our AS (AS40385) already, so far I have just fired up BGP with Comcast, so as to "take away" part of the traffic from AS701. However, I think I think we are running into a problem described here:
When I advertise our full /16 subnet to Comcast, even with 5 (!) as-prepends, all traffic is still attracted to Comcast. I think this may be (see above) because Comcast is requesting elevated local preference from their peers, and Comcast and Verizon have many peers in common.
The workaround is to advertise the first half of our subnet, Comcast gets 184.108.40.206/17, Verizon originates 220.127.116.11/16. (And we still don't have to do BGP with Verizon.) This negates any as-prepending because the /17 route is more specific. I hate to engorge the routing table any further, but this seems to work for now. This Comcast AS does not offer any options via communities.
Is this very common? I guess you have to work with the vendor to fix it, that's why BGP stands for "Border Gateway Politics", eh? Or is there something here I'm not understanding because we are originating 18.104.22.168/17 and Verizon is originating 22.214.171.124/16?
Thanks in advance,