Here's a good example:
I have a server located in my country, and I purchased from two upstream/transit providers to route my traffic to the world. Upstream A is located in far away region, and Upstream B is located in my country.
So I setup routing preference both for my server, although it worked well for most of my customers, yet there's one local ISP in same country where server is located, and even though it purchases upstream/transit services from same providers A and B, yet the routing for that ISP goes to the out of region to Upstream A rather than the local Upstream B.
Why the ISP routers prefer outside route even though the local upstream provider has/share that same BGP announcement to all its peers including this ISP? What can I do to fix this issue for that particular ISP?
