Hi all, I have a doubt about the bellow scenario, where the ISP1 use eBGP sessions to its peers and is a BGP Transit AS. NSP 1 ------------------ ISP 1 Router2 ----------- NSP 2 | | | | | | | annunce /21 | | | Customer1 --------------- ISP 1 Router1 announce /20 The "Customer1" is client on both ISPs (ISP1 and NSP1) and have an /20 IP prefix. To NSP1, it announce two /21 prefixes. To ISP1, it announce a /20 prefix. If traffic comes from NSP 2 (connected only to ISP 1) to Customer1, the ISP 1 Routers try to send data over NSP 1, ignoring the Custormer1->ISP1 link. To solve this question, an solution that I found is filter Customer1 prefixes in BGP session between NSP1 and ISP1 Router2. But this don't appear scalable... Is this solution right ? What is the better solution for this scenario? How large ISPs solve this kind of problem? Thanks, Rafael