Internet traffic exchange between two participants on an IXP is facilitated by Border Gateway Protocol (BGP) routing configurations between them. They choose to announce routes via the peering relationship – either routes to their own addresses, or routes to addresses of other ISPs that they connect to, possibly via other mechanisms. The other party to the peering can then apply route filtering, where it chooses to accept those routes, and route traffic accordingly, or to ignore those routes, and use other routes to reach those addresses.