We revisit the problem of incentive-compatible interdomain routing,
examining the quite realistic special case in which the utilities of autonomous
systems (ASes) are linear functions of the traffic in the
incident links and the traffic leaving each AS. We show that
incentive-compatibility toward maximizing total welfare is achievable
efficiently, and in the uncapacitated case, by an algorithm that can be
easily implemented by the border gateway protocol (BGP), the standard protocol for interdomain routing.