T4P: Hybrid Interconnection for Cost Reduction

Abstract

Economic forces behind the Internet evolution have diversified the types of ISP (Internet Service Provider) interconnections. In particular, settlement-free peering and paid peering proved themselves as effective means for reducing ISP costs. In this paper, we propose T4P (Transit for Peering), a new type of hybrid bilateral ISP relationships that continues the Internet trend towards more flexible interconnections at lower costs. With a T4P interconnection, one ISP compensates the other ISP for their peering by providing this other ISP with a partial transit service. In comparison to paid peering, T4P is able to reduce the combined transit/peering costs of an ISP due to the subadditive nature of transit billing. As a cost-effective alternative to existing interconnection types, T4P expands and strengthens the connectivity of the Internet, e.g., between content and eyeball networks. After analyzing incentives of ISPs to adopt T4P, we use real traffic data from several IXPs (Internet eXchange Points) to quantify the T4P economic benefits. Our evaluation confirms the promising potential of T4P.