Content peering in content centric networks

The settlement-free peering relationships play a vital role in today's Internet, notably in helping ISPs cope with the dramatic increase in traffic load caused by the recent surge in the demand for videos and user generated content. Because of the added caching capability of CCN, peering in CCN can be expanded to encompass not only content that is permanently stored in the ISP's network, but also content that is temporarily cached at CCN routers in the ISP's network. Intuitively, this content-level peering is likely to benefit the networks involved in the peering relationship; however, this comes at a non-trivial cost. In this paper, we try to answer the question of whether the additional overhead and complexity to extend content-level peering is justifiable in view of the benefits it brings. To this end, we formulate the content-level peering problem as an optimization problem to study its maximum potential benefit. We conduct extensive numerical experiments to evaluate the potential peering benefit under realistic AS-level peering graphs, using realistic video traffic. The experimental results show that the interconnectivity of the peering graph significantly affects the maximum benefit of content-level peering. Compared to local greedy caching, cooperative caching can bring higher peering benefits; yet it is sensitive to parameters like the peering link bandwidth and the AS-level cache size.