Scalable routing for tag-based information-centric networking

Routing in information-centric networking remains an open problem. The main issue is scalability. Traditional IP routing can be used with name prefixes, but it is believed that the number of prefixes will grow too large. A related problem is the use of per-packet in-network state (to cut loops and return data to consumers). We develop a routing scheme that solves these problems. The service model of our information-centric network supports information pull and push using tag sets as information descriptors. Within this service model, we propose a routing scheme that supports forwarding along multiple loop-free paths, aggregates addresses for scalability, does not require per-packet network state, and leads to near-optimal paths on average. We evaluate the scalability of our routing scheme, both in terms of memory and computational complexity, on the full Internet AS-level topology and on the internal networks of representative ASes using realistic distributions of content and users extrapolated from traces of popular applications. For example, a population of 500 million users requires a routing information base of 3.8GB with an almost flat growth and, in this case, a routing update (one content descriptor) can be processed in 2ms on commodity hardware. We conclude that information-centric networking is feasible, even with (or perhaps thanks to) addresses consisting of expressive content descriptors.