Caesar: A Content Router for High-Speed Forwarding on Content Names

Internet users are interested in content regardless of its location; however, the current client/server architecture still requires requests to be directed to a specific server. Information-centric networking (ICN) is a recent vein that relaxes this requirement through the use of name-based forwarding, where forwarding decisions are based on content names instead of IP addresses. Despite previous name based forwarding strategies have been proposed, almost none have actually built a content router. To fill this gap, in this paper we design and prototype a content router called Caesar for high-speed forwarding on content names. Caesar introduces several innovative features, including (i) a longest-prefix matching algorithm based on a novel data structure called prefix Bloom filter; (ii) an incremental design which allows for easy integration with existing protocols and network equipment; (iii) a forwarding scheme where multiple line cards collaborate in a distributed fashion; and (iv) support for offloading packet processing to graphics processing units (GPUs). We build Caesar as an enterprise router, and show that every line card sustains up to 10 Gbps using a forwarding table with more than 10 million content prefixes. Distributed forwarding allows the forwarding table to grow even further, and to scale linearly with the number of line cards at the cost of only a few microseconds in the packet processing latency. GPU offloading, in turn, trades off a few milliseconds of latency for a large speedup in the forwarding rate.