A common starting point among ICN efforts (and clean-slate designs in general) is the mismatch between the TCP/IP core design goals and current Internet usage. Despite this common starting point however, there have been quite a few different design proposals for ICN (e.g. DONA, CCN and CONET to name a few), with similarities and dissimilarities among them when it comes to functional organization, the mechanisms adopted and the service models provided.
The upcoming special issue of the IEEE Communications Magazine on Information-centric networks (expected for July 2012) will feature an article that describes the PURSUIT architecture at some level of detail, filling a gap in the ICN literature and clearing the picture of what PURSUIT does for ICN. The architecture described in the article is a product of collective work that has taken place in both PURSUIT and PSIRP, PURSUIT’s ancestor project.
In the article we provide a thorough description of how several things are realized in PURSUIT, such as locating an item (commonly referred to as name-based routing), managing the network topology through an explicit topology management system and forwarding data with new, novel forwarding techniques such as LIPSIN. Apart from the technical description, we also point out the clear separation of the network core functions, that is, Rendezvous, Topology and Forwarding, an approach that has been a main driver in PURSUIT thinking.
Based on this architectural background, the paper proceeds to show how PURSUIT can accommodate dedicated content replication operators (similar to today’s CDNs), acting as mediators between information providers who can offload content distribution and access networks who minimize inter-domain traffic and improve user experience in turn. With respect to caching, PURSUIT supports two options: (i) on-path caching that can take place at any nodes throughout transport paths according to local policies, (ii) οff-path caching that allows access networks to orchestrate local caching of popular information. Both forms of caching allow for avoiding needless connectivity costs by network providers and improving quality of experience for users.
Finally, PURSUIT provides native mobility support, as it decouples information resolution from data transfer in both time and space. Regarding time, information providers and consumers do not need to be simultaneously connected to the network. Regarding space, information consumers can be served by any source providing the desired information, e.g., depending on location, even for different chunks of the same item. Since caching is also an integral part of PURSUIT, it is far easier to serve mobile devices from current or recent attachment points than it is with today’s IP architecture.
A pre-print version of the article is available online.