Towards Content-Centric Geometric Routing Wouter Taverier*, Sahel Sahhaf*, Didier Colle*, Mario Pickavet* and Piet Demeester* * Ghent University, IBCN-iMinds, INTEC, Gaston Crommenlaan 8 bus 201, B-9050 Gent, Belgium Email: {wouter.tavernier.sahel.sahhaf.didier .colle.mario.pickavet.piet.demeester}@intec.ugent.be Abstract-Content delivery is a crucial feature of existing cloud and telecom networks. This is confrmed by the tremendous success of media streaming services such as Spotify and Netfix, as well as the content and fle-distribution systems such as BitTorrent. A recurring problem in these type of network services is about keeping the protocol overhead as low as possible while maximizing the efciency of such systems in terms of network delay to customers. In this paper we propose the use of a routing system-inferred coordinate system to improve: i) content server selection upon receiving content requests, and ii) the mapping of content to servers/caches. We describe the required protocol mechanisms, and evaluate potential gains using coordinates of Geometric Tree Routing and compare it to pure IP-based mechanisms or measurement-based content systems relying on coordinates. The proposed approach can be further extended in order to include alternate geometric systems for example supporting hyperbolic geometries. I. INTRODUCTION Content delivery has become an essential aspect of current cloud and telecom networks. The wide range of media services such as Spotify, Netfix, or content distribution systems such as BitTorrent are omnipresent on our smartphones, tablets, smart tvs and pcs. Most of these services somehow rely on caching and replication. However, being proprietary and deployed in isolation, these content distribution technologies do not allow to uniquely and securely identify named information independently of the distribution channel. In many cases, these technologies are implemented as an overlay, leading to needless inefciency. Content-Centric Networking (CCN) [1] aims at enabling data to become independent fom their network/physical lo cation, application, storage support but also their transport en abling in turn in-network transparent caching and replication. CCN design focusing on name-based data access therefore gets increase interest from the network research community. The conventional CCN concept of proposing name-based data access at the network level where content names get overloaded with a locator semantic exacerbates the memory scaling limits of shortest path routing already observed in many experimental studies and theoretic investigations. This approach is confonted with the issue that these name spaces have not been designed to sustain forwarding performance and scaling compared to IF address space which can be effciently aggregated, summarized and translated. This paper argues that efcient and scalable content-based forwarding requires to keep addresses or locators (instead of names) as information unit for routing/forwarding decision. 978-1-4799-8030-7/14$31.00 ©2014 IEEE The name of a resource indicates what we seek and an address (locator) indicates where it is. In addition, the selection of the addressing space for CCN should also elevate the memory scaling problem induced by shortest path routing. Therefore, we propose an alternative model for Content-Centric Net working (CCN) in which content names are assigned locators and content routing is performed on these locators. Routing decisions being performed on locators, this model avoids name-to-locator resolution by intermediate nodes but instead considers that name resolution provides suffcient information for the receiver to determine the best route towards the selected destination. The rest of this paper is structured as follows. Section II details the architecture of the proposed CCN approach and provides elements of the design and diferent steps of the content-centric geometric routing approach. Next, the concept is evaluated in a simulation setup, as well as validated at a lower level through emulation, both documented in Section III. Section IV recapitulates the learned lessons and formulates some potential future work. II. ARCHITECTURE AND DESIGN A Content-Centric Networking system consist of two fun damental functions: the localization function and the routing function. The localization function performs by using infor mation name as input to determine the corresponding locator, say x. The ruting function (distributed by nature) determines locally and independently for any destination the adjacent node along a loop-free path such that incoming messages directed to this destination can reach it. Obviously, by unifying the interpretation of the locator x and its interpretation of such information as distance d fom the end-point or terminal perspective, a distance metric can be defned. Putting all these ingredients together, leads to consider a locator space that can be processed at the end-points by a localization function and at intermediate nodes by a routing function. A. Geometric ruting and coordinate systems It remains to determine which locator value space would best ft this role. An obvious choice would be a so-called topology dependent label space. However, such value space is prone to renumbering even in case of non-local topological change; hence, unsuitable. Ideally, geometric space whose values are coordinates assigned in a way which closely refects the topology-inferred graph distances (e.g., hop count or weighted path length) while being robust to topology changes. Several attempts have been made in order to identify geo metric spaces for applying greedy ruting in order to reduce