Content-oriented Networking

Video traffic has been and will be increasingly prevalent in the Internet. Some video content providers (CPs, e.g., YouTube and Hulu) have even begun to provide high-definition video streaming services. As the bit rate of multimedia traffic increases, the TCP/IP architecture may reveal its inefficiency in delivering time-sensitive multimedia traffic. Another important multimedia application is multicasting/broadcasting over IP networks (e.g., IPTV). However, the endpoint-based Internet is not suitable for multicast/broadcast due to issues including multicast address assignment and complex group management. Such ineptness leads to limited deployment and complicated multicast frameworks. At present, many voluminous contents (most of which are multimedia [1]) are delivered to numerous users by peer-to-peer (P2P) systems such as BitTorrent. In BitTorrent, for each content file there is a tracker, which informs a new peer of other peers. A peer exchanges missing parts (called chunks) of the content file with other peers. However, from a networking perspective, the delivery performance of BitTorrent is inefficient since a peer can download chunks only from a small subset of peers who may be distantly located. In general, P2P systems have limited information on peers downloading the same content and the network topology among them (e.g. proximity). In these “content-oriented” applications/services, an end user cares not about hosts, but about contents. However, the current Internet relies on the host-to-host communication model. This mismatch leads to application/service-specific solutions, which may be costly and/or inefficient. Two representative examples are: • Web caches and content delivery networks (CDNs) transparently redirect web clients to a nearby copy of the content file. • P2P systems enable users to search and retrieve the content file. To address the above mismatch, there have been studies on content-oriented networking (CON)1 (e.g. [2–4]). They strive to redesign the current Internet architecture to accommodate content-oriented applications and services efficiently and scalably. The essence of CON lies in decoupling contents from hosts (or their locations) not at the application level, but at the network level. Note that these proposals also solve or mitigate other Internet problems such as mobility and security. We argue that the new CON paradigm will: • Free application/service developers from reinventing application-specific delivery mechanisms • Provide scalable and efficient delivery of requested contents (e.g., by supporting multicast/broadcast/anycast naturally) In this article, we classify the prior studies on CON, discuss their technical issues, and identify further research topics. After demonstrating the performance of CON proposals, we conclude this article.