1 Contract-Switching for Managing Inter-Domain Dynamics

The Internet's simple best-effort packet-switched architecture lies at the core of its tremendous success and impact. Today, the Internet is firmly a commercial medium involving several competitive service providers and content providers. However, current Internet architecture neither allows (i) users to indicate their value choices at sufficient granularity, nor (ii) providers to manage risks involved in investment for new innovative Quality-of-Service (QoS) technologies and business relationships with other providers as well as users. Currently, users can only indicate their value choices at the access/link bandwidth level, not at the routing level. End-to-end (e2e) QoS contracts are possible today via virtual private networks, but with static and long-term contracts. Further, an enterprise that needs e2e capacity contracts between two arbitrary points on the Internet for a short period of time has no way of expressing its needs. We propose an Internet architecture that allows flexible, finer grained, dynamic contracting over multiple providers. With such capabilities, the Internet itself will be viewed as a " contract-switched " [15] network beyond its current status as a " packet-switched " network. A contract-switched architecture will enable flexible and economically efficient management of risks and value flows in an Internet characterized by many tussle points [4]. We view " contract-switching " as a generalization of the packet-switching paradigm of the current Internet architecture. For example, size of a packet can be considered as a special case of the capacity of a contract to expire at a very short-term, e.g. transmission time of a packet. Similarly, time-to-live of packet-switching is roughly a special case of the contract expiration in contract-switching. Thus, contract-switching is a more general case of packet-switching with several additional flexibility in terms of its economics and carefully reduced technical flexibility due to scalability concerns particularly at the routing level. In this book chapter, we report our recent work [15, 6] on contract-switching and a sample intra-domain contracting scheme with bailouts and forwards. We describe a contract-switching network architecture for flexible value flows for the future Internet, and for allowing sophisticated financial engineering tools to be employed in managing the risks involved in composition of e2e QoS contracts. We concentrate on the design of our contract-switching framework in the context of multi-domain QoS contracts. Our architecture allows such contracts to be dynamically composable across space (i.e., across ISPs) and time (i.e., over longer