Spawning Networks

16 he ability to rapidly create, deploy, and manage new network services in response to user demands presents a significant challenge to the research community and is a key factor driving the development of programmable networks. Results from this field of research are likely to have a broad impact on customers, service providers, and equipment vendors across a range of telecommunication sectors, calling for major advances in open network control, network programmability, transportable software, and distributed systems technology. In the near future competition between service providers is likely to hinge on the speed at which one provider can respond to new market demands over another. Existing network architectures such as the Internet, mobile, telephone, and asynchronous transfer mode (ATM) exhibit two key limitations that prevent us from meeting this challenge: • Lack of intrinsic architectural flexibility in adapting to new user needs and requirements • Lack of automation of the process of realization and deployment of new and distinct network architectures In what follows we make a number of observations about the limitations encountered when designing and deploying network architectures. First, current network architectures are deployed on top of a multitude of networking technologies such as land-based, wireless, mobile, and satellite for a bewildering array of voice, video, and data applications. Since these architectures offer a very limited capability to match the many environments and applications, the deployment of these architectures has predictably met with various degrees of success. Tremendous difficulties arise, for example, because of the inability of TCP to match the high loss rate encountered in wireless networks or for mobile IP to provide fast handoff capabilities with low loss rates to mobile devices. Protocols other than mobile IP and TCP operating in wireless access networks might help, but their implementation is difficult to realize. Second, the interface between the network and the service architecture responsible for basic communication services (e.g., connection setup procedures in ATM and telephone networks) is rigidly defined and cannot be replaced, modified, or supplemented. In other cases, such as the Internet, end user connectivity abstractions provide little support for quality of service (QoS) guarantees and accounting for usage of network resources (billing). Third, the creation and deployment of a network architecture is a manual, time-consuming, and costly process. To help deal with complexity, network designers capture the blueprint that parameterizes the design space into an architecture. Network architectures identify the network hardware and software components, and show how they can be arranged to Spawning Networks