On the Interface of Programmable Network Elements

There is now increasing interest in active and programmable networking. Increasing amount of research is ongoing on topics ranging from dynamic service and network management, to control plane switch programmability, to active network capsules carrying code in every datagram. This is in addition to the already established trend of added functionality of gateways, proxies and servers in the network. Together the two are accelerating the rate at which advanced functions are being introduced into the network, where service providers attempt to provide enhanced and differentiated services. While different players have different motivation to increase the programmability of network elements, the primary motivation for a service provider is to provide differentiated services using commodity components. Whereas economic reasons drive network providers to use commodity infrastructure technologies for optical transport, switching and servers, service differentiation is essential to maintain profitability. In this paper we report on our work on the programmable interface of network elements. The interface separates the service generic facilities of an otherwise commodity network node from the service specific functions implementing the service model of offered by the network operator. These service specific programs might be provide by end-users, by the service provider, by an independent service developer or by the network element manufacturer. However, the essential issue is that the functions running above the interface do not have nor require intricate knowledge of the implementation of the service generic facilities. In this paper we describe the interface, discuss some of our prototyping of services and applications to verify the functionality of this interface.