Netscript: a programming language for packet-stream processing

The central goal of this dissertation is to introduce a general-purpose language-based system called NetScript to simplify the development, deployment, and management of protocol and service software in a computer networks, specifically programmable or active networks. NetScript is the first system to: (1) Introduce a high-level dataflow language to program processing of packet flows, including protocols and services; (2) Integrate constructs for packet syntax declaration, classification and processing, as well as composition of packet processing modules, to unify and simplify the construction of communications software; (3) Introduce compiler-generated instrumentation of network services to simplify and unify their management; (4) Support dynamic deployment and composition of distributed flow processing modules, implementing end-to-end services on active or programmable networks. NetScript views network protocol processing in analogy the PostScript paradigm. PostScript views a printer as a programmable printing engine that executes page-descriptions. Similarly, NetScript views a network node as a programmable processing engine that executes programs that process packet of a programmable, networked engine. Whereas, currently protocol software must be re-written for each architecture, NetScript programs can run unmodified on heterogeneous architectures and platforms. NetScript enables rapid evolution of network technologies by creating a dynamically programmable infrastructure, one that can be flexibly extended with new or enhanced services. Specifically, NetScript defines a novel programming model for programming services on active or programmable [1–3] networks. NetScript programs can be dispatched to nodes in a network to dynamically extend the network with new protocols and services. Its programs are dataflow components that perform primitive operations on packet-streams. NetScript simplifies and automates essential components of network management. Currently, network management instrumentation must be designed and specified by committee separate from protocol design and implementation. This is a process that can take several years. NetScript unifies and automates the creation of management instrumentation at design-, implementation-, and compile-time. NetScript has proven useful for implementing a variety of networked applications. Example applications are IP routers, firewalls, protocol analyzers, network address translators, traffic shapers, queuing disciplines, intrusion detection systems, transport protocols and IP telephony systems.