VINT Project Overview

The rapid diffusion of internetworking technology brings two major sources of stress to the underlying protocol mechanisms and associated design methods: scale and heterogeneity. Scale must be considered in evaluating both the correctness and performance of wide area internet protocols at every level (from routing, to transport and session protocols). Heterogeneity of applications translates into a larger number of interacting protocols, service requirements, and traffic patterns. In light of these phenomena we claim that current protocol design and engineering practices are critically inadequate and must be changed in order to produce robust and evolvable network technology in the future. The proposed Virtual InterNetwork Testbed system hopes to transform network protocol design and engineering practices in the same way that simulation and VHDL-based methods transformed chip and board level design. The following innovations will allow us to meet this goal:

Composable simulation framework

The simulator architecture will provide a framework for composing simulation modules. This will create synergy between disjoint simulation efforts and enable the simulation of complex interdependencies between protocols. This framework is intended to model the modularity of the Internet architecture itself, which allows rapid and independent development of new protocols and applications.

Abstraction techniques and tools

It is hard to identify, and focus on, the relevant phenomena buried within the mountain of data generated by a realistic simulation of an operational network. A crucial aspect of making simulation more valuable is to provide the ability to vary the level of abstraction, in both the analysis of the data and in the simulation itself. These tools will allow users to identify relevant phenomena using high-level simulations and then use detailed simulations to study the phenomena more extensively. Key to this technique will be providing useful correlation of detailed and high-level simulations.

Visualization techniques

Many relevant network phenomena remain invisible when only aggregate statistics are collected. Visualization techniques are crucial in enabling users to identify interesting aspects of the simulation. These visualization tools will assist users in framing design questions and guiding the debugging process with detailed and coarser grain evaluations.

Emulation interface

The emulation interface will allow actual network nodes to interface with the simulator. This will enable more complete debugging of code before deployment, and will also allow simulations to more accurately represent the behavior of the actual deployed code.

Libraries of Network Topologies and Traffic Generators

The load mix of the Internet is shifting rapidly (now to WWW, and perhaps soon to audio and video), and the topology has always been in flux; it is important to provide simulation researchers with the ability to explore the implications of these topology and load shifts. By providing an extensive, and extensible, library of network topologies and traffic generators, it will be possible to test protocol performance over a wide range of conditions. The common library of simulation environments will also allow more comparison between different simulations, easing the verification of the simulation results.

Project Summary for 1996-97

Project Summary for 1997-98