A Large-Scale, Highly Configurable Network Emulation Facility

University Of Utah, Salt Lake City UT

Investigators

Abstract

Today there exist three environments in which to perform network research: live networks, network simulators, and static small-scale testbeds. Although each environment has benefits, each also has many limitations. This project proposes to build a new type of experimental environment, an "Internet in a room," which will not only complement the strengths and weaknesses of existing experimental environments, but work synergistically with some of them, such as simulation. The proposed instrument, a large-scale network emulation facility, will be a unique resource for network experimenters. The researchers are currently building a prototype, based on donated equipment and University of Utah funds. Under this proposalthe researchers will continue this early work, make the testbed "real" through developing significant software and deploying additional hardware, work closely with others to integrate it with network simulators, and provide professional staffing so that the facility is of maximum use to external researchers. A crucial goal is to make the facility universally available to any external researcher, without administrative or technical obstacles to simple and straightforward use. Single-node systems research and development has flourished as the barriers to entry have plummeted. Inexpensive, commodity, open, hardware (x86 PC) and software (Linux, *BSD), have made such R&D possible for all researchers, without large budgets. We propose to develop the software for an instrument that will bring similar benefits to network researchers, and apply it to a first instance of hardware. A significant aspect of this proposal is joint work with other researchers domain experts, especially net-work simulation experts at Georgia Tech to exploit the facility's unique capabilities for network emulation, to learn how best to use it, and to guide its evolution. The emulation facility's unique characteristics include: (1) significant scale: 250 nodes, each of degree at least four. (2) user-configurable lowest-level control over the testbed's "physical" characteristics, such as error models, latency, bandwidth, packet ordering, processing power, and buffer space. (3) accurate emulation of wide-area networks via internal traffic-shaping nodes; (4) capture of low-level device/OS costs such as interrupt load and memory bandwidth; (5) experimentation on the router software itself, as well as ease of maintainence and robust security, is provided by fully user-replaceable router OS/software; (6) "ns" compatible specification language and integration with the Georgia Tech "software backplane for emulation," allowing experiments easily to move between simulation and emulation; (7) remote configurability and availability to researchers world-wide, both time and space-shared; (8) isolated control, monitoring, and data acquisition network; remote power control and serial line console /debugging for all nodes; (9) incorporation as an integral part of the national Active Network Backbone (ABONE).