No abstract

We describe a wireless sensor network designed for the long-term study of rare and endangered species of plants. We wish to monitor plants and their environment via high-resolution cameras and temperature, humidity, rainfall, wind, and solar radiation sensors. Our units must be “invisible” (camouflaged), very low energy, and must allow distributed local computation. Data rates are 1 to 100 bytes/second per node, but networks can be large — an early prototype had 60 nodes. Failures are expensive and we must exploit redundancy whenever possible. Nodes are stationary but for energy reasons may decline to participate in transmissions. We have designed two wireless routing protocols that satisfy these constraints. Multipath On-demand Routing (MOR) computes multiple optimal routes to avoid depleting the energy at any given node. Geometric Routing scales to large networks, relying on Geographic Routing when possible and on selected global information otherwise. We have simulated and are implementing both protocols.

is in the soware group at Fore Systems, where his responsibilities include the switch control sofiare described in this article. ERIC COOPER cofounded Fore Systems to commercialize ATM LANs. As president and CEO, he has overall responsibility forATMtechnohgv at Fore Systems. ROBERT SANSOM is cofounder and executive vice president of Fore Systems, Inc. He manages Fore Systems' business development and is responsible for Fore Systems' technical stmtegv.

This paper describes the design of an implementation of the Transmission Control Protocol using an extension of the Standard ML (SML) language. SML supportshigher-order fimctions, modularity, and type-safe module composition.We find that by using SML we can achieve good structure and good performance simultaneously. Good structure includes a modular decomposition of the protocol stack and of the TCP implementation, a control structure that imposes a total ordering on all events and processes them synchronously, and a test structure that allows component testing to catch problems before system integration.Strategies that help achieve good performance include using fast algoritbrns, using language constructs that make it easy to stage function evaluation, and language implementation features such as compacting garbage collection. The Fox Project is addressing both questions by producing implementations of network code in the Standard ML (sML) [12, 11] progr amming language. "

No abstract