Data network connectivity developments, networking business news, and related computing items.
Thursday, August 19, 2004
: "The NIST Net
network emulator is a general-purpose tool for emulating performance dynamics in IP networks. The tool is designed to allow controlled, reproducible experiments with network performance sensitive/adaptive applications and control protocols in a simple laboratory setting. By operating at the IP level, NIST Net can emulate the critical end-to-end performance characteristics imposed by various wide area network situations (e.g., congestion loss) or by various underlying subnetwork technologies (e.g., asymmetric bandwidth situations of xDSL and cable modems).
NIST Net is implemented as a kernel module extension to Linux .. In use, the tool allows an inexpensive PC-based router to emulate numerous complex performance scenarios, including: tunable packet delay distributions, congestion and background loss, bandwidth limitation, and packet reordering / duplication. " Last modification 2002. 4:31:17 PM
The Network Simulator - ns-2
: "Ns is a discrete event simulator targeted at networking research. Ns provides substantial support for simulation of TCP, routing, and multicast protocols over wired and wireless (local and satellite) networks. " It supports Network Emulation
, "The simulator acts like a router allowing real-world traffic to be passed through without being manipulated. The ns packet contain a pointer to the network packet. Network packets may be dropped, delayed, re-ordered or duplicated by the simulator. Opaque mode is useful in evaluating the behavior of real-world implementations when subjected to adverse network conditions that are not protocol specific." Tutorial available
. 4:26:50 PM