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sectionM-5.txt
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NEST - Columbia University's Network Simulation Tool
_A_d_d_r_e_s_s:
Alexander Dupuy
450 Computer Science
Columbia University
New York, NY 10027
_E-_m_a_i_l: nest-request@cs.columbia.edu
_P_h_o_n_e: (212) 939-7000
FAX: (212) 666-0140
_D_e_s_c_r_i_p_t_i_o_n
The NEST simulation package developed at Columbia is an
environment for rapid prototyping and simulation of distri-
buted networked systems. NEST users can develop and test
distributed systems and protocols (from crude models to
actual system code) within simulated network scenarios.
NEST is organized as a simulation server, responsible for
execution of complex simulation scenarios, and a separate
graphical interface for simulation control. The
client/server model permits distribution of NEST over a net-
work environment. Thus, complex simulations may be migrated
to powerful remote computational servers. Alternatively,
complex studies/development efforts by multiple teams may
utilize a shared multi-site simulation/integration testbed.
Simulation servers are created using the NEST library, a C-
language library which runs under most Unix variants, and on
POWER (IBM RS/6000), SPARC, MIPS, 680x0 and VAX architec-
tures. The NEST library provides a simple, high-level
message-passing facility among a set of concurrent light-
weight processes which simulate a distributed system.
The interface provided by the NEST library allows users to
link in their own C code and run it on one or more nodes in
a simulated distributed environment. NEST provides the
_________________________
The information in this section is provided in accor-
dance with the copyright notice appearing at the front
of this guide.
September 4, 1992 NNSC Section M.5, Page 1
following operations in this environment:
o+ send messages to neighboring nodes
o+ receive messages (optionally, with timestamps)
o+ check for available messages
o+ control passage of simulation time
The user can also provide C code which simulates the
behavior of a channel, and associate it with one or more
communications channels. More than one function can be
associated with a channel, and the following operations are
provided:
o+ alter contents of messages
o+ control transmission delay of messages
o+ drop messages (cause them to not be received)
Finally, a monitor function can be provided by the user,
which runs periodically in the simulation, and can perform
modifications to the network scenario as noted below in the
description of the NEST generic monitor. In addition, the
functionality provided by most available Unix libraries is
accessible within a simulation server.
Users interact with NEST through the NEST generic monitor,
an X-based graphical interface supporting editing and modif-
ication of simulation scenarios as well as dynamic reconfi-
guration of a simulation during execution. Thus, it is pos-
sible to study the dynamic response of a distributed system
to failures, burst-loads or other complex dynamical changes.
The nest monitor provides the following operations for mani-
pulation of the network simulation scenario:
o+ create and delete nodes
o+ create and delete links
o+ start and stop functions running on nodes
September 4, 1992 NNSC Section M.5, Page 2
o+ change the function associated with a node
o+ change the list of channel functions associated with
an edge
o+ change the weight parameter associated with an edge
o+ change the monitor function which runs periodically
o+ show the current status of a node in the simulation
NEST includes documentation and complete C source code for
both the NEST library and the NEST generic monitor. The
NEST library will run under most Unix variants, including
AIX, SunOS, Ultrix, 4.x BSD, and System V. The NEST generic
monitor is an X application which uses the XView library.
The currently released version of NEST is version 2.6.
_N_e_t_w_o_r_k _A_c_c_e_s_s
NEST documentation and full source is available via
anonymous FTP from cs.columbia.edu [128.59.16.20] in the
nest directory. Some files are stored as compressed tar
archives - be sure to remember to use binary mode when
transferring them!
There are several files in the ~ftp/nest directory:
nest-2.6.tar.Z Source for Nest 2.6 library & UI display
nest-2.6-patch.* Patches to Nest 2.6 library - please apply all
nest-25-doc.tar.Z Lineprinter formatted documentation
nest-25-doc2.tar.Z Scribe and PostScript formatted docs
_W_h_o _C_a_n _U_s_e _t_h_e _S_e_r_v_i_c_e
The NEST software is distributed under this arrangement for
research and evaluation purposes only. Any redistribution
or commercial use of the software itself in any form is
prohibited without further licensing from Columbia Univer-
sity.
September 4, 1992 NNSC Section M.5, Page 3