REAL 5.0 Overview S. Keshav Cornell University skeshav@cs.cornell.edu   August 13th 1997


REAL is a network simulator originally intended for studying the dynamic behaviour of flow and congestion control schemes in packet-switched data networks. It provides users with a way of specifying such networks and to simulate their behavior. It provides around 30 modules (written in C) that exactly emulate the actions of several well-known flow control protocols (such as TCP), and 5 research scheduling disciplines (such as Fair Queueing and Hierarchical Round Robin). The modular design of the system allows new modules to be added to the system with little effort. Source code is provided so that interested users can modify the simulator to their own purposes. Online documentation and source code are part of the distribution.

The simulator takes as input a scenario, which is a description of network topology, protocols, workload and control parameters. It produces as output statistics such as the number of packets sent by each source of data, the queueing delay at each queueing point, and the number of dropped and retransmitted packets. This release includes a graphical user interface (GUI) written in Java by Hani T. Jamjoom at Cornell University.The GUI allows users to quickly build simulation scenarios with a point-and-click interface.  For more details, please see the RealEdit home page.

The GUI also allows scenarios to be simulated on a server generously loaned to Cornell University by Digital Inc. This makes it unnecessary for users to download, compile and build the simulator in order to run simulations. Instead, the scenarios, once created, are shipped to the server for execution, and the results are shipped back to the GUI for display.

Platforms

REAL is written in C, and will run on Digital Unix/ SunOS/ Solaris/ IRIX/ BSD4.3/Ultrix /UMIPS systems on VAX, SUN, SPARC, MIPS, Alpha, SGI or DECstation hardware. For a full list, see the Installation manual.  The simulator has been ported by Warren Toomey and Elan Amir to the i386/FreeBSD 2.0.5 platform. Click here to get their patches to REAL, or ftp them from ftp://minnie.cs.adfa.oz.au/pub/www/REAL/Real_FreeBSD.tar.gz.
 

Manuals

REAL manuals can be found here. The Installation manual will help you install the simulator in your local environment. The User manual is a step-by-step tutorial on using REAL for beginning users. The Programmer's manual is a tour of the files in REAL, and a cookbook for modifying REAL and Nest.

An early description of REAL is in Computer Science Department Technical Report 88/472, UC Berkeley, 1988. It gives an overview of REAL and some examples of network analysis using REAL. For copies send mail to Anne Fuller, Office Supervisor, fuller@cs.berkeley.edu. For a description of the changes made in REAL 5.0 compared to REAL 4.0, please see the changes page.
 

Mailing List

Warren Toomey (wkt@cs.adfa.oz.au ) maintains a mailing list of REAL users. To reach users on this list, send mail to real@minnie.cs.adfa.oz.au. Send subscription and unsubscription requests to majordomo@minnie.cs.adfa.oz.au. To subscribe send a message with the single line

subscribe real

in the body of the message.

Warren also maintains a searchable archive of mail sent to this mailing list over the last several years.
 

Availability

The current version, REAL 5.0, is available as

REAL5.0.tar.gz.
REAL5.0.tar.Z

The older version is also available:
REAL4.5.tar.gz

You can directly download it if your browser knows how to deal with gzipped or compressed files. Otherwise, save it as a file, say REAL5.0.tar.gz. Then type

(substitute uncompress for the .Z file). This will create a directory called sim in which you will find the docs subdirectory. Read the installation manual, which is called installation.html, for detailed instructions.

Licencing

If you intend to use REAL, please complete the licence document here and send it off to the appropriate place. If you want to be informed about bug fixes and updates, please register yourself when the sim/src/Configure command is executed during installation.


The fine print

REAL is based on a modified version of the NEST 2.5 simulation testbed from Columbia University.

Copyright 1989, 1990, 1993 The Regents of the University of California. Copyright 1997 Cornell University. All Rights Reserved. Permission to use, copy, modify, and distribute this software and its documentation for educational, research and non-profit purposes, without fee, and without a written agreement is hereby granted, provided that the above copyright notice and the following three paragraphs appear in all copies.

NEST, Copyright 1988 Columbia University, a Network Simulation Testbed, written by Alex Dupuy. Direct technical questions regarding NEST to Alex Dupuy dupuy@cs.columbia.edu  and questions regarding NEST distribution to Prof. Jed Schwartz jed@cs.columbia.edu.

IN NO EVENT SHALL THE UNIVERSITY OF CALIFORNIA OR CORNELL UNIVERSITY BE LIABLE TO ANY PARTY FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, INCLUDING LOST PROFITS, ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF THE UNIVERSITY OF CALIFORNIA OR CORNELL UNIVERSITY HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

THE UNIVERSITY OF CALIFORNIA AND CORNELL UNIVERSITY SPECIFICALLY DISCLAIM ANY WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS ON AN AS IS BASIS, AND THE UNIVERSITIES HAVE NO OBLIGATIONS TO PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS