"tcpmcu" eases teaching and administration of Cisco routers

March 19, 2001

freesoft.org, a website specializing in free software and Internet networking technology, announces the version 0.1 prerelease of tcpmcu, a TCP Multipoint Control Unit. tcpmcu allows multiple users to share a single TCP Telnet session, all seeing the same output. Allowing users in different locations to share a Telnet session aids teaching and improves coordination among users. The software, written in C and designed for use on UNIX systems, is publicly available from the following URL:


tcpmcu was written by Brent Baccala, freesoft.org webmaster, and motivated by suggestions from Bruce Caslow and Valeriy Pavlichenko, authors of Prentice Hall's popular "Cisco Certification" text. The three men were searching for a way to coordinate router configuration over the telephone. "The hard part is figuring out what the other guy is typing if you can't see it," Brent says. "This program lets everyone see what everyone else is typing, no matter if you're in Germany or California."

When using tcpmcu, users telnet to the program, which relays the connection to another port, possibly on a different computer. Additional users telneting to the tcpmcu are then multiplexed onto the existing session. Any user can type keystrokes, which are echoed to everyone sharing the session. Output from the computer system is likewise copied to all the users. Multiple tcpmcu's can run on a single computer; users can differentiate between them by picking which port number to connect to.

Possible uses include:

tcpmcu is similar to other MCU technology, including T.120 shared whiteboards (Microsoft NetMeeting) and shared GUI sessions (AT&T VNC). Unlike T.120 or VNC, tcpmcu is purely text-based, requires much less network bandwidth, and therefore is better suited for wide area networks.

Future directions in the development of tcpmcu include improved authentication and implementation of a "view-only" mode, which would allow some users to watch a session but prohibit them from typing on it.

Download tcpmcu from: