Re: Cu-Seeme and Appletalk?

John D. Balogh, +1 814 863 1252 (JohnBalogh@psu.edu)
Fri, 12 May 1995 10:34:01 -0400


>I run CU-SeeMe over appletalk and it works just fine.

Good.

>I believe when the number 230,400 kbps comes up,

That should be either 230.4 Kbps or 230400. bps. The "K" implies a factor
of 1000 times the unit.

>one is talking about the bus capacity.

Yes. Just like ethernet is 10.0 Mbps (10000.0 Kbps) and a "bus" LAN.

>This is then divided up amongst the users who are connected to that
>certain bus.

Not exactly, but probably very good observation of reality.

If 100 users are connected, but only 2 are communicating between each
other, the 2 will "see" an effective bandwidth of 230K +/-.

If all 100 users are communicating but using different protocols
(TCP, UDP, AppleTalk, XNS, IPX, etc.) and different applications
(Telnet, FTP, CU-SeeMe, disk accesses, etc.) the effective bandwidth will
be less than 230K per user, but the exact rate will depend on the
integration of all the other requests and their durations.

If all 100 users are communicating with the same protocol and application
(say, TCP and FTP) and they all request the same ammount of data at the
same time, it is probable that they each will get 1/100 of the available
bandwidth (2.3 Kbps in this case). This is hard to test without 100
cooperating people in one room, fingers poised above the mouse button
waiting for the signal: "3, 2, 1, CLICK!".

In practice, some protocols are more piggish than others and will "slow"
the network down. Also some programs are more suseptable to network
delays and will allow the user to observe any slowness or high use.
Conversly, some protocols are efficient and some other programs are
very tollerant of network delays and losses.

Hope this helps!

-
Name/Rank/Serial#: John Balogh, Systems Engineer, JohnBalogh@PSU.EDU
Employer: Penn State University, Office of Telecommunications
Phone: +1 814 863 1252 Fax: +1 814 863 4092
SNAILmail: 101 TELECOM, UNIV. PARK, PA 16802-5800, USA
WWW: http://jdb.psu.edu/john.html