Bandwith Question--Local

Joseph Erhard-Hudson (
Thu, 22 Feb 1996 17:56:18 -0800

This is purely practical--don't want to jump into the overall bandwidth debate.

**First the situation; questions to follow**

I work for an academic department of a rural agriculture college (Washington
State University), which has several branch campuses, and the administrative
powers would love to have us expand our branch campus service.

We would like to be able to offer multi-site classes, i.e. teleconferencing
on a 2-3 day/week basis. The university currently has a TV/satellite-based
system which is effective but extremely expensive--basically you're paying
for a tv studio and crew, up to $10k/semester. At that you might as well
hire an instructor at the remote site.

CU-SEEME and some QuickCams seem like a good deal, cost-wise. It might
allow sufficient visual contact to get by, and we could even go to phone
lines for the audio if bandwidth became an issue.

So here's a schematic of what I envision:
| | | |
V V | |
------------------------ ------------ ------------
| Lecture Site | | Remote 1 | | Remote 2 |
| | audio link?-> | aud/vis | | aud/vis |
| Camera 1 (lecturer) | ---^-------- ---^--------
| Camera 2 (display | | |
| materials)|------------------------------------------
| Audio |

So, one master site, sending two visual and one audio signal.
One or two remote sites recieving master site.

Also, A/V output from remote sites, sending back to master site only.

Students can see and hear teacher, teacher can see and hear students. Students
at different sites can't see but hopefully *can* hear each other (if only
one remote site, this issue is moot).

NO LURKERS! This would be a dedicated hookup only for the sites described.
Also, only one computer at remote sites: show it to all students with some
manner of display projector.

Standards: Good audio. High detail for materials, rapid motion not as
vital. Low detail on lecturer, but less jerky would be nice.


I can determine today what the equipment would cost. What will be the
bandwidth cost? Not in dollars, but in Mb/sec or what-have-you. I realize
my specs are
sketchy, but we're in the pilot stage right now anyways, getting ready to
test over local network and expand from there. Ballpark figures are what I

We have a campus network of sorts, but I need to determine if our
university's switches are up to it, and if not, what sort of connection we
need to buy for our department if it comes to that.

Also, what sort of bandwidth would we need at the remote site(s)?

Many thanks for any advice you can give.

Joseph Erhard-Hudson