Re: VRML usage (from www-vrml@wired.com)

Andrew C. Esh (andrewes@cnt.com)
Fri, 21 Apr 1995 18:07:35 -0600 (CST)

On Thu, 20 Apr 1995, Nathon Gunn - PHAM/F93 wrote:

> Regarding the data lag for audio transmission in virtual worlds... is it
> totally obvious (ie am I way behind) that we could find some way to use
> phones for the audio (ie telephone), and computers for the data. In
> crude ways, i do this when I guide people via phone through VR demos I
> send on disk or have them download. It is just so much more reliable
> than voice packets. Is it a step backwards?

In a way, it is, but in general, you have the right concept. We need to
use a connection for time sensitive (synchronous) data, which the
Internet is not, during periods of high use. The Internet can *appear* to
be usable for things like audio, but only when there is enough spare
bandwidth to ensure that the packets will get through. This will not be
the case now that the Internet is popular.

We can use a dedicated circuit, like the phone line, but let's use
something like ISDN, and move things digitally. The 3000 Hz bandwidth
supplied by the audio phone line (Plain Old Telephone Service - POTS) is
just too small for modern uses.

For the feedback part, which you're going to want, should be send on a
high bandwidth broadcast network, just like Cable TV. Satellites, like
those that transmit to those mini-dishes that are being sold now, have
too much lag (1/4 second) to be effective in an interactive environment.
Maybe Spread Spectrum Radio would work, if the Cable companies don't pick
up on this.

---
Andrew C. Esh                 mailto:andrew_esh@cnt.com
Computer Network Technology   andrewes@mtn.org (finger for PGP key)
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