This documentation is a revised edition of the
MICE documentation of
National Support Centre London
Revision by Jens Elkner (

Other User documentation

User Guide to sd

The Session Directory tool (sd) from Lawrence Berekeley Laboratories (LBL) is the basic and most effective way of starting or joining a multicast session. If can be used to start sessions on your local machine, your local net or across the whole of the MBONE. Therefore exercise great care. The "ttl" ("time to live", which limits the scope of your session packets) should be set according to your needs since it determines how far your transmission will carry. Always start your experiments with a ttl of 1. You can then increase it to 16 which will keep the session traffic in your site.

Browsing the MBONE

The standard use of sd is to browse the MBONE events which have been entered after an announcement has gone to The tool might look like this


Here you could select a session with the mouse (usually left button) and then open the session. The figure shows that the 2nd Int. WWW Conf. (Chicago) has been selected. In the lower window there is further information on that session, including a WWW page for the "agenda".

Some sessions will only have one medium (e.g. vat) and some will have three, audio, video and shared drawing space. If you are limited, the wb sessions are the easiest to multicast, in the sense that less data is transferred, followed by audio (vat) and finally video (nv, ivs or vic).

Starting your own session

To start your own session in sd, follow these steps. Here we assume that audio, video and shared drawing space will be needed. For example,


This shows a "A MICE Seminar" in the "Name" field and "Jo Smith on RSVP" in the "Description" field. Internally, the information seen above is stored in the file $HOME/.sd_cache as follows:

  s=A MICE seminar
  i=Jo Smith on RSVP
  c= 1 2868982096 2869007296
  m=audio 43021 50164
  m=video 46617 3831
  m=whiteboard 50572 59942
The multicast address for all tools is, and nv will be used, since this is the default video format. On audio, "vt" was chosen rather than the default.

Finally, you may wish to alter the behaviour of a tool started from sd. Here is an example of $HOME/.sd.tcl that will allow you to start some tools with non-standards arguments.