Subject: Some tips for MBone session announcers (& writers of announcer programs)

From: Ross Finlayson <[email-masked]>
Date: Sun, 24 Aug 1997 02:25:18

In recent weeks (& especially last week) we've seen a large number of
frivolous sessions announced to the default SDP directory.  This is due in
part to the fact that "MBone session announcing netiquette" has not yet
been well publicised.  However, design flaws in some of the newer session
announcing programs also seem to be a contributing factor.

To help reduce the clutter in the default SDP directory, here are some tips
for making MBone session announcements (& some tips for people who have
implemented session announcing programs).

1/ Scope
If you're creating just a 'test' session, then please limit its scope, so
that the rest of the world doesn't have to be bothered by it.
[Tip for session announcement program implementors: Make the default scope
for new announcements small.]

2/ Lifetime
As the SDP spec notes, sessions that are unbounded in time - i.e., have no
expiration date - are strongly discouraged.  Please add a (realistic)
expiration date on your session announcement.
[Tip for session announcement program implementors: Make it difficult, if
not impossible, to create a session without an expiration date.  Also, make
the default expiration date small - e.g., 2 hours after the start time, as
is done by "sdr", for instance.]

3/ Modifying announcements
If you wish to make a change to a previously announced session - e.g., to
change the start time or fix a typo - then please do so by editing the
existing announcement, rather than creating a new announcement.
[Tip for session announcement program implementors: Remember that a session
is identified, in part, by the <session id> field in "o=".  If an existing
session announcement is changed (e.g., by editing), then the <session id>
field should remain the *same as before*, otherwise receivers will think
that the modified announcement is for a completely new session.  (Note:
Even some versions of "sdr" seem to get this wrong.)]

4/ Start time
If you're announcing an event that occurs in the future, please try to set
an accurate start time.  Some session browsers make use of the start time
to order its list of sessions, and/or to allow the launch of a session to
be automatically scheduled to occur on its start time.
[Tip for session announcement program implementors: Make it easy for the
user to set a start time when announcing a new session.]

	Ross.