Re: Ready for ISDN

Richard Cogger (R.Cogger@cornell.edu)
Wed, 8 Feb 1995 10:43:11 -0500


At 8:16 PM 2/7/95, Michael Sattler wrote:
>At 07:49 2/7/95, Michael Coyle wrote:
>
>>If a viewer connects to a reflector at 28.8k, will he drag down the
>>performance of other ISDN connections.
>
>No. CU-SeeMe is smart enough to back off slow connections. My web page
>has Larry's or Tim's post on this subject.
>
>-----------------------------------------------------------------------+
>Michael Sattler <msattler@jungle.com> San Francisco, California |

Oops. With current v3 reflector and current versions of the desktop apps,
only the sender responds to loss reports, and only to the aggregate of all
loss reports from all receivers. So a sender will back off until the
average loss is 5% or less. But if paths to receivers vary significantly
in capability, the average may result from modem users geting 75% loss and
others getting none, and yes, all of the senders will have slowed down (see
the "cap" drop on your own window).

Tim is just about to start on changes to the reflector (and some to the
app) so that the reflector will look at loss reports and pre-emptively drop
packets for slow receivers that the network (or their slip server) would
have dropped anyway. When we have this out, slow receivers will not drag
down the conference and also will not load up network elements handling
(dropping) packets they're not going to be able to receive anyway.

Also, there will be some other refinements to make everything better for
the bandwidth-challenged and for those interacting with them.

Cheers, -Dick