Re: Speed negotiation between Reflector and CU-Seeme

Scott Brim (
Tue, 24 Jan 1995 15:46:49 -0500

At 15:12 01/24/95, Alan Larson wrote:
> If this is wrong, why are about 80 - 90 percent of the packets sent
>to me by reflectors being lost? If there were congestion control, the
>transmit rate would back off.
> If this is wrong, why does CU-SeeMe blast the leased line to our
>remote office so badly that terminal sessions over the line stop

Thanks for asking. As one insightful person pointed out, the fastest
way to get an answer on the Internet is to post misinformation, but I
still wish people would ask first.

As has been discussed here before, CU-SeeMe backs off based on
aggregate packet loss. To simplify, leaving out the little tweaks, if
>= 5% of the packets it sends are lost it will back off 5%, until it
reaches a minimum of 10Kbps. Since sender backoff is based on the
aggregated fate of the sender's packets, one not unlikely reason your
line might be melting is if you are connected to a reflector where
other participants have much more available bandwidth than you do.
This is why the receiver should be able to control how much the
reflector is going to send to em.