Re: Refs or no refs

Brian Godette (bgodette@idcomm.com)
Tue, 28 Oct 1997 11:42:31 -0700


At 12:13 AM 10/28/97 +0100, you wrote:
>Brian Godette wrote:
>> Now take into account that in 10 seconds with a 28.8
>> connect you can receive roughly 35Kbytes of data you begin to see that=
this
>> isn't such a big deal (roughly 2% of your total bandwidth per client).=
Now
>> if you're really paying attention, you'll notice that 38% of your=
bandwidth
>> is consumed when a conference reaches 20 clients (you're receiving
>> information from N-1 clients), which is why the 15Kbps max transmission
>> rate starts to make sense, it gives you about a 9% buffer zone for a
>> conference that size.
>Wow.. You are the technical expert ! So !=20
>15kbps max transmission =20
>(Althought I can=B4t believe it that it must be that low, but your
>calculations were convincing. So I must set up the max sending rates
>according to the number of participants, dynamically, after loging on a
>ref !)
>
>But I hope that
>28kbps max receiving=20
>is allowed for 28.8 connections.
>
>So what are the expert=B4s advices for the min transmission and receiving
>rates,
>with the same technical elegance ?

Min's are irrelevant, neither the client or reflector pays any attention to
it, except as max-min settings on the ref that have the effect of kicking
you off (for no good reason since those numbers don't matter anyways).

This is verified for the WP 2.1.2 client by running self-refs with a min
xmit of 128kbps and a max xmit of 90kbps. Stops at 90, but when sending a
completely black image it xmits at 21fps (fps limit of the quickcam on this
machine) @ 18kbps instead of resending the same frame several times it only
send each frame once.

And for a reflector, how is it going to send a minimum amount of traffic if
there isn't that much traffic to begin with? In other words, max-min-recv
is meaningless to a reflector.

As for DC's, at least with WP 2.1.2 flow control is non-existant except for
max xmit rates, the only thing effecting the xmit rate of the other client
is packet loss reporting. So for example you could connect to someone
xmiting at 90Kbps and you have a max receive rate of 15 (just for the sake
of testing, otherwise that's be a nonsense receive rate for anything but a
14.4), you'd receive whatever the max receive capabilities (for a 28.8
roughly 28-30Kbps) of your link up to 90Kbps. The senders xmit rate would
then fall down to match your link's receive abilities after a few minutes
due to the loss reports. So for DC's even fewer settings are relevent, the
only one being max xmit, at least as far as WP 2.1.2 is concerned.