Anselm Martin Hoffmeister wrote:
If you consider two aspects of "network speed", it becomes more obvious
what causes your video over WLAN problems.
There is of course the link bandwidth as an important way of measuring
"speed". Scaling down video to quite tiny video windows (in theory)
scales down the needed network bandwidth by the power of two, in respect
to the video window width. Thus, if near-to-fullscreen video runs
perfectly fine on 100M, quarter width video (16th part of the screen)
should run as well on 10M. In theory at least...
However, another factor of X performance has to do with the network
latency, which describes the average packet travel time over the
network. The easiest way to get an idea of this packet travel time is to
"ping" the remote side - and usually you will notice that a wireless
link, especially if over a WLAN bridge and connected through other wired
networks at both ends, has an enourmous delay compared to direct wire
connections. As the X protocol usually depends on messages to be passed
and acknowledgments to be passed back, a notable delay degrades display
performance. This might be changed by using a X proxy system like NX, if
this removes the acknowledgement requirement.
Regards
Anselm
After I read this I checked the RTT for two LTSP clients, one wired (ws001)
and one connected via a wireless bridge (ws002) with the following results:
[EMAIL PROTECTED] Desktop]$ ping -c 5 ws001
PING ws001.olicana.org (192.168.1.100) 56(84) bytes of data.
64 bytes from ws001.olicana.org (192.168.1.100): icmp_seq=0 ttl=64
time=0.167 ms
64 bytes from ws001.olicana.org (192.168.1.100): icmp_seq=1 ttl=64
time=0.164 ms
64 bytes from ws001.olicana.org (192.168.1.100): icmp_seq=2 ttl=64
time=0.161 ms
64 bytes from ws001.olicana.org (192.168.1.100): icmp_seq=3 ttl=64
time=0.165 ms
64 bytes from ws001.olicana.org (192.168.1.100): icmp_seq=4 ttl=64
time=0.162 ms
--- ws001.olicana.org ping statistics ---
5 packets transmitted, 5 received, 0% packet loss, time 3998ms
rtt min/avg/max/mdev = 0.161/0.163/0.167/0.016 ms, pipe 2
[EMAIL PROTECTED] Desktop]$ ping -c 5 ws002
PING ws002.olicana.org (192.168.1.101) 56(84) bytes of data.
64 bytes from ws002.olicana.org (192.168.1.101): icmp_seq=0 ttl=64
time=1.19 ms
64 bytes from ws002.olicana.org (192.168.1.101): icmp_seq=1 ttl=64
time=2.05 ms
64 bytes from ws002.olicana.org (192.168.1.101): icmp_seq=2 ttl=64
time=1.60 ms
64 bytes from ws002.olicana.org (192.168.1.101): icmp_seq=3 ttl=64
time=1.59 ms
64 bytes from ws002.olicana.org (192.168.1.101): icmp_seq=4 ttl=64
time=2.81 ms
--- ws002.olicana.org ping statistics ---
5 packets transmitted, 5 received, 0% packet loss, time 4008ms
rtt min/avg/max/mdev = 1.195/1.852/2.811/0.551 ms, pipe 2
So it looks like you are right, latency not bandwidth is the problem.
This is
rather unfortunate. I had a plan to reduce the bandwidth requirements but
I suspect it may not be so easy to reduce the latency (unless anyone has any
great ideas...).
-------------------------------------------------------
SF.Net email is sponsored by:
Tame your development challenges with Apache's Geronimo App Server. Download
it for free - -and be entered to win a 42" plasma tv or your very own
Sony(tm)PSP. Click here to play: http://sourceforge.net/geronimo.php
_____________________________________________________________________
Ltsp-discuss mailing list. To un-subscribe, or change prefs, goto:
https://lists.sourceforge.net/lists/listinfo/ltsp-discuss
For additional LTSP help, try #ltsp channel on irc.freenode.net
