Am Freitag, den 16.09.2005, 21:35 +0100 schrieb Simon Langley: > I use a laptop as an LTSP client. I can watch films on it fine on a wired > network so there is no fundamental problem. When I am using an 802.11g > (=54Mbps) it's hideously slow and choppy, running at about a quarter of the > correct speed. This is so even if the video size on the screen is > absolutely > tiny. The amount of data passing across the network in this case cannot > possibly be enough to swamp the network connection on its own and nothing > else is running at the same time. > > There is clearly a speed difference between a 100M wired LAN and an > 802.11g network, but not so much so that one works fine and the other > barely at all. I am still trying to diagnose my problem, but I suspect it > is not as simple as just raw network speed.
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 ------------------------------------------------------- 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
