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Re: [school-discuss] Wireless network ambulance for classrooms w/o wired network connectivity

Don Christensen wrote:
cdmiller wrote:

Damiano Verzulli wrote:

Daniel Howard wrote:

[...] convert our elementary school's network to support LTSP/thin clients, one of the challenges we have is that due to construction [....]

Please note that, while driving along the way of the LTSP/thin_client adoption, another challenge you might face with, expecially employing wireless-lans, it's the bandwidth!

As the standard LTSP rely on the X protocol and the X protocol consumes lot of bandwidth, I think that with a 11Mbps links you could experience some problems!

Having run rooms full of X Terminals and workstations using X applications and NFS mounted home and application directories on 10 Mbps wired links in the semi distant past with no trouble, I personally don't see the bandwidth concern with using X over 802.11b, and 802.11g is also cheaply available. The ease of sniffing passwords etc. on unencrypted wireless or wired networks is of course a different problem.

- cameron

I wouldn't base wireless performance estimates off of wired experience.
You would have to know what the collision avoidance algorithm is and how
well a wireless network deals with congestion. I'm not sure that a hub-based
wired network would even be comparable.

I wasn't sure about the wireless / wired hub analogy either so I asked around,

There is no collision avoidance with wired Ethernet, (CSMA/CD). IEEE 802.11 uses CSMA/CA with Acks and optional RTS/CTS. Wireless AP's generally tend to appear to users like wired hubs rather than switches in terms of congestion, according to my colleges wireless guy. He says to expect lower individual node speeds than with a wired hub. Makes sense as CA tries to ensure some fairness in bandwith usage.

- cameron