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On Fri, 18 Jun 2010, David Johnson wrote:
On Friday 18 Jun 2010 17:39:28 stinga@xxxxxxxxxxxxx wrote:G'day, Since we are talking about wireless over a large distance, we are at the other end and want high speed (as fast as posible) across a small distance, across the road. At the moment we can't string fiber for many reasons, but I might cut a slot in the road one day for it. What other options are there? We have a laser link between two other buillings, but they are not cheap.I guess it depends on what you consider "high speed" - 100 Meg? Gig? 10 Gig? Probably a point-to-point 802.11n wireless link would be fast enough without being hugely-expensive. That'll give you 300 Mbit/s, albeit half duplex. Use a pair of routers that will do bridging with cantennas or off-the-shelf directional aerials.
Don't belive the hype about link speeds and Wi-Fi... 802.11b touts an 11Mb/sec speed - and it might just do that - at the signal level. At the user level you're lucky to see 5Mb/sec. Same for 'g' - 54Mb/sec at the signal level and 22Mb/sec at the user end.
So for 'n' - I'd be surprised if you actually saw more than 100Mb/sec out of a touted 300Mb/sec link.
Also, that half duplex will bite you when you come to do heavy-duty bi-directional traffic - e.g. VoIP... Or have one person streaming one way with another streaming the other - e.g. one person sending a big email and another fetching one...
A real-live test: My Acer Aspire One using iperf over Wi-Fi to my home server box gets 23.5Mb/sec - AAO is only 802.11g - Wi-Fi is 802.11n. I don't have any 'n' hardware other than the access points...
(it gets 94.1Mb/sec via the eired Ethernet interface, so it's not the AAO that's the slow bit)
Actually - just thought, I do have an 'n' device my N900... however it's rather dissapointing and only gets 6.43Mb/sec over it's Wi-Fi interface. I suspect that's the CPU more than anything else.
Gordon -- The Mailing List for the Devon & Cornwall LUG http://mailman.dclug.org.uk/listinfo/list FAQ: http://www.dcglug.org.uk/linux_adm/list-faq.html