[MLB-WIRELESS] ./: Can 802.11 Become A Viable Last-Mile Alternative?

Tony Langdon, VK3JED vk3jed at optushome.com.au
Mon May 13 20:29:04 EST 2002


At 08:15 PM 13/05/2002 +1000, you wrote:

>The problem with 802.11 technologies is the use of ISM bands.
>Was having a convo at a local telco office earlier today about it, it 
>seems the
>doubt about wireless networking WRT service delivery is one of 
>reliability, or a
>case of too many unknowns. They aren't willing to touch it because their SLA's
>then are vulnerable to factors completely outside their control, outside
>anyone's control - ISM band.

Agreed, and I have real concerns about 802.11b being used for commercial 
ISPs.  Even without malicious intent, I discovered that a microwave oven 
3-5 metres (and on the other side of an internal wall) from a WLAN 
installation can cause up to 35dB degradation of the S/N ratio.  I did some 
tests, complete with nice Excel graphs.

And one of the radio guys in Canada had problems with an unreliable 
wireless ISP - turns out they put the router on top of a microwave oven and 
whenever someone nuked their lunch, the ISP's customers went down! :-)

Then there's amateur television - another use that's "higher up the pecking 
order" than 802.11b - signals 18 MHz wide.  More common on that band in 
Adelaide, and the power levels are increasing to overcome the problems 
caused by 802.11b!

I forsee fewer problems with our wireless network for a couple of reasons:

1.  We're not intending to make a profit (and hopefully not charging)
2.  We're aware of the issues, and are likely to take them into 
account.  Our decentralised network is likely to be more resistant to 
interference from other sources.
3.  We're not burdened with 99.999% uptime requirements and consumer 
expectations.

>Any goon can rip the door off a microwave oven, stick it on their roof and 
>sleep
>knowing they've DoS'ed the nerds in their neighbourhood. It doesn't take 
>l337 hax0r to do
>this (unlike most DoS), just an uncompetitive IQ.

And someone with a death wish and disregard for public safety and EMR 
regulations.

>An industry won't invest in a comms technology whose very basis is completely
>unregulated, unpredictable and uncontrollable.
>And that my friends, is the reason we have to do it.
>Nobody in industry is going to do it for us - some may try, but public 
>networks
>and commercial networks will never interoperate so it's unreasonable to 
>expect a
>cooperative effort.

I agree.  This is an environment which lends itself more to our community 
style of operation.

73 de Tony, VK3JED
http://vk3jed.vk.irlp.net


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