[MLB-WIRELESS] Channel management

evilbunny evilbunny at sydneywireless.com
Fri Dec 13 23:20:17 EST 2002


Hello Simon,

SB> 1. Channels 1 through 10 have a maximum power output of 4 watts EIRP,
SB> however channels 11 through 13 have a maximum of 200 milliwatts EIRP.
SB> Obviously, a link which only spans a short distance should use the
SB> latter segment.

1 to 9, 10 to 13 (this is under review by the ACA at present to make
it uniform of 4W across the entire band)

SB> 2. The more networks on the same channel, the more packet dropping (from
SB> mismatching SSID's) must be done. This is counter-productive.
SB> Unfortunately outside sources will also undoubtedly effect this too,
SB> such as commercial hot-spots and so forth.

Erm I don't think this quite what happens... any number of other
things that can generate noise without being different SSID's... I
don't think you have a hope in hell of even being practical in this
respect...

SB> 3. Using channels sequentially in an area is also counter-productive due
SB> to noise generated by channel cross-talk. I believe it's recommended
SB> that only 3 or 4 channels being used in one area at a time (i.e. you use
SB> channels 1, 4, 7, and 10, and don't touch the ones in between). In the
SB> real world, it's more difficult than that, but it's not helpful to have
SB> two nodes in close proximity using, for example, channels 1 and 2 for
SB> different network segments respectively.

White paper out recently, due to the bell shape of the spread spectrum
usage across the band that makes apparently 5 channels useable with
the 13 allowable (without overlapping so badly to cause problems)

SB> 4. There needs to be one single channel network-wide if roaming is ever
SB> to be achieved. Julian Featherston reminded me of this recently (thanks
SB> Julian :) and has suggested Channel 1. I concur, as it's both easy to
SB> remember and falls under the 4 watt EIRP license.

untrue, wireless cards can automatically switch between channels
without much hassle at all, however network roaming in the mobile
phone sense is a little impractical at best... But that's only a
present issue due to decent routing protocols etc etc etc

SB> 5. The ACA's "public playground" concept needs to be adhered to, and
SB> it's not fair on other 2.4GHz users to stomp all over the entire band
SB> available. Nor is it legal to unreasonably interfere with existing
SB> users, such as cordless telephones, bluetooth, and so forth.

Agreed, even some commercial operators are taking this approach that
unless we all get along, everyone is set to loose... Some in a very
pro-active way (in a good sense, at least on the surface it appears
that way)

-- 
Best regards,
 evilbunny                            mailto:evilbunny at sydneywireless.com

Laughter is the closest distance between two people.

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