The issue is not that the implementation is messed-up (switching modes), but rather that the AP must clear the air (via
promiscuous CTS) before sending any OFDM-encoded frame.
If it doesn't, then the B units in the area might not set CCA, and, if they send a frame while either the AP or one of its
'G' clients is attempting to receive a frame, interference will result.
You get 'mixed mode' as soon as a single 'B' unit is associated, even if its not sending any traffic.
802.11a and 802.11b were ratified at the same time (Sept 1997). 802.11g came along later.
Jim
On Jun 27, 2004, at 9:23 AM, [EMAIL PROTECTED] wrote:
There are wireless units that supports both 5.8 and 2.4 at the same time
those are the dual-band units, i.e.
http://www.linksys.com/products/group.asp?grid=33&scid=35
As Larry said, mixed mode is used if u have both G and B units in use on
the same AP, the reason that G mode will not support B units, is that B
units do not understand the OFDM modulation used by G (to boost
performance to 54 Mbit/s). B uses CKK and Barker code. But in mixed mode
the chipset uses different modulation for each session, this is not very
well implemented so if you have G and B units on the same AP, the G units
will take a big performance hit because of the switching between OFDM and
CKK.
Martin Madsen
Your wireless router can only transmit/receive on one frequency band...
thus you cannot mix 2.4 GHz B and G with 5.8GHz A... A stands alone, and
I think it has gone the way of the Betamax.
Your router may be allowing you to set it for "B only" or "G only", and
I am guessing mixed mode would be used if you have some B and some G
enabled clients on your network.
Larry
-----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of car val Sent: Saturday, June 26, 2004 6:11 PM To: [EMAIL PROTECTED]; [EMAIL PROTECTED]; [EMAIL PROTECTED]; [EMAIL PROTECTED]; [EMAIL PROTECTED] Subject: [SOCALWUG] the "A" protocol
Hi SOCALWUG Membership,
I'm missing something??
I know the "B" was the first protocol transmitting at 11Mbit/s freq 2.4MHz
Protocol "A" was second transmitting at 54Mbit/s freq 5.0 MHz this was more for commercial use, and was transmitting freq 5.0 MHz had less interference with wireless phones (2.4 Mhz)
then "G" came along at 54Mbit/s freq 2.4MHz this protocol was able to pick up both "B & A"??
my question, my Linksys wireless Router (WRT54GS)
has wireless settings for transmitting at
1) Disabled 2) Mixed 3) "B" 4) "G"
shouldn't it be as follows??
1) Disabled 2) Mixed (would be "G") 3) "B" 4) "A"
Second Question, I never see Wireless "A" AP, or Router advertised??, do they exist??
TIA carval
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