Is it B or G I'm receiving?

Does anyone have any idea how to discern whether or not a received
signal is "802.11B" or "802.11G"? I mean short of having both
adaptors.

Does a "G" signal show up on a "B" survey?

As the frequencies are the same it seems to me that you could see
signal but not be able to connect. Is this a correct assumption?

TIA

Gord

I doubt if a "b" survey list would show a "g" signal (but a "g" survey will
show a "b" signal). The presence of a "g" signal might cause the channel to
appear busy, but the energy would not be decoded as a signal.

"Gord Ipsofacto" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed)...
>
>
> Does anyone have any idea how to discern whether or not a received
> signal is "802.11B" or "802.11G"? I mean short of having both
> adaptors.
>
> Does a "G" signal show up on a "B" survey?
>
> As the frequencies are the same it seems to me that you could see
> signal but not be able to connect. Is this a correct assumption?
>
> TIA
>
> Gord

> I doubt if a "b" survey list would show a "g" signal (but a "g" survey
will
> show a "b" signal). The presence of a "g" signal might cause the channel
to
> appear busy, but the energy would not be decoded as a signal.

Hmm
I have a 801.11b card in my palmtop and I use ministumbler and WiFiFoFum
to scan for wireless networks - the card itself can only do 11Mbs but
ministumbler states higher AP speeds like 22, 44, 56Mbs along with
information about AP manufacturer etc. I believe that all 801.11 standards
are backwards compatible and that the connection is actually established
at the highest possible speed made possible by both devices (of course
except for 801.11a which is 5GHz as oposed to 2,4GHz )

T.P.

802.11g is back-compatible with 802.11b, but not the other way around. A
frame sent at any datarate other than 1, 2. 5.5, or 11 Mbps is
undecipherable to an 802.11b-only adapter, by definition.

802.11g access points may transmit beacons at datarates (and therefore using
encodings) that are defined in the 802.11b standard. These beacons include
information elements that define the supported datarates and encoding
types.The AP manufacturer can be deduced from the first three bytes of the
source MAC address in the beacon frame.

So, if an 802.11g AP is broadcasting beacons at 1 Mbps, an 802.11b client
can receive them. If a "real" 802.11b client driver is running the adapter,
then its site survey will probably not show an 802.11g network, because it
will not be able to interpret the datarate parameters specifying rates over
11 Mbps (that is, "g" is not a concept designed into "b" drivers). If
Airsnort or Netstumbler runs the adapter in promiscuous mode, then these
tools know how to interpret "b" and "g" information elements, and so can
tell if the AP supports "g".

Many vendors support a "g"-only option in configuring the AP. As far I can
tell, the standard does not require the beacon to be transmitted at any
particular rate. If the AP is configured to support hybrid nets, it's
reasonable to assume that the beacon goes out at a rate supported by all
clients - i.e., 1 or 2 Mbps. If "g"-only is configured, it seems to me that
the AP is permitted to use a non-"b" rate.

"Yankes [Wroc]" <(E-Mail Removed)> wrote in message
news:c8scpj$ltr$(E-Mail Removed)...
> > I doubt if a "b" survey list would show a "g" signal (but a "g" survey
> will
> > show a "b" signal). The presence of a "g" signal might cause the channel
> to
> > appear busy, but the energy would not be decoded as a signal.
>
> Hmm
> I have a 801.11b card in my palmtop and I use ministumbler and WiFiFoFum
> to scan for wireless networks - the card itself can only do 11Mbs but
> ministumbler states higher AP speeds like 22, 44, 56Mbs along with
> information about AP manufacturer etc. I believe that all 801.11 standards
> are backwards compatible and that the connection is actually established
> at the highest possible speed made possible by both devices (of course
> except for 801.11a which is 5GHz as oposed to 2,4GHz )
>
> T.P.
>
>

In rereading the original post, I see I answered the question(s) too
narrowly.

802.11g supports 802.11b. An 802.11g AP can talk at "g"-only datarates to
802.11g clients, and at "b" datarates to 802.11b clients. That's a hybrid
network.

Your "b" adapter cannot decipher "g"-only transmissions, or even recognize
them as signals. It *can* connect to an 802.11g AP that is configured to
support hybrid networks. Its conversations with the AP will use 802.11b-only
datarates and encodings. If the AP supports hybrid networks, it probably
sends its beacon frames at an 802.11b datarate, so it will appear to be an
802.11b network to an 802.11b client.

"Gord Ipsofacto" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed)...
>
>
> Does anyone have any idea how to discern whether or not a received
> signal is "802.11B" or "802.11G"? I mean short of having both
> adaptors.
>
> Does a "G" signal show up on a "B" survey?
>
> As the frequencies are the same it seems to me that you could see
> signal but not be able to connect. Is this a correct assumption?
>
> TIA
>
> Gord

>
>
>Does anyone have any idea how to discern whether or not a received
>signal is "802.11B" or "802.11G"? I mean short of having both
>adaptors.
>
>Does a "G" signal show up on a "B" survey?

Yes.
>
>As the frequencies are the same it seems to me that you could see
>signal but not be able to connect. Is this a correct assumption?

No, .11G is backwards compatible with .11B. Or .11G would be dead in
the water (like .11 A).

>TIA
>
>Gord

B and G are completely compatible. If your throughput is over 5 or 6MB
(and you have a .11G card) you can count on it being .11G.
------------
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