Naive wireless question

Hi,

Is there any difference (hardware-wise) in the "radios" (chipsets)
on the AP end of a 802.11b/g/n link and those on the "client" end?

I.e., is the difference merely one of antenna gain, Tx power
and *firmware* (meaning software that conceivably *could* be
rewritten vs. software that is deeply and immutably buried within
the chipsets)?

Said yet another way, could 'n' PC's with wireless cards be
*wired* together (distributed appropriately) and act as a set
of 'n' AP's?

Thx,
--don

On 07/14/2011 09:49 AM, Don Y wrote:
> Hi,
>
> Is there any difference (hardware-wise) in the "radios" (chipsets)
> on the AP end of a 802.11b/g/n link and those on the "client" end?
>
> I.e., is the difference merely one of antenna gain, Tx power
> and *firmware* (meaning software that conceivably *could* be
> rewritten vs. software that is deeply and immutably buried within
> the chipsets)?
>
> Said yet another way, could 'n' PC's with wireless cards be
> *wired* together (distributed appropriately) and act as a set
> of 'n' AP's?

This is the first time I've seen "software" used to mean "less mutable 
than firmware".

-- 

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" was written for you.
See details at http://www.wescottdesign.com/actfes/actfes.html

On Thu, 14 Jul 2011 10:29:27 -0700, Tim Wescott <tim@seemywebsite.com>
wrote:

>On 07/14/2011 09:49 AM, Don Y wrote:
>> Hi,
>>
>> Is there any difference (hardware-wise) in the "radios" (chipsets)
>> on the AP end of a 802.11b/g/n link and those on the "client" end?
>>
>> I.e., is the difference merely one of antenna gain, Tx power
>> and *firmware* (meaning software that conceivably *could* be
>> rewritten vs. software that is deeply and immutably buried within
>> the chipsets)?
>>
>> Said yet another way, could 'n' PC's with wireless cards be
>> *wired* together (distributed appropriately) and act as a set
>> of 'n' AP's?
>
>This is the first time I've seen "software" used to mean "less mutable 
>than firmware".

You don't think microcode is a subset of software? 

Don Y <nowhere@here.com> writes:
>Is there any difference (hardware-wise) in the "radios" (chipsets)
>on the AP end of a 802.11b/g/n link and those on the "client" end?

No. 

>I.e., is the difference merely one of antenna gain, Tx power
>and *firmware* (meaning software that conceivably *could* be
>rewritten vs. software that is deeply and immutably buried within
>the chipsets)?

The software is not even buried within the chipsets. It runs on
whatever controller device drives the chipset. 

>Said yet another way, could 'n' PC's with wireless cards be
>*wired* together (distributed appropriately) and act as a set
>of 'n' AP's?

Yes, you can turn your PC/mobile phone/whatever into an access-point.
You should be able to google that for any number of linux based solutions.

Hi Tim,

On 7/14/2011 10:29 AM, Tim Wescott wrote:
> On 07/14/2011 09:49 AM, Don Y wrote:

>> Is there any difference (hardware-wise) in the "radios" (chipsets)
>> on the AP end of a 802.11b/g/n link and those on the "client" end?
>>
>> I.e., is the difference merely one of antenna gain, Tx power
>> and *firmware* (meaning software that conceivably *could* be
>> rewritten vs. software that is deeply and immutably buried within
>> the chipsets)?
>>
>> Said yet another way, could 'n' PC's with wireless cards be
>> *wired* together (distributed appropriately) and act as a set
>> of 'n' AP's?
>
> This is the first time I've seen "software" used to mean "less mutable
> than firmware".

<grin>  Sorry, I was trying to acknowledge the potential for
"*immutable* firmware" being buried *in* the radio's chipset
as distinct from (mutable) firmware in the MCU/CPU that talks
to that subsystem.

Software, slushware, firmware, underware... we're running out
of terms to finesse the various subtleties!  :-/

Hi Doug,

On 7/14/2011 12:24 PM, Doug McIntyre wrote:
> Don Y<nowhere@here.com>  writes:

>> I.e., is the difference merely one of antenna gain, Tx power
>> and *firmware* (meaning software that conceivably *could* be
>> rewritten vs. software that is deeply and immutably buried within
>> the chipsets)?
>
> The software is not even buried within the chipsets. It runs on
> whatever controller device drives the chipset.

So, replace the MCU and you can repurpose the device at will?

>> Said yet another way, could 'n' PC's with wireless cards be
>> *wired* together (distributed appropriately) and act as a set
>> of 'n' AP's?
>
> Yes, you can turn your PC/mobile phone/whatever into an access-point.
> You should be able to google that for any number of linux based solutions.

Conversely, I can turn an access point into a "client" (?)

I thought the hardware in an AP might have hardware acceleration
for AEK, etc. that might be omitted in the hardware present in
a typical client...

Don Y <nowhere@here.com> writes:
>On 7/14/2011 12:24 PM, Doug McIntyre wrote:
>> Don Y<nowhere@here.com>  writes:
>So, replace the MCU and you can repurpose the device at will?

Yes, but you may not be able to get datasheets/user manuals for 
whatever hardware depending on manufacturer and their policies.. 


>> Yes, you can turn your PC/mobile phone/whatever into an access-point.
>> You should be able to google that for any number of linux based solutions.

>Conversely, I can turn an access point into a "client" (?)

You could write new firmware to turn it into a bridge (ie. client), yes. 
Not very effective though. 

>I thought the hardware in an AP might have hardware acceleration
>for AEK, etc. that might be omitted in the hardware present in
>a typical client...

Some APs do have hardware crypto acceleration, but I couldn't tell you
where along the chain they are. Some do not. 

On Jul 14, 11:33=A0pm, Doug McIntyre <mer...@geeks.org> wrote:
> Don Y <nowh...@here.com> writes:
> >On 7/14/2011 12:24 PM, Doug McIntyre wrote:
> >> Don Y<nowh...@here.com> =A0writes:
> >So, replace the MCU and you can repurpose the device at will?
>
> Yes, but you may not be able to get datasheets/user manuals for
> whatever hardware depending on manufacturer and their policies..

I have yet to see a chipset manufacturer who publishes data on
how to talk to the chipset MCU.
At the beginning, there was documented stuff around (PRISM IIRC).
Then someone persistently bought all out and deleted all data which
could be deleted from the public domain.

Dimiter

------------------------------------------------------
Dimiter Popoff               Transgalactic Instruments
http://www.tgi-sci.com
------------------------------------------------------
http://www.flickr.com/photos/didi_tgi/sets/72157600228621276/

Spehro Pefhany
> Tim Wescott
>>This is the first time I've seen "software" used to mean "less mutable
>>than firmware".
> You don't think microcode is a subset of software?

Not in counterdistinction to "firmware".

-- 
Fredrik Östman

Hi Doug,

On 7/14/2011 1:33 PM, Doug McIntyre wrote:

>> So, replace the MCU and you can repurpose the device at will?
>
> Yes, but you may not be able to get datasheets/user manuals for
> whatever hardware depending on manufacturer and their policies..

Understood.  My interest wasn't from a "practical" standpoint but,
rather, from a conceptual one.

>>> Yes, you can turn your PC/mobile phone/whatever into an access-point.
>>> You should be able to google that for any number of linux based solutions.
>
>> Conversely, I can turn an access point into a "client" (?)
>
> You could write new firmware to turn it into a bridge (ie. client), yes.
> Not very effective though.

But, through no fault of the *radio's*... (?)

>> I thought the hardware in an AP might have hardware acceleration
>> for AEK, etc. that might be omitted in the hardware present in
>> a typical client...
>
> Some APs do have hardware crypto acceleration, but I couldn't tell you
> where along the chain they are. Some do not.

OK.  Thanks!