What and why is "SoftAP"?

It seems that Microsoft and some other Wi-Fi device vendor has this
concept/solutoin of "SoftAP". Basically it can enable your station Wi-
Fi to behave like an AP called "SoftAP", allowing other device or
computer to connect to it. If this "SoftAP" station is connected to
Internet, other computers connected to the SoftAP can also browse
Internet.

This concept sounds quite new and interesting to me although it seems
out there for a while already, but I have some questions about this
concept. What are benefits of using SoftAP? When can I use this
feature? And more specifically how SoftAP solution is better than Ad-
hoc AP connection?

If you can point me some document or web site about it, that will be
great too. Thanks a lot in advance

Jeff Liebermann wrote:
> On Thu, 16 Oct 2008 18:29:47 -0700 (PDT), "(E-Mail Removed)"
> <(E-Mail Removed)> wrote:
>
>> It seems that Microsoft and some other Wi-Fi device vendor has this
>> concept/solutoin of "SoftAP". Basically it can enable your station Wi-
>> Fi to behave like an AP called "SoftAP", allowing other device or
>> computer to connect to it. If this "SoftAP" station is connected to
>> Internet, other computers connected to the SoftAP can also browse
>> Internet.
>>
>> This concept sounds quite new and interesting to me although it seems
>> out there for a while already, but I have some questions about this
>> concept. What are benefits of using SoftAP? When can I use this
>> feature? And more specifically how SoftAP solution is better than Ad-
>> hoc AP connection?
>>
>> If you can point me some document or web site about it, that will be
>> great too. Thanks a lot in advance
>
> Start here:
> <http://research.microsoft.com>
> Inscribe "softap" in the search box for a few references.
> Basically, it's part of MS's MESH Networking Academic Resource Kit.
>

I hate to ask what may seem a glaringly obvious fact/question, but does
SoftAP actually "integrate" properly with an actual existing "real" Mesh
network (ie. real access points doing routing etc.).
Basically, can you do customisation such that it can route traffic to
another node?
I've always wondered, since my foray into mesh (small as it may be) will
involve using an oldish PC instead of a real AP, so I do need to find
some decent mesh "management" software (I think it's routing software
I'm needing - preferably for Windows).

Thanks for your reply. My further question would be since ad-hoc mode
is there already since the begining of Wi-Fi and can also do something
like sharing Internet. What is the reason of using SoftAP, instead of
just enabling the ad-hoc connection? Is there benefit of SoftAP
(Infrastructure mode) beyond Ad-Hoc P2P Wi-Fi connection?

>
> SoftAP emulates an access point in an infrastructure type network.
> That means that for clients to talk to each other, they have to go
> through the central access point. *That's NOT the case with an ad-hoc
> network, where each client talks directly to the destination client.
> Totally different topology and functions.
>
> --
> Jeff Liebermann * * je...@cruzio.com
> 150 Felker St #D * *http://www.LearnByDestroying.com
> Santa Cruz CA 95060http://802.11junk.com
> Skype: JeffLiebermann * * AE6KS * *831-336-2558- Hide quoted text-
>
> - Show quoted text -

On Oct 17, 5:32*pm, David Fairbrother <5k00l54...@schoolsarge.org>
wrote:
> SoftAP actually "integrate" properly with an actual existing "real" Mesh
> network (ie. real access points doing routing etc.).
> Basically, can you do customisation such that it can route traffic to
> another node?
> I've always wondered, since my foray into mesh (small as it may be) will
> involve using an oldish PC instead of a real AP, so I do need to find
> some decent mesh "management" software (I think it's routing software
> I'm needing - preferably for Windows).- Hide quoted text -

There is a simple fact to keep in mind while thinking about all of
this:

From a structural point of view, there is nothing special about a
typical Wi-Fi router acting also as an AP.

Its essential hardware components can be easily replicated using a PC/
dongle combination. There are some issues with spatial diversity of
antennae, maximum power output, etc., but the core of the system, the
part that does teh routing, frame processing, creation and maintenance
of roaming state, etc, can all be replicated using software inside a
PC.

So the answer to your question is that anything is possible. What is
actually done by SoftAP engineer is limited by the motivation of that
engineer. At present, in October 2008, the market for SoftAP's is
still in a state of flux - it's almost as if each company that
attempts to to create a convenient, easy-to-use, SoftAP system is
subdued by some entity that would rather they did not. See:

http://www.nat32.com/nat32e/htm/softap.htm

So you might have trouble finding, for Vista, a dongle+driver-software
combination that allows your Vista PC to act as an AP. I tried in vain
a few months ago. Not sure if anything has changed since.

Gool luck hunting,

-Le Chaud Lapin-

On Oct 17, 8:30*pm, Woden98 <wgao_perso...@yahoo.com> wrote:
> Thanks for your reply. My further question would be since ad-hoc mode
> is there already since the begining of Wi-Fi and can also do something
> like sharing Internet. What is the reason of using SoftAP, instead of
> just enabling the ad-hoc connection? Is there benefit of SoftAP
> (Infrastructure mode) beyond Ad-Hoc P2P Wi-Fi connection?

Bit of clarification, as Jeff pointed out:

The SoftAP is actually not related to ad-hoc mode.

If you take two laptop computers, N1 and N2, and two Wi-Fi dongles, D1
and D2, in the desert, and you put D1 and D2 both in ad-hoc mode, each
using the same Wi-Fi channel, and induce N1 to generate an ethernet
frame such that the target address of the frame is the MAC address of
D2, D2 will receive the frame and pass it up the protocol stack. This
is the meaning of ad-hoc mode. By contrast, in infrastructure-mode,
N1 and N2 effectively route frames through the AP, after going through
a process of negotiating state withing the AP, which includes, at very
least, listening to the AP to determine what channel should be used.

If you are an academic, and your goal is to create a new type of
wireless router, then having a SoftAP helps greatly. For example, you
might be interested in tackling the mobilility problem, where
applications must retain "connectivity" even though their
interconnected topology is highly dynamic. Infrstructure-mode of the
AP attempts to solve this mobility problem at the link-layer, by
playing tricks with the Wi-Fi infrastructure. Ad-hoc mode does not
try to solve the problem at all, in which case, you would solve it
yourself using higher-level abstractions, essentially replicating what
the infrastructure of AP's are doing, but at network-level.

In either case, if all you have is say, Linksys or Cisco AP, you would
not be able to do anything, because you would not be able to program
the router.

A SoftAP would allow you to write sophisticated routing software on
the same device to which the radio is attached, the PC.

-Le Chaud Lapin-