Hello,
I'm a CS student (undergrad) wanting to do a wireless-related project
for the Google Summer of Code.
As advised by Johannes Berg, I am posting on here in order to know the
mentors and to get a better understanding of the requierements.
>From the publised list, I am most interested in the roaming project.
Please, can anyone tell me who will be mentoring it, so I cand get in
touch with him/her?
Thanks,
--
Mircea
On Wed, Mar 18, 2009 at 7:42 AM, John W. Linville
<[email protected]> wrote:
> On Wed, Mar 18, 2009 at 03:36:00AM +0200, Mircea Gherzan wrote:
>
>> I'm a CS student (undergrad) wanting to do a wireless-related projec=
t
>> for the Google Summer of Code.
>>
>> As advised by Johannes Berg, I am posting on here in order to know t=
he
>> mentors and to get a better understanding of the requierements.
>>
>> From the publised list, I am most interested in the roaming project.
>> Please, can anyone tell me who will be mentoring it, so I cand get i=
n
>> touch with him/her?
>
> I think Luis Rodriguez penned the descriptions of those projects,
> so he might be the best person to ask about them. =C2=A0In any case,
> I would be happy to mentor such a project if you so desire.
This is what we have, through some brainstorming on IRC and a few
e-mails with a few people.
https://www.linuxfoundation.org/en/Google_Summer_of_Code_2009#802.11_Wi=
reless
The application deadline was last Friday, March 13, 2009 so I suppose
that went in as-is. I volunteered a few people but if there are others
willing to help mentor some of these projects please just go right
ahead and add your name to the list or let me know and I'll add you.
So there are three GSoC project ideas listed there:
* Add AP support to Network Manager
* Improve wireless roaming
* Integrate GeoClue to help with regulatory compliance
The last one is the one which I hope to be able to mentor the most on
but will also obviously need some help from Dan. That one is also
being reviewed in conjunction with a similar project idea for GNOME
GSoC:
http://live.gnome.org/SummerOfCode2009/Ideas
Seems GeoClue is welcomed for many reasons onto the desktop.
Whether or not these GSoC projects get picked up by Google I still
think its worth to put this out there and see if people are will pick
some of this work up.
OK so as for the question about roaming -- I'm up to help mentor it.
Anyone else?
Luis
> From the publised list, I am most interested in the roaming
> project. Please, can anyone tell me who will be mentoring it,
> so I cand get in touch with him/her?
I wonder where the list has been published?
Basically, a patches version of the old madwifi driver still
roams better than mac80211-based WLAN cards. The latter have
currently mostly written for "Hotspot"-operation. That is a
laptop in the vincinity of one access-point.
In my company, I'd be in need for real roaming, as a storage
warehouse has often 10-40 access-points and the client needs to
know when to switch to a new one, ideally proactively. And as a
moder fork-lift is quite fast, you'll need to be quick and
adept :-)
Helmut Schaa once indicated that he has something in petto, but
that was weeks ago. But maybe he still has ideas/hints about
this.
I could help with testing things in a "real" environment, as a
storage warehouse of one of our customers is just round the
corner :-)
If I would have to implement it, I'd do rought this:
1) create a consistent picture of available access-points
You can do:
a) scan when needed
b) constantly background scanning
c) a combination of those
With c) I mean the following scheme:
WLAN card receives the broadcasts of the APs anyway, no matter if
you do an "iwlist XXX scan" or the "iw" equivalent or not. So
this information could be store into some sort of "database"
inside mac80211.
Now consider you client is moving, e.g. in a car, on a bike, or
(in my case) your device is mounted to a fork-lift terminal.
That means that you have to age the information in
your "database". Old entries aren't as reliable for roaming
decisions as new ones. And entries that didn't get an update for
n seconds (e.g. 5 seconds) are useless.
Also consider that still some network admins think that "hidden
ESSID" is a security feature and turn this beast on. So even
with a got SNR a new entry in your bss list might not be
eligible for roaming, because the AP might have a different
SSID.
2) Decide when to roam
You should really do this before your current connection stalls,
e.g. when you find that some other AP is X points better then
the current one.
3) Decide who roams
In history, we had fullmac drivers (like orinoco_cs or
wlags_h2_cs) that did all the roaming. For some chipsets used
for embedded or portable devices, we still have those (e.g.
libertas_sdio, libertas_cs, the ar5000-driver). But now we have
mostly software chipsets, so concentrate on this.
However, the fullmac driver do their own roaming. After they did
that, they notified WPA-Supplicant about the fact. That worked
quite well, even with WPA and WPA2.
However, I've heard many people that said a roaming decision
should be done in user-space, by Network-Manager or
wpa_supplicant and that this is not the business of
kernel-space.
Now I also have some experience with very light embedded devices
(e.g. one with an AVR32 CPU has just 8 MB flash, yet it runs
Linux!). For me the idea of putting Network manager there isn't
appealing. However, wpa_supplicant is there anyway :-)
But I also claim that within mac80211 you have more information,
in a "realtime" manner. If you want to relay all of this to
user-land: okay, possible, via nl80211. But then your device
will wakeup one or more user-space processes and consumes more
power (one of my handheld devices can, with a 3200 mAh
accumulator, survice for more than 8 hours with full WLAN
connectivity!).
However, you can't do thing "against" the community, so if the
word is "we do this in NM", then you'll have to do that. :-) In
this case be prepared to dive not only into mac80211, cfg80211
and nl80211, but also into wpa_supplicant and/or nm (at least
partially).
Some more thoughts: when one roams via wpa_supplicant /
Network-Manager, it's usually quite easy to roam to very
different networks, e.g. you can have two network entries "Home
SCHURIG, WPA2" and "Company, MNSOLUTIONS, 802.11x with TTLS,
CHAP and Radius".
However, in an environment where you have lots of identically
configured APs (e.g. 30 APs on different channel, but all with
the same ESSID and the same encryption scheme) it's usually
beneficial to roam at a driver level.
4) Think about the future
There are 802.11 extensions for a fast handoff. Not sure if you
want to implement anything of this, but at least consider them,
so that adding support for them won't be harder than it should
be :-)
On Wed, Mar 18, 2009 at 03:36:00AM +0200, Mircea Gherzan wrote:
> I'm a CS student (undergrad) wanting to do a wireless-related project
> for the Google Summer of Code.
>
> As advised by Johannes Berg, I am posting on here in order to know the
> mentors and to get a better understanding of the requierements.
>
> From the publised list, I am most interested in the roaming project.
> Please, can anyone tell me who will be mentoring it, so I cand get in
> touch with him/her?
I think Luis Rodriguez penned the descriptions of those projects,
so he might be the best person to ask about them. In any case,
I would be happy to mentor such a project if you so desire.
John
--
John W. Linville Someday the world will need a hero, and you
[email protected] might be all we have. Be ready.
Am Mittwoch, 18. M=E4rz 2009 schrieb Holger Schurig:
> > From the publised list, I am most interested in the roaming
> > project. Please, can anyone tell me who will be mentoring it,
> > so I cand get in touch with him/her?
>=20
> I wonder where the list has been published?
> Helmut Schaa once indicated that he has something in petto, but=20
> that was weeks ago. But maybe he still has ideas/hints about=20
> this.
Sadly I did not find time to work further on that topic :( but I did qu=
ite
some research and have some ideas and am still interrested.
Helmut
On Wed, Mar 18, 2009 at 10:35 AM, Luis R. Rodriguez <[email protected]> =
wrote:
> On Wed, Mar 18, 2009 at 7:42 AM, John W. Linville
> <[email protected]> wrote:
>> On Wed, Mar 18, 2009 at 03:36:00AM +0200, Mircea Gherzan wrote:
>>
>>> I'm a CS student (undergrad) wanting to do a wireless-related proje=
ct
>>> for the Google Summer of Code.
>>>
>>> As advised by Johannes Berg, I am posting on here in order to know =
the
>>> mentors and to get a better understanding of the requierements.
>>>
>>> From the publised list, I am most interested in the roaming project=
=2E
>>> Please, can anyone tell me who will be mentoring it, so I cand get =
in
>>> touch with him/her?
>>
>> I think Luis Rodriguez penned the descriptions of those projects,
>> so he might be the best person to ask about them. =C2=A0In any case,
>> I would be happy to mentor such a project if you so desire.
>
> This is what we have, through some brainstorming on IRC and a few
> e-mails with a few people.
>
> https://www.linuxfoundation.org/en/Google_Summer_of_Code_2009#802.11_=
Wireless
>
> The application deadline was last Friday, March 13, 2009 so I suppose
> that went in as-is. I volunteered a few people but if there are other=
s
> willing to help mentor some of these projects please just go right
> ahead and add your name to the list or let me know and I'll add you.
>
> So there are three GSoC project ideas listed there:
>
> * Add AP support to Network Manager
> * Improve wireless roaming
> * Integrate GeoClue to help with regulatory compliance
>
> The last one is the one which I hope to be able to mentor the most on
> but will also obviously need some help from Dan. That one is also
> being reviewed in conjunction with a similar project idea for GNOME
> GSoC:
>
> http://live.gnome.org/SummerOfCode2009/Ideas
>
> Seems GeoClue is welcomed for many reasons onto the desktop.
>
> Whether or not these GSoC projects get picked up by Google I still
> think its worth to put this out there and see if people are will pick
> some of this work up.
>
> OK so as for the question about roaming -- I'm up to help mentor it.
> Anyone else?
=46orgot to add Kroy, which seemed interested in the GeoClue stuff.
Luis
On Tue, Mar 17, 2009 at 6:36 PM, Mircea Gherzan <[email protected]> wrote:
> Hello,
>
> I'm a CS student (undergrad) wanting to do a wireless-related project
> for the Google Summer of Code.
>
> As advised by Johannes Berg, I am posting on here in order to know the
> mentors and to get a better understanding of the requierements.
>
> From the publised list, I am most interested in the roaming project.
> Please, can anyone tell me who will be mentoring it, so I cand get in
> touch with him/her?
Just a heads up deadline is in two days.
Luis