[robocup-humanoid] Summary of rule discussions in Mexico/Regarding WiFi

[Alejandro Malo Tamayo]

Hi ;-)
My point is regarding the different capabilities of  the layers: 11 WiFi Channels <=number of A or B Class networks. Sorry if I don't use the OSI layers to explain my point. Internet protocols suffice and are usually used when you program. Maybe you can also suggest an OSI based SDK. Also I realize that  36 teams each with a 1Mb/s bandwidth theoretically would not clog a  54Mb/s network, but I recon that I miss many details how the 2.4GHz band is used. Sorry if  let my confusion and ignorance speak.
Sorry to mention it, WEP has flaws. Again I understand it is a remote possibility, but  ...  But You might want to  read its wikipedia entry. WPA or WPA2? or SSL/TLS?
Best Regards
Alejandro Malo

On Sep 3, 2012, at 1:57 PM, Daniel Seifert <dseifert at fumanoids.de> wrote:

> On Mon, Sep 3, 2012 at 8:09 PM, Alejandro Malo Tamayo <alexmalo at ctrl.cinvestav.mx> wrote:
> Dear humanoid teams
> Regarding the WiFi limitations and restrictions please see the respective sections of the wikipedia WiFi entry. That might give more insight into the problem. 
> 
> As a user I realize that WiFi is an evolving standard. If I understand correctly the number of channles is geographically dependent. It has between 11 and 14 channels (Link Layer), but they are overlapping channels, non overlapping channels must differ by five or more. So really there are only three independent channels. 
>  
> For 2,4GHz we assume 11 channels to not exclude any teams. For practical purposes you usually go for a difference of less channels to minimize interference, but either way it is obvious that considering the amount of leagues and fields we will never get a "clean" setup. But this is not necessary if everything is harmonized or improved. One option, for example, would be to go to 5 GHz as this offers additional channels to chose from and this band should be less crowded (but suffers other problems). Other options include limiting audience interference (their phones may connect to our open and visible APs automatically) by using hidden ESSIDs or employing WEP, and of course making sure that only few APs are actually running (that's why we do not allow teams to have their own AP).
> 
> We will have a survey later this month which in part covers this topic in order to collect feedback from the teams.
> 
> In Mexico, if I remember correctly each team had a subnet (Internet layer). 36  humanoid teams, not considering other categories.  They had to share channels. You might also consider restricting the use of channels.
> 
> Subnets are in OSI layer 3, whereas the 802.11b channels are on OSI layer 1. They have nothing to do with each other. The humanoid league had a total of 6 APs running (one for each field), which channels were set to maximum difference possible based on location and in coordination with the neighboring SPL league (which had 4 APs).
> 
> Best regards
> 
> Daniel
> 
> -- 
> dseifert at fumanoids.de
> Phone +49 30 838 75-117 (Office), -125 (Lab)
> 
> Freie Universität Berlin
> Institut für Informatik
> AG Intelligente Systeme und Robotik
> Arnimallee 7
> 14195 Berlin
> Germany



Alejandro J. Malo Tamayo
Control Automático/Cinvestav
Av IPN 2508
Mexico 07300
http://www.ctrl.cinvestav.mx
alexmalo at ctrl.cinvestav.mx