#4805 BLOC Update.: OLPC laptops interfering with other 802.11b/g traffic

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#4805: OLPC laptops interfering with other 802.11b/g traffic
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  Reporter:  kimquirk  |       Owner:  mbletsas
      Type:  defect    |      Status:  new     
  Priority:  blocker   |   Milestone:  Update.1
 Component:  wireless  |     Version:          
Resolution:            |    Keywords:          
  Verified:  0         |  
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Comment(by satch89450):

 Hello, my name is Stephen Satchell. I'm the network guy at the THINK
 conference (previously known as the Hacker's Conference as organized by a
 group of people on The WELL). My responsibility is to oversee our
 conference demonstration rooms and to oversee the Internet connection we
 use at the conference, I believe the people who brought the little green
 laptops are already providing information, so this many be redundant.
 However, as we say here in Reno, Nevada, a triple check beats a double
 cross.

 Background: the conference site has a network of four access points within
 the building in question. I don't have a lot of details about those access
 points, because another gentleman is the Wireless Czar for the
 conference...but I do know that the conference site's access points are
 set up to permit handoff fairly well -- if you want to pay the price to
 the hotel. The THINK network -- the official one -- also has four access
 points. Three of them have the same SSID, while one of them has a
 different one. The channel assignments were selected to minimize conflict
 with with Chaminade network. I counted two rogue access points (set up by
 conferees outside the "official network"). Then there was third rogue
 network with the name "mesh" in it...

 I can relate my own experience with the problem, because my personal
 experience is what led us (me, and the OLPC laptop owners) initially to
 suspect that there was an interference problem. I have a Sony VIO running
 Windows XP (stop booing and hissing, I'm fixing that problem) that has
 built-in 802.11b wireless. I used this laptop on the NOC table to debug
 things on my network, both wired and wireless. Also on the NOC table was
 one of the official access points, with the THINK ssid. I could not
 connect to it. The OLPC units were across the hallway in the other demo
 room -- air distance of about 12 feet.

 When all of the OLPC units were shut off, I was able to get an "excellent"
 connection (as reported by the VIO wireless software) with the access
 point six inches away. With the OLPC units open and turned on, I couldn't
 even access the wireless network.

 People in the main conference room didn't have problems with OLPC
 interference (with SSID "hackers-m") until the units were brought in and
 passed around the room.

 I understand from one of the two owners that two of the units did *not*
 have the most up-to-date software on it, so this could have been a problem
 that has already been fixed. (The irony is that this gentleman was trying
 to download the lastest version, but his laptop -- an Apple one, if memory
 serves -- was unable to complete the download. Catch-22!) Also, when the
 laptops had their networking disabled as claimed by the owner, the problem
 appeared to go away as well.

 One side issue: the "network off" mode wasn't sticky. When the units
 reportedly turned off and then back on, the nework would come back up and
 not stay in the disabled condition.

 The workaround I did was to go into my heap of stuff and yank out a couple
 of 24-port Ethernet switches with 100-base T ports, expand the wired
 network at the laptop tables, and extend wired Ethernet to a lounge area
 where laptop users like to congregate. This reduced the load on the
 wireless network.

 I don't recall if the software was updated during the conference, or
 tested. As it was, I got five hours of sleep during 72 hours, so I wasn't
 as sharp as I would have liked to be. Also the OLPCs were not mine.
 (Should I fix that last? Hmmm...)

 If you have questions, you can send them to satch at internetworkexpert.com
 and I will do my best to answer them. I would prefer you use my work
 address, as *everything* I had at the conference is currently at the
 office, including my contact lists.

-- 
Ticket URL: <http://dev.laptop.org/ticket/4805#comment:13>
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