Upgrade G1G1 using autoreinstallation method

[David Leeming]

Hi John,

Sorry for silence, I am just back from a trial deployment in East Sepik
(wiki will be updated later today)

See feedback from OLPC Australia:

(note that setting up an XS is not a short term option in our trials in PNG,
as there is no permanent power supply a the school)

>>> Just wanted to give everyone an update. I bought a DLink DWL-2100AP
which is what David and Ian are trying to implement for their XO rollouts.
We found that we could not get DHCP working on the AP at all for either an
XO or for an IBM laptop running Ubuntu. We tried several different firmware
versions (although the AP is seemingly locked to European firmware and we
can't use the US ones) and the only way we could use it was as an AP that
forwards DHCP requests to the network.

>>> We've spent about 4 hours today trying to troubleshoot the issues and I
am unfortunately going to have to recommend that the APs be plugged into a
network which plugs into an XS server for DHCP to get the XOs connected.
David, where you can't have an XS server you could always buy a different AP
or other DHCP allocation device per site for DHCP resolution as these APs
seem to be inappropriate for the job (at least the Australian ones).

>>> As per my email to the devel list, we purchased an identical AP and
mostly duplicated the problem you're seeing, but were unable to find a fix.

>>> We tested different firmware versions and different settings. Googling
for the issue was interesting as most people simply gave up and used these
APs as wireless bridges. Ultimately the clients will associate with the AP
fine, but they simply will not get a DHCP address and there are a lot of
messy log messages that don't help at all.

>>> I think setting up XS server at the sites (where possible) and turning
DHCP off on the AP is the most sensible way forward. I know this contrasts
slightly with David's experience but this is what we found. Let me know if
you find anything else.

>>> If you want me to source APs that do work both for the future and
perhaps to act as the DHCP servers for your existing sites, please let me
know. A disappointing outcome but with a bit more notice we'd be happy to
help recommend and source better hardware in the future. We literally knew
about Ian's trip through Australia and the purchase of the APs the day
before he arrived.

>>> it seems these APs are not highly regarded and apparently in particular
have issues in high temperature conditions, so you may have worse issues
ahead of you :/ Please let us know what we can do to help.


-----Original Message-----
From: John Watlington [mailto:wad at laptop.org] 
Sent: Tuesday, 17 June 2008 5:58 a.m.
To: David Leeming
Cc: John Watlington; 'Bert Freudenberg'; devel at laptop.org
Subject: Re: Upgrade G1G1 using autoreinstallation method


On Jun 14, 2008, at 6:09 AM, David Leeming wrote:

> Hi John,
>
> To see if we could duplicate our problem, we tried with another AP:  
> We have
> a VSAT set up near the village where we are deploying a trial with 50
> children in PNG. It has a reliable wireless AP and you can  
> associate both
> "grown up" laptops and XOs no problems. The XOs will then see the  
> Internet
> and also other XOs and the activities will share OK. This AP has a  
> DHCP
> server on the wireless side. In fact, there is no other as the AP  
> connects
> straight to the VSAT modem, which does not have DHCP set up, via a  
> switch.
> If one pulls the cable out on the LAN side of the AP the XOs cease  
> to share
> and quickly drop out and look for the mesh. So, this duplicated the  
> problem
> I described.

More and more interesting.

Have you been able to follow up on what Pia Waugh found ?   Does it
seem relevant ?

> I am now told that a jabber service is needed to keep the XOs  
> interested and
> reliably collaborating, that maybe is the cause? Do you concur?

You absolutely don't need a jabber server for laptops to associate with
an access point.   Something else is wrong here.

>> Not knowing more about what you've done, I have
>> to ask a lot of v. simple questions.
>>
>> When you say "move on", you have manually associated each
>> laptop with the AP once, right ?   And the ESSID hasn't changed ?
>>
>> How realiable is the failure ?   Do all XOs "move on" to mesh
>> mode, or is this only a problem with a (random) few ?

?

>> How many XOs on each channel ?

?   As JG mentions, if you have too many laptops per AP, this is
a known problem.  How many are you trying ?

>> You could be seeing a failure of DHCP to actually occur.
>> Have you checked /var/log/messages on a failing laptop ?

John