Very interesting. Thanks to share and thanks to Terry for this detailed report.
Lionel. 2014-02-07 16:10 GMT+01:00 Adam Holt <h...@laptop.org>: > *[Terry Gillett summarizes his weeks of testing, **with this very > revealing report below. That's tgill...@gmail.com <tgill...@gmail.com> of > the Village Telco project: can we/Nepal/Lesotho/others help him add the key > takeaways to http://wiki.laptop.org/go/Wifi_Connectivity > <http://wiki.laptop.org/go/Wifi_Connectivity> so the "almost 2 million > XO-1s worldwide" can benefit? Spoiler Alert: XO-1 deployments must > carefully buy the correct Wifi Access Point, EG "Linksys WRT54GL" or > "Billion 7404VGP" appear to solve most all problems. Likewise we've had a > lot of success in Haiti with the TP-Link TL-MR3020.]* > > > SUMMARY > > The core problem is that XO-1 laptops will not reliably connect to a range > of wifi Access Points (AP). By comparison, XO-1.5 and later laptops will > successfully connect to the same APs. > > The behaviour of a group of XO-1s is different from that when they are > tested individually. A single XO-1 may connect quite reliably, but when > used in a group of ten or more, many individual XO-1s will fail to connect > to the AP. > > Note that this issue is just about connecting to the AP, it is not about > whether the AP can sustain a large number of connections or handle the > associated data throughput requirements. > > A number of routers configured as APs have been tested to establish a > baseline. > > The test process used requires 10 XO-1 laptops and is as follows: > > 1. Set up the AP on an unoccupied wifi channel, at least two and > preferably three channels away from unoccupied channels. > 2. Connect each XO-1 individually to the AP and check that it is operating > correctly and has adequate signal strength. > 3. Power off all the XOs > 4. Start up one XO and allow it to connect successfully. > 5. Start up the other none XOs > 6. When the last XO has completed its boot up sequence, check the > connection status of each XO. > > The result of a connection test for each XO is one of the following: > 1. Successful automatic connection > 2. No connection, but AP icon shows in Network Neighbourhood (NN) window > 3. The AP icon does not appear. > > Typically there will be a mix of XOs in each of the three states. > A Pass requires that all ten XO-1s are successfully connected at the end > of the test without manual intervention. > > The proportion of XOs in each state will typically vary from 20 to 80% in > a Failed test. > The proportion of successful connections seems to vary by router type, but > changes in repeated tests. > Individual XOs will typically be in different states in repeated tests. > > A range of routers has been tested with this procedure and the results > appear in the table below. > > The only two routers that passed the test were the Billion and the Linksys. > Interestingly both these routers date from the same vintage as the XO-1. > > Note that testing with less than five XO-1s results in a much greater > likelihood of a Pass result, and if the same AP is tested with ten XO-1s it > will likely fail. > > A Pass result with ten XO-1s is considered (at this point) to be a > reasonable indication of likely success in a real world deployment with > greater numbers of XOs. > > The working hypothesis is that modern APs have implemented the wifi specs > and/or default configurations in a way that has resulted in an > interoperability problem with the wifi implementation in the XO-1. > > > ROUTER TEST RESULTS > > Billion 7404VGP (old, Star Int, proprietary OS) Pass > Linksys WRT54GL (old, Broadcom, DD-WRT) Pass > > Netgear FWG114P (old, proprietary OS) Fail > TP Link WR710n (new, proprietary OS) Fail > > TP Link WR703 (Atheros AR9331, OpenWrt) Fail > > TP Link WR842 (Atheros AR9287, OpenWrt) Fail > TP Link MR3020 (Atheros AR9330, OpenWrt) Fail > TP Link WDR4300 (Atheros AR9341, OpenWrt) Fail > VT MP01 (Atheros AR23xx, OpenWrt) Fail > VT MP02 (Atheros AR9331, OpenWrt) Fail > > -- > Unsung Heroes of OLPC, interviewed live @ http://unleashkids.org ! > > -- > Unsung Heroes of OLPC, interviewed live @ http://unleashkids.org ! > --- > You received this message because you are subscribed to the Google Groups > "Unleash Kids" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to unleashkids+unsubscr...@googlegroups.com. > For more options, visit https://groups.google.com/groups/opt_out. >
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