[Server-devel] [laptop.org #8321] Questions about XO mesh networking
Bryan Berry
bryan.berry at gmail.com
Thu Mar 27 09:57:06 EDT 2008
Matt, you will need to configure Jabber on the School server so that the
XO's are not running in mesh while they are at the school. You want them
to use a regular access point because 200 XO's all meshing in one place
will crash your network.
Jabber emulates the mesh-functionality so kids can use the sharing
features even though the mesh is effectively turned off when you use a
regular wireless router.
You set the Jabber server individually on each XO by doing the following
from the command line:
sugar-control-panel -s jabber servername
Here is the wiki page on EJabber config, it's a bit complex
http://wiki.laptop.org/go/Ejabberd_Configuration
Wish I could help more but we've got teacher training starting in 2 days
and a ton of work ahead of us.
On Thu, 2008-03-27 at 08:06 -0400, Greg Smith (gregmsmi) wrote:
> Hi Matt, (Bryan or Sulochan, please see questions for you below),
>
> Sorry we didn't get you an answer before this but thanks for reaching
> out and following up!
>
> Do you have a server (e.g. school server) in place?
>
> We probably do not have a tested and approved wireless AP with router,
> firewall and DHCP. The original idea was that routing, firewall and
> DHCP are done on the server.
>
> That said we may be able to find someone to help test and qualify an AP
> with your requirements.
>
> You may want to focus on connectivity and defer mesh support until
> later. I know that mesh is a core application but there are some open
> issues with it right now.
>
> What is your time frame?
>
> If you come up with a list of absolutely must have minimum things you
> need done and a date, that helps focus everyone on getting you launched.
> Then we can add the next level of applications in a second pass.
>
> If we don't nail your answer by tomorrow AM US ET, I'll bring it up on
> the server and development lists to see if I can get more input.
>
> Bryan and Sulochan,
>
> I know its crunch time in the Himalayas but some input ASAP would be
> greatly appreciated for this roll out in Cambodia.
>
> What access point did you deploy? Do you have a suggestion for one that
> has a built in router?
>
> Are you going ahead with the mesh turned on or should we defer that?
>
> BTW congratulations on your success and thanks for all your great blogs,
> e-mail lists, forums and feedback (http://www.olenepal.org/)! It really
> helps other sites and helps focus development on real user needs. The
> fun part is just beginning :-)
>
> Thanks,
>
> Greg S
>
>
> -----Original Message-----
> From: matt wolstencroft [mailto:mwolstencroft at fastmail.com.au]
> Sent: Thursday, March 27, 2008 4:58 AM
> To: Greg Smith (gregmsmi)
> Subject: Fwd: Re: [laptop.org #8321] Questions about XO mesh networking
>
> Hi,
> I have been trying to find out from help at laptop.org what wireless router
> will be compatible with our 200 XOs after we found out that the WRT54Gv7
> has problems due to WDS. So far I have had no response and my colleague
> Phillip gave me your email in the hope that you might be able to help. I
> have included the email history below to give you some context.
>
> Could you recommend a wireless AP with router, 2 antennas (pref rev
> tnc), compatible with 802.11g & 802.11b, stateful firewall, DHCP, 4
> 10/100 LAN ports and costing around $100? The main criteria is that it
> does not have any problems with XO mesh networks.
>
> Any assistance would be greatly appreciated.
>
> Thanks, Matt
>
>
> --
> Matt Wolstencroft
> mwolstencroft at fastmail.com.au
>
> --
> http://www.fastmail.fm - One of many happy users:
> http://www.fastmail.fm/docs/quotes.html
>
> ----- Original message -----
> From: "matt wolstencroft" <mwolstencroft at fastmail.com.au>
> To: help at laptop.org
> Date: Mon, 24 Mar 2008 20:19:49 +1100
> Subject: Re: [laptop.org #8321] Questions about XO mesh networking
>
> Hi,
> Thanks for the quick response. I have a few more questions :
>
> 1. Will automatic MPP be turned on in future builds?
>
> 2. According to the OpenWrt website, the WRT54Gv7 cannot run the openwrt
> firmware. I just want to clarify that in this case we will have to
> replace the router?
>
> 3. The DLink equipment is just an AP. Could you recommend any wireless
> routers? Or is there a more up to date list than this :
> http://wiki.laptop.org/go/Wireless_Access_Point_Compatibility?
>
> Thanks very much for your help,
> Regards,
> Matt
>
> On Sun, 23 Mar 2008 20:01:45 -0400, Support at rt.laptop.org said:
> > On Sat Mar 22 01:44:19 2008, mwolstencroft at fastmail.com.au wrote:
> > > Hi,
> > > I have just started working at Reaksmy school in Cambodia with 200
> > > XOs (build 656). Access to the Internet is via a satellite which is
> > > connected to a linksys WRT54G v7 with the latest firmware
> (v7.00.4).
> > > The wireless configuration of the router is as follows :
> > >
> > > Channel : 11
> > > Encryption : none
> > > Wireless SSID broadcast : enabled
> > >
> > > Documentation I have read suggests that the mesh networking should
> > > work in the following manner:
> > >
> > > - majority of XOs in the mesh act as mesh points : "uses its WiFi
> > > interface to both access the network itself and to relay traffic
> > > from other mesh points"
> > > - certain XOs will act as mesh portals (MPP): "connected to an
> > > external network, and that forward traffic in and out of the mesh"
> > > - an XO will associate itself with a mesh based on the following :
>
> > > 1. The laptop will issue a DHCP request, followed by a RREQ for a
> > > Mesh Portal anycast address and wait for RREP replies, on all
> three
> > > channels being proposed for OLPC meshes (1, 6, and 11) before
> making
> > > any decisions.
> > > 2. If any channel provides a lower hop count to a Mesh Portal, it
> is
> > > selected unless its signal strength is significantly lower.
> > > 3. If all channels provide the same hop count to a Mesh Portal,
> > > random selection is used.
> > >
> > > I have a few questions regarding the mesh networking and the
> > > configuration of the WRT54G:
> > >
> > > 1. Is automatic MPP turned off in build 656 and is it enabled as
> per:
> > >
> "http://wiki.laptop.org/go/Test_Config_Notes#Turn_on_MPP_Capability"?
> > It is turned off now and in all current builds.
> >
> > > 2. What are the determining factors that affect which XOs become
> > > mesh portals?
> > Every laptop that can see a AP can become a MPP if that functionality
> > is enabled.
> >
> > > 3. We have been seeing intermittent dropouts of connection to the AP
>
> > > forboth XOs and normal laptops. Are there any known problems with
> > > the WRT54G and the XOs?
> > From Michail Bletsas, in charge of connectivity:
> > "Using WDS frames for the mesh traffic turns out that it creates
> > serious interoperability problems with WDS-capable access points that
>
> > implement Dynamic establishment of links with other WDS peers (like
> > the ubiquitous Linksys WRT54 router/AP). We found that out during
> > field testing and it took several months to identify all the failure
> modes."
> >
> > So the answer to whether you should/can use WRT54Gx APs is "only if
> > you can upgrade them to an OpenWRT variant". "A good starting point
> > should be the DLINK DWL-2100AP which uses an Atheros Chipset."
> >
> >
> > >
> > > 4. Is there any recommended/tested firmware for the WRT54G v7? Is
> > > openwrt tested/supported?
> >
> > It has been tested by users, but no offical testing has been
> undergone.
> > Users report that OpenWRT does not have the problems of the original
> > firmware.
> > > 5. If we were to replace the WRT54G is there a list of preferred
> > > wireless equipment for OLPC systems?
> >
> > See answer to #3.
> >
> > > 6. Some documentation I have seen suggests that wireless APs should
> > > be configured to use channel 1,6 or 11. Is this still the case?
> >
> >
> >
> > > 7. If the steps listed above are correct then we should see XOs
> > > forming and connecting to mesh networks on channel 1,6,11 however
> > > they always seem to form a mesh on channel 1. Is this correct?
> >
> > XO's search all 3 mesh channels, looking for a school server running
> > on that mesh channel. When they don't see a school server on any of
> > the three channels, they connect to a serverless mesh on channel 1.
> >
> > > 8. Can XOs connected to different mesh networks currently see each
> > > other?
> >
> > No. Each mesh channel is a totally independent network running at a
> > different frequency. However, if there is a school server with
> > multiple antennas, it can route packets between the networks.
> > Therefore, if there is a school server with 3 mesh antennae, XO's can
> > use all 3 channels, and all see each other.
> >
> >
> > >
> > > 9. Our XOs can see the AP in the neighborhood view and when they
> > > connect to it, they become disconnected from the mesh network. Is
> > > this correct behavior?
> >
> > Yes. When MPP mode is disabled, an XO will only connect to either an
> > Access Point or a mesh
> > channel, but not both.
> > > Any assistance would be greatly appreciated. Thanks in advance,
> > >
> > > Matt Wolstencroft
> >
> > The above answeres were provided by Ben Schwartz (author of the
> > Distance activity), and the quotes were from Michail Bletsas.
> >
> > Keep in mind I am not an OLPC employee, I am a support volunteer. if
> > this does not answer your questions try countries at laptop.org, as it is
>
> > answered by OLPC staff.
> > --
> > Thanks,
> > FFM
> > OLPC Support Volunteer
> --
> Matt Wolstencroft
> mwolstencroft at fastmail.com.au
>
> --
> http://www.fastmail.fm - One of many happy users:
> http://www.fastmail.fm/docs/quotes.html
>
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