[Server-devel] Blog post on Nepal's pilot schools

[Bryan Berry]

Greg, 

>I think I understand now. Its 8Mb/s from school to Katmandu
> Administration building (Data center) and thin pipe (~256Kb/s) from
> there to Global Internet. Is that right?

Correct

>The only unknown would be if Jabber/Mesh traffic will flood that 8Mb/s
> link. 

Exactly, and we won't really know if the mesh traffic will flood the
link but I expect it will, esp. if kids share stuff like we hope they
will. Also, we don't yet know how much signal loss we will have b/w the
datacenter and the school. 

>XS in the Katmandu Data Center will solve your power, physical security
> and on site management challenges!

Power will still be a huge issue because we have 8 hours of
load-shedding per day (no grid electricity) so we have to have UPS's on
the school sites and physically secure those UPS's


On Tue, 2008-03-11 at 09:41 -0400, Greg Smith (gregmsmi) wrote:
> Hi Bryan,
> 
> I think I understand now. Its 8Mb/s from school to Katmandu
> Administration building (Data center) and thin pipe (~256Kb/s) from
> there to Global Internet. Is that right?
> 
> If so, why don't you leave the school server in the Data Center in
> Katmandu? 
> 
> DHCP and DNS will be fine with that in terms of BW. Xos have to find the
> XS to get an address from DHCP so there may be some extra config needed
> on the Wireless AP, but that should be doable. I expect Moodle and even
> backup will be OK as long as everyone doesn't backup at the same time. 
> 
> The only unknown would be if Jabber/Mesh traffic will flood that 8Mb/s
> link. That should be manageable with the right constraints on the mesh.
> If Jabber is very sensitive to latency that could be an issue but I
> think its designed to run over the Internet and your latency should be
> on the order of ms.
> 
> Yanni,
> 
> Do you expect any issue with 150 Xos connecting to a jabber server over
> an 8Mb/s link? Is there any extra configuration needed minimize the
> jabber BW (TTL or anything else)? If you can answer re: XO build 656 or
> another well tested/blessed build that will help as they need to image
> them ASAP. Let us know if you need more info or those are not well
> defined questions.
> 
> BTW Sulochan also asked a bunch of wireless question on this list
> yesterday if you have a chance to look at those.
> 
> FYI for all, here's a good link with test cases and details on Mesh
> testing and XO/XS dev/test in general:
> http://wiki.laptop.org/go/Test_Config_Notes 
> 
> XS in the Katmandu Data Center will solve your power, physical security
> and on site management challenges!
> 
> Its risky to change the design so close to production but unless there's
> a clear technical issue it seems like a big benefit.
> 
> Thanks,
> 
> Greg S
> 
> -----Original Message-----
> From: Bryan Berry [mailto:bryan.berry at gmail.com] 
> Sent: Tuesday, March 11, 2008 5:06 AM
> To: server-devel
> Cc: Greg Smith (gregmsmi)
> Subject: Re: [Server-devel] Blog post on Nepal's pilot schools
> 
> Thanks Greg!
> 
> Regarding bandwidth, it is very expensive here in Nepal. We'll be very
> lucky if we get 512 kbps for both schools and most likely it will only
> be 256 for both.
> 
> >Based on that, I assume web/library surfing wont be an issue. The only 
> >challenges I see are backing up Xos or delivering new XO images. I'm 
> >told that delivering new images works well in Uruguay. I think there is
> 
> >a mechanism to push-cache images to the school server so Xos stay on 
> >the LAN/Mesh for upgrades. Can anyone confirm that?
> 
> >If you want to backup over the WAN we need to think about that some 
> >more. Kids love to take pictures and make videos so it could be a big 
> >data flow....
> 
> Our wireless WAN backbone will actually have fairly high bandwidth,
> around 8-11 mbps. It only gets expensive once we purchase Internet
> bandwidth.
> 
> Using olpc-update to connect to servers in Boston will be a non-starter.
> We have to set up our own update server in Nepal. I have read a little
> bit about it on the wiki but will have to work on it firsthand. 
> 
> >I want to know how the kids like it, what the teachers think, what they
> 
> >want next, what they like and don't like.
> >Everything that will help adapt and improve the overall solution!
> 
> One of the interesting things I have discovered is that ultimately the
> success of the project hinges on the support of the teachers. They are
> at the school all the time and have the respect of the local community.
> We can't hang out at the schools all the time to make sure things go
> well. Technical support, reliable power, using the laptops for
> meaningful purposes, this responsibility ultimately rests on the
> teachers.
> 
> thanks for your continued support Greg!
> 
> 
> Regarding donations, awesome! will send you the info soon
> 
> 
> --
> Bryan W. Berry
> Systems Engineer
> OLE Nepal, http://www.olenepal.org
> 
> 
> ------------------------------
> Message: 2
> Date: Mon, 10 Mar 2008 18:18:39 -0400
> From: "Greg Smith (gregmsmi)" <gregmsmi at cisco.com>
> Subject: 	
> To: <server-devel at lists.laptop.org>
> Cc: galanis at laptop.org
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> 
> Hi Bryan,
> 
> Great blog and information. Thanks a lot for sharing it!
> 
> I'm counting on you to keep gathering info and sharing all the details
> of how this deployment goes. I want to know how the kids like it, what
> the teachers think, what they want next, what they like and don't like.
> Everything that will help adapt and improve the overall solution!
> 
> Great idea to put Squid and dansguardian in the school HQ! However, I
> was unsure from your blog how much BW they have in each school. Do you
> have a rough number for that?
> 
> They say that 1Mb/s works fine in Uruguay for schools of several hundred
> students. However, they take turns using the WAN so only one class is
> online at a time. Also, I saw a presentation by someone who was at the
> Mongolia deployment. He said they have 512Kb/s and that works fine there
> too. Both of those are second hand info so not completely confirmed.
> 
> Based on that, I assume web/library surfing wont be an issue. The only
> challenges I see are backing up Xos or delivering new XO images. I'm
> told that delivering new images works well in Uruguay. I think there is
> a mechanism to push-cache images to the school server so Xos stay on the
> LAN/Mesh for upgrades. Can anyone confirm that?
> 
> If you want to backup over the WAN we need to think about that some
> more. Kids love to take pictures and make videos so it could be a big
> data flow.... 
> 
> On your wireless design, I heard a wireless test engineer (Gianni,
> copied) talk about Mesh testing at OLPC HQ Sunday. I think he can help
> you define the right configuration if you have open questions. 
> 
> Are you all set with the in-school wireless design using the Deliberant
> DLB-2700?
> 
> I'm looking in to XO failure rates to help you size the spares pool. I
> hope to have some feedback later this week.
> 
> What else do you need to get up and running in 4 weeks? 
> 
> Any open questions on XO imaging and initial XO test?
> 
> If you are done with technical school server questions for Phase 1, I'll
> wrap up documentation on how to replicate a Nepal style school server
> (we can brand it a Sulochan Special :-). 
> 
> Then its on to phase 2 design if that fits your and Martin's agenda or
> I'll move to use cases and user requirements for XO. I will need
> feedback from your teachers and your education team for that!
> 
> Thanks,
> 
> Greg S
> 
> PS I'll help do some fund raising too. Mostly amongst my family and
> friends but send me the info and I'm good for a small check ASAP.
>