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

Tue Mar 11 19:00:18 EDT 2008

8 Mb/s is a thin pipe.   We hope to have six times that bandwidth
between the server and the laptops (and that isn't nearly enough...)
You are proposing that every bit shared between laptops go back
and forth over than link at least twice (to/from the jabber server).

We cannot recommend any software but the upcoming Update1
release.

John

On Mar 11, 2008, at 9:41 AM, 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
> Message-ID:
>
> <B02C78B842B89E448937F82241C96A2B0495FF35 at xmb-rtp-20c.amer.cisco.com>
> Content-Type: text/plain;       charset="us-ascii"
>
> 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.
>
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