[Server-devel] location and muscle of the school server
Bryan Berry
bryan.berry at gmail.com
Thu Feb 21 10:00:51 EST 2008
Sameer ji,
You make a good point. We have only have 14 hours per day of electricity
in Nepal so the issue of power is very acute for us.
A school server that caches websites, serves up Moodle pages, serves as
a mesh portal for the mesh network, and does some kind of content
management will definitely be a power hog compared to the XO.
Additionally, it will require a lot more maintenance than the XO's. I
am confident that kids and locals will be able to repair the XO's but I
doubt many communities (at least in Nepal) will have local people w/ the
Linux skills to manage the School Server.
We are considering centralizing many aspects school server for our fall
deployment. Our Networking guy, Mahabir Pun, has had a lot of success
connecting rural villages to the Internet w/ long haul point-to-point
wireless links that connect to the nearest city. He places a caching,
e-mail, and voip server in the city. This works because the wireless
links are high-speed and quite stable.
We intend to put the servers on site for our April pilot but we may
centralize them later.
Centralizing servers won't work well if bandwidth to the schools is
limited and/or expensive.
As a side note, in Nepal we will try to avoid satellite Internet
connections wherever possible. The monthly bandwidth costs are just too
expensive over time. Comparatively, long-haul wireless links w/ cheap
equipment from Motorola, Microtek, or Ubiquiti are much more
cost-effective.
--
Bryan W. Berry
Systems Engineer
OLE Nepal, http://www.olenepal.org
> Message: 3
> Date: Tue, 19 Feb 2008 18:28:42 -0800
> From: Sameer Verma <sverma at sfsu.edu>
> Subject: [Server-devel] location and muscle of the school server
> To: server-devel at lists.laptop.org
> Message-ID: <47BB905A.3030509 at sfsu.edu>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>
> I've been reading up on the specs for running the XS (XSX - the one that
> relies on off-the-shelf parts) and one thing that keeps bugging me is
> that if we don't have reliable power infrastructure on site (which is
> why XO makes a lot of sense) how can we expect to run a
> common-off-the-shelf server that consumes 200W of power?
>
> I see in the specs that the model of using an XO with external drive as
> a school server is an option, but I wonder how far that has been
> explored. It is a great idea (after all, all nodes on a mesh are just
> that - nodes) but given the current development, it doesn't look like an
> XO has enough to run Squid, etc. I take it that the current run of XS is
> short-term?
>
> Another point that came up a couple of days ago (when I was discussing
> this with a colleague) is why can't the server be further upstream at a
> data center where it has adequate power and cooling?
>
> Of course, any pointers would be great.
>
> cheers,
> Sameer
>
> --
> Dr. Sameer Verma, Ph.D.
> Associate Professor of Information Systems
> San Francisco State University
> San Francisco CA 94132 USA
> http://verma.sfsu.edu/
> http://opensource.sfsu.edu/
>
>
>
> ------------------------------
>
> Message: 4
> Date: Wed, 20 Feb 2008 18:05:01 +0545
> From: "sulochan acharya" <sulochan at gmail.com>
> Subject: Re: [Server-devel] Mesh Network feature XO-XS
> To: "Ricardo Carrano" <carrano at ricardocarrano.com>
> Cc: server-devel at lists.laptop.org, devel at lists.laptop.org
> Message-ID:
> <26a279680802200420u2723cac2ma7a0e195a3a41f41 at mail.gmail.com>
> Content-Type: text/plain; charset="iso-8859-1"
>
> Hi Ricardo,
> I have iwpriv showing
> NULL on all the fwt_list .
> What should it be set to?
>
> best,
> Sulochan.
>
>
> On Feb 19, 2008 5:41 PM, Ricardo Carrano <carrano at ricardocarrano.com> wrote:
>
> > Sulochan,
> >
> > You should check your forwarding (layer two) table with : iwpriv msh0
> > fwt_list <index> (<index> is 0,1,2,...)
> >
> > Look for an entry that forwards the frames destined to the anycast mac
> > address of the server (c0:27:c0:27:c0:00) via the mac address of the first
> > XO.
> >
> > Traceroute/path will show you layer three (IP) routes.
> >
> > Regards,
> > Ricardo Carrano
> >
> > 2008/2/19 sulochan acharya <sulochan at gmail.com>:
> >
> > > Folks,
> > > I can not hop from xo to xo to xs.
> > > Here is what I did:
> > >
> > > One XO closer to the server with active antenna.....and i can ping the
> > > server from this laptop.
> > >
> > > Another XO closer to the first laptop ( i can chat with this XO) but
> > > further away from the server.
> > >
> > > Now technically i should be able to ping the server through the first
> > > laptop, but I cant :(
> > >
> > > Is there some additional things i need to (like adding packages) go
> > > through to get this to work?
> > >
> > > Or is it just out of range? If so how it is different from one laptop
> > > talking to another laptop?
> > >
> > > Is there a way i can check that the packet is being relayed (other than
> > > doing trace rout ) ?
> > >
> > > Also, can i for test purposes change the mesh DHCP to give out ipv4 and
> > > not ipv6? Would this make
> > > some other features not work?
> > >
> > > best,
> > > -Sulochan
> > >
> > > _______________________________________________
> > > Devel mailing list
> > > Devel at lists.laptop.org
> > > http://lists.laptop.org/listinfo/devel
> > >
> > >
> >
> -------------- next part --------------
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> ------------------------------
>
> Message: 5
> Date: Wed, 20 Feb 2008 18:10:14 +0545
> From: "sulochan acharya" <sulochan at gmail.com>
> Subject: [Server-devel] mesh network
> To: krstic at solarsail.hcs.harvard.edu, "John Watlington"
> <wad at laptop.org>, server-devel at lists.laptop.org
> Message-ID:
> <26a279680802200425p533da885y7a1a44d81ea5dc7 at mail.gmail.com>
> Content-Type: text/plain; charset="iso-8859-1"
>
> Hi John and Ivan,
> I am having some trouble getting my mesh to fully work. Basically i can get
> two antennas to work at the same time.
> They are both using the same firmware and work separately. Also i cant hop
> from xo to xo to the server. It would be great
> if you guys can give me a great brief overview of how the networking is
> handled by the XS. I am trying to set it up for the Nepal pilot in April.
>
> thanks in advance,
> best
> Sulochan
> -------------- next part --------------
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> ------------------------------
>
> Message: 6
> Date: Wed, 20 Feb 2008 10:57:00 -0300
> From: "Ricardo Carrano" <carrano at ricardocarrano.com>
> Subject: Re: [Server-devel] Mesh Network feature XO-XS
> To: "sulochan acharya" <sulochan at gmail.com>
> Cc: server-devel at lists.laptop.org, devel at lists.laptop.org
> Message-ID:
> <a31fbec40802200557r394eab13h5481c281698af129 at mail.gmail.com>
> Content-Type: text/plain; charset="iso-8859-1"
>
> Hi Sulochan!
>
> Assuming it is your XO2 fwt_list, it should be populated with paths to XO1
> (via XO1) and XS (via XO1 or XS, depending whether the XS is in reach).
> The way it is (empty) this means your XO has no path for any other XO. It is
> lonely and sad ;-)
> But, please keep in mind that these entries expiry (I don't recall how long
> does it take - but it's not long), so you should check them during the test.
> Is that the case?
>
> On Feb 20, 2008 9:20 AM, sulochan acharya <sulochan at gmail.com> wrote:
>
> > Hi Ricardo,
> > I have iwpriv showing
> > NULL on all the fwt_list .
> > What should it be set to?
> >
> > best,
> > Sulochan.
> >
> >
> >
> > On Feb 19, 2008 5:41 PM, Ricardo Carrano <carrano at ricardocarrano.com>
> > wrote:
> >
> > > Sulochan,
> > >
> > > You should check your forwarding (layer two) table with : iwpriv msh0
> > > fwt_list <index> (<index> is 0,1,2,...)
> > >
> > > Look for an entry that forwards the frames destined to the anycast mac
> > > address of the server (c0:27:c0:27:c0:00) via the mac address of the first
> > > XO.
> > >
> > > Traceroute/path will show you layer three (IP) routes.
> > >
> > > Regards,
> > > Ricardo Carrano
> > >
> > > 2008/2/19 sulochan acharya <sulochan at gmail.com>:
> > >
> > > > Folks,
> > > > I can not hop from xo to xo to xs.
> > > > Here is what I did:
> > > >
> > > > One XO closer to the server with active antenna.....and i can ping the
> > > > server from this laptop.
> > > >
> > > > Another XO closer to the first laptop ( i can chat with this XO) but
> > > > further away from the server.
> > > >
> > > > Now technically i should be able to ping the server through the first
> > > > laptop, but I cant :(
> > > >
> > > > Is there some additional things i need to (like adding packages) go
> > > > through to get this to work?
> > > >
> > > > Or is it just out of range? If so how it is different from one laptop
> > > > talking to another laptop?
> > > >
> > > > Is there a way i can check that the packet is being relayed (other
> > > > than doing trace rout ) ?
> > > >
> > > > Also, can i for test purposes change the mesh DHCP to give out ipv4
> > > > and not ipv6? Would this make
> > > > some other features not work?
> > > >
> > > > best,
> > > > -Sulochan
> > > >
> > > > _______________________________________________
> > > > Devel mailing list
> > > > Devel at lists.laptop.org
> > > > http://lists.laptop.org/listinfo/devel
> > > >
> > > >
> > >
> >
> -------------- next part --------------
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>
> ------------------------------
>
> Message: 7
> Date: Wed, 20 Feb 2008 11:37:42 -0500
> From: John Watlington <wad at laptop.org>
> Subject: Re: [Server-devel] mesh network
> To: sulochan acharya <sulochan at gmail.com>
> Cc: server-devel at lists.laptop.org
> Message-ID: <FBA9C394-4C7F-49C1-BCC4-560089BFC5F8 at laptop.org>
> Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed
>
>
> Sulochan,
> Ricardo is one of the people developing and testing the mesh for
> OLPC, and he
> is already helping you.
>
> If you can't hop from XO to XO, it sounds like your problems are not
> in the school server.
> What channel are you using ? Are you sure that both laptops and
> the server are on the
> same channel ? Are there any other 802.11 networks in the area ?
> What channel are they on ?
>
> What does ifconfig and iwconfig report on all three machines ?
>
> The networking on the XS side is best described by:
> http://wiki.laptop.org/go/
> XS_Configuration_Management#School_Specific_Configuration
>
> Outside of setting a few special bits in the Active Antenna interface
> to get it to act as
> a mesh portal, the setup is a standard networking gateway. Those
> bits used to be set by:
> /etc/init.d/olpc-mesh-config
> http://dev.laptop.org/git?p=projects/xs-
> config;a=blob_plain;f=fsroot.olpc.img/etc/init.d/olpc-mesh-
> config;hb=HEAD
> (and still are), but they are primarily set by a udev script
> (enabling hotplug of the active antennas):
> /etc/udev/rules.d/10-olpcmesh.rules
> http://dev.laptop.org/git?p=projects/xs-
> config;a=blob_plain;f=fsroot.olpc.img/etc/udev/rules.d/10-
> olpcmesh.rules;hb=HEAD
>
> If your fwt_list doesn't show any other mesh nodes, start there...
>
> John
>
> On Feb 20, 2008, at 7:25 AM, sulochan acharya wrote:
>
> > Hi John and Ivan,
> > I am having some trouble getting my mesh to fully work. Basically
> > i can get two antennas to work at the same time.
> > They are both using the same firmware and work separately. Also i
> > cant hop from xo to xo to the server. It would be great
> > if you guys can give me a great brief overview of how the
> > networking is handled by the XS. I am trying to set it up for the
> > Nepal pilot in April.
> >
> > thanks in advance,
> > best
> > Sulochan
>
>
>
> ------------------------------
>
> _______________________________________________
> Server-devel mailing list
> Server-devel at lists.laptop.org
> http://lists.laptop.org/listinfo/server-devel
>
>
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