Re: Mesh Dreams = OLSR
On Aug 24, 2010, at 5:24 PM, Richard A. Smith wrote: On 08/24/2010 10:13 AM, Reuben K. Caron wrote: Consider the benefits of using open source software versus our closed source firmware and partnering with communities like Freifunk whose network is ~ 800 node, guifi.net is almost 10k nodes in Barcelona, Athens Wireless is 5k nodes. The largest of our mesh problems did not have to do with scalability on sheer number of nodes but rather scalability in density. Is there any information available on how these networks perform when there are 50 - 100 of them next all in the same room or in adjacent rooms? Yes! And the answer is very very simple: turn down the txpower! ;-))) best regards, Aaron (OE1SYS) PGP.sig Description: This is a digitally signed message part ___ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel
Re: Mesh Dreams = OLSR
On Aug 24, 2010, at 5:24 PM, Richard A. Smith wrote: On 08/24/2010 10:13 AM, Reuben K. Caron wrote: Consider the benefits of using open source software versus our closed source firmware and partnering with communities like Freifunk whose network is ~ 800 node, guifi.net is almost 10k nodes in Barcelona, Athens Wireless is 5k nodes. The largest of our mesh problems did not have to do with scalability on sheer number of nodes but BTW Richard, as far as I remember the problems with 802.11s seemed to be: 1) the standard is not a standard and it was intentionally crippled 2) the drivers were very b0rked and broken (and Marvel did a terrible job with the driver software) Scalability to less than 30 laptops in one room was the result. A standard good AP and standard laptops can go to 30 in one room (with standard settings). So, there was definitely something broken with the Marvel solution. Fix layer 2 first, then look at layer 3. PS: can you forward my answer to the lists? I am not subscribed... PGP.sig Description: This is a digitally signed message part ___ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel
Re: Mesh Dreams = OLSR
The largest of our mesh problems did not have to do with scalability on sheer number of nodes but rather scalability in density. Is there any information available on how these networks perform when there are 50 - 100 of them next all in the same room or in adjacent rooms? Yes! And the answer is very very simple: turn down the txpower! ;-))) Can you provide me with a pointer to the numbers? Whats the maximum number of nodes can you have operated in a given area and what sort of network traffic tests did you run? Well, the community wireless networks are not very much about very dense settings. We try to cover large areas with external (outdoor) antennas but still have very many nodes in one single mesh covering a whole city or so. See the attached current map of the Funkfeuer.at network. BUT!! Because we don't have a mesh with 100s of laptops in one room, does not mean, we don't know physics ;-) Since you asked if I know an example where there are many laptops in one room: One example that I know that worked brilliantly well with many wireless devices in one room was the RIPE meeting in Amsterdam. There they regularly have many small APs below the desks in the meeting room and these are turned down very much in volume (txpower). The effect is that they only cover a small area ( remember, power decreases by the square of the distance). So this is a way to avoid a lot of noise of many laptops in a small room. Another feature that you IMHO should look at is 802.11n devices (and of course also turn down the volume there!). These offer higher bandwidths in addition to actually using the multipath effects. When you have many many laptops in one room and everybody screams/sends very loud then you have lots of echos (multipath fading) bouncing off the walls etc. 802.11n thrives off these multipath effects. As I said - first solve layer 1 2 issues and then think about layer 3 meshing. I hope I could help. Best regards, L. Aaron Kaplan (OE1SYS) PS: please forward my answers to the list or allow me to post to the list. I am not subscribed there . Thx. PGP.sig Description: This is a digitally signed message part ___ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel
Re: Mesh Dreams = OLSR
(...) BTW Richard, as far as I remember the problems with 802.11s seemed to be: 1) the standard is not a standard and it was intentionally crippled 2) the drivers were very b0rked and broken (and Marvel did a terrible job with the driver software) Scalability to less than 30 laptops in one room was the result. A standard good AP and standard laptops can go to 30 in one room (with standard settings). So, there was definitely something broken with the Marvel solution. Fix layer 2 first, then look at layer 3. Yes, Yes, I'm not trying to defend the previous mesh implementation in any way. Pretend the previous OLPC mesh does not exist. And in fact on a XO 1.5 it does not exist. OK. Didn't know. I'm saying that the bulk of our rollouts are dense scenarios connected to an AP. If we can do better density than an AP with less equipment then thats something to go for. yes, you can - take the RIPE example: just reduce the txpower and have multiple APs. There are also some very smart APs with a central controlling AP out there (Cisco has some of those). These APs balance out the clients magically. If you can't do better than an AP then unless you are doing the minimal-infra wide area part of mesh there isn't much in it that will help the bulk of OLPC rollouts. Well - the issue is IMHO that OLPC always sold the public on the mesh idea. So it is somewhat of a bummer that the mesh is gone now. I might add that the Funkfeuer/Freifunk -style outdoor meshes are still another totally cool option: you can mesh the different schools this way very cheaply. So that is another thing to consider IMHO. PS: can you forward my answer to the lists? I am not subscribed... Sure but I'm not on iaep so I can't help there. thx! PGP.sig Description: This is a digitally signed message part ___ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel
Re: Mesh Dreams = OLSR
On Aug 24, 2010, at 7:11 PM, Reuben K. Caron wrote:
On Aug 24, 2010, at 11:24 AM, Richard A. Smith wrote:
The largest of our mesh problems did not have to do with scalability on
sheer number of nodes but rather scalability in density. Is there any
information available on how these networks perform when there are 50 - 100
of them next all in the same room or in adjacent rooms?
Here is a link to a paper that actually tested in a physical 49 node lab with
various configurations:
http://dev.laptop.org/~reuben/Elsevier2008_OLSR_compare.pdf
This differs from most other papers that I have read that use theoretical
simulations.
Yes, IMHO you *need* the real world simulations (and even then it is very easy
to make measurement mistakes and arrive at arbitrary conclusions [1]). I
started to only trust big real world deployments.
Thanks for the link, still have to read it in detail. BTW: the conclusion
section of this paper already confirms our previous discussion about reducing
txpower: Currently hop counts up to 5 are achievable with routing protocols in
the full 7x7 grid when the power is set to 0dBm with 30 dB attenuators.
;-)
a.
[1] @ARTICLE{Kurkowski05manetsimulation,
author = {Stuart Kurkowski and Tracy Camp and Michael Colagrosso},
title = {Manet simulation studies: The incredibles},
journal = {ACM SIGMOBILE Mobile Computing and Communications Review},
year = {2005},
volume = {9},
pages = {50--61}
}
http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.110.7902rep=rep1type=pdf
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Re: Mesh Dreams = OLSR
On Aug 24, 2010, at 7:20 PM, Richard A. Smith wrote: On 08/24/2010 01:01 PM, L. Aaron Kaplan wrote: Well - the issue is IMHO that OLPC always sold the public on the mesh idea. So it is somewhat of a bummer that the mesh is gone now. Let me re-phrase what I said before all the rumors start to fly and I get in trouble. The idea of mesh is still alive and well at OLPC. We still very much believe in mesh. Ah ok. As said - I was not very much in touch with the current operations and decisions at OLPC. Sorry about that. Whats not there in 1.5 is OLPC-original-mesh-routing-in-the-wlan-firmware. One can still accomplish mesh via thin firmware. ok And if you use multiple 1.5's out under a tree with no AP ah-hoc networking still allows them all to communicate just like XO1. perfect :) Almost nothing has changed except that now we don't melt down the 2.4Ghz RF spectrum when a bunch of them are near each other. Having been once burned by mesh we are taking the show me it works in a school stance before jumping back into the mesh-routing game. We need to see definitive numbers not just speculation. makes sense. Like you said. There are AP's that will do all the fancy Tx power management without any mesh-routing. sure. But those you have to pay extra for ;-) But they work... agreed. Hm well, you at least got me thinking how we can make a small dense indoor mesh working without APs interesting challenge. Like think about replacing those smart APs by a distributed version. Interesting... a. PGP.sig Description: This is a digitally signed message part ___ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel
Re: Mesh Dreams = OLSR
On Aug 24, 2010, at 7:32 PM, Reuben K. Caron wrote: On Aug 24, 2010, at 1:29 PM, L. Aaron Kaplan wrote: Hm well, you at least got me thinking how we can make a small dense indoor mesh working without APs interesting challenge. Like think about replacing those smart APs by a distributed version. Interesting... a. Maybe a suitable challenge during a Wireless Mesh Battle(1). (1) http://battlemesh.org/ sure :) Maybe the next one :) So far they were always outdoors. PGP.sig Description: This is a digitally signed message part ___ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel
Re: New, more realistic multi-hop network testbed
would it make sense to at least enter that request into the projectdb since that is what it was made for? (apart from the feature requests which will be taken care of at some time, it does hold the data and hence it can help in tracking the XOs) On a different note: in larger mesh networks (athens wireless comes to mind) you do encounter strange effects when you go to a couple of hundred of nodes. So I would not underestimate the need for a massive test. Massive means maybe 1000 ;-) After all you can reach that number of 1000 kids quite easily. a. On Jun 8, 2008, at 5:55 AM, Kim Quirk wrote: Some thoughts from a QA perspective: I consider the 100 laptops that I budgeted, ordered and help install in Peabody to be the QA collaboration testbed, which is expected to be used to recreate problems from the field and test out next release solutions. Since we had to dismantle Peabody, most of these laptops (about 70 of them) have been loaned to Poly in 1CC. Now that we have both a QA Lead and an intern, I expect we will need to refocus 20-30 laptops back to the QA testbed full time and we have signed a lease on the new test facility, which will be ready for the full 100 laptop test bed (or perhaps 200 laptops) by mid-July. Secondly, we also need to be working on the longer term solutions, such as those being investigated by Poly, Nortel, Michail, and Ricardo. If this also requires a 100 laptop test bed then we need to build one. We need to order these laptops and start making permanent homes for them. If the first step is to order 10 laptops, I will order them. Poly - What I can't tell from your progress reports is exactly what is needed for us to get to the next level. On the surface it sounds like you had to rebuild chat to make it work with cerebro. If so, does that mean all activities would have to be modified to a new API? What else is needed? How does the cerebro solution fit into the rest of the stack and the other technologies we are working on for 8.2.0 (August) and future releases? If the cerebro solution is still in research and there are a lot of issues that still need to be worked out before we can release it, then we need someone to help track all the issues and help resolve them through the stack in order to get something to release stage. Let's work with Michail on this as he probably needs to take the lead. As a first step, I will order 10 laptops for Poly to find permanent homes for throughout the MIT campus. Kim On Sat, Jun 7, 2008 at 12:02 PM, C. Scott Ananian [EMAIL PROTECTED] wrote: Honestly, I'm getting very burned out over the politicking here. Ricardo, Polychronis, and the Nortel guys seem to be the ones doing the real heavy lifting here on the mesh network. When they ask for something, I think we should give it to them. Ricardo and Polychronis agree that a sparse network testbed may be useful -- in addition to, not instead of, a dense collaboration testbed -- why can't we just say, yes, do that then. Wad is right, we still need a collaboration testbed, but as Poly points out this is currently Collabora's area of responsibility. --scott -- ( http://cscott.net/ ) ___ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel ___ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel --- there's no place like 127.0.0.1 ___ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel
Re: New, more realistic multi-hop network testbed
On Jun 6, 2008, at 10:31 PM, Polychronis Ypodimatopoulos wrote: In the spirit of escalating collaboration/communication use cases to more realistic scenarios, I 'd like to propose creating the following multihop network testbed. This testbed will involve about 70 nodes, but most are already deployed (about 50 nodes already exist at 1CC and 8 at the Media Lab). About 10-12 new XOs are necessary to form the multi-hop network: http://maps.google.com/maps/ms? hl=engl=usptab=2ie=UTF8oe=UTF8msa=0msid=116432384591811010127.00 044f046ce8f6f83aae3 Hi Pol! outdoor or indoor? Might be a good outdoor test for XO durability :)) You might need some external directional antennas since there is so much 2.4GHz noise there. a. ___ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel
Re: New, more realistic multi-hop network testbed
This is mainly an outdoor test with indoor nodes ;-) The idea is be as realistic as possible and try to replicate the actual village environment, only in its worst possible form: Including the high radio noise levels of MIT. We should not enforce connectivity by means of external antennae, but rather experiment with the reachability of the XO as it is, potentially by adding active antennae in between. Having this testbed in place, we can try a mobility test also, eg. having a mobile phone or an XO walk from end to end. makes sense. But I would not be surprised if you need external antennas for good thruput. Keep us updated :) Which reminds me! You do have a radome on the main building, right? Is there something with 5Ghz (radar) there? a. ___ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel
Re: 15 computer science collegians looking for a project
On May 5, 2008, at 8:38 PM, NoiseEHC wrote: I have registered on said page but when I click to my projects it goes to wiki.laptop.org and all I can see an empty page. Are those people over dang! thanks, you found a bug. Actually a regression. It already worked. Will have to investigate. viewing my application will decide by using that empty page? Since I cannot see any change tracking feature on the wiki, I am not sure how could people track/discuss new projects either. The idea is that the bot in projectdb.olpc.at reads the Talk: page about the project proposal on the wiki.l.o. That way - people will be able to talk and discuss a project application on a community level. Let's say in a mediawiki style. Then these comments get fed back into the projectdb and the persons who really have the vote bit set can decide about a project proposal. But the main concern so far was: 1) do we get the data in correctly and 2) can we export it to B* ? These community features can be implemented in hack sessions on weekends usually. One of the textboxes is not too clear to me on the new project page. 1. Description of your experience, both with hardware and software. - Am I supposed to write about my work experience regarding the new project? experience in general. Why are you the right person to do that project ? Why shall I define it again if I already did it on my registration form? Or is it about something else? (I am not a native speaker.) ah, ok, the redundancy bug maybe. The rest was clear for you? a. ___ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel
Re: Ad-hoc Networking
On Apr 27, 2008, at 8:53 PM, Robert Withrow wrote: Aaron Kaplan wrote: there *are* open source layer 2 and layer 3 mesh software solutions out there. Not to forget Open80211S.org (http://www.open80211s.org/). yup! what is the current status on that actually? a. ___ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel
Re: Ad-hoc Networking
On Apr 24, 2008, at 2:26 AM, Carl-Daniel Hailfinger wrote: Looking at trac, wireless is one of the biggest sources of bugs and the community can hardly do anything about it. Normally, somebody who complains can be told to fix the code, but with a closed wireless firmware, complaining is the only possible action. Folks, we can just repeat it once more: there *are* open source layer 2 and layer 3 (Holger got that wrong, he said layer 4) mesh software solutions out there. So in case you can not use the marvell solution (which I am a big fan of, I would personally take that if available since it does not need CPU support), then there are many protocols out there to chose from. http://www.olsr.org being the most widely deployed and tested one. But there are also others. Depends on what you want or need. All of these need some CPU cycles however. The advantage on the other hand is of course that it will run on any hardware / any laptop and most wireless cards. The best supported ones are those with broadcom chipset. The new atheros driver is also getting pretty good. So: for energy conservation go with marvell 802.11s! It is a wonderful job and I have the highest respect for Michailis. Regardless of any chaos at 1CC. If you can't have marvell 802.11s.. you still have many choices. There even are very good protocols from the .mil sector out there. For the people who love details: And yes, the olsrd daemon was proven to scale. So you don't have to worry about that. Proof? wind.awmn.net/?page=nodes And yes, wireless interference is a major problem for all devices operating in 802.11a/b/g freq. ranges. This is not the fault of any mesh protocol. The bands are just overcrowded. I propose that you look at 802.11a. Or new ranges. Lots of extra space there. Who am I ? Why should you believe this mail? I built up a city wide wireless mesh in Vienna with some folks here. http://www.funkfeuer.at/ . Holger is also close to the freifunk.net people (and I am too). --- there's no place like 127.0.0.1 ___ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel
Re: Walter leaving and shift to XP.
On Apr 23, 2008, at 1:25 AM, Joshua N Pritikin wrote: By my judgment, I'm glad Richard Stallman isn't running OLPC. He would have delayed the launch until we have a GPL'd replacement for the mesh firmware. As it is now, we have a laptop which is more pure license- wise than any other laptop available at about half the cost of the competition. And we have had mesh networking in production for about six months. Who else has mesh networking? Nobody. That's not an ideal not true ;-) there are plenty of open source solutions out there which just need to be installed. see www.olsr.org for one example. --- there's no place like 127.0.0.1 ___ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel
Re: Wireless Congestion Management Option
On Apr 2, 2008, at 5:24 PM, John Watlington wrote: Meshes of access points don't tend to change topology over time. The laptop mesh very well might. The need to handle this is one of the problems causing congestion. Anybody find new algorithms for mobile meshes ? As well there are plenty - even to many - new algorithms out there! So, no shortage of those. But... most are not tested in practice. AFAIK the current trends go more into finding the proper metric . At www.olsr.org we currently work at implemting ETT metric (and maybe MIC). This will have a very nice effect on meshes since the routes will be chosen also on thruput and interference avoidance. That especially the last point is very very crucial with anything concerning wifi. best, a. ___ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel
Re: Gen2 pointing device
What about a second camera and tracking head movements? Sonar? Can't I just point with my nose? http://www.olpcaustria.org/mediawiki/index.php/Headtracker working on it... a. --- there's no place like 127.0.0.1 ___ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel
Re: New lurker! :-)
Running activities in the jhbuild (sugar-emulator) environment on Ubuntu is going to be tough. We've not done much to support running Sugar on distros other than Fedora 7. That could be an interesting project, but certainly it would require you to upgrade at least to something like Feisty to get most of the support packages needed by Sugar. The doku in wiki.l.o about running Sugar native in ubuntu gutsy worked very well for me. So, Ed you might want to try that. ___ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel
Re: [OLPC Networking] Wireless porting
very interested over here as well... Would it be out of the way to post the original proposal? BTW - on a side note: polychronis: great work with the mesh view! Simon Dorner mentioned that having small faces of the kids in the mesh view would be even better. Humans tend to remember faces much better than Xo signs with different colors. best, aaron. On Oct 13, 2007, at 1:12 AM, Polychronis Ypodimatopoulos wrote: Hi, What platform do you plan to port the driver to? Pol Alex Gibson wrote: To Jim , Walter, Ivan and others We (UTS) sent a proposal on doing the wireless driver porting to you a fortnight ago and we are still yet to here from you. Can you please confirm that you received it or not. If not what address/es are best to re-send it to. Thank you Alex Gibson Technical Officer Faculty of Engineering University of Technology Sydney ___ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel ___ Networking mailing list [EMAIL PROTECTED] http://lists.laptop.org/listinfo/networking --- there's no place like 127.0.0.1 ___ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel
new list: [EMAIL PROTECTED] - international network mailinglist for OLPC grassroots organizations
[EMAIL PROTECTED] http://lists.laptop.org/listinfo/grassroots please subscribe there in case you are running a local OLPC grassroots organization or if you are active in one. Like: OLPC Argentina OLPC Romania, etc... Upon subscribing, please briefly describe which organization you are from. Most of us only know the people in the center of attention but not so much the people from the local groups. The goal of the list is to exchange experiences in running local country organizations. Promotion work, legal issues, marketing, etc. In short: anything related to local groups. I strongly believe that the local groups over the long run can have an important impact to the whole project. So let's get started! thanks for your attention, Aaron Kaplan. --- C.O.S.H.E.R. - Completely Open Source Headers Engineering and Research ___ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel
