Pretoria community wireless network

[phazer_]

Anyone have details about the Freenet guys?

I am thinking of putting up a wireless node using the Jawug kit (http://www.jawug.za.net/JawugKit).

Perhaps over time try to get Pretoria to be connected to the Jawug mesh.

Who would be interested in setting up a Pta mesh? If enough people we can setup a website (I can do hosting) and maybe start a Pawug :D

I am based in Lynnwood ridge close-ish to the CSIR and Menlyn shopping centre.

[martin]

I'm definitely interested! Also had a look a the JawugKit. I'm located in the Southern most part of Centurion at the moment.

[louisp]

Count me in.. I'm definetly available to help as much as possible.

Currently staying in Faerie Glen, next to Pick 'n Pay

:)

[TheRoDent]

First things to do, is to go register yourselves on nodedb.com. That way you can start planning the interconnects.

[louisp]

Done ages ago!!

[sauermfj]

I can set up some web space for a Pretoria Wireless User Group....
How about:
http://www.airhive.net/phpwiki/index.php/PretoriaWirelessUserGroup ??
Can also setup forums etc. etc.

[sauermfj]

I am located in Rietvalleirand, although our business operates from the CSIR buildings in Lynnwood. wanna connect there?

[gripen]

Im keen. My location is Hatfield, Pretoria. Im trying to arrange a linkup to the varsity. There is a bunch of reasons why this would be useful..
I see nodedb is down. Anyways, we have a couple of guys already on a mailing list of sorts for a pretoria wireless group. Can you send me the details of your mailing list etc and I will merge everyone..

Now to get some proper wireless kit. Gonna be a bugger since Im in a building-dense area. Still debating which is better - omni or directional. Not sure where I would point a directional yet :p

[sauermfj]

I think directional for linkups, omni for local.
You can have both with these modems that split the signal....
And you can split the signal with splitters, just like TV cable.
Would you like us to source equipment for you?

[daffy]

Do not split the signal.
End of story.

Do a little research on the "Hidden node problem" that is inherent to long distance point-to-multipoint systems.
Also do a little bit of research on how splitting RF can cause some very nasty impedence mismatches.

Bottom line.. (same as the top line.. har har.. bad pun)
Do not split the signal.

[sauermfj]

I know an idea did the rounds of having multiple radio's on the boxes (some upgrade?), so I thought a good alternative could be to split the signal.
But I'll take your word for it! Do you have a link to the article?

[daffy]

There are tons of documents on the Hidden Node problem. Just google...

http://aqua.comptek.ru/test/HiddenNode/hidden_node_en.html
This one has nice graphs and data to look at :)

[captainwifi]

Hidden node is solved by
www.qorvus.com and http://frottle.sourceforge.net
via the Token Ring protocol. Ethernet suffers from hidden node in a
wireless setup.
www.hyperlinktech.com sells wi-fi splitters than can split a signal into
four attached sector antennas. But a signal splitter halves the power, so on
a 4-way splitter a Prism 802.11b 200mw card will be reduced to 25mw
on each section. I believe impedance mismatch can be solved by using
exact length Lm-400 cable to each antenna.
Two parabolics back-to-back on a signal splitter functions in exactly the
same way as an Omni, only your signal is now two tight 8degree beams and you are not picking up 360degree interference. It is an ideal way to repeat a
signal since you are not introducing latency's . Alternativly you could intall
two Senao prism 802.11b cards in the PCI slots of a Mini-itx computer and purchase www.qorvus.com software for R600 per machine to setup a
wi-fi system than simply works. Wi-fi is incredibly complex as more users get added, my point is that there is no need to reinvent the wheel. Get www.qorvus.com software and get your project of the ground.

If only those morons at www.wavestream.co.za would use signal splitters we might not have a trashed 2.4ghz spectrum. Please whatever you do , don't
use Omni's , you are polluting the spectrum and degrading your network.

Let each client install a parabolic and aim it at a sector 60,90degree etc
antenna in either infrastructure mode or ad-hoc. Infrastructure is great if
you have a prominent high-site.

[daffy]

There are so many holes in that post, I dont know where to begin.

Sure, you can use frottle, but then you need the frottle client installed on every wireless client.

Yes, proper splitters are available, but that often defeats the whole purpose of having seperate sectors.
4 x 90 degree sectors = 360 degrees. Put them all on seperate radios, and you've achieved a number of things.
1) You can now support at least 4 times more throughput (without taking collisions into account)
2) Your collision domain is now a quarter of what it would have been, meaning less collisions (which also means, more actual throughput)
3) Noise recieved on one sector doesn't polute the signal on any of the other sectors, because they aren't actually connected together.

Qorvus have nothing on MikroTik. (MikroTik is slightly cheaper, has more features, been around longer, has better support, supports more hardware, etc)

Our fabulous friends at Wavestream do actually use signal splitters, and Amps. So they dont have to use as many radios, they do pickup noise from everywhere, and they amp that noise, and then rebroadcast it. I WILL PERSONALLY TRACK YOU DOWN AND BEAT YOU WITH A STICK IF YOU DO THIS!

Ad-hoc is great for mesh networks, but where possible, try to use Infrastructure.
I think TheRoDent did some playing around with ad-hoc on his long distance links, and found that infrastructure mode still worked better. Perhaps he can give a better explaination.

[captainwifi]

Mikrotik is good and is used on the outer nodes of mesh. www.qorvus.com software based on opensource www.locustworld.com mesh and incorporates frottle. Frottle is just one layer in this mesh software implementation of AODV routing protocol.
Jon Anderson from locustworld adapts the output power from the Senoa card on the
fly as each node relays data in his implementation of AODV.
The other option to www.qorvus.com is www.cuwireless.net which uses the Hazy routing protocol. The CPE's connect in infrastructure mode to the mesh node.
Client nodes will be WRT54G linksys AP's. Your mesh nodes are connected in Ad-hoc up
to a max of 3 or 4 nodes daisy chained, this mesh get's fed by a DSL or leased line or Transtel line.
Signal splitters are ideally not used to create more than on repeater node for ad-hoc
mesh nodes. A second Senao card rather is added to form a repeater.
Setting up just 4 repeaters with vanilla AP's reduces the signal by 1/16000.
With mesh it is 15% of each hop. So if you start with 11meg you are down to
3-5 meg at the fourth hop. If you can do with 1meg of bandwidth and your signal must go over a mountain, set up a two AP's one in master other one in slave each on a
different channel and connect them via cross-over ethernet.

By using Wi-Fi and Cat5 cable and www.aviosys.com ethernet camera module and a realtime Ogg-Vorbis Linux video compression box one can build a cost effective video surveillance systems for streets and business. www.qorvus.com quoted webcam prices are just to expensive. The aviosys.com ehternet cam module is sold by
www.miro.co.za. What I thought about is say one shop training a camera on the opposite shop and recording it any activity on a linux box. So a criminal would have to strike BOTH shops to get to the surveillance tapes. In a cris-crossing mesh each shop
could watch the other. If you have any better ideas let me know.

The next great hope for broadband video surveillance and wi-fi internet is to get
http://madwifi.sourceforge.net to release the Linux drivers for Atheros 5ghz chipset -- Ad-hoc mode and implement 5ghz Ad-hoc - the core of mesh routing - on www.cuwireless.net . WE are not there yet.

[malec]

we already have a mailing list going. greedyflyza, if you could just post the subscription method here again pls :P join up, it's quite an effective means of communicating and sharing ideas.

next i think we need a site. so give us some things you'd like to see on the site ...

[malec]

Also, we should decide on a name.

We can either go with PAWUG or something like PWP (Pretoria Wireless Project), which is a little softer on the non-techie ear ...

[sauermfj]

well, have a look at my web portal at www.airhive.net
I've got 1000+ links in the links section that are related..
also willing to host wireless user groups under forums and wiki sections.

If you're putting up a seperate web site, I suppose its good to have a forum and Wiki sections.

[martin]

Also, we should decide on a name.

We can either go with PAWUG or something like PWP (Pretoria Wireless Project), which is a little softer on the non-techie ear ...

How about using Tshwane (TAWUG) instead of Pretoria? I think Tshwane includes both Pretoria and Centurion if I'm not mistaken.

[mbs]

TAWUG = more PC, given the recent stink in the newspapers...

[gripen]

the signup instructions for our mailing list are as follows:
simply send some kind of email to ptawless-subscribe@sum1.gotdns.com

Its nothing much other than a discussion and planning tool for now. Until we get a website up and running - and an actual network

[malec]

we need to start identifying high sites as well. so if you have any ideas, post em.

[sauermfj]

any site that has a microwave tower nearby should be good.
i know of two good ones: muckleneuk and the CSIR uwave tower.
somewhere in lyttleton should be good for centurion.
the denel hill and waterkloof area is good for moreletta and other eastern 'burbs
basically the whole magallies is nice.
anybody staying in aforementioned areas?

[malec]

suermfj, you could provide us with local hosting given a domain, ye?

[gripen]

the problem is the sponsoring of high sites so effectively we need to be able to implement with standardised equipment. This should cater for open areas (ie residential) and built up areas (ie. in the city). Im in the latter so I would need some trickery to get LOS to anywhere. Now where would I point my directional antenna?
I could of course use something inconspicous from my office at university which is about 40m up. With enough power I could probably reach Pretoria east with good LOS - so it may be a possible high site.

Daffy, any suggestions?

[malec]

OK, I've put up some forums @ www.pwp.za.net/forum/

[martin]

any site that has a microwave tower nearby should be good.
i know of two good ones: muckleneuk and the CSIR uwave tower.
somewhere in lyttleton should be good for centurion.
the denel hill and waterkloof area is good for moreletta and other eastern 'burbs
basically the whole magallies is nice.
anybody staying in aforementioned areas?

I live in Centurion but in the southern suburbs. Lyttleton will probably only cover the northern part of Centurion.

[Robone]

Hey Malec...Dataspace is great....thanks for inadvertently putting me in touch with them via your forum. Looks like you guys in Pretoria are getting things jacked up. Maybe I should move there :)

[malec]

Hehe, no problem man :P

[venterap]

Basically I am your bog-standard, common or garden-variety internet user with a small network at home and a smaal business that I want to put on the Internet, currently using ISDN dialup to Telkom. Not too bad except my line goes down when things get damp and costs for 24/7 is way too high. What I NEED is a 24/7 connection, fair bandwidth, more speed, no capping crap. I've been looking all over at MyWireless, MyADSL, iBurst but everyone is bitching and moaning. Then I see this WiFi-thing and I read the howstuffworx about WiFi.

The community-based thing looks reasonable, but the bottom line is: what do I get out of it. I suppose it depends on what I put in. That's the question: what do I put in? I have all these questions that I cannot really get answers on.

What does "mesh-networking" mean?
Does it entail me getting some sort of rdio transmitting/receiving equipment being put in place, other than the card going into the PC?
What sort of money are we talking here?
How does it compare to forking out big wads to SenTech/Telkom/etc?
What about bandwidth etc?

etc, etc

Can someone explain this whole thing in fairly simple terms? Or point me to a place/thread where it was already done.

Other than that, I will be interested in joining the WUG in Pretoria. I live in Moreleta Park, on the north-facing slope of the hill. LOS to CSIR or Faerie Glen hill.

[sauermfj]

Hi there
I'll try and answer this with a simplified explanation, since I do not know what your knowledge background is. Excuses if I pitch it too simple / too complex.
Imagine a rugby coach standing in the middle of his team throwing the ball to and fro as practise. That is how your signal from your cellular phone (a player) travels to the cellular tower (the coach).
Now, if you practise a backline move - a switch , a skip if required etc., passing the ball between players (wireless mesh nodes); that is how mesh networking works.

What it comes down to, is that you do not need a cellular tower / big access point.
Each community member can tap into the wired internet and provide access to the internet via his point.

There are various forms and models ranging from the free community network that is not connected to the internet, to a free net connected to the network, and the model I'm working on where there is optional billing for the person providing the internet tap-off.

For now, you can join a community network and get great access speeds on the community network itself, but may still get the same speed to the internet.

The main problem with south africa is that Telkom controls the Fiber optic that lands at Melkbosstrand, and almost everybody uses that fiber to go overseas.
The oversell on that fiber is about 10kb/s nominal throughput.

[gripen]

I'll climb in here since I have some time to kill. Firstly, please register at pwp.za.net if you haven't already

I will try answer your questions:
what do you get out of it... well we wont be selling internet access (at least not on the WLAN) so other than that you will get the following: local mail server, chat facilities, LAN gaming without lugging hardware around, file sharing ie. getting already downloaded updates and what not. then theres also the community aspect and the fun in learning something new and watching it grow.

What do you put in? Well you need to basically become a user of the WLAN. You would hopefully provide some of the infrastructure to carry the "signals" and the traffic in wireless LAN be it as a backhaul or backbone link or a repeater-type of link. Or you could be a regular user with a basic node. Here you will be putting in your support, your knowledge and experience as well as your willingness to learn and help others new to the network.

Mesh networking is where every node connects to each other node. This is the fastest i.t.o speed or throughput but it gets cumbersome and very expensive as the network scales since you have to have a direct link to everybody within your local network range.

The card going in the PC or the Access Point connecting to your PC is important but not overly critical. The antenna you use is more important to meeting your selected goal. In effect, you will need hardware (card,AP type of thing), cabling and antenna(s).

Concerning money.. Im not going to lie to you - it is expensive. A decent setup will set you back about R2000 but it really depends what you are doing and how you connect to the network. A basic node setup with a nearby link to a backbone type of node will cost you a minimum of about R850. Remember it is once off as there are no running costs. So there is no forking out of any kind of wads like with the other guys.

I want to stress that we are not selling you anything and you are not buying anything from us (PWP or JAWUG). In the case of the JAWUG kit etc its not for profit. These two initiatives are not-for-profit organisations.

Also, this is not an alternative to your dialup/ISDN/ADSL/Sentech/iBurst connection. I guess if all you do is email then it could be. You could also get a friend to share his connection using a proxy of sorts over the wireless links but thats your problem not ours.

Bandwidth is tricky. The throughput depends heavily on your antenna/signal and how you connect. The target performance for backbones is 15mbps for example. Whereas, basic nodes will achieve around 1Mbps. This is our goal. You may get more or less. Effectively, it will be at least a little bit faster than your regular net connection.

But please do signup at www.pwp.za.net and follow discussions detailing the stuff explained above. www.jawug.za.net is also a very useful resource and has loads of info. You need not have any wireless gear to belong to PWP.. all are welcome

malec, daffy etc guys - please poke holes in my descriptions above if required. Im no expert

[venterap]

Sauermfj, greedyflyza, thanks for the quick reply. It does not look at this stage if this is for me, but I'll keep a beady eye on things. Basically what I need is internet access at reasonable speed and no cap, and if I understand you correctly, such a network as you are planning is mostly a closed community with one or two nodes offering access to the wider world. So i'd still be sitting with the same problem of having to pay Telkom or somebody else quite large amounts of money for no real benefit.

On the other hand (Darren), what if the few nodes where there is access to the outside had a DigiNet or very big ADSL pipe with no cap for everyone else in the network to use? Would the costs be spread accross the whole network? I got so pissed off about the ****ty service from Telkom that I seriously considered getting a DigiNet line, but, eish!, the cost is horrendous, and then I'd still be sitting with Telkom! Another thought popped into my head just now: Any permanent connection that I or my small business alone would use will be sitting idle for most of the day, with little peaks and bursts of activity every now and then. I guess that would be true for almost anybody except maybe gamers? What sort of contention ratio would be acceptable for such access?

Of course, going overseas through Telkom, the bets are all off, because of the oversubscription of the fibre, but what if you got hold of some satellite-based connection? Latency could be a big problem esp for gamers.

Ta-ta for now,
Dries Venter

[Decotey]

how about neuron ;)

[gripen]

Well.. providing internet access brings in complexitys including reason for telkom/ICASA to get suspicious. Look, its highly likely that using the wireless medium you will get access to capped ADSL or shared (I hate that word) access to somebody's internet connection.

What we are saying is that we are not selling you an internet connection. You will not pay any of us monthly. It is possible that we get a nice fast connection to share but you know how people are.. somebody will try to download internationally on the thing the whole time no matter what. It would be nice to get an ADSL line, use a capped account and then the shared proxy for international browsing. This would be possible even for a sentech modem if they didnt throttle it so much. 15KB/sec international could easily be good enough for the browsing needs of about 15 people since not everyone will be browsing at the same time. R650 / 15 = just over 40 bucks a month which isnt too bad.

The thing with a wireless community is that you pay once and probably not again. So you are on the network potentially waiting for some to share their net access with you. This will make it easier for you to get lower cost net access (not directly from PWP but using the infrastructure -- think of the disclaimer on all torrent sites - same idea) but this would be good if you only want browsing. For downloading, you are going to need your own fast connection.

Thanks for you interest though.. pop into PWP forums when you are ready to join or want to get an update of where we are i.t.o progress. Speak to your mates as well and see if they would be interested.. it could be a case of PWP helping you to linkup to your friends in your area (depending) using the backbone.

[TheRoDent]

If pwp needs permanent hosting, contact me for a shell account.

[malec]

Thanks Rodent, we'll take you up on that offer. Will be in contact

[mySAP]

But would'nt it be possible to connect the mesh together via those in the mesh that have ADSL via bridging/routing the network interfaces.
IE WLAN on one end and ADSL on the other ...etc.

Just an idea ?

[gripen]

please continue this discussion/idea on the pwp forum.

Thanks

www.pwp.za.net

[malec]

just a quick bump to let ppl know we now have our wiki up @ http://www.pwp.za.net

thanks again to RoDent for the hosting

[TheRoDent]

Yay!
Finally!

[malec]

Ya its been a while I know :p