Mount Hua

A few weeks ago I was climbing Mount Hua in China (thanks to the generosity of Atcom). Some photos of Mount Hua including the infamous “plank walk” from the China trip below:

It’s not quite as scary as it looks. Not quite. The adventurous young lady in the picture is Grace, one of my good friends from Atcom. The rest of the walk was tough but worth it with many spectacular views. It’s a 2200m climb to the mountain peaks via some very steep stairs. In fact one stair after another for about 6 hours.

One interesting difference for me was all the people. When I have done similar mountain walks in Australia or the US there are very few people. On Mount Hua there were people everywhere, and little kiosks every 500m where you can buy hot food and cold drinks, and even hotels at the top of the mountain.

I can thoroughly recommend visiting China – the Xian area I visited was great. Xian has lots of wonderful history and was once the capital of China. Compared to Westerners the Chinese take a very long view of history – 1500 years is like yesterday for them as their culture has been continuous for thousands of years. I’m still absorbing exactly what that means to your outlook on the world – I live in a country that is just over 100 years old.

Squatter Life in Berlin

In March I visited Germany to attend Cebit. It was nice to meet some of you there! After Cebit I visited Elektra who lives in a squatter community in Berlin. This is a really different way of living and fascinating for me. Rather than buy or rent homes, they live in modified commercial trailers or trucks. These have been insulated and converted into small, comfortable homes. They use solar power for electricity and small amounts of gas or wood for heating. As it’s squatted land, they pay just the small capital cost (e.g. a few thousand Euro) for the homes, rather than rent or a large mortgage. People there come from all walks of life, and have jobs just as varied as people living in conventional homes. They use mesh Wifi for Internet access (indeed many Wifi developers like Elektra live in these communities).

In the first photo you can see Elektra working on her electric recumbent bike – I took this for a fun ride while in Berlin. It cruises happily at 30 km/hr with just a little it of peddling.

An Open Source Life

The “open source” life I have been living over the past few years has taken me on all sorts of adventures to wonderful places. I have met many great people and made some wonderful friendships. I can trace this all back to a decision in late 2005 to open source the hardware designs I was working on. I remember at the time thinking long and hard about this decision. But there is no way I would have had these travel experiences, met these people, or built great hardware and software had I stayed in a cubicle. Open source equals a good and fortunate life.

I have wanted to upgrade my site for a while. I was happy with the content but it needed a better look and feel. There were also some bugs in the simple web store I was using. For example it didn’t force selection of a shipping option so I kept getting orders with no shipping. Bart from the Flusko project suggested using WordPress, as it has nice themes and a bunch of plugins for various stores. Key advantages are a unified look and feel across the blog and static pages, easier navigation, and finding the Store is now much easier.

As I was already using WordPress for my blog this sounded like a good idea. With a bit of encouragement from Rosemary (she cracked up laughing when she saw the old web site) I was off. Like a lot of jobs we put off I actually started enjoying the work after a few days.

Managing Projects by Risk

Like all projects there were some major challenges. My style of project management is to work on the riskiest tasks first. If you nail the riskiest tasks there is much less to go wrong later and the schedule becomes more predictable.

WordPress Look and Feel

The first challenge was to get my head around the WordPress 3.0 and select a theme to get the look and feel I wanted. To get started I installed WordPress 3.0 on a local test machine. I fooled around with themes for a few days before settling on Atahualpa. I checked browser compatibility. I found a bug with the default WordPress 3.0 Twenty Ten theme on Firefox 2.0 – the body text on pages is offset way to the right. Atahualpa renders just fine on Firefox 2.0 and 3.x so Atahualpa is it.

Being a very geeky and not very arty person this phase was actually quite intimidating for me. I didn’t trust my judgement to come up with a good looking site. Where do I start? But like any project a good approach is to break it down into little steps, try a few things, make a few mistakes, and ask questions. I am content with the result and particularly happy with the banner. Fortunately I have lots of cool photos from 4 years of open source work.

The next challenge was the shopping cart.

Shopping Cart

I had to find a web store that could handle my weird shipping rules. For IP0X sales I don’t have per item shipping, just one fee for an entire shipment. However this is not a flat fee – I have several different shipping options (Air Mail and EMS Courier). For some products I don’t charge for shipping. I also need dual currency support at the same time on the same page. Most store applications support just one currency across the site at any one time.

Anyway my shipping rules and currency support were strange enough that none of the free WordPress shopping carts plug-ins seemed suitable. After playing with different cart plug-ins for a few days I chose to hack the WordPress Simple Paypal Shopping Cart. This was easy to use and was simple (one 700 line PHP source file), which made it easily hackable. So over a couple of days I added options for shipping and multiple currency support that exactly suited the needs of my store. The modified PHP file is here.

To add a store item to a page you insert a “short code” to the WordPress page:

  [ wp_cart:IP04 IP-PBX with 0 modules:price:399.00:currency:AUD:needs_shipping:1:anchor:#cart:end ]

This is the entry that creates the “Add to Cart” button for the IP04, like this:

I added new PHP code to support the “currency”, “needs_shipping” and “anchor:” fields. The anchor field tells the cart where on the page to return after an item is added to the cart, for example “store.html#cart”. The default behaviour for this cart is to return to the top of the page which gets annoying when adding multiple products. I use the anchor to return to the shopping cart after each product is added.

The “needs_shipping” flag needs more explanation. When one item in the cart has “needs_shipping” set the checkout button is disabled until a shipping item is added to the cart. You can see various shipping items on the IP0X Store Page. Each shipping item is just like a regular product in the store. Here is the EMS Courier short code:

  [ wp_cart:EMS Courier:price:60.00:shipping:0:currency:USD:is_shipping:1:anchor:#cart:end ]

The “is_shipping” flags tells the cart this item is a shipping item which then enables the checkout button. Until a shipping item is selected the customer cannot proceed to the checkout. For items that have shipping included I just don’t include a “needs_shipping” flag in the item short code. I think it’s cool I can hack an store app just for my specific needs. Open source e-business.

Migrating Static Pages from ASCIIDOC

The V1.0 web site used ASCIIDOC to render the static pages. This was actually quite a nice system. I could edit my pages using my favourite editor on my laptop, then use a Makefile to render the pages and automatically upload them. Writing web pages in ASCIIDOC is quick and easy, and the source is human readable even before rendering.

However this meant I had a bunch of web pages in ASCIIDOC markup format that I needed to convert to plain html so I could post them into the new WordPress pages. So I wrote a simple interpreter in Perl to partially render all the pages, called a2h.pl. The output was pasted into the WordPress editor and with a few manual tweaks to the HTML I was happy with the results. I like writing little Perl scripts for these sorts of jobs. Saves a lot of time and prevents many errors that I would make with manual markup. Also some coding work made the web site migration project more interesting. But I do miss using emacs to edit my web site, these web based editors are just not the same.

One not so nice thing about database-driven web sites is the use of page numbers like “/blog/?page_id=434″ rather than “about.html”. You can get around this with the WordPress permalinks feature but this involves some .htaccess magic on the server. Not sure if I can do that on my hosted web site so I chickened out and just used some redirect pages like “about.html” below:

<html>
<head>
<META HTTP-EQUIV="Refresh"
      CONTENT="0; URL=/blog/?page_id=434">
</head>
</html>


This means all my existing links like /ucasterisk/index.html won’t break.

Integrating Static Pages with Existing Blog Pages

Next step was to integrate my static pages with the existing blog posts. Of which there are many. My first attempt was to export the posts from the live rowetel.com/blog and then import them to the test machine using the WordPress Import/Export feature. This worked but all the post IDs were messed up after the import. So a post that had been “?p=1″ was now “?p=450″. That wouldn’t do as it would break a bunch of my links.

So after some head scratching I tried another approach. I used phpMyAdmin to dump the live blog database (just like a regular wordpress backup). I then installed this data into a new database on my test machine using phpMyAdmin and fired up a fresh copy of WordPress 3.0. Which unfortunately just sat there and displayed nothing. I guess it doesn’t like starting up with a populated database, especially one from an earlier version of WordPress. I found a few ways around this:

1. Create a fresh database with nothing in it then start up WordPress 3.0. Then use phpMyAdmin to restore all of the database tables from the live site except wp_options.

2. Manually point your browser at the admin login page, “http://localhost/wordpress/wp-admin/. For some reason this would work when the index page of the blog wouldn’t come up.

3. It’s also possible to edit the wp_options table using phpMyAdmin to change any options (like the site URL) that might be messing up WordPress when you install the database on a test machine with a different URL. Using phpMyAdmin is also handy for resetting your password when the blog won’t display.

Anyway the above approaches gave me a working WordPress 3.0 test machine that had all of my old blog posts with the correct post IDs. From there I could import my new static pages into WordPress to get the final merged site. The page_ids of the static pages were also changed during the import but as they were new it didn’t really matter – no one was linking to them yet. I wrote a bunch or little redirect files (as above) to handle redirection of the static pages.

Doing a complete install on a test machine was also great practice. As I built the test site I wrote a check list which I used when I worked on the actual live site. When it takes you 10 minutes to find some obscure theme option it’s a good idea to write it down!

Command Line e-business

When some one places an order on my store I get a PayPal email. I save the email to a file the use a Perl script called paypal2invoice.pl that slurps up this email and converts it into an itemised invoice. Yes, I really do use the Linux command line to generate invoices!

[david@bunny invoices]$ ./paypal2invoice.pl DRR-PO-577-Luke.txt
found postal address
qty_ip04: 1 shipping:  cart_total: $540.00 AUD
[david@bunny invoices]$


I have documented the Serval Arkaroola Demo over on the Village Telco blog. I am very happy with the photos in that post and what I learned on the day about possibilities for mesh telephony.

Thanks to Paul and the Serval team for inviting Rosemary and I along. It was especially thoughtful of Paul to invite Rosemary, as she often has to stay at home and look after our family and business when I go flitting around the world. She has contributed a lot to my projects and especially the Village Telco through her support. Here is Rosemary getting on the plane to Arkaroola at day break:

It also sports an integrated FXS port (this was a separate module on the V1.2 Betas). There was a bug with the FXS port that Atcom asked me to take a look at – no transmit or receive audio. After a few hours of work I found that the 48V DC was present, and Asterisk was detecting on/off hook events. This suggested that most of the FXS port was working OK, just no TX or RX audio. For example there was no dial tone in the phone and DTMF digits weren’t being detected by Asterisk.

I poked around with the oscilliscope and found nothing on the DRX net (audio signal from phone) from the FXS module. However when I looked at the DTX net (audio signal to phone) I saw this:

A “trinary” (3 level) signal! When I took the phone off hook and hit a DTMF key I could see the signal changing, a sign that the DRX signal was mixed up with the DTX signal. The “trinary” nature was due to two outputs driving the DTX net at the same time, e.g. a 0V and 3V3 averages to 1.65V. I guessed that this meant the DRX and DTX signals were mixed up. A little research of the earlier V1.1 design proved the point – the DRX and DTX nets had been swapped accidentally, and we had missed the subtle change during review. With some skillful PCB work Alen swapped the nets and reported dial tone re-appeared on his V1.3 PCB.

Apart from that the V1.3 design seems to be working OK. Next step is to get the Wifi side calibrated and test the printed antennas.

The lines between nodes may not be accurate – the mesh network will form links on an ad-hoc basis.

Significant effort has been required to set up each link (days of effort, several return visits). The quality metric we look for is a “ping -s 1400″ packet loss of less than 10% and clear quality speech on the phone calls.

Some patterns are emerging. All of the non-trivial links (Eiros, both University sites) have required a Nanostation 2. These links would not function with just a Mesh Potato. Omni-directional antennas struggle in the interference-rich environment of Dili. I have found a similar problem on my test mesh here in suburban Adelaide – several 100 metre links links with omni-directional antennas suffer poor packet loss.

This is an unfortunate result – mesh networks depend on omnidirectional antennas, but omnidirectional antennas suffer from interference. This is an expensive and unwieldy Catch 22 – on nodes at the end of long distances links we are requiring both a Nanostation 2 and a Mesh Potato:

This is very expensive (due to the cost of the Nanostation 2) and awkward to set up as a directional antenna require alignment. The network is more fragile as the link quality is sensitive to small shifts in the physical positioning of the mast (mast arrangements tend to be less robust in the developing world). It also requires more specialised training and knowledge to set up.

I am hoping that as the network density builds and the nodes get closer together (e.g. 50m or less), the need for directional antennas and hence Nanostations will reduce. We might be looking at a backbone based on directional antennas, with many mesh nodes hanging off each backbone link in a star topology.

Lemi reports a clear win for the Village Telco concept between the two University sites, “But at the University they are very happy because now they don’t need to use mobile to call each other.” This is a key, but often overlooked “killer app” for the Village Telco – local calls over a few 100m. In many parts of the world there are no land lines or even PBX systems and the only way to call another office is a 50 cents/minute GSM call. Note that no server, billing system or PSTN gateway is required for this killer application – just a network of mesh potatoes.

I think the lack of external connectivity is what makes this killer app so hard to understand for 1st world people – we intuitively associate VOIP with long distance and a PSTN gateway of some kind is always part of the picture. We have forgotten how magical a simple local call is.

To their credit the Fongtil guys now have 7 sites (10 nodes) operational:

1. Blind Union (MP)
2. University Caicoli Next to Blind Union (MP+NS2)
3. University Liceu (MP+NS2)
4. Ase Training Center (MP)
5. FTM (eyes of human right) (MP)
6. FONGTIL (2 MP+2NS2+LENOVO SERVER)
7. EIROS (MP+NS2) next to Tiger Fuel

This demonstrates another important principle of the Village Telco – some smart local guys with minimal training can set up an operational mesh telephone network. Where we still need work is the “ease of setup” meme – setting up reliable links has been difficult, expensive and time consuming in Dili.

Another important metric is up-time – how reliable is the network? Can people rely on it to make phone calls? As the network builds we will gather experience and data on up-time. We will also get some data on scalability – this will be the first time a 100 node Village Telco network has been attempted.

This completes WP3000 of the Project Plan – April workshop and 10 node Pilot network. Next step (WP4000) is to supply 90 more Mesh Potatoes to build the 100 node network over the next few months. Atcom have been kindly working very hard at assembling a special batch of MPs for this project, which should be ready for deployment in June.

Links

Dili Village Telco Project Wiki
Dili Village Telco Part 1
Dili Village Telco Part 2
Dili Village Telco Part 3
Dili Village Telco Part 4
Dili Village Telco Part 5
Dili Village Telco Part 6
Dili Village Telco Part 7
Dili Village Telco Part 8

1. Technical tasks we consider basic are difficult in the developing world. For example 2 hours to reflash a Nanostation 2 here compared to a few minutes for some one who is experienced. A short video would really help with complex tasks as it conveys subtle timing information and gets around the need for English comprehension.
2. Special care and attention must be given to training. It must be possible for the students to repeat the exercises without any external support (e.g. via the Internet or local expertise) once the teacher leaves.
3. Basic configuration of the Mesh Potato (e.g. setting the IP/Phone number) is easy to teach and works well. It meets the ease of use vision of the Village Telco. However setting up reliable mesh links needs to be dramatically simplified. There are many complex variables that currently require a high level of skill.
4. A way to determine if long power cables are causing problems would be very useful. This problem is compounded by the need for high masts. Power problems can be very difficult to diagnose or debug.
5. Power being switched off or going down is a common problem. For example some one would simply unplug the MP power supply and a link would go down. Unlike a cell network, we depend on end users to keep their Mesh Potatoes and hence the network up.

   One subtle issue are socket adaptors, for example to convert between US and local style power sockets. These are often of poor quality and cause intermittent problems.

   Servers need to tolerate going up and down several times a day, and tolerate issues like a DHCP server or Internet link being unavailable without freezing.

6. Keeping the mesh up for 24 hours can be a major challenge. People unplug power, masts move, or operators just don’t check if the network is running.
7. Don’t rely on the Internet. It can be very slow or unavailable. Don’t rely on contact with your server over the mesh. Your system should work fine without the Internet and provide fall back capability (for example local node-node calls) without contact with a central server.
8. Interference can be a big problem in urban areas of the developing world. Poor DSL infrastructure means everyone is using Wifi to distribute Internet or bridge LANs across town. To fix interference problems requires a high level of skill and expensive, hard to source equipment. More work is required to make interference problems easier to diagnose and correct.
9. There is a trade off in mesh Wifi between omni antennas and interference. You need omni for the mesh, but omni antennas have poor performance in areas of high interference. Interference problems can be solved with directional antennas or routers with directional antennas, however this equipment is expensive and hard to procure in the developing world. David Carman has suggested the idea of a MP antenna that can be omni or directional via a slide in reflector. This may help from a cost and procurement perspective.
10. Mesh node installation can be a major engineering exercise and potentially dangerous due to the heights involved and local safety standards. For typical links of a few hundred metres line of sight is required. If you have 15m trees, this means 15m masts. In flat terrain it’s not as simple as the “simple pole a few metres above the roof” that I had visualised. This has been a problem for me in two mesh networks I have deployed on flat terrain. However networks deployed in hilly terrain have some natural height that can be put to good use. In low interference environments, non line of sight paths are more viable as low signal strengths can be better tolerated.
11. Local calls (MP-MP) are the killer application for the people in Timor Leste that I spoke to. There was little interest in gatewaying to the GSM network or overseas calls via VOIP. In areas with GSM coverage many GSM calls are to the same number, or even to the office down the hall. GSM call costs are so crippling people will sacrifice the convenience of a mobile phone. In areas with no GSM coverage the ability to make a simple local phone call can save hours of travel along poor roads, and potentially save lives.

Links

Dili Village Telco Project Wiki
Dili Village Telco Part 1
Dili Village Telco Part 2
Dili Village Telco Part 3
Dili Village Telco Part 4
Dili Village Telco Part 5
Dili Village Telco Part 6
Dili Village Telco Part 7

A morning walk is a habit of mine where ever I go, e.g. in South Africa, or Germany, or Sweden. OK, so maybe not Sweden, it was -10C in the morning when I was there in March. I find it fascinating to observe how people live in different countries. For example what their homes look like, what their day is like. The day-day life interests me much more than the tourist attractions.

You see little shops opening for the day. Every 10th house has a small shop selling water, soft drinks, or food like fresh bread rolls. People were sweeping the front of their homes, although to me it looked like they were just moving dust from one side to the other. Kids playing and semi-domesticated dogs digging through garbage heaps. The dogs scare me, you never know what they are carrying. Every mosquito here is a potential carrier of Malaria or Denge fever. So it’s mosquito nets at night and lots of insect repellent. Most people I pass on the street look at me suspiciously: the Timorese have had a bad time with foreigners for the last 400 years. Our lives and cultures are worlds apart, a gap difficult to bridge even if you speak Tetum.

The last few days have been a bit slow on the technical side, we are all a bit worn out after 9 days straight. We have been doing some training and exercises, and plugging away at improving the mesh links. They guys here are very keen to improve their Linux skills, so we spend a lot of time on command line tasks and installing software. However I feel satisfied that the Fongtil guys know how to set up a good link and can work through the problems. They are determined and motivated.

Little things can be show stoppers here. For example Lemi wanted to install Smokeping as an exercise but without bandwidth apt-get can’t be used to install Ubuntu packages. So a local repository was required which means another few hours to set up.

When manually entering this script on a Mesh Potato:

#!/bin/sh /etc/rc.common
# Copyright (C) 2008 OpenWrt.org
 
START=97
start() {
        [ -f /etc/udhcpd.conf ] && udhcpd
}


An extra whitespace line was accidentally added at the top of this script, so the script wouldn’t run. How do you debug that if you don’t have experience with shell scripts? No one around here who can help you. These sorts of problems can bring geeky activity to a screeching halt in the developing world.

I had a very pleasant afternoon yesterday with Anders Hofstee from Catalpa International, and Australian non-profit in the Ermera District of Timor-Leste. Ermera is about 3 hours drive from Dili (which might mean 30km-50km here on the Timorese country roads). Anders arrived in an old ambulance, as his primary role is health care. However he has also been setting up an 8 node mesh network using Ubiquity hardware flashed with open-mesh firmware. Living in the country, he has nice hills to use instead of masts and no interference! The network is used for local data, for example sites 5km away to Ander’s custom medical database.

On a typical day Anders might suture a nasty machete wound, transport a body in his hearse, hack some database code, and tweak his mesh network.

Local data is the killer service for the Ermera mesh network. The ability to send a written blood test report over a 5km line of site path makes an incredible difference. The alternative is a 1 hour drive (each way) to pick up the same report. After the 1 hour drive you may find the person you are meeting hasn’t showed up, as there is no other way to communicate with the courier. So two hours wasted for nothing.

The current alternative to a data network is police reading documents out into VHF radios, line by line, where they are transcribed at the other end. If you have a medical emergency and need to break into the radio net, you better hope the police pause long enough!

Likewise, local phone calls are the killer application here (just like Dili). Anders is very keen to try the Mesh Potato out in Ermera, in particular for communications between services like the police, local government, ambulance. He made a very good point, “When you call a service, you don’t care who you reach”. So one Mesh Potato per police station is fine, you don’t need one per policeman like a mobile phone or VHF radio.

I am keen to try the MPs out in areas without interference and good LOS paths so I will get a few MPs to Anders as part of the Dili Village Telco project. He had just downloaded Afrimesh and was keen to try it out. One thing he liked about the Village Telco was stand alone operation. For example if you turn on two Mesh Potatoes they just start talking, no server or Internet connection is required. The open-mesh system requires some sort of contact with the “Supernode” or the node won’t come up.

It was also cool to introduce Anders to Lemi and the Fongtil guys, as well as the Info Timor guys. So I thinks that’s all of the Timorese mesh networking guys connected (pardon unintended) now!

Batman over Ethernet

With Elektra’s kind support over the Village Telco mailing list we managed to get a reliable link from the Fongtil tower to the training room inside the building. On the Supernode and a MP inside we configured batman to work over Ethernet. This effectively piped the mesh network down the Ethernet cable into the training room where it was re-broadcast. Nice trick, but the geek factor to required to get this working was high. So now we have good ping results from inside the training room to other nodes on our pilot network.

Over the next few weeks the Fongtil guys will attempt to expand the network from the Blind Society end. Key question is how interference prone the additional links will be. Luckily our sites are closer together at that end. Lemi plans to install Mesh Potatoes at a variety of NGOs so they can have free phone calls between each other. This is a very worthwhile application as currently GSM phone calls must be carefully timed and kept very short due to the high cost.

For me, it’s back to the land of low humidity, bandwidth and push bikes rather scooters! I’ll be back in East Timor in July.

Links

Dili Village Telco Project Wiki
Dili Village Telco Part 1
Dili Village Telco Part 2
Dili Village Telco Part 3
Dili Village Telco Part 4
Dili Village Telco Part 5
Dili Village Telco Part 6

I have hired a scooter, a great way to get around in Dili. Curiously, I feel safer on a scooter here than home in Australia as the road conditions and heavy traffic limit the speed to around 40 km/hr. I get beeped a lot and abused by taxi drivers so I must be riding like a local. Riding is a game of dodge the pot holes, which I occasionally loose.

The air conditioning is awesome, riding the scooter is the only time I am really comfortable with the climate. Scooting along on a warm tropical evening in the near complete darkness here is magical.

This photo is a little cut off, but check out Mum, Dad, two small children and 4 litres of high explosive (petrol) all along for the ride!

Our good friend Alipio from Info Timor is very serious about Ubuntu Advocacy:

Once a day it rains. And when it rains, it really rains. Streets get flooded, creeks and drains become rivers. This can go on for 5 minutes or 5 hours. In my case it went on just long enough for the scooter ride back to the hotel!

The entire course can be abbreviated to:


Applications -> Accesories -> terminal
# sudo su -
# /etc/init.d/network-manager stop
# ifconfig eth0 10.30.1.20
# ifconfig eth0
# ssh 10.30.1.1
# ping 10.130.1.10
# ping 10.130.1.10 -s 1400
# ping 10.130.1.12
# ping 10.130.1.12 -s 1400


The 10.130.1.10 node had a good link, the 10.130.1.12 node was marginal. The long pings (-s 1400) showed up the bad link. The 10.130.1.1 node is the Supernode. They logged into that first and ran the ping tests from there.

The Ubuntu network-manager can be a trap, it messes up your eth0 interface when it attempts to get an IP via dhcp. So I showed them how to switch network-manager off, however I imagine that line is just Linux-magic to them.

Coming from a developing world Windows background, it is hard to understand that a little white box 30m in the air can have a command line interface you can ssh into. For that matter it’s hard to understand ssh, or ifconfig, or a command line interface.

One pair of students stood out – a Cambodian sys-admin who is here helping out with the Univeristy Windows network, and his friend who (I think) was a Timorese Univeristy student with excellent English. They meticulously wrote every step down, then they took turns repeating the exercises multiple times.

Great to see such enthusiasm from people who have never used a Linux command line before. Such hunger to learn. If any of you want an adventure, these people will happily attend any IT course you can teach over here. Basic networking, database, web, anything would really help these guys get off the ground floor.

Ahh yes, nearly forgot to mention the network. We didn’t get close to my 24 hour uptime target. As I emerged from my hotel I saw the Blind Society node has spun around 180 degrees in the night! The boys fixed that fairly quickly. At about noon I noticed the batman scores wildly fluctuating and the ping performance had dropped. So I strolled around to the Blind Society to find the Nanostation again pointing a bit off path but also swaying nicely in the wind. The pole is fixed to the tree half way up and so moves with the wind! DOH! Probably OK for an omni but no good for a directional Nanostation.

After 7 days here strapping poles to trees is starting to seem normal to me.

The University node is only about 50m away and has a proper mast (with guy wires even) so we moved the Nanostation to there, leaving just the Mesh Potato on the Blind Society pole. Now we have received signal strengths of -45dBm between the Nanostations! At night they are glowing a dull red colour.

However still not a perfect link to the Blind Society MP, so I suspect lots of other Wifi in that area. I can see quite a few 8dB type omnis sticking up within a few 100m of that site.

Links

Dili Village Telco Project Wiki
Dili Village Telco Part 1
Dili Village Telco Part 2
Dili Village Telco Part 3
Dili Village Telco Part 4
Dili Village Telco Part 5

I really want to set up some links and gather a few days performance data with Smokeping and Munin before I leave.

One possibility of improving the link was fitting a directional antenna at one or both ends. The Fongtil guys had an assortment of antennas from previous projects. We tested them but couldn’t get signal levels better than the standard MP omni.

We have two Nanostations running the Supernode firmware. So we decided to fit one to the Blind Society mast. As described in previous post we reasoned this would give us some benefit from the directional Nanostation antenna and increased link margin. The disadvantage is the Blind Society would have poor omni coverage for expanding the mesh. So we decided to fit both a Mesh Potato and the Nanostation to the same mast.

We gathered up the team and a bunch of equipment and headed back to the Blind Society. Ase (Ah-say) and Mateus did an amazing poll climbing trick. They just grabbed a pole with both ends and went hurtling upwards using arm power alone. It was like Batman (the TV series, not the mesh routing) except I swear they were sliding up the pole. These guys have a very high power-weight ratio.

The results were really good, 0% packet loss on short and long ping packets, and a Batman score between 220 and 255. The ping tests I used were:

# ping 10.130.1.0 -c 100 -i 0.1 -q
# ping 10.130.1.0 -c 100 -i 0.1 -s 1400 -q


Sending the packets at 100ms intervals gave the link an additional hammering. Finally, the breakthrough we had been waiting for! The received signal was measuring -54dBm at both ends, a very strong Wifi signal.

I there aren’t too many other links like this one – Nanostations are expensive kit. We placed both the Nanostation and the MP01 on the Blind Society mast. They mesh together automatically (very cool) so the Blind Society get a phone and the mesh is spread in an omnidirectional pattern. Not so cool – we used two nodes (MP plus Nanostation) to do the job of one.

Next milestone is to see if this link can stay reliable for 24 hours.

We also installed another node at the University campus across the road from the blind. Ase (Ah-say) and Matues showed some more climbing tricks:

So now we have 4 nodes, consisting of 2 Nanostations and and two Mesh Potatoes. There is still an issue with the links between the Fongtil tower and inside the Fongtil building, we will debug that and so some more network training tomorrow.

I am sweaty, sunburnt, hot, a little dehydrated, but mildly happy. We inch forward.

Links

Dili Village Telco Project Wiki
Dili Village Telco Part 1
Dili Village Telco Part 2
Dili Village Telco Part 3
Dili Village Telco Part 4