Network

Network Node Classification

Administering an ever expanding network such as ours requires alot of time and effort. To successfully do this, and to keep things running as smooth as possible, we have defined a basic heirarchy for classifying network nodes.

At the top of this heirarchy are the most important (or 'mission critical') nodes, and working towards the bottom of the heirarchy we find nodes that are less relied upon for network continuity.

brain dump about the networking experience at LCA08

One of the key things about helping at an event like LCA08 is documenting things so that the team won't have to suffer the things you went through!

So begins the process of dumping ones brain to the Wiki...

Hopefully this might help others in their journey into building their networks =)

What is an Open Access Network (OAN)

An Open Access Network (OAN) refers to a horizontally layered network architecture and funding model that separates physical access to the network from service provisioning. Where the same OAN is used by a number of different users and/or providers that share the investment and maintenance cost.

OAN networks are now in hundreds if not thousands of local settings around the world and come in all shapes and sizes ranging from local neighborhoods to metropolitan wide networks connecting many homes and buildings. They are not just limited to only one type of network system as they can include hybrid combinations of both commercial and community networks with many forms of technology including fibre, copper wire, and wireless.

SPLAT! - Line of sight (LOS) O’Halloran Hill

SPLAT! is an RF Signal Propagation, Loss, And Terrain analysis tool for the spectrum between 20 MHz and 20 GHz. It provides site engineering data such as the great circle distances and bearings between sites, antenna elevation angles (uptilt), depression angles (downtilt), antenna height above mean sea level, antenna height above average terrain, bearings and distances to known obstructions, path loss based on the Longley-Rice Irregular Terrain Model, and minimum antenna height requirements needed to establish line-of-sight communication paths absent of obstructions due to terrain.

Below is the predicted LOS for OHalloran Hill, it assumes both up and down tilt and no signal path loss, only path obstruction.

Go West

Go WestWith the network growing rapidly to the North and soon the South we are starting to see the West beginning to blossom with activity. The West is one of the hardest areas in Adelaide to establish a wireless network but when people work together it is amazing what only a few people can achieve if they work together.

If you have a roof with views in the Western Suburbs and haven’t yet thought of joining the wireless community movement now has never been a better time…

MRTG - The Multi Router Traffic Grapher


The Multi Router Traffic Grapher (MRTG) is a tool to monitor the traffic load on network links. MRTG generates HTML pages containing PNG images which provide a LIVE visual representation of this traffic.

Check 10.114.2.2/mrtg/ to see what it does on the wirless network (note not all routers are currently listed)

What is a Wireless Internet Service Provider (WISP)

Air-Stream Wireless is not a WISP but some Internet Service Providers (ISP) do sell Internet access over wireless these companies are known as a Wireless Internet Service Providers (WISP) and often use identical equipment and share the same radio frequencies used by Air-Stream.

A WISP offers a connection to the Internet, they are not a Wide Area Network (WAN) nor are they structured like an Open Access Network (OAN). They are managed and financed in quite a different way compared to Air-Stream Wireless and should not be seen as anything other than a gateway to an Internet connection.

Only Milliwatts instead of Watts


Over the past year the Elizabeth Amateur Radio Club (EARC) call sign VK5LZ have been helping to expand community wireless networks for use by not-for-profit community groups, disability organisations, the open source community and local people on the licence free public park spectrum 2.4 GHz and 5.8 GHz.

Although the Amateur Radio Club is licensed to transmit at much higher power levels at these frequencies they have choosen to run low power 802.11a & b wireless LAN equipment, enabling the club to participate as an Access Point Node at their site on the Elizabeth Water Tower.

The aim of the community network is empower communities and help bridge the digital divide, by providing very low cost non-profit wireless networks where people can easily share IT resources and communicate.

Advertising your SSID

One of the ways to minimise interference is through advertising your SSID so that other users of the band can take steps to avoid interference and conflicts.

For this purpose Air-Stream advertise the SSID on all their AP’s including backhaul links between sites. This not only makes it easier for users to connect, but also provides other wireless users with all the information needed to minimise interference.

This information can be acquired easily via any wireless device when completing a site survey providing information about the user, channels used, general location and the direction in which antennas maybe pointed.

For example an Air-Stream AP will use the SSID: Air-Stream-Location Name and a Back Haul link may have an SSID: Air-Stream-LoacationFrom-LocationTo

Information on AP polarisation can also help to minimise interference as AP’s are designed to send signals in all direction and by changing your polarisation can offer up to 20db reductions in interference.