What is the NBN?

Where is the NBN in the Internet?

The NBN or National Broadband Network is a business that has installed new technology connections for Australia's internet.
In the past, the Internet has been connected to businesses and homes by a mixture of old wired technologies.

Using light in a 'fibre optic' cable allows far better performance for the internet and this is the main technology being used by the NBN.

In the past an ISP or Internet Service Provider would provide cable or lease wire phone lines to connect to existing business or home premises.

The NBN now (mostly) owns the connection infrastructure between premises and ISP's.
Rental is then paid to the NBN for ISPs to sell internet services to business and home customers.

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Why are there Problems with Internet Connections with NBN?

1. Connection to Premises
The major parts of the NBN internet are connected by very fast fibre optic cable. This is the 'backbone' for traffic between cities and the main internet connections.
For cost reasons, the fibre optic cable is not used, in most cases, to connect from the main backbone to existing business or residences.

The last part of the connection is by a range of technologies even, in some cases, using existing telephone wire connections. This means that the speed of the fast fibre optic cable is restricted by the last part of the connection to your home or business. New residential developments and buildings should get the high speed fibre-optic cable as part of their construction.

2. ISP Capacity Estimates
Because ISPs are renting infrastructure from the NBN they have previously underestimated customer demand and not rented enough capacity, again leading to restrictions on internet performance.
This problem seems to be less widespread as ISPs understand customer needs on the NBN.

3. Technology Problems
In some instances the NBN has had problems with the sharing of the fibre optic connection between premises over certain types of wired connections, especially the cabled (HFC) areas.

What are the types of Internet Connections with NBN?

The diagram shows some typical connections that are used from the main 'backbone' fibre optic cable to the 'nodes'.
A node is a distribution point that connects many businesses, homes or multi-story residences in an area to the internet.

Some of these will have direct fibre optic cable connections but many will have copper wire connections via existing telephone wires or cables.
In the case of remote rural areas it is not possible to lay a cable all the way so satellite connections are used.

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The NBN owns all the infrastructure up to the ISP connection.
The black boxes labelled NBN are the various types of connection boxes that might be used to connect to the premises. These boxes are sometimes called NTD or Network Termination Device.
Usually there will be an ISP supplied device (modem) also connected to provide the services to the client. These have not been shown for clarity.

What do the parts look like?

At your residence there will be a connecting box on the outside of the house.
This may not be visible if you are in a unit.
A cable will come out of this NBN box, inside the residence to connect with a modem.

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NBN Modem or NTD

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The modem is the connection to the NBN so that any ISP you choose can provide service from this point. It is often referred to as NTD or network termination device.

From the modem a network cable will run to a router or a wireless router.

Wireless Router

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Most ISPs will supply a 'wireless router' which has both wired connections and sends out WiFi signals for wireless connection of devices.
The wireless router in the picture is labelled Optus but these devices are made on contract for any ISP.

All have a similar function; to distribute or 'route' the internet signals to wired or wireless devices.
Some wireless routers will have external aerials for WiFi showing.
Others, like that in the picture, have an internal aerial.

All the connections from the modem to the router and router to wired devices will be by network cable ("Ethernet" cable).
The network cable provides connections for the Ethernet, the technology which is used between internet devices.

Your ISP may replace the router for free if you have significant problems and it is not unknown for these devices to fail.
Do not be afraid to call your ISP for help with the internet connection as YOU are paying for the service.

Network Cable for Ethernet Connections

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These cables look similar to telephone cables but have slightly bigger plugs.
An Ethernet cable is not suitable for connecting telephones.

Umm. but where does the telephone connect?

With an NBN connection, the telephone is connected through the internet using a technology called VOIP (Voice Over Internet Protocol).
The wireless router will have at least one telephone type connection at the rear to allow a suitable telephone to connect to the system.

This means that:

  • the NBN system must be powered for the telephone to work
  • a blackout means no telephone is available unless you have a mobile
  • some old handsets may not work with this type of connection
  • if you have a back-to-base home alarm it may not work with NBN (contact your supplier)

Internet Speed

There is a lot of talk by ISPs about internet speed and the numbers might look big but the speeds are measured in bits per second.
For comparison, measures of device storage (like a mobile phone) is in bytes which are commonly made up of a group of 8 bits.
Note that the numbers above are download speeds which means the speed of files coming from the internet to your device or home.

Upload speeds , which refers to files going from your home to the internet, are variable from roughly one tenth of the download speeds to about half the download speed.
The speed depends on the connection to the NBN. A business connection may pay to have equal upload and download speeds.

Download Speeds are important for searching the internet, watching internet TV, downloading apps and streaming music.

Upload speeds are important if you are sending files to someone else, using Cloud services or using internet communication.

(see below if you want more about these numbers)

The internet speed through wired connections to the home has changed over the years:

  • The first 'dial-up' modems were about 128 kbps (ie 128,000 bits per second. This technology took over the telephone line completely to operate)
  • ADSL - internet shared with telephone on telephone lines - 425 kbps (ie 4 times the previous)
  • Cable - internet through special coaxial cable (HFC) - 25-100 Mbps (ie 50 times the previous)
  • FTP - NBN internet, optical Fibre-to-The-Premises - 100+ Mbps (nearly 800 times the earliest modems)

By comparison, the 4G mobile network can deliver around 20 Mbps but this tends to be more variable than wired connections due to varying network congestion.
This is because the speed of a wireless connection is affected by how many are connected to a particular point.
You may get as much as 100 Mbps on 5G mobile but it is very dependant on distance from a tower and congestion.

How fast do I need it?

For ordinary internet, download speeds around 20-50 Mbps is OK

This should be just adequate for internet streaming video / TV but it may not work well if that speed is not maintained in the evenings when many households want to use it at the same time.
Most ISPs now use the speed that is maintained most evenings as a guide so most internet plans of 20+ Mbps are adequate for most purposes.

ISPs also want to sell higher speed services but the expense is not worth it unless you have high useage like many people wanting to each watch different video or movies at the same time.
This is usually typical of a family situation with multiple devices.

Upload speeds are not always a problem for many people but having at least 5 Mbps is just satisfactory but higher is better if you use uploading more frequently.

Bits n Bytes on NBN

This all means that a 1 Megabyte file (eg the words for one small book) will take about 8 seconds to transfer on a 1 Mega-bit per second (1Mbps) connection
The speed measurement in Mbps (rather than Megabytes) seems to be a historical artifact related to early computing where byte sizes were not standard.

[Here is the math in case you want the detail:
A 1,000,000 byte file (one Megabyte) on a 1,000,000 bits per second (1Mbps) internet will not take 1,000,000/1,000,000 = 1 second to be transferred. That 1,000,000 byte file is 8 x 1,000,000 = 8,0000,000 bits so will take 8,000,000/1,000,000 = 8 seconds to transfer.]

Other Internet Connections

The NBN is not a supplier for the mobile phone network which is provided by telecommunications companies as a separate network.
The mobile phone network is however connected to the internet so that mobile phones can get internet information.

Suppliers of public WiFi services have to be connected to the NBN to provide internet services.
These public wifi connections are thus subject to the problems of the NBN.

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