South Brisbane Fibre - ftth


It doesn't seem that long ago when we connected our first customer to a dial up modem in January 1995 at 28.8Kbps. 

Although HFC cable came along around 1999 for some people, we were very pleased to be able to connect to 1.5Mbps ADSL in mid 2002.  This era was an explosion in Broadband Internet in Australia with hundreds of ISPs providing ADSL services. 

Soon after we took the plunge and installed our own DSLAMs into several Telstra exchanges in mid 2004. This allowed 8Mbps ADSL1 and later around 20Mbps with ADSL2+, that is if you lived very close to an exchange or were not prevented from getting broadband by a RIM or "pair gain" system.

For business customers it allowed SHDSL combining up to 4 pairs of copper (9.2/9.2Mbps), and later midband-Ethernet (E-SHDSL) allowing even more pairs to provide 40/40Mbps if you were close enough to the exchange, there was enough copper, and you were willing to pay the money for so many copper pairs.

The old copper network has certainly performed way beyond what it's makers intended!


The NBN (National Broadband Network) is meant to revolutionise and replace the copper network with fibre at 100Mbps to 93% of the population, with capability for 1000Mbps (or 1Gbps) should it be required for residential customers. Starting in Tasmania the NBN is slowly spreading throughout the mainland, and in Queensland is being built out in Townsville, Toowoomba and soon around Aspley and Goodna.

South Brisbane exchange fibre

Independently of NBN, the South Brisbane exchange area (West End, Highgate Hill etc., basically postcode 4101) is being migrated to fibre to the home/premise (ftth/fttp) technology.  The fibre equipment servicing the South Brisbane exchange area will be a few km further away than the old exchange and will be housed in the tall Woolloongabba exchange close to the famous cricket ground of the same name.

Telstra will initially be offering fibre speeds of up to 100/5Mbps, which happily I can say they have delivered!


This is an early taste of NBN technology for Brisbane and a big improvement from my previous 6/1Mbps ADSL2+ connection I got at home over copper! Telstra is putting fibre in the ground because the exchange is being removed to allow a new Children's hospital to be built, with the Queensland State Government paying Telstra $77 million to move out.  You can see the hospital construction almost on top of the poor old little South Brisbane exchange building.

It has been a bit controversial in the industry as it's also a re-monopolisation of the exchange, i.e. all competitors DSLAMs (who for example offer innovative services like Naked DSL, which doesn't require a customer to have a regular phoneline service, IPTV and VoIP) will also be removed.  Telstra will again become a monopoly provider (just like NBN will also eventually be), although this time over fibre instead of copper.

Fibre network being built

This page gives a pictorial overview of what is happening in and on the ground in 4101, as I have experienced it, over the last little while.

All around South Brisbane exchange (4101) these days are dozens of trucks, vans, diggers, concrete trucks, and perhaps hundreds of Telstra staff. contractor staff and traffic control installing new pits and distribution cabinets on the footpaths, and of course lots of blue fibre cable connecting them all up..

The fibre network is of a type of network called GPON (Passive Optical Network). A fibre from the exchange carries a signal at 2.5Gbps down and 1.5Gbps up and this bandwidth is shared between 16, 32 or 64 homes.

What "passive" means is there is no electricity needed between the exchange building and the fibre ONT (optical network terminal) at our home.  This mirrors the old copper network for telephone reliability in case of a power outage (except in newer and overbuilt areas where the copper was serviced by RIMs and CMUX-AU street cabinets which needed electricity and therefore needed battery backup.)

Here is a distribution cabinet being constructed.  As you can see underneath there are fibres going in and coming out, but there is no electricity going in.  Once installed it acts as a big patch panel allowing customer services to be changed, added and removed if needed. 

It is also where the signals on the single fibre from the exchange is split into individual fibres for each home (up to 64, but usually 16 or 32) and also the signals from each home are combined on the way back to the exchange.  Needless to say this fibre sharing, through splitting and combining, saves the need for a lot of fibre from the distribution cabinet to the exchange.

Why don't the signals sharing the fibre interfere with each other like when multiple people talking loudly in a room? 

On the way from the exchange down to the homes, all the traffic destined for any of the homes sharing the fibre, is simply lined up and is sent to all the homes who share the fibre.  Fortunately the traffic is encrypted and can only be decrypted by the appropriate OLT.  This is a form of TDM (Time Division Multiplexing).

On the way up from the homes to the exchange, if the OLT were to simply send their traffic at a random time, there is a good chance that there would be a collision and confusion.  Protocols are used to share this upstream bandwidth and ensure everyone gets a fair turn at sending their traffic.  This is a form of TDMA (Time Division Multiple Access). A highly technical explanation about GPON TDMA can be found here.

The physical fibres can be joined together or spliced.  A machine very carefully aligns the two fibres end to end and melts them together at high temperature using a plasma/fusion splicer.

Here are two splicing enclosures which manage the physical fibres and stop them getting all tangled. 

The left one is the fibre splices which go back to the exchange.  In case there is a fibre cut between here and the exchange due to a backhoe, there are other spare fibres going on a different path back to the exchange (one path is called "East" and the other path called "West") to form a kind of fibre ring.  The switchover to the spare fibres might not be automatic and might require some repatching in the exchange to get the service working temporarily until the damaged fibres can be repaired.

The right one is the customer fibres of which you can see there are a lot more after being split from the exchange fibres.

Getting connected to the fibre

About 3 months before my fibre install, some Telstra techs knocked on the door and informed me they were here to inspect my conduit, i.e. the tube between the pit in our footpath to under our house (an old queenslander) where the existing copper phoneline comes into our property. 

Fortunately it was in good condition and they were able to push through a flexible plastic rod from the street to under our house.  They then tied a string to the end of the rod and pulled it back out.  You can see the ends of the string in the old pit and under our house below. So our home was now ready for fibre installation day when the string would be used to pull the fibre from the pit into under our house.

A good reason to go to fibre by the way is that the copper networks are ageing and water can get into the copper cable joints (sometimes due to a bad batch of gel joint sealant).  This can cause noise on the line and lead to broadband dropouts.  Here is our new pit with my copper line being repaired just a week before our fibre was installed.

Finally the schedule day of fibre connection arrived. 

Did I mention how delicate the optic fibre really is?  It's in a coloured sheath to allow the technicians to know which fibre they are working on.  The sheath can be stripped off and although it's hard to see, the actual fibre is thinner again.  Only a single fibre is installed into each house.  In other computer fibre networks there is usually a pair of fibres, one for each direction of traffic flow.  In the PON network the traffic travels up and down the one fibre using different "colours" of light, again requiring less fibre.

Here is our new pit ready to have the fibre pulled through.  On the right we have the fibre already pulled through and inside a protective grey conduit.

Here is the pit end of my house fibre, the other end of which has already been pulled through the conduit from the pit to under our house, being connected to the LM (Lead-in Module) in the pit.  This is a mechanical splice, i.e the optical fibre in the street is mechanically accurately held end to end to the fibre connecting to my house, allowing the laser light to flow in both direction.


The fibre under the house has been carefully run along beams and walls. Every couple of meters are warning labels to say this is an optical fibre cable with a warning not to damage it. Here you can see the two fibre connectors for the final couple of meters.

The fibre from the street will now again be mechanically spliced to the final piece of fibre cable connecting to the ONT, this time in a small junction box. 

Here is the ONT/NTD (Optical Network Terminal/Network Termination Device) inside our house.  As you can see on the left photo it can support two phonelines, as well as four broadband connections (only 1 is enabled currently).  It also needs to be near a 240V power outlet and the fibre enters at the far right.

The right photo shows it mounted on the wall.  The fibre enters the ONT through the floor via a square conduit.  The yellow is my network cable going to my router which connects to the ISP via PPPoE.  Most people will get a new router from their ISP to replace their older ADSL2+ router.  The black cable is power going to a plugpack.  The grey wire is the phoneline which goes into a small junction box and then upwards to our regular phone.  The small box closest to the floor is blue networking cables heading off to other rooms in the house.

A battery backup is available for the ONT, which as I mentioned does require power, but this only keeps the voice line working and not the broadband.  However these days with most people having a cordless phone, which would also require power, and with multiple mobile phones in the house, I doubt many people will bother with the additional expense of battery purchase and replacement.  Most people will be more upset that broadband is not working than the phone not working.

The technician tested the signal level over the fibre and all was OK!  Then he made a call to Telstra to switch over our phoneline and ADSL from the copper to the fibre.  A couple of txt messages went backwards and forwards and we had dial tone on our phoneline.  A few minutes later our router connected to our ISP over PPPoE and I managed the speed test at the top of this page.


The two Telstra techs installing the fibre into our home were very efficient and professional and took around 2.5 hours from when they arrived to when the phone and broadband connection were working on the fibre.  It was a painless experience to get the phone and broadband working again.  The Internet speed is just like working in a large corporate office in a well connected and fibred building. 

As a test I downloaded a 1GB file in less than 2 minutes and it averaged 93Mbps.  Later I downloaded a 10GB file and it took just under 18 minutes averaging 80Mbps.

My only minor "complaint" is that strangely Telstra "only" offers speeds of 8/384Kbps, 30/1Mbps and 100/5Mbps on their ftth product while NBN offers 12/1, 25/5, 50/20, 100/40Mbps.  Please Telstra can we please have the higher upload speeds?  One day Telstra will sell the South Brisbane exchange fibre to NBN at which point no doubt the speeds will be aligned.

Here is a partial list of Fibre service providers in South Brisbane exchange, but of course I recommend OntheNet :-)

You can see more photos in the media here and video from Telstra here

edit 17/11/2011 - added some technical corrections about GPON, TDM and TDMA.