Understanding broadband speeds on fixed networks
Filed under: ADSL, broadband, networks, technology
It’s fair to say that many of us would find it difficult to live without broadband connections nowadays.
As a network engineer I have seen internet technology evolve in leaps and bounds over the past years. While networks get smarter and faster, there are some factors that may influence the general customer experience that are useful to know and I’d like to share them with you.
Fixed, or wireline, networks operate over copper or fibre cables that are either laid underground or aerially across telegraph poles in some areas.
In all cases, on the ADSL, ADSL2+ or BigPond Cable broadband networks, the customer’s equipment is a key factor affecting the speeds they will experience with their service.
- The specifications and configuration of a customer’s PC and modem will affect connection speeds.
The customer’s location is also a key factor in the speeds that they will experience in all cases.
- With a terrestrial technology such as ADSL, the speeds will vary based on the customer’s distance from the exchange, the type and length of the copper cable connecting the customer to the exchange, and prevailing line noise (signal interference) conditions at the time.
- For the ADSL2+ product, availability also depends on whether the customer’s exchange is enabled with ADSL2+ technology.
- BigPond Cable capability is only available in Sydney, Melbourne, Brisbane, Adelaide, Gold Coast and Perth, and the service speeds may vary between cities based on Telstra’s roll-out plans.
- For example, the BigPond Cable Extreme® product can provide maximum download speeds up to 17Mbps in Brisbane, Adelaide, Gold Coast and Perth, and maximum download speeds up to 30Mbps in Sydney and Melbourne only.
There are a number of other factors that affect speed:
- The number of people using a network at the one time and what they are doing on the network and the source of their content, especially when it is content sourced beyond Telstra’s network. For example, downloading movies will use more bandwidth than sending emails.
- Factors outside the Telstra network, such as content server delays.
- The source of the data being downloaded can also affect download speeds. For example, data being downloaded from international websites must travel a lot further and through many more network elements than data being downloaded from websites in Australia.
Note: ‘Mbps’ means megabits per second.
Next week, my Telstra Wireless colleague will write about the factors that affect our wireless networks, such as the Next G™ network. In the meantime, I’d like to hear your views and opinion on this story, or feel free to delve into some of the content at Whirlpool’s network forum.

















“the customer’s equipment is a key factor ”
“customer’s location is also a key factor”
Stop saying “customers” it’s your crap service, we pay to use it and your equipment lets us down with bad connection.
Yes it is a pain trying to live in a world without broadband these days. I live in an area within 1.5 kms of an adsl2 + enabled exchange, and used to live 500m down the road with a decent adsl2+ broadband service. I move and Telstra put me on a pair gain without even the option of a transposition to inferior ADSL, and charge me for the privilege of denying me any wired broadband service options right in the middle of Sydney.
My equipment is just dandy thanks, Telstra’s archaic pair gain technology is the problem.
Do I sound bitter? You betcha.Thanks Telstra, you’ll never have me as a customer again.
How do I ‘unlike’ Michael? My equipment is just fine (brand new), my home is just fine (brand new), your company’s commitment to supplying basic infrastructure is at fault.
How could I ever have expected to buy a brand new home 11km from the CBD and end up yet another victim of pair gain?
Back to the late 20th century for me, thanks a lot. Or are Telstra just holding off for the NBN to arrive..?
Agree nick telstra’s lack of investment shows.I live 27k’s out of town and syuffer pair gain as well.We have adsl2 avaialbe at our exchange,but no thanks to mr lack of money spending on new ifrastructure, i suffer the same problem as you.Suppose i hold my breath for NBN otherwise you and i will have to move suburbs!