Ask LH: Why Can’t My ISP Guarantee My Speed?

Ask LH: Why Can’t My ISP Guarantee My Speed?

Dear Lifehacker, My home connection is meant to be ADSL2+, but I have never exceeded 5.0Mb/s for downloads. My ISP tells me that is all the speed I can expect living 3.6 km from exchange. Is that true? Am I right in thinking that going through a VPN my download speed would be much worse? And can I do anything other than wait for that very elusive NBN? Thanks, Slowed Down P’d Off

Speedometer picture from Shutterstock

Dear SDPO,

Broadband speeds are incredibly variable, but then that’s because there’s a lot of variables at play. There is, as your ISP has noted, the issue of range when using ADSL2+, and certainly a download speed of 5.0Mb/s isn’t outside the ordinary if you are 3.6km from the exchange. Another 1.4km away, and you wouldn’t be able to get an ADSL2+ connection at all.

Distance, however, isn’t the only variable, because it also depends on the location and connection quality of whatever you’re trying to actually download, and whether it’s peered locally, or being accessed purely from a connection nearby or overseas. As such, even on the fastest connections, you can still experience remarkably slow speeds. A good example of this would be when Apple rolls out its main full point iOS upgrades. Apple can afford decent local peering, but even so, the strain on its servers means that day one upgrades can be painfully slow.

The use of a VPN involves obscuring the location of your connection by channelling your traffic through a secondary, usually overseas server, so some speed degradation is more or less inevitable, although the degree of speeds loss can vary by provider and server load.

So what can you do? The NBN, even in its new heavily diluted “MTM” mix should improve download matters once it finally starts properly rolling out, but that’s a statement that has to be qualified with some heavy caveats, because it will depend on the type of NBN you end up getting. If you’re lucky enough to still be in an area that will get FTTP NBN, you should get greatly improved speeds, but the reality in the FTTN/HFC areas is significantly less certain.

There’s a lot of debate about the state of the copper used for the last mile delivery of FTTN, and that could hit speeds badly. NBN Co has committed to using DOCSIS 3.1 as an upgrade for HFC users, but it’s still a shared spectrum, which means that if your neighbours are all busy heavily streaming or downloading when you want to, bottlenecks are likely. Most troublingly, most of the provisions for “minimum” download speeds that were part of the old NBN model have been scrubbed out of the MTM mix, which could mean that genuinely low speeds still counted as “NBN” connections, because there’s no longer any bottom floor.

4G would be your other alternative, because it can peak very high, but again there are catches. It’s highly dependent on environmental variables, because it’s not fixed line, and again you’re looking at shared spectrum, so while it may peak quite high especially for CAT6 style LTE devices, those peaks can also become very tiny troughs. The bigger issue for 4G is that mobile data remains significantly more expensive than fixed line data, so for anything but small scale downloads it’s quickly cost prohibitive.

Cheers Lifehacker

Have a question you want to put to Ask Lifehacker? Send it using our [contact text=”contact form”].


  • ADSL technology is unfortunately very distance-sensitive. Typical attenuation for ADSL2+ is 13.8 dB/km. At 3.6km from the exchange you’re looking at 49.68 dB of attentuation which will give you approximately 5.291 Mbps sync speed.

    So yes, what your ISP told you is true. Your alternatives depend on where you live, but include cable, ISDN, ethernet broadband, satellite (expect high speed but high latency), NBN or a few other options I can’t recall right now.

  • Basically there are a few things that affect your download speeds.

    (1) The speed from you to your ISP. If downloading from a server AT your ISP, you should get this speed. This speed should approximate what your modem says it is in its diagnostics.

    (2) Peering arrangements between your ISP and other ISPs. The Internet is what the name says: a vast collection of inter(connected) net(works). If your ISP has a thousand customers all connected at 10Mbps and only one gigabit link to its neighbours, the total bandwidth of all customers (excluding connections within the ISP) will still never exceed 1Gbps, or 1Mbps per customer. This is the dirty little secret of the ISP business; everybody oversells their available bandwidth, because statistically people don’t download at the exact same time. In practice they pick a bandwidth level then provision to ensure that a minimum speed of XMbps is available at least Y% of the time for some value of X and Y. Premium ISPs pick bigger numbers.

    (3) The state of the Internet between your ISP and whereever you’re downloading from. The ISP can’t do much about this, except by using multiple trunks to improve bandwidth and reliability. Multiple high-speed trunks cost quite a bit.

    (4) The capabilities of the servers at the other end.

    The ISP’s revenue is tied to (1) and, for servers, to (3). Their costs are tied to (2) and (3). An ISP offering really cheap Internet is probably cutting costs, so you can expect to get a slower speed.

    If you think your speed is being gimped per (2), you can sometimes get a rough indication by running a traceroute (Windows: tracert) and seeing where speeds between you and the server slow down or become unreliable. Your chances of taking this as evidence to your ISP are poor, unfortunately – traceroute is not a very reliable tool, and if you get through to tech support to complain they will either not know about it or will know enough to tell you that it’s unreliable.

  • Short answer: Nobody cares, that’s why you get shitty service.

    There’s no competition in the cables between your house and the exchange, you get what you’re given, which appears to be utter crap for a good chunk of the population. Because there’s no competition here, there’s no incentive for Telstra (who own the cables) to improve the situation.

    Same thing with the NBN, you’ll get what you’re given. Hell most other people keen to provide services aren’t allowed to! TPG is exploiting a loophole, but if you’re in a normal house, you’ll get NBN, and you’ll like it, dammit (eventually, maybe).

  • I live approx. 4km away from the exchange & I can’t even reach 2Mbps.
    Because of where I live, ADSL is my only choice at this time.

  • My tip for getting great internet speed, live near a hospital.

    Every place I ever had great internet, has been on the same exchange as the local major hospitals. Telstras contracts with State Government / Health Dept usually means they are usually better, the one attached to the Brisbane Children hospital got full Fibre upgrade so the whole suburb(s) got Fibre to Home (Telstra owned – not NBN)

  • Rather than providing an estimated speed range that a customer could expect to receive, providers should pinpoint a more accurate speed that customers can expect at their home address and provide this in writing.

Show more comments

Comments are closed.

Log in to comment on this story!