80 down, 20 up, releasing a bottleneck in the home

A couple of weeks ago, I upgraded the Internet connectivity at home, from an ADSL service which could be a little bit wobbly (likely due to poor condition on some of the cabling) and usually hovered between 2Mb and 3Mb down, to FTTC – reducing the copper run from about 3.5km down to about 200m.

The service is sold as “up to 80Mb/sec” downstream, with upload of up to 20Mb/sec, which turns out to be achievable on my line, as my ISP’s portal reported the initial sync as 80Mb, and this gives around 75Mb of usable capacity at the IP layer once you’ve knocked off the framing and encapsulation overheads.

I eagerly headed off to thinkbroadband.co.uk and speedtest.net to run some tests. They confirmed I’d only get 40Mb/sec until I replaced my trusty but ageing Cisco 877 – that’s one bottleneck I already knew about and had a replacement router coming. But, never the less, I was happy with a >10x uplift on the previous downstream speed, and off I went happily streaming things, as can be seen from my daily usage…

Yes, some of that usage in the first day or two would have been repeatedly running speed tests in giddy abandon at the bandwidth at my disposal, but the daily usage is now generally higher.

There’s a number of reasons that could be behind that, but I suspect that among the most likely are services which support variable bit-rate video delivery, which include things such as YouTube and BBC iPlayer will be automatically upping to the higher quality stream.

The new router arrived on the 9th, and it was off with the speedtests again… and that’s where I found an interesting bottleneck in the house.

I could happily get 75Mb/sec in one room – where the router and main access point was. However, in the lounge, which is in an extension at the back of the house, I could only get around 30Mb/sec, despite having an access point in the same room.

I’ve ended up with multiple access points in the house, because the original “cottage” was built in 1890 and has fairly thick walls made of something very, very tough (from experience of hanging up pictures) which is also largely impervious to radio waves it seems, while the extension is attached to the “outside” of one of the original external walls, as well as being the furthest point away from where the Internet access comes into the house. This meant that I wasn’t left with much choice but to infill using a second wireless AP.

But both APs are of a similar spec and support 802.11a/b/g/n, and I was connecting on the less congested 5Ghz spectrum on both. So, where was the bottleneck?

The attention turned fairly quickly to the HomePlug AV network which I was using between the front and back of the house. It hadn’t caused me much concern in the past, but now it was prime suspect in my quest to wring the maximum out of my shiny new upgraded circuit.

Finding the longest piece of cat5 cable I have (a big yellow monster of a cable), and running that through the middle of the house to the AP, revealed that my suspicions were correct, but I also knew that the bright yellow cable snaking through the kitchen couldn’t stay there.

In the next few days I learned more about HomePlug than is probably healthy, and that will form the basis for my next article…