The need for speed

So, the latest BT advert had someone streaming music, and it keeps stalling. They are selling FTTC as a fix for that.

So, let's try and understand this shall we. A streaming audio can be of the order of 200kb/s. But the slowest broadband lines, even on old 20CN exchanges, are rarely as low as 250kb/s. Under 2% of A&A BT circuits have a sync under 300kb/s at present. Audio can stream at lower rates.

So, basically, any working ADSL line will be able to stream audio without pauses.

But that is not the only possible issue. The streaming can be stalling for several other reasons

• The line is filled with other data at the same time (downloading email, web pages, torrenting, etc). This issue applies regardless of speed, and even an 80Mb/s FTTC can be full of traffic causing streaming audio to stall. In fact, you need some sort of QoS stuff (like the way A&A prioritise small packets) to fix that, something a normal BT FTTC would not provide. So that can't be the reason as FTTC would not be a valid fix.
• The far end could have capacity issues, or some peering link in the Internet could be full. Again, this would not be fixed by FTTC, so not the issue.
• The back-haul over the BT network could be congested. This is usually at the ISPs control. It is, again, not something that is fixed by changing to FTTC. If the ISP has full links that cause that level of congestion, a solution is to move to an ISP that does not. FTTC is not the fix.
• The line could have some sort of fault with lots of loss or some such. The fix is not FTTC, it is fix the fault.

Basically, unless that example is an incredibly long line with 250kb/s DSL trying to run a higher bit rate down it, then FTTC will be no help. Sadly, such long lines are normally in remote villages which don't have FTTC. Even so, that would be an obscure example to pick for an advert.

I'm not saying FTTC is bad, no. It is good. What I am saying is that raw line speed is not always at all relevant to the issues you are trying to fix. This is a perfect example - it is really unlikely that the line speed is the cause of the broken audio.

All this advert does is propagate the myth that speed is all that matters. What is often more important than speed is lack of congestion in back-haul and over the Internet, low and consistent latency, and lack of packet loss on the line. Even OFCOM don't actually bother measuring these.

Even the government is hung up on speed, but with arguments about ensuring people have access to government services via the Internet, e.g. on-line VAT returns, etc. These are things that don't need speed, but they do need connectivity.

There are speed milestones, levels where completely new services become possible. At a few Mb/s it possible to have streamed video in real time. Below that you can have downloaded video. At higher rates you can have multiple streamed video in real time, and very high resolution video. There may, some time, be yet more speed milestones for some new services we have not invented. That said, entertainment is the main use of high bandwidth, and that comes down to how many bits/sec of useful information can a person consume (eyes, ears, touch, etc), and we are hitting that sort of limit with TV higher resolution than we can see, and sound higher fidelity than we can hear, so entertainment is not likely to push the limits a lot more than it does now. So higher speeds are useful, but far from the only factor.

Everyone is just concentrating on speed!