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Rory Cellan-Jones

Understanding broadband speed

  • Rory Cellan-Jones
  • 13 Mar 08, 16:31 GMT

What do broadband firms mean when they offer you 鈥渦p to 8mbps鈥? And just how likely are you to get that speed if you sign up? I suspect most people鈥檚 answers to those questions would be 鈥渘ot sure鈥 and 鈥渇at chance鈥.

I was pretty confused about the speed issue but after spending some time with BT broadband engineers I now feel a little clearer. had summoned a group of IT journalists to its Gatwick headquarters to tell them about the exciting future that its new broadband products promised. But it turned out that all anyone really wanted to talk about 鈥 on both sides 鈥 was speed.

BT is obviously worried that the 8 million users getting their broadband from the ISPs who use its network will blame it for the fact that they aren鈥檛 getting the speeds that they expect. It appears uncomfortable with the advertising of headline speeds of 鈥渦p to 8mbps鈥 or 鈥渦p to 24mbps鈥. Why? Because it knows that nobody will actually experience those speeds when they are using the internet.

The engineers explained that customers needed to look at two different things 鈥 line speed and throughput. Line speed is what the line between your modem and the exchange can theoretically achieve. So if that is 8mbps, you might achieve that if you lived right next to the exchange 鈥 but if you live three miles away, have a sub-standard modem or suffer electrical interference within your home (Christmas tree lights are one culprit, apparently) then you are likely to get much less.

Then there is throughput, which is the speed at which data arrives down the line while you are online, doing anything from reading web pages to downloading video. Throughput is what is measured by the various web speed-checkers, and it is bound to be slower than your line speed because it looks at what happens when you leave the exchange and head out onto the internet, where you can hit congestion.

Perhaps rather than advertising an 鈥渦p to 8mbps鈥漵ervice, ISPs should describe it as 鈥渂etween 512kbps and 7.5mbps鈥. But that might be rather harder to sell. is talking to the broadband firms about how they advertise speeds 鈥 and everyone seems to agree the current system is broken. But what should replace it? Your ideas would be welcome.

Comments

  • 1.
  • At 05:40 PM on 13 Mar 2008,
  • tim atherton wrote:

when I recently applied for ADSL2 with O2 they tested my line first and told me what to expect. Surely it is not beyond possibility for all ISPs to poor their info to build a map of expected throughput so each user can see how their own ISP measures up? O2 told me to expect 9.5mbps and we actually get 11.5 out of a possible 16.

  • 2.
  • At 06:15 PM on 13 Mar 2008,
  • Michael Atkinson wrote:

Think of broadband like the M25. Speeds of up to 70 mph may be achieved. Yeah, right.

  • 3.
  • At 06:32 PM on 13 Mar 2008,
  • Dave Hatfield wrote:

The first thing that ISP's could make clear is when they are talking about bits as opposed to bytes.

I suspect that when they talk about 8mbs they mean 8 million BITS per second which is only 1 million BYTES per second.( Or perhaps they're still talking about BAUDS which is pretty obsolete)

Computer memory, discs and many other measurements are typically expressed as BYTES per whatever.

It gets confusing. How about some clarity on the terminology?

  • 4.
  • At 06:50 PM on 13 Mar 2008,
  • steve wrote:

Why not just advertise the MINIMUM speed that you will attain? When you buy other products (food/petrol for example) THEY are able to state the minimum you will achieve for your money.
On a similar vein, Why are we forced to purchase a full telephone line package just to get access to most broadband providers???

  • 5.
  • At 06:55 PM on 13 Mar 2008,
  • Ron Norton wrote:

Broadband is sold in the same way Computers are sold.
You quote the biggest figure you can think of.
What is the difference between 8Mb and 8MB? The small "b" is a bit, the "B" is a byte. A bit is one unit and a byte in modem speak is 8 units. So an 8Mb line sounds good but it realy is 1MB per minute. All downloads are in KB's or MB's. So the larger number is quoted to impress but in fact bares no resemblence to the files you download, unless you multiply them by 8. It is like saying a car can do 123200 yards per hour when we all say 70 MPH.

The main reasons for poor speeds are, distance from the exchange (copper wire and resistance), the speed of the site you are getting the file from, the number of users in your cluster, and what they are doing when you are online, finally how many people are using broadband, as all ADSL broadband must go to a BT exchange before being unraveled.

  • 6.
  • At 06:57 PM on 13 Mar 2008,
  • Jon Lilley wrote:

ISP's should stop advertising max speeds full stop, and and just one price. Why should a customer pay more for a speed that they will probably never get, when Joe Bloggs next door pays for a slower speed, and probably gets exactly the same service and speed!

  • 7.
  • At 07:26 PM on 13 Mar 2008,
  • James wrote:

This is entirely to do with the technicalities of ADSL! e.g. Cable brings the oppisite i.e literally a 'rock solid' line (which I fortunately have) Why has the journalist and more importanly the so called engineer not emphasized the technicalities of cable?

...I mean seriously...

  • 8.
  • At 07:37 PM on 13 Mar 2008,
  • ram wrote:

maybe alter your minimum speed and increase that minimumm, so when showing a range like 4Mbp- 8Mbp is better than 512kbp- 8mbp ,

  • 9.
  • At 08:37 PM on 13 Mar 2008,
  • karen bicknell wrote:

what about virgin 10mb fibre optic?

  • 10.
  • At 09:17 PM on 13 Mar 2008,
  • Jeff Horton wrote:

This proclaimed speed from the ISPs is indeed a true ripoff. We're 7km from our exchange and only get 512k.
The wires are 20years old. Until they replace the entire system with fibre optic cables ( at a cost of 拢zillions) we're all stuck with what we have at present in rural areas. Pricing should be based on actual speed obtainable not how much you download.

  • 11.
  • At 11:55 PM on 13 Mar 2008,
  • Andrew Oakley wrote:

Steer well clear of any ISP offering up to 8mbps (eight millibits per second) - that's seven million times slower than 56k dial-up!

Instead, look for an ISP offering up to 8Mbps (eight megabits per second).

The capitalisation of the M makes a huge difference. For example, two Olympic swimming pools hold around 5Ml (megalitres), whereas a teaspoon holds 5ml (millilitres).

This isn't computer jargon - just standard units. It's taught in primary school maths lessons.

  • 12.
  • At 12:11 AM on 14 Mar 2008,
  • Michael wrote:

I think the general public will be a bit miffed when they realise that the marketing people have exploited the fact that few people know the difference between bits per second and bytes per second.

A byte is 8 bits, which means that what people think is a 2MB connection is actually 2 Megabits, or 125 kilobytes per second, ditto 4 MB only equals 250KB per second.

We have all been lead to believe that we have blazing fast internet connections wheras in reality its been simpler to deceive rather than come up with the goods.

Sound familiar?

  • 13.
  • At 12:40 AM on 14 Mar 2008,
  • Chris wrote:

The most important thing is that any advertised speed is standardised by Ofcom, in the same way, for example, cars are tested for safety with an NCAP rating.
I would propose that all ISPs are tested to see what actual speed will be recieved in the home (this should be for an average house an average distance from an exchange). All adverts then display their 'tested' figure so the consumer can see which ISPs are faster than others.
The up to 8mbps is nonsense! Can you imagin financial institutions getting away with "Invest in this fund and get up to 15% pa", no, because there would be a fall out when everyone received just 5% for example.

  • 14.
  • At 04:56 AM on 14 Mar 2008,
  • SB wrote:

So when exactly are BT/VM going to introduce 100Mb as standard? Probably in about 10 years time would be my guess. By then 1000Mb will be more common and as usual, the UK will be left behind.
Why don't they just bite the bullet and invest heavily into the national telecommunications backbone and let the UK be one of a (very) few countries to have an excellent telecommunications infrastructure.

  • 15.
  • At 07:46 AM on 14 Mar 2008,
  • Hugh Groves wrote:

Surely if one of the major obstacles to line speed is the distance from an exchange, then surely if I went to an ISP's website that I was interested in purchasing broadband off of I could just enter my postcode and they would be able to give me a much more accurate figure?

  • 16.
  • At 09:35 AM on 14 Mar 2008,
  • Stuart wrote:

Ignoring the fact that the article actually has micro- and killibits: Why do people have a problem with "up to" 8Mb as an advertised speed?

As long as the companies are honest and don't try to hide the "up to" in tiny letters then they are advertising what you can potentially get. No-one is saying we should stop adverts for food products with competitions on them because the "you could be a winner of millions of pounds in cash" is only likely to a few, so why complain that only a few are likely to get close to full speed?

Even an old 56Kbps dialup never gave you 56Kbps, yet no-one complained they weren't getting full speed and that they were being sold short.

Interference and line quality are part of the situation. The companies can't alter the advertising based on individual areas, since even a single broadcasting area will have a variety of speeds. Some ISPs offer you an estimate of how fast they think your line will support based on other lines in the area. People should just research properly and understand that there's a reason it says "up to".

  • 17.
  • At 09:36 AM on 14 Mar 2008,
  • Wayne wrote:

Speed is a secondary problem as long as your getting 512k+ it's fine most people won't notice when surfing, a more important issue is transfer limits hiding in FUPs (fair use policies).

Well I would first get them to read a dictionary on the definition of "unlimited"

With lots of video services now avaliable (iplayer,4od,sky, etc)
People should be concerned about hitting those hidden limits and possible extra hidden charges.

BT seem to be trying to divert attention away from their lack of investment in the core network capacity.

  • 18.
  • At 09:44 AM on 14 Mar 2008,
  • Stephen Ash wrote:

When you ring an ISP to sign up they take your phone number. From then they can actually perform a line check to see the maximum you can actually get. The BT call centre was adamant I could get 8Mbps but I calmly informed them that I knew it was 4Mbps (as I work in IT). After checking she grudgingly admitted I was correct after all. So I signed up to Sky instead who actually gave me the correct statistics and were much cheaper

  • 19.
  • At 09:50 AM on 14 Mar 2008,
  • Malcolm Powell wrote:

It's really very simple. Measure the line speed at the point a customer applies for the service and offer them a choice of speeds up to what the line will actually do. The technology already exists to do this. A mechanism also needs to exist to review the line speed at the customer's request to cope with cases where it deteriorates or improves.

  • 20.
  • At 09:52 AM on 14 Mar 2008,
  • Rob wrote:

Once a connection has been set up, it is easy for the ISP to determine the speed of your line, the speed you achieve is the price you pay. Instead of 'up to 8meg', it could be 'up to 拢30 p/m!!'

  • 21.
  • At 10:25 AM on 14 Mar 2008,
  • Steve wrote:

How about charging me for the speed I am actually getting. The lower the speed the lower the charge. That should make the ISP's cringe a little!

  • 22.
  • At 10:52 AM on 14 Mar 2008,
  • Ian, Swansea wrote:

I think that companies should do more to make sure that your line is capable of getting the speed you are buying. If you want to pay for ("up to") 8mbps, the ISP should make sure that your line is capable of that, by sending an engineer out to check.

If your line cannot meet the speed, they should offer you a proportional discount, or suggest a downgrade to a slower speed package. That way, people don't have to feel robbed when they pay for a faster package, only to find that they aren't getting a faster service.

  • 23.
  • At 10:53 AM on 14 Mar 2008,
  • Daniel Pette wrote:

I would like to enquire why do we need 8Mbit/s if the thoughput is still around 2 mbit/s, i think first of all they need to lower contention ratio and increase throughput before even thinking of upgrading Broadband. I personally have a full 16Mbit/s connetion to the exchange, however the download speeds are nowhere near the mark. Hence the question!

  • 24.
  • At 10:55 AM on 14 Mar 2008,
  • wrote:

To #10 the reason Virgin Media wont upgrade their lines to support 100Mb is because they dont have competition from BT. Only when BT acheive the capability will the price drop enough for 100Mb to be anywhere near marketable. Again BT receive the most income and still in essence run a network monopoly. It is up to the regulator to force BT to make the required upgrades. Until those who are BT customers do this by writing to their MP's and to Ofcom it will never happen. So all of you taking the time to type and whinge here stop for a moment and do something that will make a difference. (I'm with Virgin and as such get what I'm promised)

  • 25.
  • At 11:00 AM on 14 Mar 2008,
  • Tim wrote:

According to broadband providers websites, I am unable to get more than 512Kb over a BT line. I suspect this is due to my distance from the exchange. I am not prepared to pay the cost of even the slowest (say 2mb) package when I know I will not get that speed. I think packages should be sold in bands (e.g. 6-8mb) and if that speed is not possible for your address, you should not be offered that package.


What is being done to deliver high speed broadband to the whole country? I have no real choice of broadband supplier - I would have to buy cable broadband (probably bundled with a TV and/or phone package that I do not want). Then I would have to hope that it delivered the speed it promised.


What annoys me even more is so called "unlimited" broadband that has a limit (usually as part of a "fair use policy"). So it is NOT unlimited! Even if the limit was a terabyte a month it would still be limited. I think the term unlimited should be banned unless it truely is unlimited. Surely it contravenes the trades descriptions act or something similar?

  • 26.
  • At 11:14 AM on 14 Mar 2008,
  • Andy, Cairo wrote:

The difference between upload and download speeds is also not fully explained.

It would be good to live in an area with cable or fibre-optic. Unfortunately, I live half-way between 2 exchanges and can barely get 2Meg though this is a fantastic increase over dial-up.

This comment was sent from a ship in the Mediterranean Sea equipped with satellite broadband capable of 350kps, usually fast enough.

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