Business v residential contention ratio

[#1]

Hi

I have residential FTTC at the moment.  Someone I know has told me that, apart from better support, the other advantage of business FTTC is that I'd get a better contention ratio (20:1 v 50:1).  Is that correct ?

Brian

[#2]

Moderators Note
This topic has been moved from ADSL Broadband to Business.

[#3]

@brabb  Whoever told you that hasn't got a clue, contention ratios are a thing of the past and have never been relevant to FTTC connections. There is no difference between residential and business connections, apart from the support and I'm not sure if that's much better.🤔

[#4]

Thanks realale (is there such a thing in Madrid ?? 😜)

Can you expand on that please?

I always thought that the contention ratio was just the available bandwidth divided by the number of concurrent users - but others seem to think that it is something the ISP can influence ?

Confused from Durham 😁

[#5]

@brabb 

This is how ADSL worked years ago. Things have now moved on. The speed that you will get is the maximum that your line will support up to your contracted maximum.

[#6 · Accepted solution]

See What is the contention ratio of my broadband service? | BT Business (custhelp.com)

Whilst looking for relevant references, I stumbled on this from 20 years ago - Plusnet  |  Home & Business Broadband Internet Access & Phone Services UK - it is stunning to see how much things have changed - we now get 80mbps FTTC services for less than we used to pay for 2mbps contended ADSL.  This article contains the key phrase "a 50:1 contention ratio at the exchange" inferring that the contention is a consideration on BT Wholesale's back haul network where these days the pipes are much fatter and faster.

This post https://community.plus.net/t5/ADSL-Broadband/Contention-ratio-on-fibre-vs-value/m-p/868524#M162078 (and the one following from the well informed JoJo) point to the demise of contention ratios in 2012.

[#7]

Thanks all (esp Townman).  That's very useful background.

It strikes me that, to the casual user (eg me 😜) there can be confusion between 'contention ratio' (which used to actively impose different bandwidth on residential v commercial users, as has been explained here) and (local) 'contention': when I first got FTTC 4 years ago I got about 35mBps, now lots more people are using that fibre connection, there is more contention and I now only get 20mBps ...

Brian

[#8]

Hi Brian,

What you report here is not "contention" but the impact of "cross talk".

VDSL runs at much higher frequencies than ADSL and such signals can bleed between circuits (radio interference) known as cross talk.  As more users take up the FTTC service in a cabinet, the cross talk increases and degrades performance.  Higher error rates leads to more frequent retransmission and thus a lower DATA throughput rate.  In such circumstances, slower SYNC rates can lead to more effective DATA transmission rates by the lowering of transmission errors.

It is complex stuff and the above is somewhat of a simplification of the reasons we see slower speeds on FTTC services.

[#9]

@Townman  You must have done a bit of digging to find that historical info.

@brabb As Townman has explained I think you may be confused by reduced connection (sync) speeds on FTTC because of increasing numbers of users on a particular cabinet. The interference between the signals in the cable bundles (known as crosstalk) reduces the modem sync speeds.  This is not contention, but more the laws of physics and the behaviour of modem electronics.

[#10]

Thanks both.  That's interesting.