This topic

Contention within BT FTTP Network?

converse420 — Sun, 07 Jun 2020 19:56:25 GMT

Contention within the Virgin Cable/DOCSIS network is well known and demonstrated a clear benefit to using BT as a preference.

From memory, I seem to recall that the downstream speed for FTTP is about 2.5Gb. With service offerings rising to approx 500 Mbps, does anyone know how contention is managed ?

Regards

Dale

Re: Contention within BT FTTP Network?

NigelB72 — Sun, 07 Jun 2020 21:25:52 GMT

I don't know about full fibre but I'm on G-Fast with a quoted speed of 130mbps... I regularly get 140+. My brother is on VM and about half a mile from me. He's on their 100mbps (last time I checked) and he gets around half that on a good day...at peak times it can be less... I clock at the lowest 120mbps during peak times.. we are within a mile of Leicester city centre... Hope this gives you an insight into the difference..

Re: Contention within BT FTTP Network?

pippincp — Mon, 08 Jun 2020 07:51:35 GMT

Simple, increase bandwidth. BT's service offering is now 900Mb.

Re: Contention within BT FTTP Network?

converse420 — Wed, 10 Jun 2020 19:22:19 GMT

Thanks pippincp,

I'm not sure how to ask the same question differently....

BT FTTP Is GPON right?

I seem to remember from my BT days that for each 'trunk' there was capacity of 2.488 Gb/s which depending on configuration was 'split' passively amongst a number of clients (up to 32:1 as I recall). So my question is has Openreach updated to a higher spec, as if not I cannot see how BT could provide 900Mb to more than 2 or three clients served by a particular 'trunk' without significant contention?

Thanks

Re: Contention within BT FTTP Network?

licquorice — Wed, 10 Jun 2020 19:34:21 GMT

As far as I'm aware, that capacity is now 10 Gb/s rather than 2.5Gb/s. Obviously relying on the fact that not all clients will (a) be 900Mb (b) all operating at full capacity simultaneously. I don't know if the number of clients are reduced from 32, but that is a possibility. Perhaps providing 2x 10Gb/s links for 2x 16 clients.

Re: Contention within BT FTTP Network?

iniltous — Wed, 10 Jun 2020 20:07:27 GMT

As with all things , there is a trade off to keep a service affordable , it doesn’t necessarily follow that all 32 splits are used, but even if they are, the chance of every customer demanding their maximum bandwidth simultaneously is remote, theoretically everyone won’t get the throughput they are ‘paying for’ if everyone did hammer their connection at the same time, but what in the real world would they be doing to run out of bandwidth, 100 HDR streams over the 32 would just about be possible, how likely is it that each one of the 32 is watching 3 HDR streams ?
The VM over utilisation problem ( supposedly resolved ) may well have had more customers sharing a link or the original links didn’t have a similar bandwidth, so it’s not a direct comparison, I dare say many domestic consumers with 900Mb+ connections rarely come close to needing a 20th of that , and if some killer application becomes commonplace and FTTP does hit over utilisation problems , it can be upgraded.

If the point is, 32 x 900Mb is more that 2.5Gb, that is true, but what would be the point of providing enough bandwidth to satisfy a maximum of 32x 900Mb, when all that bandwidth needs to be paid for ( ultimately by the end users much more ) for it to sit idle

Re: Contention within BT FTTP Network?

converse420 — Sat, 13 Jun 2020 15:13:42 GMT

I think it may still be 2.5 Gb/s, but I did see that there was an Openreach announcement about using Nokia kit to achieve 10Gb/s at the end of May:

https://www.ispreview.co.uk/index.php/2020/05/openreach-adopts-nokias-10gbps-fttp-broadband-kit-for-uk.html

Re: Contention within BT FTTP Network?

pippincp — Sat, 13 Jun 2020 15:47:55 GMT

@converse420wrote:
I think it may still be 2.5 Gb/s, but I did see that there was an Openreach announcement about using Nokia kit to achieve 10Gb/s at the end of May:
https://www.ispreview.co.uk/index.php/2020/05/openreach-adopts-nokias-10gbps-fttp-broadband-kit-for-uk.html

How would a 10Gb ONT mean the infrastrucre is still 2.5Gb. Openreach would not be able to offer 1Gb connections on a 2.5Gb infrastructure. You have totally misread the article.

Re: Contention within BT FTTP Network?

converse420 — Sat, 13 Jun 2020 18:05:45 GMT

Thank you,

I am not aware of any evidence that the Openreach GPON deployment is not 2.5/1.2Gb/s. I'm happy to be corrected with evidence.

I understand the situation based on my own technical understanding and other news and documents that become available.

Your have played back my original question by stating that :Openreach would not be able to offer 1Gb connections on a 2.5Gb infrastructure.

having looked at the tech, I now have a better understanding of how BT can sell 900Mb in this environment and can se how they might be managing this.

I 'suspect' that we are still on the original 2.5 Gb/s spec and the new Nokia solution will allow 10Gb, requiring new OLT and ONT devices.

Another reference for information

It would be nice if anyone on this forum could provide fact rather than speculation (and I include myself in this)!

Re: Contention within BT FTTP Network?

pippincp — Sat, 13 Jun 2020 19:25:34 GMT

You can suspect whatever you like, TBH I don't care. The Nokia solution you are reading about is to be able to offer up to 10Gb synchronous connections instead of the present asynchronous offering.

As this is all hardware related you now have to figure out how a hardware change will allow a 2.5Gb network to be able to provide a 10Gb synchronous connection with no additional fibre.

I look forward to your reply.

Re: Contention within BT FTTP Network?

converse420 — Sat, 13 Jun 2020 20:15:47 GMT

I'm actually sad and disappointed by your response, as you have provided so much value to this forum in recent years.

1. I don't know if the available bandwidth on FTTP is 2.5GB, but I have this on good faith. My post suggests that there is a 10GB solution in the future using Nokia technology as posted.

2. My original post asked about contention on the 2.5GB GPON network, not 'how a hardware change will allow a 2.5Gb network to be able to provide a 10Gb synchronous connection with no additional fibre.'

I just want to understand the technical details.

Happy to continue his discussion....

Re: Contention within BT FTTP Network?

pippincp — Sat, 13 Jun 2020 21:20:41 GMT

OK to understand it we have to go back. and look at arcitecture of the network and realise there is a relation between a fibre and the hardware used to supply a connection. As an ex VM customer I assume you know the differences between EuroDOCSIS 2.0, 2.1, 3.0 and 3.1. (different hardware for increased speeds).

As each hardward comes along it expands the bandwidth of the existing network with VM it was more complicted due to the tech involved, multiple node splits etc. It was all hardware related.

Similarly with openreach using GPON bandwith expansion was achieved via hardware changes, initially at 2.5Gb per fibre up to 10Gb per fibre asynchronistaclly. They have been there for about the last 2 yrs, this is how Openreach can offer 1Gb connections to ISP's presently.

What the Nokia hardware you've referred to is the ability to offer 10Gb synchronous connections with a hardware upgrade.

Back in 2014 it was proved possible to transmit 43Tb/s over a single fibre. Article HERE

Where I think you are becoming confused is the difference between synchronous and asynchronous. Asynchronus gives a lower upload speed to download speed ratio which is what Openreach is using at present for retail connections. The new Nokia hardware will lift that where they will now be able to allow a synchronous (i.e. equal up/down) connection.

Re: Contention within BT FTTP Network?

converse420 — Tue, 16 Jun 2020 15:14:55 GMT

Thanks pippincp,

I think what was missing for me was the usual 'news articles' that we normally see from BT indicating an upgrade from 2.5 to 10Gb at some point over the past few years, as there is a lot of legacy information, but the truth is often hard to find!

On the plus side my address went live in the Openreach tracker for FTTP today, so I've finally been able to place an upgrade order for FTTP.

Fingers crossed, I may be about to reenter the 21st Century!

Thanks again

Re: Contention within BT FTTP Network?

Rob364 — Tue, 16 Jun 2020 15:40:57 GMT

Open reach have also gone into partnership with ADTRAN.

https://www.adtran.com/index.php/openreach-partners-with-adtran-to-build-ultrafast-ultra-reliable-broadband-to-customers-throughout-the-uk

If you want to waste a bit of time.

https://portal.adtran.com/web/fileDownload/doc/33822

https://www.adtran.com/index.php/blog/970-why-combo-pon-makes-next-generation-pon-better

Re: Contention within BT FTTP Network?

pippincp — Tue, 16 Jun 2020 18:28:19 GMT

Adtran has just joined the list of contractors Openreach already has.