Hi

Many thanks for the info. Although surely a 32 way split with GPON at 2.5Gbps, would only guarantee 78Mbps per customer. Of course not everyone is using their connection at the same time it's how they get away with it, but as soon as you had 2 customers using their 1Gbps service, they will drop to almost half speed, and that is assuming the remaining 30 customers are not using their connection.

At least they have the option to upgrade to XG-PON in the future.

Regards

Phil

Bingo and welcome to the world where Gigabit is sold across the globe

The Gigabit XG-PON is a tick the Gigabit paper exercise at present in my opinion.

In reply to a post by PhilipD:

Many thanks for the info. Although surely a 32 way split with GPON at 2.5Gbps, would only guarantee 78Mbps per customer. Of course not everyone is using their connection at the same time it's how they get away with it, but as soon as you had 2 customers using their 1Gbps service, they will drop to almost half speed, and that is assuming the remaining 30 customers are not using their connection.

Nope: two customers using 1G download will be perfectly fine. *Three* customers using full 1G download will get a share of ~800M each.

The reality is, nobody canes a 1G link 24x7. And if they did, the cost of the transit would be way more than the monthly rental of a residential service; the ISP would get rid of them under their abuse / fair usage T&Cs. A 1G leased line lets you fill it 24x7, and that's one reason it's so expensive.

Shaping policies can stop big users swamping out the smaller ones.

The same sort of aggregation happens upstream anyway. Do you think if an ISP sells a thousand 330Mbps residential FTTP services, they will buy 330Gbps of transit upstream? No. Statistical multiplexing comes into play. They'll scale it based on their actual usage during their "busy hour" - and maybe accept a small amount of degradation to the greediest users during that time.

Hi

Sorry was getting maths confused regard 2 customers getting half.

One thing we know for sure, is no matter how fast our Internet connections become, we just use up what is there.

Of course no one canes a 1G link 24/7, and if they did they would likely get booted off, however the reality is people do cane their connections at specific peak times, it's what causes contention and slow downs now.

There is little point in buying a 1G fibre connection if at times you are most likely to want to us it, you are getting considerably less. It just becomes 1G in name only. Luckily the way the industry is policed now, they will not be able to sell that connection as 1G if people see less, so that's something.

Regards

Phil

Edited by deleted (Wed 13-Feb-19 18:40:30)

You have to remember that most customers currently take a 40Mbos / 55Mbps variant - that leaves ample PON capacity to support customers on high rates including Gigabit services.

As soon as the PON circuit reaches capacity it can be upgraded to XGPON - customers paying for Gigabit services are already contributing towards that future upgrade.

Its no different to monitoring on Cablelinks and L2S for scheduled capacity upgrades

In reply to a post by PhilipD:

One thing we know for sure, is no matter how fast our Internet connections become, we just use up what is there.

You might think that, but you would be wrong. I have a 10Gbps connection on my console server at work (most of my working day is spent in remote sessions onto that server managing a HPC facility) and I have never maxed it out ever. Everything else is too slow. Do a speed test and it struggles to show over 1Gbps let alone 10Gbps. Best I have got was about 8Gbps to another server within the University.

I only max out my actual desktop which has a 1Gbps link transfering files within the University.

In reply to a post by TechServ:

As soon as the PON circuit reaches capacity it can be upgraded to XGPON - customers paying for Gigabit services are already contributing towards that future upgrade.

Except XGPON requires new ONT's as well OLT's. If you have insufficient capacity for say 330/50 users it is probably cheaper to put a new splitter in with extra backhaul. I find it hard to believe they only pull a single fibre to each DP point (it would be madness to do so).

I also thought that Openreach where using lower split rations than 32:1, with 16:1 being stuck in my mind. Personally I would avoid going higher than 9:1 if it where me.

In reply to a post by PhilipD:

A typical domestic street may not have enough spare fibres to offer everyone a 1Gig connection speed. The other reason 1Gbps is available but not the norm and hard to get, is so BT can take part in the Gigabit Broadband Voucher Scheme.

At split rations at or below 1:9 you could deploy CDWM PON for symmetrical 10Gbps to all nine splits simultaneously. I don't think anyone has suitable splitters to deploy outside quite yet but the technology exists for indoor usage. I am sure if Openreach put out a procurement request it could be filled pretty quickly.

Basically you pair up the 18 CDWM wavelengths and use suitable BiDi SFP's. Though I doubt you would get the exchange end in an SFP if you wanted to avoid splitters in the exchange. Probably need at least a QSFP+ or more likely a X2 or XENPAK format.

In reply to a post by jabuzzard:

I find it hard to believe they only pull a single fibre to each DP point (it would be madness to do so).

I don't think the splitters go at the DPs. Some DPs only serve 2 or 3 properties.

From what I've read, a splitter node contains four 1:32 splitters, so can serve up to 128 properties. There would then be multistrand cables from this to the individual DPs.

Could I please put in a plea on behalf of all the readers and lurkers who would like to learn from the information on this forum. Some of the posts are quite impenetrable even to those with a good technical knowledge, due to the excessive use of acronyms, and the poor English and the typos. It would be wonderful if the expert posters could define acronyms the first time they are used, and read through and correct the post before uploading it.

In this thread, what is someone not already in the know to make of CDWM? Is "split rations" really the right term? XG-PON HPC ONT OLT BiDi SFPs QSFP+ X2 XENPAK......???

Could someone write or provide a link to a brief primer about FTTP infrastructure written in plain technical English? Naming and describing the ducts poles manholes cables cabinets splitters aggregators drops prisms terminals, the nature of the electrical and optical signals and the processing of them, power supplies, and anything else commonly involved. With that to hand maybe we mere mortals can understand what the rare specialists are on about.