In reply to a post by Thinker27:

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.

Totally agree.

In reply to a post by Thinker27:

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.

Totally agree that people should define an acronym before using it as it is good practice but not sure the A to Z document you're requesting actually exists here or anywhere on the internet as most of us have been hunting for it for some time.

The best way I have found to learn about broadband is to get involved in the conversations on this forum (rather than lurking) and simply ask questions of those in the know and you will pick things up as there is no shortcut to learning.

[Edit] Don't think anyone on purpose uses poor English and creates typos, its just the way things are. I check my posts several times before I press post and I still find typo's afterwards. Please remember its a forum not an exam

Edited by deleted (Thu 14-Feb-19 23:01:04)

In reply to a post by dect:

Totally agree that people should define an acronym before using it as it is good practice but not sure the A to Z document you're requesting actually exists here or anywhere on the internet as most of us have been hunting for it for some time.

The best way I have found to learn about broadband is to get involved in the conversations on this forum (rather than lurking) and simply ask questions of those in the know and you will pick things up as there is no shortcut to learning.

[Edit] Don't think anyone on purpose uses poor English and creates typos, its just the way things are. I check my posts several times before I press post and I still find typo's afterwards. Please remember its a forum not an exam

Thanks for the honest reply dect to which I totally agree with you, spending time reading and learning does indeed further our knowledge but I must be a really slow learner.

You joined Wed 05-Dec-18 09:53:52

I joined Sat 21-Jun-03 23:45:43

I certainly am a slow learner although I must admit I don't spend my life on here.

It didn't make a hell of a lot of sense to me, either. Looked like someone vomited acronyms onto a post.

Sorry I sounded like a schoolmistress, frustration got the better of me. I do have the greatest respect for those who give up their time to help, and I appreciate everyone is busy.

I try and note snippets of information to build up a picture, and also research new concepts via google.

If I may set out my understanding of how it all works, perhaps others could correct it and add the proper names for the parts and more detail.

In the telephone exchange (does it have to be a telephone exchange? are there other places? presumably it is usually here because of the existing ducts. what is the proper name for this part of the network?) there is some electronic equipment, essentially a router (called a?) for connecting subscribers' data to the Internet backbone (operated by Openreach?) via "backhaul". The backhaul medium is optical fibre.

Does the ISP (internet service provider) have any physical equipment here of are they just billed for the connection and throughput?

All routing is done by electronics and all transport is done through fibre, so the router has an electronic to optical converter on its output and vice versa on its input. There are always two connectors on each interface, one for upstream data and one for downstream. (Is this true? I imagine there are standard lasers and phototransistors and the two directions would interfere if on the same fibre. Or at least it is easier to provide only a single converter on each connector.)

The data is all IP packets, unchanged between the fibre and the router, and the packets to/from different users are all mixed together in the routers to get them through the system as efficiently as possible. Each packet contains a destination IP address, a source IP address, and the payload (user data) and the routers look at the addresses to route the packets from node to node through the internet.

Fibre cables radiate from the exchange into the community. What does a cable look like? How big, how many fibres? Any copper in it for power? They go in a tube about 25mm diameter with a yellow stripe called a subduct, and through larger ducts. They may run up and between poles. Are there joints in this path, or are great lengths pulled out from a reel? If jointed, how and in what housing? Are there any cabinets? What and where are splitters and aggregators? Is any electricity used?

In the destination building is an ONT (optical network terminal), also called a modem, which is an optical-electronic interface. There may be a TP (termination point) or BFP (building flexibility point) that anchors the end of the external cable, with a fibre link to the ONT. The ONT presents an Ethernet socket for a copper cable to connect to a router.

Hyperoptic deliver a fibre cable to a router in a multi-unit building and then Cat 5E copper cable to individual flats. Openreach provide a fibre to each flat.

There are a number of different topologies of fibre network, one (name?) being a single fibre (pair?) that runs all the way from the exchange to the premises and another being a passive optical network where a fibre is split by prisms into multiple branches to separate premises (GPON?) The consumer doesn't get to choose or know which system they will be provided with.

You seem to be asking someone to write, in a forum, a complete explanation of how the Internet is implemented in the UK, along with a description of every item of equipment down to the level of the various types of optical cables that may be used in every possible circumstance nationwide, by a number of different companies as well as Openreach.

That simply isn�t going to happen. Quite apart from the speed a lot of that changes literally every three months.

A good start would be to read the guides on the parent (Main) site of these forums, and then spend a few hours browsing the kitz website.

I have a noddy guide in my sig, covering things at a simpler level and with a glossary of many terms, but not the ones you are listing. My site is also in need of considerably updating but the essentials in it are still correct.

Edited by RobertoS (Fri 15-Feb-19 02:11:21)

In reply to a post by jabuzzard:

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.

Except XGPON runs alongside GPON, so you provision new customers on XGPON and perhaps move a heavy user onto that platform too, or run some combination of the above, and run them beside one another rather than using an additional port. Migrate over a period of time as other operators have migrated people from BPON to GPON and you're good.

I'm not aware of any evidence or basis in fact or capacity planning for restricting a GPON split to just 9 users, especially when the average user is purchasing less than 100Mb. 250Mb per user is profound overkill.

There are standard capacity planning methods and Openreach probably use them. Simplified it's to take the average load at peak time and ensure there's enough headroom for a user on the highest available tier to burst.

As even FTTP customers are only using a few megabits per second at peak times and OR are quite asymmetric 2.4G/1.2G is fine, even if there's a 1G/220M customer on the split.

The spare fibres are for fault usage. The normal process is to manage increased demand by opening up an XGPON signal as an overlay.

WDM-PON is not practical right now. It needs cooled DFB lasers and the split has to be much smaller than with XGPON.

XGPON - 10 Gbit PON. Shares 10Gb downstream and usually 2.5Gb upstream, but 10 is possible with more expensive equipment in homes, between usually 32 end users.

GPON - Gigabit Passive Optical Network. 2.4G downstream, 1.2G upstream shared between usually 32 end users.

BPON - Broadband PON. 622Mb downstream, 155Mb upstream between 32+ users.

WDM-PON - Wave Division Multiplexed Passive Optical Network: Uses different wavelengths / colours of light for each connected customer so they don't share capacity, each have their own wavelengths. Needs extra equipment on both sides of the fibre link.

DFB - Distributed Feedback Laser diode. More stable and expensive than the Fabry-Perot interferometer that may be used for other PON.

Post deleted by Ignitionnet

In reply to a post by busterboy:

I certainly am a slow learner although I must admit I don't spend my life on here.

If I lived where you lived I wouldn't be on here either I may have more time because I'm retired but that has its disadvantages as well

Hi

You are ahead of the curve of most people and the applications needing that sort speed haven't arrived yet for the masses. There have been the same conversations about data speeds and it being more than enough for decades yet we keep needing more. At one time 256Kbps was considered ample for ADSL and before that 64Kbps ISDN ran whole offices, I worked in one with 4 terminals connecting back to HO over ISDN and it all worked fine. There were conversations about did we need 2 lines for 128Kbps for a new office but decided no office needed that much

Remote desktop sessions don't use much bandwidth, most of the time they are transferring very little data unless you are transferring files, then the file transfer speed is mostly bottle-necked by the protocol and server. So not surprised you don't use all that capacity or get close.

Regards

Phil