Talk:Passive optical network

The text continuously talks about NTD but diagrammatically only draws the NTU presumably because of the CPE boundary. But in the spirit of making textual and diagrammatic versions self consistent and because both are clearly needed in the descriptions of services and boundaries I think the diagrams should be extended to include the NTD with some sense of boundary between "the network" and the customers premises. — Preceding unsigned comment added by Geeohgeegeeoh (talk • contribs) 23:48, 14 September 2018 (UTC)Reply

The last I saw some PON gear which works on TDM, they all had a power cable sticking into it. so what exactly is passive about it?

^{the above comment was by 59.145.141.130 on 2006-06-27T03:12:29 Riick 06:25, 10 March 2007 (UTC)}Reply

Answer: The passive part is the optical fiber itself. "PON" is something of a misnomer because any fiber optic transport system has a "passive" piece of it - the fiber itself. "PON" colloquially means a point to multipoint optical transmission system.

^{the above comment was by 70.250.189.35 on 2006-07-19T23:33:03 Riick 06:25, 10 March 2007 (UTC)}Reply

Answer 2: Passive in this case means to things. 1. There is no active/electrical component on the connection between OLT and ONT (e.g an active attenuator). That is why the signal send may be quite high at the OLT. 2. The signal is passivly distributed through a splitter and not activly multiplexed. That is why it is quit at the outer location since no active cooling is needed and it doesn't need that much space (on the contrary consider DTAG's DSLAMs for VDSL) —Preceding unsigned comment added by Typicalname (talk • contribs) 13:49, 2 March 2009 (UTC)Reply

TDM is simply a service over PON, and is irrelevant to this issue.

^{the above was Jayshuler's 2006-10-11T12:48:58 edit of 70.250.189.35's comment Riick 06:25, 10 March 2007 (UTC)}Reply

This article should not be merged into PON (passive optical networks). FTTP is a network architecture that has two major implementations: PON (including GPON, EPON, GEPON, etc) and Active Ethernet (many naming variations). FTTP should remain the umbrella article, with links into more specific article.81.2.106.242 06:15, 6 October 2007 (UTC)Reply

The introduction currently says, "A PON configuration reduces the amount of fiber and central office equipment required compared with point to point architectures." However, my understanding is that PON does not use less equipment in the central office than active FTTP does. It requires more powerful OLT lasers in the CO. In some (but not all) cases it may be more compatible with legacy equipment already in the CO. But I don't understand why it necessarily requires less equipment in the CO. Please discuss. Riick 09:10, 10 March 2007 (UTC)Reply

It depends if by "point to point" you are refering to the legacy copper architecture, then yes PON requires much less CO equipment than traditional copper. If we are only considering fiber optics, then the concern may be unfounded. FTTP is refering to the name of the grander network architecture, whereas PON is describing the method in which the technology is implemented. PONs are inherent to and exists within FTTP, and therefore the two use the same amount of equipment. FTTP networks use PONs to multiplex service though a single fiber and then split to many end users in order to reduce installation and maintenance costs and to improve reliability. You see, it's difficult to talk about one without mentioning the other.

Now if we're comparing Point to Point PON vs. Point to Multipoint PON, the multipoint scenario described in the BPON standard uses much less CO equipment and fiber originating from the CO. A PON laser is able to serve 32 ONTs instead of just one end device. This significantly reduces not just the fiber equipment in the CO but also the fiber facilities leaving the CO to the point in the field where the signal splits.

It is also true that certain legacy equipment that was installed prior to FTTP and used for other purposes can be reconfigured for current FTTP applications. --Toddyboy711 20:06, 16 May 2007 (UTC)Reply

The above response by Toddyboy711 is well-written, informative, and appreciated. However, my concern has to do with the fact that there are actually three FTTP technologies: PON, direct fiber, and AON. Since standardized terminology has not exactly been a strong-point of the fiber-optic communications industry, I will have to be clear about what I mean. By PON I mean the technology that Toddyboy711 is calling "point-to-multipoint PON". By direct fiber, I mean any technology where each fiber leaving the CO serves one and only one household (one example is what Toddyboy711 calls point-to-point PON). And by AON (also called "Active FTTP"), I mean a technology that is very similar to PON in layout and amount of fiber used (see FTTP#Active_optical_network for details). Unfortunately, both AON and direct fiber are both called point-to-point by the industry, despite the fact that they could hardly be more different from each other. At the time I wrote my original question, I thought this article was incorrectly characterizing AON. Instead I now think that it does not mention AON at all. I will remedy this when I have time, unless someone else gets to it before me. -Riick 08:12, 18 May 2007 (UTC)Reply

(As an intesting sidenote, I believe the reason that AON and direct fiber are both called point-to-point is due to ambiguities in the definition of what a point-to-point network is. Depending on who you ask, a point-to-point network seems to mean (1) a network where each signal only needs one "hop" to reach its destination (as in direct fiber), (2) a network where more than one "hop" may be required but where each "hop" is over a point-to-point link (as for AON), or (3) a network where every node has a direct connection to every other node (as in what a tangle of wires!)) -Riick 08:12, 18 May 2007 (UTC)Reply

I am new to PON details, but am starting a evaluation of PON vs direct fiber architectures for a project. My experience is that Wikipedia is a good place to start for new investigations because one can get an overview and drill down in to sources from there. I found the introduction misleading as to needing less equipment in the CO." —Preceding unsigned comment added by Fkittred (talk • contribs) 19:26, 9 February 2009 (UTC)Reply

An attempt was made by an unregistered user to include bitrates for PON and GPON. Besides being entirely incorrect, I don't believe it is the purpose of the "PON" article to go into details about each standard. There are other pages with specifics for both BPON and GPON standards. Simply giving a clear and concise definition of what PON means, with minimal mention of equipment and providers seems sufficient.

For the record, bitrates are offered at different service levels depending on the service provider. There are no standard bitrate offerings, and they tend to change quite often even within the same prover. The BPON standard states the total allocated downstream bandwidth of of the shared PON is 622 Mbps and 2.4 Gbps for GPON. Of course a provider can and will oversubscribe the PON. The equipment is NOT the same between the two standards. Moving from BPON to GPON requires both new OLTs and ONTs alike. I don't believe there is any requirement for GPON equipment to be backwards compatible. The only thing that doesn't change are the PON elements themselves (the fiber medium, splitters, distribution hubs, etc.) Toddyboy711 (talk) 21:43, 26 November 2007 (UTC)Reply

Upon further research, BPON and GPON both redirect to PON. This may warrant some mention of speed capability. ITU G.984.1 states GPON is either 1.2 or 2.4 Gbps down. The G.984 page simply links you to the ITU specs. I am indifferent about including this info, as long as it is correct and properly cited. Toddyboy711 (talk) 22:17, 26 November 2007 (UTC)Reply

"As of early 2007, only time-division multiplexing was technologically practical." This information may be up to date, but a statement like "As of early 2007" implies that the research is old and should be updated, either by including new information, or changing the statement to reflect mid 2009 (or the relevant date).Locopingvin (talk) 13:30, 12 August 2009 (UTC)Reply

What was the reason for choosing exactly these splitting ratios: 1:2, 1:4, ..., 1:64 ? Why not for example 1:6, 1:18, 1:40 ? --PtBg (talk) 19:56, 20 January 2010 (UTC)Reply

Splitting ratios:

In PON enviornments, the splitter is basically a prismic device which allows one input signal to be split into two equal output signals. The prism "divides" the input optic signal into two equal output signals at half the power. Therefore, each individual split is a binary action. For every split there is a -3db drop from the initial input power.

Input assumed at 0 db:

   1:2 = -3 db
   1:4 = -6db
   1:8 = -9db....

Example: a 1:4 is essentially a 1:2 with each leg of the outut fed to another 1:2 to make it a 1:4 split. Therefore, assuming an input signal of 0db (at the input to the 1:4) the four (4) individual outputs from the 1:4 would be -6db each. A 1:8 would take each leg of the 1:4 applied another 1:2 splitter at each leg, to achieve a 1:8 split.Thus, each output of the 1:8 would be -9db.

Each 1:2 split is appproximately a half power split (3 db each leg - less any optical anomalies associated with the optical merge, mechanical interface etc - (fresnal refraction, cleave error, dirt, or any other unpredicted anomoly). Therefore, input to a 1:2 splitter would produce two legs out at half the optical power of the input signal. Each expansion of the optical "tree": will add a -3db to the original input signal. —Preceding unsigned comment added by Labratory (talk • contribs) 03:46, 9 February 2010 (UTC)Reply

The splitters have nothing to do with Fresnel or prisms. The splitters are fused-taper couplers made possible by evanescent field coupling and are generally manufactured as a 2x2 device. They're made by shaving off part of the cladding (to make a D-shape) and then fusing two such fibers together. Larger splitters are made by cascading these.Dickersm 99 (talk) 14:28, 1 July 2010 (UTC)Reply

I just realized that the "Current status" section is actually from 2008, so hardly "current' any more. Three years at least out of date. Need to update and use citations that give dates at least. W Nowicki (talk) 23:48, 24 August 2011 (UTC)Reply

Someone should really think about rewriting this article in the English language, it reads like pure gibberish. Is this a real thing or just some joke? — Preceding unsigned comment added by 96.127.207.100 (talk) 05:30, 2 October 2013 (UTC)Reply

Alas, this is the kind of jargon that is used in the telecommunications industry. It is actually better than some since it spells out some of the acronyms and has some wikilinks for more info. But yes, please do rework into more language that actually conveys some information. W Nowicki (talk) 15:58, 2 October 2013 (UTC)Reply

For example:

By mid-2008, Verizon had installed over 800,000 lines. British Telecom, Saudi Telecom Company, Etisalat, and AT&T were in advanced trials in Britain, Saudi Arabia, the UAE, and the USA, respectively. GPON networks have now been deployed in numerous networks across the globe, and the trends indicate higher growth in GPON than other PON technologies.

Removed and we can start adding information that is verifiable from the sources cited. W Nowicki (talk) 23:53, 2 October 2013 (UTC)Reply

Follow-up: it looks like an unregistered used at Special:Contributions/186.15.41.111 just reverted the work on citations and put back the uncited promotional assertions? The first edit summary was "this seems to be promotion" and then more edits without summaries. Not sure what the idea was. If there is a problem with the language, please change it to be less promotional, not more. And please do not remove citations that do support the statements in the sentences where they are cited. In the above example:

By mid-2008, Verizon Communications was using PON for its FiOS service.<ref>{{...}}</ref>

The given citation does support that Verizon was indeed using it. Saying things like "numerous networks across the globe" is vague and promotional. Where else would it be? Although of course this is a telecommunications network, nothing to do with globes, so should avoid that idiom which adds no information. W Nowicki (talk) 22:51, 15 October 2013 (UTC)Reply

Alas, the anonymous user added the uncited content back in. Time to enlist help and see if we should semi-protect this page, unless the user participates in this discussion? W Nowicki (talk) 22:05, 16 October 2013 (UTC)Reply

I'm here because I answered a {{helpme}} request about this article, and I've looked over the recent edit history. First, though, the History/Security section is a copyvio of http://www.armoredshield.com/armored-spon.html, even in the older versions of the article. A rewrite of the section is necessary.

I'm not sure what is motivating the IP editor, but I've warned him to stop his disruptive editing, because that's what this is. If he continues, warn him appropriately on his talk page; we can block him if it gets that far. I'm unwilling to protect the article at this point unless there's evidence of sockpuppetry, and there's none here right now. Thanks. KrakatoaKatie 20:28, 18 October 2013 (UTC)Reply

A bit more info in response to some posts in #what is passive, some 12 years ago.

The jargon garbage in the article noticed in other posts above stems from the fact that it seems to be deliberately written in a biased way with nary a mention of other systems, let alone their advantages or disadvantages. It's also almost entirely unreferenced.

This article utterly fails to mention Active Optical Network (AON), another FTTP techology, which delivers dedicated individual Fibres To The Premises (FTTP) [or To The Home, FTTH], with some companies (in the UK at least), providing full gigabit upload and download speeds. AON uses an active powered switching system, somewhat like a commercial Cisco powered Ethernet switched network (I think, I'm just an ex-PC office network engineer). I think this was the original plan for the Australian National Broadband Network back in around 2009, which I think is the more expensive option.

PON has a number of disadvantages for the customer, in that a passive optical switch (a bit like an Ethernet passive hub, which also needs power) shares a single main fibre's capacity in a street cabinet with a number of individual subscribers. This is called FTTC, Fibre To The Cabinet. "The last mile" to the premises, (and that article is also entirely filled with almost meaningless techo-jargon) as the article doesn't explain in the lede, is often through slow standard copper (or aluminium) telephone wires. At busy times the individual devices overload the shared fibre, and you get buffering, or latency and unsatisfied customers. This, I also believe is what got foisted on Australia by later governments, especially because it's meant to be cheaper, although costs have spiralled.

This information is signally lacking in the article, but I don't have the technical knowledge (or time) to write a section or article on Active Optical Networks.

More info: How Fiber-to-the-home Broadband Works (FTTH / FTTP) MinorProphet (talk) 13:52, 22 September 2019 (UTC)Reply