[PCWorld]

Post your comments for Fiber Forces Fibs? here

[coastie65]

I have FiOS and it is FTTH. When Verizon came out, the Fiber cable was too short (300') and he had to go back and get a 600' cable. These are premade with a plug at each end. One end plugs into the Hub at the line and the other end plugs into the box on the house. Any extra cable is coiled and stored in a compartment in the box at the house.It is all fiber to the router plus the Cat5 cable from the router to the computer. I also have FiOS TV and the only Coax runs from the router to the splitter under the house and then to the TV's. With Comcast, the only fiber runs from a connection over on the next street and is buries along side the cross street at mid block to a connection. The only changes made on the lines was to change out the taps where the cable connected at the line to go to the house. I just saw an article that said Verizon presently has FiOS available to 10,000,000 homes and expects to have it available to 18,000,000 homes by 2010. Don't have to figures on AT&T coastie65

[mystica555]

Your article improperly states FIOS as "Fiber to the Curb". FTTC is what AT&T U-Verse is doing: Fiber to Curbside and/or Pole Mounted DSLAMs, then V-DSL to the house. This V-DSL is about 50 megabits total. This is similar to what the cable companies do, as they string fiber to "Nodes" that change the signal into up-to 1ghz of RF. Except this much RF has a far greater potential speed - and a much larger group of houses to feed. Weigh this as you will.
With the advent of DOCSIS 3.0, you can expect to get at least 150 megabits up to possibly 300 (4x to 8x channel bonding, download) and up to 150 megabits for upload (4x channel bonding) per node. This, added with Switched Digital Video, will keep cable competitive for a long time.
While FIOS is the current leader, and while a fiber running -directly- into someones home can provide for multiple gigabits of data, actually utilizing this massive amount of bandwidth will take effort, lots of money, and you wont see it for decades.

[coastie65]

As I see it, the problem with cable is NOT the speeds or probable speeds, but band width. Yes cable can and probably will stert upping the speeds, but as long as you are limited in the amount of usable bandwidth, you still don't have anything and you will still be limited on what you can download. coastie65

[mystica555]

When it comes down to sheer bandwidth, both fiber as well as cable have ample room to spred their legs. If anything, the limiting factor for cable will be the current 54mhz split between "return" and "forward" transmission. If this could be adjustable on a network-wide scale, ie, each tap, node and each amplifier in-line being able to dynamically vary their frequency allotments, there would be no issues, now or in the future.

If you mean simply the amount of internet speed your cable/fiber ISP allows you to use, well, the difference between potential and 'offered' speeds will always have disparities. However, the technology behind both cable networks and fiber-to-the-home have a rather high potential. Below I shall attempt to explain.

1ghz of RF = nearly 3x OC-48 bandwidth-wise. How do I get this figure? Simple. Take 1000mhz / 6mhz channels. Subtract the first 60mhz(actually 54, but I go with 60, assuming a guard band or something) and you get around 155 6mhz wide channels. Each of these channels, with current QAM-256 modulation runs at a 42 megabit datarate.

42 * 155 = 6510 - 6.5 gigabits of data. An OC-48 is all of 2.4 gigabits of data.

870mhz systems give you 5.6 gigabits possible,750mhz systems give you 4.8 gigabits.

Given the impending Switched Digital Video revolution, HFC cable systems have plenty of life left. (SDV = your TV requests only the channel it needs; if others in neighborhood are watching, only 1x channel bandwidth is consumed, vs everyone getting many channels they don't need wasting space. Given prime-time programming, I guess that only the major networks and a few special interest channels will have active watchers, freeing up hundreds of megabits of data vs the 'blast everyone with every channel' methodology that exists now.)

This is a speculative figure, but even if every SD channel and every HD channel were being watched, (similar to everyone getting everything now, but 6-10x digital channels can fit in 1 analog channel) 1.3 gigabit is needed. (200 SD channels at ~4mbit/ea + 25 HD at 19.8mbit/ea.) Even with VOD taking another 2 gigabits, (assume 50 HD streams at any time per node and another 250 SD streams(or some combination of the 2)(Is this realistic? maybe in a decade!) and even the smallest 750mhz plant installations have more than 1.5 gigabits free. With nodes being split into smaller customer groups, you may never even approach these guesstimated limits. Sure, turn more things into HD and this can change, but until VOD takes off a lot more, there's ample bandwidth for a long time. Killing analog and going to SDV Digital is about the best thing so far.

FIOS' original BPON *(Broadband Passive Optical Network) on the other hand, is currently OC-12 (622mbit) x 32 users (155mbit / OC-3 upstream), or an upgraded GPON (Gigabit PON) is currently OC-48( 2.4gbit downstream/ 1.2gbit upload) x 32-64 users. Mind you, TV is not being sent over this bandwidth; only data. TV is being provided exactly like an HFC system: 1550nm laser into 1ghz of RF with the 'node' being the FTTH box in your house)

In smaller groups this is advantageous and certainly has the potential for much higher upload rates per-user. This is FIOS' winning feature: having a rather fast and un-used (for now) upstream vs the smaller, more-distributed and currently slower potential of DOCSIS 3.0. Cable TV networks will need at least one more major plant upgrade (mentioned above, amps taps and nodes) before similar upstreams can be envisioned. Until then, I doubt that FIOS will offer greater-than-100mbit residential offerings, and I strongly believe that cable operators will continue to split heavily-used nodes into smaller and smaller segments to combat bandwidth limits. Got a neighborhood where everyone has 5 tvs watching VOD continuously? Maybe a few hundred college students leeching? There are now node solutions that fit in the same enclosures as normal trunk amplifiers. Potentially every single line-mounted amp faceplate could be changed and become another 300mbit x 150mbit node, another full spectrum of SDV, and you immediately double / triple / quadruple / more your available amount of data for the installed customer base, by segmenting the same service into 1/2, 1/3 or 1/4 of the people. Less people = more for each individual.

I'd say it'll be about 20 years before fiber-to-the-house makes a substantial difference in the types or quantity of services offered, after the VDSL and HFC camps realize their last-mile (last-20-feet?) solution needs improvement. VDSL will be the first to run out of space unless new CPE and DSLAM equipment can be developed to squeeze even more out of 26gauge copper. 50 megabits is only 50 megabits, regardless of how few people (1) share it.

Cable next only by default, as fiber can have a limitless headroom with Dense Wave-Division Multiplexing. If every cable customer had the full spectrum available individually, fiber in this position would make no difference whatsoever, as evidenced by the "1ghz of RF = 6 gigabits of data" argument above. But you share the 1ghz with a neighborhood/apartment complex and this is when FTTH shines.

[coastie65]

Hey msytica and welcome to the forum. :D WHEW!!! you have really done your homework. Admittedly, I have only spent a little time on this subject. I don't see but so much happening with cable due to the cost factor. Sure they will work to some extent to improve speeds as long as it is cost effective and and doesn't hurt the bottom line. I have had FiOS internet since Sept '06 as soon as it became available. Verizon is already bumping up the speeds in this area and they are still building the system. I presently have 15 MBPS down and 2 MBPS up. With the new packages, I think I will get 20 MBPS Down and 5 MBPS up at no additional cost. I haven't received the "OFFICIAL" notification from Verizon yet, just saw the article in the paper. Thank You for a well thought out and informative post. Incidentally, the only coax with the FiOS TV is from the Router to the TV's as it is fiber from the HUB on the line to the router on my desk. coastie65

[mystica555]

Thanks for the welcome!
For years now I have actually been rather fascinated by how different things worked, and ever since my youth of re-wiring my grandfather's cable tv setup to now finally working for a cable industry supply company as a CSR I have tried to read up and learn as much as I could on cable networks and how they worked. A lot of this is from years past, only the FIOS speeds and new DOCSIS 3 stuff did I learn about more recently.

With regard to cable companies continuing to upgrade and put more money into the networks, there are a couple of considerations. Currently they have every network part with exception of amp-enclosure nodes to continue splitting and partitioning their networks until the bitter end. To replace an amplifier for a node faceplate is only a few thousand dollars and maybe 1 or 2 man hours, versus an entire rebuild of a network that could go into months if not years and cost millions. Each segment of a node ofcourse will require its own laser and receiver at the head-end/hubsite office, and enough interconnect bandwidth to link into the CMTS and VOD servers and whatnot, so corresponding head-end equipment is needed every time a node is split.

Even with all this considered, node splits are still far cheaper than new plant construction,
and literally double to quadruple the amount of bandwidth you have
going to a given geographical area.

How fast and pro-active cable systems are at splitting high-traffic nodes will largely be driven by FIOS / other FTTH competition. DOCSIS 3.0 will be the natural and easiest progression path, with many cable systems eager and ready to make the switch and speeds will be driven by customer demands to meet the FIOS speed. Comcast is estimating a couple of years before full network-wide DOCSIS 3.0 implementation, and others are sure to follow (if they haven't started already!) The transition between Broadcast Analog/Digital and Switched Digital Video will definitely ease the network limits as well.

Past this, the very long term is up in the air. FTTH still has far greater per-user and per-plant-segment capacity on the upstream, and until HFC eliminates that 54mhz upstream/downstream split, and more evenly distributes the return traffic it will always be that way. The amount of equipment plant-wide to replace would be nearly as much work as the rebuilding efforts of the 90s, save for the fiber pulls. Its not impossible, but it'll take a lot of demand before any progress is made on shoring up this massive disparity between available upstream vs downstream. I don't even think that there are products like this on the near-term horizon, let alone available for use today.

My personal opinion is that rather than replace the entie tap/amp/node infrastructure that they will probably just create new fiber segments for that last-mile and splice to their existing metro-area rings - which were part of their last major network upgrade. Once this happens, there is relatively little that would need to be done in the future to upgrade; a simple CPE device swap and head-end device swap is all that you would need. And, then you have exactly the same service that FIOS provides: fiber optic data for internet and coax between the FTTH box installed and your TV equipment.

Having everything optical is also a good thing when it comes to using this connection for telephony as well: with the current cable amplifier network systems, if the node enclosure runs out of battery backup power before your backup battery or UPS does, then you are left without phone service. With fiber, unless a line is physically cut you will get signal to your telephony adapter. Light needs no amplification until you go massive distances, maybe 50miles or more, and most cable hub-sites are closer than this in terms of wire-length. In fact, most metro areas are less spread-out than this distance, so even if there was only 1 head-end that everything home-ran to, you would be fine without in-line amplification.

[mathion]

"For us as consumers and business users, only four interrelated factors are truly important: is the service competitively priced and getting cheaper? And is it consistent and reliable?"
No, and no. Yes and mostly.
End of story.