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Verizon Spells Out 100 Mbit/s

Verizon Communications Inc. (NYSE: VZ) is admitting that its 100-Mbit/s plans will come with a few caveats.

That's not to say 100 Mbit/s, even a bit diluted, is child's play. Verizon has come forward as the only major U.S. carrier to say that delivering 100 Mbit/s to the individual home is on its radar. (See Verizon Leads the Great 100-Mbit/s Bandwidth Race.) It's just that getting there won't be easy.

Luckily, Verizon won't have to saturate its network with 100-Mbit/s lines. "At any stage we don't have 32 people looking for 100-Mbit/s service," says Vincent O'Byrne, director of access technologies at Verizon. "We would do some oversubscription."

That means Verizon is betting that whenever 100 Mbit/s first becomes a reality, the demand will be minimal. "It's not likely that everyone would want it," says O'Byrne. "It would be a small percentage of people in any neighborhood."

Good thing, too. Verizon says that most of its central offices serve about 15,000 to 20,000 homes. Simple math would dictate that to bring 100 Mbit/s to each of those homes would require at least 1.5 Tbit/s of bandwidth going into each central office. That of course is not how things work now.

While Verizon's migration from BPON to GPON will play a big role in the movement towards 100 Mbit/s, traffic management will be just as significant.

"When you oversubscribe, you have aggregators behind the OLT [optical line terminal] which take advantage of the dead space of the transmission from one OLT to another," says O'Byrne. "It is taking advantage of statistical multiplexing and the fact that not everyone is accessing that 100 Mbit/s at the same time."

In the long run, Verizon is considering the possibility of upgrading its network with Wavelength Division Multiplexing (WDM), or WDM-PON. This technology sends a full wavelength to each house, greatly increasing the potential capacity of each fiber.

"We're making sure that when we deploy our GPONs, that we have the capability when there is a need, to increase our network's output. Part of our overall strategy is to make sure our network can evolve to WDM," says O'Byrne.

For now though, O'Byrne says that Verizon is expecting GPON to have a long lifespan that won't get cut short by WDM-PON.

"There are different substantiations of WDM," O'Byrne says. "There are some variants that allow you to evolve off the present GPON, and they sort of become another GPON channel."

But even with network capacity upgrades, oversubscription, and multiplexing, signing up for 100-Mbit/s service won't mean you'll get that bandwidth all the time. "100 Mbit/s isn't guaranteed," O'Byrne says. "If you ran a test on the network, it would read 100 Mbit/s, but if enough people were demanding it at the same time, we couldn't guarantee each would get the 100 Mbit/s."

— Raymond McConville, Reporter, Light Reading

<<   <   Page 2 / 3   >   >>
Duh! 12/5/2012 | 2:57:30 PM
re: Verizon Spells Out 100 Mbit/s Quote:
If you ask me, there are two possible reasons for this:
* Regulatory reasons. FTTH could easily be unbundled, PON is messy.
* Operators have been fooled by vendors. It does happen, you know. PBT, anyone?
End quote:

And if you ask me there is one and only one possible reason for this:
* Active Ethernet does not scale for mass-market deployments in moderate-to-low density areas. Too many fibers coming in to the CO, too many fibers to fit into existing duct, too many fibers to repair quickly in event of a dig-up. And if you go to remote nodes in the field to eliminate those problems, you're back to the powering and maintenance issues that come along with VDSL and ADSL2, but without the cost avoidance of reusing copper distribution and drop.

Of course, if 80% of your subs live in high rises and your duct network has a median radius of 5 or 7 km, then active Ethernet works just fine.


Didn't we have this conversation a few months ago?
redface 12/5/2012 | 2:57:29 PM
re: Verizon Spells Out 100 Mbit/s Brookseven wrote:

"No, there is no low cost solution for WDM-PONs. There will have to be a new generation of thinking before such parts could exist. Have you actually thought about the components involved? If so and you think they will be cheap anytime soon, you are on something."

I am sorry, Brookseven. But you are wrong. The reason that KT has deployed WDM-PON on a limited scale and the reason Verizon keeps mentioning WDM-PON is because WDM-PON is getting pretty close to TDM-PON in terms of price/performance. By that I mean WDM-PON is probably 2x to 3x more expensive than TDM-PON TODAY. Having done some WDM-PON development myself, I know exactly the components involved. Yes, they can be competitive to TDM-PON in terms of cost. The ONU end of the WDM-PON has a component which is almost identical to a diplexer in form factor and functionality, which means it is cheaper than a triplexer. In WDM-PON, there is no DFB laser. Low cost FP laser diodes are used instead.
bollocks187 12/5/2012 | 2:57:28 PM
re: Verizon Spells Out 100 Mbit/s 7,

What vendor makes a profit with the GPON solution ?
redface 12/5/2012 | 2:57:28 PM
re: Verizon Spells Out 100 Mbit/s Actually the WDM-PON laser is just a coolerless low cost FP laser with a 0.1% AR coating on the front facet. Reflective SOA is just another name for the same thing, more or less. They are both based on laser injection locking, with a seed wavelength signal provided by a wavelength sliced broadband light source. Wavelength slicing is done using AWG. A batch AR facet cost does not increase manufacturing cost very significantly. Otherwise it is identical to a diplexer in optical path and build. The cost of manufacturing this ONT in the high volume manufacturing limit is about the same as that in diplexer, and cheaper than a triplexer which is frequently used in TDM-PON by Verizon. Of course the AWGs used in WDM-PON will increase the WDM-PON component cost significantly. However, the per channel AWG cost is getting to $30-40 these days so it is not a show-stopper either.


paolo.franzoi 12/5/2012 | 2:57:28 PM
re: Verizon Spells Out 100 Mbit/s
As said, TDM PON can be 2 wavelengths AND can be done with an FP to match the distance. If you want to do B+ distances with Novera, you are not using an FP laser.

The way to get to FP with GPON is to use a bit more aggressive rules on the ODN design AND use FEC. You will find you can use FP lasers in the ONT and meet the distances required. Of course, Verizon won't allow that small a margin in their design.

And the $30 cost for the AWG is about 1/3 the Price of an indoor diplexer ONT as shown that Novera makes in either GPON or EPON. So, yes it is significant.

seven
Duh! 12/5/2012 | 2:57:28 PM
re: Verizon Spells Out 100 Mbit/s As I understand it, Novera is using a modified F-P for their incoherent injection locking scheme. The secret sauce seems to have to do with coatings on the front facet. Their cost is probably a bit more than a BPON/GEPON FP, but not significantly more.

The cost part of the equation is more that they require 2N transceivers per PON, plus a fairly powerful broadband light source, plus athermal AWGs. Certainly all of these are subject to a learning curve... but so are the DFBs and APDs in GPON implementations, which are nearing parity with volume. And the 2N thing is structural rather than being subject to learning curve.

Oh, and the diplexor vs triplexor thing is a red herring. The overlay is an additional feature that a few operators are taking advantage of for their broadcast TV services. Apples-to-apples comparison would involve just the GPON.
paolo.franzoi 12/5/2012 | 2:57:28 PM
re: Verizon Spells Out 100 Mbit/s
Sorry, but do the quotes yourself. It is a publicly available product designed in the US.

The WDM-PON for Korea is neither FP or DFB. It is a Resonant Cavity Laser. The other technology of choice is Reflective SOAs (and those little puppies are off the charts).

Remember you have to build a colorless ONT for stocking reasons. So, you can not just use an off the shelf FP. You CAN use an FP in GPON if you change the loop characteristics. The only reason that APDs and DFBs are used today is the Class B+ optics.

Just so we are ALL clear....here is the product deployed in Korea (note the 30K ONT number - about 1/3rd of Verizon's monthly volume).

http://www.noveraoptics.com/

seven
tailpin 12/5/2012 | 2:57:27 PM
re: Verizon Spells Out 100 Mbit/s I'm trying to figure out these next-gen PON abreviations. The most common seem to be PON and lol. What's a lol-PON?
jepovic 12/5/2012 | 2:57:27 PM
re: Verizon Spells Out 100 Mbit/s "* Active Ethernet does not scale for mass-market deployments in moderate-to-low density areas. Too many fibers coming in to the CO, too many fibers to fit into existing duct, too many fibers to repair quickly in event of a dig-up. And if you go to remote nodes in the field to eliminate those problems, you're back to the powering and maintenance issues that come along with VDSL and ADSL2, but without the cost avoidance of reusing copper distribution and drop."

You're talking about P2P fiber from the CO, which indeed is pretty rare except in greenfield deployments. I'm referring to fiber to the basement (FTTB). In this case, the amount of fiber is similar to PON. Yes, you will have distributed active equipment, but it is cheaper and way more powerful than the distributed PON equipment. Power is regular 220 AC, cooling is done without fans. All that is needed is a room in the basement.

There are other advantages of using Ethernet switches as well: Efficient multiplexing on packet level, simple well-known technology (easy to train support staff, field technicians), tons of vendors, simple physical interfaces etc.

I don't understand why this model isn't used by eg Verizon on the east coast.

In suburbs, this model is more tricky. Still, PON seems awfully complicated, poorly standardised and anything but future-proof. I still think it's a dead end.
bollocks187 12/5/2012 | 2:57:27 PM
re: Verizon Spells Out 100 Mbit/s Answer - None !

It's all a 'media' show. Verizon does not know what it is trying to do - it is all reactionary.

BPON(ATM) then GPON..... seed the future with WDM-PON.......then BS-PON - lol





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