wierdo
join:2001-02-16
Tulsa, OK Reviews:
 ·Cox HSI
 ·T-Mobile US
| reply to ninjatutle
Re: but but it is about the bandwith Pair bonding is putting lipstick on a pig. You get to go from 25Mbps to maybe 40, perhaps less if everyone in your area gets U-Verse. They seem not to have learned from the crosstalk issues on regular DSL lines.
RG-6 (which isn't even what they use in distribution, they use bigger stuff) passes a lot higher frequencies than a pair of 26AWG wire will. That's why they have to get the VRAD so close, hence the cable companies not yet needing to move to FTTH, although they should, or at least push it out much closer to the end user so they can pass 2GHz or more, rather than the 560-900MHz that is common today.
Fiber can do many Gbps per wavelength. An enterprising company could easily deliver 10Gbps to each customer over fiber, if they felt like it, putting the same fiber in the ground that one would use for a (E/B/G)PON system. Instead of splitting a single wavelength among many users, they could deliver one wavelength for each user. |
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| 'They seem not to have learned from the crosstalk issues on regular DSL lines.'
What?
'passes a lot higher frequencies than a pair of 26AWG wire will. '
Yea? And? 26ga is the smallest gauge of telco wiring used fwiw. RG-6 is still has a different topology too.
Besides FTTN is just a way to get the FTTH without busting the bank or taking forever, |
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wierdo
join:2001-02-16
Tulsa, OK Reviews:
·Cox HSI
·T-Mobile US
| said by bogey780:'They seem not to have learned from the crosstalk issues on regular DSL lines.' What? 'passes a lot higher frequencies than a pair of 26AWG wire will. ' Yea? And? 26ga is the smallest gauge of telco wiring used fwiw. RG-6 is still has a different topology too. Besides FTTN is just a way to get the FTTH without busting the bank or taking forever, 1) There is this thing called crosstalk, it causes interference between data lines. Read about it.
2) 26 AWG is by far the most common used by the telcos. It doesn't pass high frequencies well, thus limiting its usefulness for transmitting lots of data compared to RG-6. Yes, the cable plant is essentially a bus topology, but it has more raw bandwidth available, meaning they don't need to go fiber yet, as most of them still have bandwidth to spare. The astute cable companies are already moving past 1GHz plant.
3) FTTN doesn't get you any closer to FTTH. It's a complete waste of money. They're eventually going to move to a PON anyway, in which case they're going to have to rip out the VRADs and completely rebuild the fiber infrastructure. The whole point of a PON is to not have electronics in the field. |
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| 1. DSL doesn't suffer from crosstalk on short loops. The only real interference DSL suffers from is T1 interference. If DSL was prone to crosstalk there would be stories on it on here since some neighborhoods have every other house on the street with DSL.
2. 26ga is the most commonly used because it's great for underground feeders. Guess what U-verse replaces.
3. The VRAD's are a good staging point. You think cutting out several miles of copper is a small step? They can still go PON or bring out a FTTC system from there. Both capable of great speeds. |
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wierdo
join:2001-02-16
Tulsa, OK Reviews:
·Cox HSI
·T-Mobile US
| said by bogey780:1. DSL doesn't suffer from crosstalk on short loops. The only real interference DSL suffers from is T1 interference. If DSL was prone to crosstalk there would be stories on it on here since some neighborhoods have every other house on the street with DSL. 2. 26ga is the most commonly used because it's great for underground feeders. Guess what U-verse replaces. 3. The VRAD's are a good staging point. You think cutting out several miles of copper is a small step? They can still go PON or bring out a FTTC system from there. Both capable of great speeds. 1. It does indeed, although it is reduced due to the lower transmission power required due to the shorter loop. The transmission power that is increased to force the high frequencies down the crappy wire. Additionally, pair bonding will necessitate many more lines with active DSL than even the most dense current deployments.
2. They're not replacing the wire from the house to the VRAD.
3. It hasn't been several miles in most places for years. Most everybody who will be served by a VRAD is already within a mile or perhaps two of an RT. They could go PON, but it will not be anything close to an optimal build. They'll have active fiber running to within a couple thousand feet of most homes and businesses. They'll have to lay in more new fiber out to the VRAD's location (or abandon the locations entirely and replicate the original copper build, only with fiber) to avoid disrupting current service while they move people over to a fully fiber loop. |
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| 1. What you said sounds nice and I'm sure it's a concern. It however still isn't happening.
2. Luckily those are usually a little beefier. 26ga is used for feeder because it's small cross section allows for a greater number of lines through cramped underground ductwork. Not an issue for the last mile.
3. You a professional telco engineer? |
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wierdo
join:2001-02-16
Tulsa, OK Reviews:
·Cox HSI
·T-Mobile US
| 1. You take this on faith?
2. Not in anything built in the last 20 or 30 years, there's no point, since the feeder is 26 anyway.
3. Nope, I've just had a significant interest in the design of such networks for many years now, so I have some familiarity with how they are built, simply by constant observation and regular reading on the subject. |
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| Ahh... you see. I get to play with the things you read about.
You realize that gauge has to increase as does distance after a certain point. It's phone 101. You can't draw dialtone if you drop below a certain resistance. That's why 26ga is harder to find the further you go out.
Crosstalk is not an issue with DSL at all in any way under a mile. |
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