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paolo.franzoi
paolo.franzoi
12/5/2012 | 4:31:10 PM
re: Bad News for Bonded Copper?


billy,


You are not comparing to T-1 but to fiber.&nbsp; You asked why bonded copper was inferior to Fiber.&nbsp; That is why.&nbsp; It is limited bandwidth and takes lots of maintenance when compared to Fiber.&nbsp; When the customer wants to upgrade to a Gb/s they are tossing your solution away.


Your comparison points that you are quoting are very nice when compared to HDSL or T-1 (which requires repeaters a lot more often than 6kft).&nbsp; Let's return to latency.&nbsp; Have you seen the 5msec requiremet?&nbsp; Eating 2msec of it in the access loop is 40% of the available latency for LTE.


So, when a carrier sits back he/she looks at it and sees that every dollar thrown at EoCu for wireless will be wasted.&nbsp; So, only in extreme cases will it be used.&nbsp; That is what AT&amp;T has said and that is what carriers worldwide are doing for their cell backhaul.


So, to fix your analysis don't use T-1 as your comparison point.&nbsp; Use Fiber.


seven


&nbsp;

billy_fold
billy_fold
12/5/2012 | 4:31:10 PM
re: Bad News for Bonded Copper?


Why no repeaters?&nbsp; I normally can put repeaters in 239 T1 repeater enclosures about every 6 Kft.&nbsp; I think that the BER provided by bonded copper is more than adequate for voice and data applications for mobile networking.&nbsp; Why are the pairs not available?&nbsp; And why do I seem to be only one stating any facts in this discussion?&nbsp;&nbsp; Sorry again.


-billy

billy_fold
billy_fold
12/5/2012 | 4:31:08 PM
re: Bad News for Bonded Copper?


Ahhhh, finally an argument that I can partially agree with.&nbsp; It is obvious that bonded copper will never be as good as fiber.&nbsp; That is a given.&nbsp; However, bonded copper is a&nbsp;very inexpensive solution&nbsp;and can provide an excellent interim solution until fiber can be plowed in.&nbsp; It won't give as much bandwidth as fiber, but it can provide a lot more bandwidth than T1s.&nbsp; It is about as close to fiber as you can get with any other technology other than fiber.


The dollars spent on EoC would not be wasted.&nbsp; As soon as fiber is plowed in, the SP can move the EoC equipment to another location.


Regarding latency, I suspect that the one way uncongested&nbsp;bonded copper latency between the cell tower and the CO is about 2 milliseconds more than fiber.&nbsp; I don't think that is enough to cause a latency issue for voice traffic.


I wonder how long it will take the SPs to plow fiber into all the cell towers.&nbsp; I suspect that there may be more than 100K of them without fiber.


-billy


&nbsp;

stephencooke
stephencooke
12/5/2012 | 4:28:07 PM
re: Bad News for Bonded Copper?


Ahhh Seven,


Stirring the pot again are we...?&nbsp; The error rate of bonded copper is far better than the error rate on the wireless so fiber vs. bonded copper is a moot point in that area.&nbsp; Start talking economics... do the fiber economics make sense everywhere?&nbsp; Of course not.&nbsp; In fact they don't make much sense in most places if the copper is already there.&nbsp; Ask the CFO, not the research guy who has spent the last decade trying to push more fiber into the network.


Try getting femtocells to put that wireless 100Mb/s symmetric (I haven't seen the app that requires this yet but maybe someday, in fact most PCs can't handle this) over their DSL at 6 kft (about 1.8km).&nbsp; Bonding the 24-pair binder using ADSL2+ can get potentially 15Mb/s/pair at that distance so it is certainly doable.&nbsp; Add vectoring (DSM level 3 as you have the whole binder - understood that it might not be contiguous from the CO) and you can get substantially more.


The copper network still has a lot of life left in it!&nbsp; See www.dslrings.com.


Steve.

paolo.franzoi
paolo.franzoi
12/5/2012 | 4:28:05 PM
re: Bad News for Bonded Copper?


&nbsp;


The 30A profile is a VDSL profile NOT a 2+ profile. &nbsp;So yes you are clearly muddled.


seven


&nbsp;

stephencooke
stephencooke
12/5/2012 | 4:28:05 PM
re: Bad News for Bonded Copper?


Seven,


I don't remember pitching at AFC...?&nbsp; Must have been the drugs.&nbsp; They are quite strong though... we used them to infect the labs of 2 major European incumbent telcos in the last month and showed them a 5-node ring with bandwidth in excess of 350 Mb/s on a wide open 30a profile and well over 250 Mb/s with a hamstrung 30 MHz profile.&nbsp; Unfortunately they measured the results so they must have been infected too...?


Want some?


Steve.

paolo.franzoi
paolo.franzoi
12/5/2012 | 4:28:05 PM
re: Bad News for Bonded Copper?


&nbsp;


Stephen,


Your DSL rings did not make any sense when you pitched them to me at AFC and they don't now.&nbsp; If you really think that the self-fext issues allow you to get 15 Mb/s per pair on standard 2+, then you are really smoking dope.&nbsp; Which will be legal soon here in CA, so you may wish to move.


The basic economic issue is that there is NOT spare copper to the cell site.&nbsp; That means that you are now digging up the street to put in more copper.&nbsp; The moment you do that then you might as well put in fiber.


As to the point about BER, the person doing the justification for bonded copper was using BER calculations that were not the same as for fiber.&nbsp; To compare apples to apples, you need to derate the bandwidth to accomodate the BER of fiber on the copper circuits.


Now, remember the 5msec delay issue on LTE cells?&nbsp; So, you can now assume you are in the Fast mode and your interleaver is off.


seven


&nbsp;

stephencooke
stephencooke
12/5/2012 | 4:28:04 PM
re: Bad News for Bonded Copper?


Seven,


You mentioned that our ring didn't make sense.&nbsp; I provided data that showed that it provides significant bandwidth in telco testing that means DSL Rings absolutely makes sense.&nbsp; Hurts to be wrong doesn't it?


Steve.

paolo.franzoi
paolo.franzoi
12/5/2012 | 4:28:03 PM
re: Bad News for Bonded Copper?


&nbsp;


No you are playing the normal bait and switch game.


&nbsp;


Your DSL ring requiring a 30A profile does NOT do 6Kft in a single hop.&nbsp; That is the old DSL bait and switch.&nbsp; My favorite was the first Ikanos pitch was that it was a 9Kft and 100Mb/s technology.&nbsp; Not at the same time of course.


&nbsp;


Which is my point here....You can run all kinds of bandwidth at very short loop lengths over lots and lots of copper.&nbsp; None of which has anything to do with the actual state of the network.&nbsp;


Copper is good for what it is good at.&nbsp; Heck there are Ethernet Phys that run it to Gigs and backplane drivers doing 10s of Gigs.


But let me remind you of your assumption.&nbsp; You have lots of free and clean copper running to a cell site.&nbsp; What the operators tell me is that this is an occasional thing and they might consider bonded copper in those specific cases.&nbsp; In the vast majority of cases, they end up having to do construction.&nbsp; Once you are there, they are not going to plow in brand new copper.&nbsp; That is the basic issue.&nbsp;


Your assumption - EVERYWHERE has LOTS of free copper.&nbsp; Reality - FEW places have LOTS of free copper.


Remember, you business case only works if you can avoid laying cable.&nbsp; The cost to lay fiber is about the same as it is to lay copper.&nbsp; So, if you have to lay anything - you are done.


seven


&nbsp;

stephencooke
stephencooke
12/5/2012 | 4:28:03 PM
re: Bad News for Bonded Copper?


Seven,


You like to think you remember how a technology works when you slander it but the truth is that we use bonded copper (typically 24-pairs of ADSL2+) to the pedestal (or Distribution Point) and then we use VDSL2 over the 500ft or less to link the homes together via home gateway nodes in each house.&nbsp; The bonded link can also use vectoring if the DSLAM supports it across that many pairs.&nbsp; On the VDSL2 side the transmission curve re-starts at each house so we can achieve what the European telcos have witnessed.


Spare copper is not required as the houses on the ring donate their backhaul (ped to CO) pairs to the bonded link.&nbsp; Any spare copper would be included in the backhaul bond to increase available bandwidth at the ped - so it would help, but is not required.&nbsp; We add QoS (traffic prioritization) so cell traffic can be prioritized above your WoW game or the telco can sell you an SLA that gives you better performance on your games as well.


Yup, you're still wrong.


Steve.

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