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[EFM] RE: [EFM-Copper] A note a about copper loops


Please note that the referenced BellSouth Loop survey (and the Telcordia
survey in the TIA document)included both DLCs, and COs. Also, bridged taps
are most frequently found on the customer end of the loop (for instance,
when a binder is running down the street, the drop cable is spliced in,
without cutting the distribution pair), so the frequency of occurrence is
independent of whether the origin is a CO or a DLC. 

The draft TIA standard is still under development, with the referenced draft
dated 2001, therefore the projected loop length statistics were developed
after the announcement of project Pronto. 

The goal of Project Pronto is to add DLCs in order to bring 80% of the
customers within 12kft, 26 AWG (15kft 24AWG), not 100% within 12kft 24AWG.
Unfortunately, SBC just announced that the project, whose completion
objective was already pushed from 2002 to 2003, is being reevaluated, based
on current economic conditions

There is no denying the fact that shorter loops give higher bandwidth. By
the same token, fiber to the home gives even better bandwidths.  Longer
reach objectives for EFM over copper would allow universal coverage to be
offered until such time as the fiber plant can be built out closer to the
end user.

Best Regards,


-----Original Message-----
From: Behrooz Rezvani [mailto:behrooz@xxxxxxxxxx]
Sent: Friday, October 26, 2001 4:52 PM
To: 'Stanley, Patrick'; Behrooz Rezvani; '';
Cc: 'Hugh Barrass'; 'Howard Frazier'; 'John M. Cioffi'
Subject: RE: [EFM-Copper] A note a about copper loops


I realize Bellsouth is the exception in RBOCS in terms of DLC penetration,
but I was trying to make the point that in fact the activity of all RBOCS
such as SBC with project Pronto forces loops to be shorter than 12 kft at a
much faster rate only starting about 2 years ago. According to RHK, by year
2004 the number of lines from DLC will exceed CO lines. I guess I wanted to
emphasis the importance of 12 Kft based SBC's presentation at Stanford

I think you are saying only 68% of lines are about 12 kft and less by 02
based on data in 97 survery and I am suggesting based on RHK that these
number may be even higher due to projects such as Pronto started just

This is not very surprising anyway. In order to provide more services (more
money) people need more bandwidth, and more bandwidth can be obtained on
shorter loops ONLY.

Best regards

-----Original Message-----
From: Stanley, Patrick [mailto:pstanley@xxxxxxxxxxx]
Sent: Friday, October 26, 2001 11:46 AM
To: 'Behrooz Rezvani'; ''; 'Copper'
Cc: 'Hugh Barrass'; 'Howard Frazier'; 'John M. Cioffi'
Subject: RE: [EFM-Copper] A note a about copper loops


Thanks for your update from the Stanford Conference.  In reference to
statistics provided on BellSouth's copper plant, I have attached a related
UAWG contribution.  Included in the 1998 contribution from BellSouth, is a
loop survey covering both CO and DLC deployments.  The data show the loop
loss equivalent of 12kft 24AWG covering 60% of loops, and loop loss
equivalent of 20kft of 24AWG covering 90% of loops.  Furthermore, it is
widely accepted that BellSouth's network contains a much higher percentage
of DLC-based deployments, as compared with the other RBOC's.

I have also attached a TIA draft standard which gives loops and noise
models, tied to market coverage. This draft standard contains a 1997
Telcordia loop survey, which covers both CO and DLC loops.  

The TIA draft standard considered only loops up to 18kft, which represent
85% of the total loops (per UAWG contribution).  Table C1, shows that of
this 85% coverage in the 1997 survey, the following data: 4500ft loops
covering 30% of the market, 12kft covering 80%, and 18kft, of course,
covering 100% of loops 18kft or less in length.  Normalizing these values to
the total market yields:

4,500  Ft	26%
12,000 Ft	68%
18,000 Ft	85%

The TIA report continues to extrapolate future data which shows these
coverage numbers increasing by ~3% by 2002.  Again, the data correlate well
with the previously referenced Telcordia survey.

I think this TIA draft standard is a useful reference for developing loops
and noise models, tied to market coverage, for copper based EFM on public


-----Original Message-----
From: Behrooz Rezvani [mailto:behrooz@xxxxxxxxxx]
Sent: Friday, October 26, 2001 3:46 AM
To:; Copper
Cc: Hugh Barrass; 'Howard Frazier'; Behrooz Rezvani; 'John M. Cioffi'
Subject: [EFM-Copper] A note a about copper loops

In a conference that was held just a week ago at Stanford there were two
good talks by George Hawley (former head transmission group at Bell labs,
and formerly a GM at Bellcore) and Jim Sackman (CTO AFC a leading DLC
company) regarding loop statistics:

1. The loop survey of 1983 was only for lines from central offices
2. By year 2004 the number of lines from DLCs will exceed all the lines from
3. 95% of lines in Bell South territory is under 12 kft(AWG-24)
4. DLC-RTs vary in size and the area of coverage.(48 lines to 10,000 lines)
typical densities are about 600 lines. serving primarily POTS, and moving to
ADSL or xDSL like. Bridge taps are generally found on longer loops,
specially from CO
5. POTS are going primary source of income for RBOCs followed by data and
6. DLCs and mid range CSA rules was signed off in 1980

Other good talks included our owns Howard's. EEtimes had a report on the
conference. The information about the speakers can be found at . I believe Prof. Cioffi of Stanford has the conference
proceeding available ($$).