Nous présenterons nos premières offres dans le courant de l’été. A la rentrée, au plus tard, elles seront disponibles au grand public.
"Employees required to maintain PON is less than HFC (x1.38) and VDSL (x1.54)"
The workers say they are being told to apply Band-Aid repairs to major problems or can’t get them fixed at all. The preventative maintenance program has been abandoned.
All the investment is going into a new fiber optics system going into select areas in Hampton Roads and elsewhere.
OECD
http://www.stanford.edu/~kseong/pubs/WTC2006.pdfIV. CONCLUSION
Dynamic Spectrum Management (DSM) is already in use
while opening new vistas of heretofore unforeseen high data
rates for DSL use. Unbundling does not prevent the use of DSM and indeed many Level 2 and Level 3 DSM gains are
possible within any regulatory situation if the equipment and
management are well conceived and designed to open
standardized interfaces with service-provider management.
Speeds to as high as 500 Mbps (35 MHz times x 15 bits/Hz)
per user line become foreseeably feasible with vectored DSLs
(and up to twice this rate or 1 Gbps using split-pair cross-overs
on up to ½ the lines in a binder) at lengths of 300-400 meters.
Such speeds within a cable of 200 lines add to 100 Gbps of
possibly shared capacity for fiber-to-the-curb DSL systems,
eliminating the need for fiber to traverse the last, most costly
segment to each customer and generally well-exceeding the
offered and projected speeds supplied by the much more
expensive passive optical approaches. Thus, DSL capabilities,
through the grace of DSM, may well extend throughout this
new millennium.
DSM is a family of techniques that optimize customer circuits for the actual conditions. The first step is to get information on the noise in the actual circuit and binder, and adjust profiles of each DSL modem. The more difficult task is to adjust multiple modems in the group in a way that improves performance for all. That's challenging, especially in real time. Today's DSL chips have highly sophisticated test capability. There's been an intense struggle over the standard of how to provide that data to a management system, a story I should be reporting.
First payoff of DSM is improved performance on marginal ADSL loops which are the most prone to expensive service problems. The future goal is doubling VDSL rate/reach for many customers. ADSL in particular is close to the Shannon Law limits on performance. VDSL chips can still be improved without hitting the Shannon Limit. No one has directly shared with me test data, but both AT&T and Swisscom have been publicly disappointed by the current generation of chips. The next generation should be better. Beyond that, progress will require an end run around the Shannon Limit, which is defined in relation to a given noise level. DSL standards before DSM assumed a standard noise level and chips are optimized to perform in a standard noise test environment. DSM effectively reduces noise and allows the entire system to be optimized for even better performance. (DSLPrime)
SFP
