A key example here is the reconfigurable OADM (ROADM) node,
which allows carriers to add-drop wavelength circuits dynamically at a given node, in
other words dynamic online RWA. This ONE design vastly accelerates service delivery
times (from days/weeks to minutes/hours) and lowers manual operational costs. Akin to
its static counterpart, a ROADM also features transport, amplification, and (dynamic)
add-drop stages (see Figure 8.3).
Initial ROADM designs were ???opaque??? and used opto-electronic transponders and
SONET/SDH fabrics to implement add-drop functions. Although these systems provided
subrate TDM grooming and client-side hair-pinning capabilities, service transparency
was eliminated. Overall, opaque ROADM nodes proved too expensive for most
carriers, as large transponder arrays were needed to terminate/launch all wavelength
channels. Additionally, related OPEX costs??”footprint and power consumption??”were
also very significant. As a result, new advances have shifted carrier interests toward
transparent all-optical ROADM designs. Today the ROADM market represents one of
the fastest-growing and most promising sectors in DWDM space [2].
Pages:
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516