Finally, many commercial DWDM OADM nodes also blend in higher-layer TDM and
Ethernet capabilities to boost wavelength efficiency. For example, various high-density
???thin-mux??? blades (muxponder) are available for subrate client tributary aggregation
and output onto DWDM wavelengths. Key examples include TDM blades (4:1 OC-12 on
OC-48, 4:1 OC-48 on OC-192) and Ethernet multiplexers (8:1/10:1 Gigabit Ethernet to
10 Gigabit Ethernet, etc). Some of these units can even provide decent levels of electroniclayer
functionality, e.g., SONET/SDH APS and/or Ethernet switching/VLAN support.
Overall, these ???grooming??? devices are blurring the boundaries between the optical and
electronic layers. Alternatively, many higher-layer Ethernet/MPLS switches, IP routers,
and SONET/SDH devices readily support powerful SMF or DWDM optics interfaces.
Today??™s ROADM technologies offer the very real prospect of dynamic ???intelligent???
optical networks. When combined with tunable laser transponders, these systems
can essentially reduce provisioning times down to minutes with little to no manual
configuration??”a huge cost savings. Note, however, that static preengineering is still
not eliminated altogether.
Pages:
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520