 GbE multiplexing Metro-optical Low-cost efficient Does not support TDM Ethernet Ethernet/IP support of IP, native without proprietary 10/100/1,000 interface with handling, single Ethernet LANs and vendor solutions core routers Next- Very cost-effective Long-term DS1, DS3, OC-x LL; generation utilization of metro scalability DS1, DS3 ATM; SONET bandwidth questionable, format DS1 Frame Relay; and bit rate dependence and STS-N Connect Source: Geyser Networks Note: Evolving technologies are not listed. LL = long lines Advances and Opportunities in Next-Generation SONET The optical network technologies applicable at the metro level include DWDM filters Tunable lasers Optical switching All-optical switching technology Acousto-optics Bubbles Holograms Liquid crystals Liquid gratings Micro-Electro Mechanical Systems (MEMS) Thermo-optics Optical amplifier Optical crossconnects Advanced optical fibers and cables Arrayed waveguides and integrated optics Tunable filters The following lists the kinds of nodal reliability for carrier-class network elements: 1:1 protection A card protection scheme that pairs a working card with a protect card of the same type in an adjacent slot. If the working card fails, the traffic from the working card switches to the protect card. When the failure on the working card is resolved, traffic reverts back to the working card if this option is set. This protection scheme is specific to electrical cards. 1:N protection An electrical-card protection scheme that enables a single card to protect several working cards. When the failure on the working card is resolved, traffic reverts back to the working card. 1+1 protection An optical-card protection scheme that pairs a single working card with a single dedicated protect card. Chapter 1 The following lists developing standards and/or specifications of some key industry bodies that are pertinent to metro access/metro core networks: International Telecommunications Union (ITU) American National Standards Institute/Alliance for Telecommuniations Indust