Chapter 2 Passport 8672ATME Module terminology 35Using the Passport 8672ATME ModuleSONET terms and acronymsThis section provides a brief listing of common Synchronous Optical Network(SONET) terms. SONET is a medium for transmitting data that uses fiber opticcables.The following terms and acronyms are frequently used with SONET information:• SONET: Synchronous Optical Network. SONET is a family of fiber optictransmission rates that provides the flexibility to transport many digitalsignals with different capacities. This ANSI standard provides fortransmission from OC-1 to OC-48 and greater.• SDH: Synchronous Digital Hierarchy. SDH is a standard technology foroptical fiber-based synchronous data transmission. SDH is the internationalequivalent of SONET.• OC-3: Optical Carrier-level 3. OC-3 is an optical fiber transmission system at155 Mb/s.• OC-3c/STM-1: Optical Carrier-level 3 concatenation. OC-3c/STM-1 is anoptical fiber transmission system that carries STS-3c/STM-1 frame structuresat 155 Mb/s. Concatenation refers to the fact that there is only one logical datastream (rather than supporting a channelized structure).• OC-12: Optical Carrier-level 12. OC-12 is an optical fiber transmissionsystem at 622 Mb/s.• OC-12c/STM-4: Optical Carrier-level 12 concatenation. OC-12c/STM-4 is anoptical fiber transmission system that carries STS-12c/STM-4 framestructures at 622 Mb/s. Concatenation refers to the fact that there is only onelogical data stream (rather than supporting a channelized structure).
