Nortel Networks Passport Module 8672A - Manual (Page 33)

Chapter 2 Passport 8672ATM Module technology overview 33
Using the Passport 8672ATM Module
SONET terms and acronyms
This section provides a brief listing of common Synchronous Optical Network
(SONET) terms. SONET is a medium for transmitting data that uses fiber optic
cables.
The following terms and acronyms are frequently used with SONET information:
• SONET: Synchronous Optical Network. SONET is a family of fiber optic
transmission rates that provides the flexibility to transport many digital
signals with different capacities. This ANSI standard provides for
transmission from OC-1 to OC-48 and greater.
• SDH: Synchronous Digital Hierarchy. SDH is a standard technology for
optical fiber-based synchronous data transmission. SDH is the international
equivalent of SONET.
• OC-3: Optical Carrier-level 3. OC-3 is an optical fiber transmission system at
155 Mb/s.
• OC-3c/STM-1: Optical Carrier-level 3 concatenation. OC-3c/STM-1 is an
optical fiber transmission system that carries STS-3c/STM-1 frame structures
at 155 Mb/s. Concatenation refers to the fact that there is only one logical data
stream (rather than supporting a channelized structure).
• OC-12: Optical Carrier-level 12. OC-12 is an optical fiber transmission
system at 622 Mb/s.
• OC-12c/STM-4: Optical Carrier-level 12 concatenation. OC-12c/STM-4 is an
optical fiber transmission system that carries STS-12c/STM-4 frame
structures at 622 Mb/s. Concatenation refers to the fact that there is only one
logical data stream (rather than supporting a channelized structure).