30Chapter 2 Using the Passport 8683POS 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-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-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).
•POS: Packet over SONET.
•PPP: Point-to-Point Protocol. PPP encapsulates common network-layer protocols in specialized Network Control protocol packets, such as IP over PPP (IPCP) and IPX over PPP (IPXCP), and BCP. Thus, it enables sending multiprotocol data over point-to-point links.
SONET/SDH transmission rates
The following transmission rates are commonly used with SONET:
•OC-3c/STM-1: 155.52 Mb/s
•OC-12c/STM-4: 622.08 Mb/s
The SONET specification defines optical both as:
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