SMDS
Encyclopedia
Switched Multi-megabit Data Service (SMDS) was a connectionless service used to connect LAN
s, MAN
s and WAN
s to exchange data, in early 1990s. In Europe, the service was known as Connectionless Broadband Data Service (CBDS).
SMDS was specified by Bellcore, and was based on the IEEE 802.6
metropolitan area network
(MAN) standard, as implemented by Bellcore, and used cell relay
transport, Distributed Queue Dual Bus layer-2 switching arbitrator, and standard SONET
or G.703
as access interfaces.
SDMS was developed by Bellcore as an interim service until Asynchronous Transfer Mode
matured. In the mid-1990s, SMDS was replaced, largely by Frame Relay
.
SMDS was notable for its initial introduction of the 53-byte cell and cell switching approaches, as well as the method of inserting 53-byte cells onto G.703 and SONET.
Län
Län and lääni refer to the administrative divisions used in Sweden and previously in Finland. The provinces of Finland were abolished on January 1, 2010....
s, MAN
Metropolitan area network
A metropolitan area network is a computer network that usually spans a city or a large campus. A MAN usually interconnects a number of local area networks using a high-capacity backbone technology, such as fiber-optical links, and provides up-link services to wide area networks and the...
s and WAN
Wide area network
A wide area network is a telecommunication network that covers a broad area . Business and government entities utilize WANs to relay data among employees, clients, buyers, and suppliers from various geographical locations...
s to exchange data, in early 1990s. In Europe, the service was known as Connectionless Broadband Data Service (CBDS).
SMDS was specified by Bellcore, and was based on the IEEE 802.6
IEEE 802.6
IEEE 802.6 is a standard governed by the ANSI for Metropolitan Area Networks . It is an improvement of an older standard which used the Fiber distributed data interface network structure. The FDDI-based standard failed due to its expensive implementation and lack of compatibility with current LAN...
metropolitan area network
Metropolitan area network
A metropolitan area network is a computer network that usually spans a city or a large campus. A MAN usually interconnects a number of local area networks using a high-capacity backbone technology, such as fiber-optical links, and provides up-link services to wide area networks and the...
(MAN) standard, as implemented by Bellcore, and used cell relay
Cell relay
In computer networking, cell relay refers to a method of statistically multiplexing small fixed-length packets, called "cells", to transport data between computers or kinds of network equipment. It is an unreliable, connection-oriented packet switched data communications protocol.Cell relay...
transport, Distributed Queue Dual Bus layer-2 switching arbitrator, and standard SONET
Sonet
Sonet may refer to:* Sonet Records, European record label* Synchronous optical networking * Saab Sonett...
or G.703
G.703
G.703 is an ITU-T standard for transmitting voice or data over digital carriers such as T1 and E1. G.703 provides specifications for pulse code modulation .G.703 also specifies E0...
as access interfaces.
SDMS was developed by Bellcore as an interim service until Asynchronous Transfer Mode
Asynchronous Transfer Mode
Asynchronous Transfer Mode is a standard switching technique designed to unify telecommunication and computer networks. It uses asynchronous time-division multiplexing, and it encodes data into small, fixed-sized cells. This differs from approaches such as the Internet Protocol or Ethernet that...
matured. In the mid-1990s, SMDS was replaced, largely by Frame Relay
Frame relay
Frame Relay is a standardized wide area network technology that specifies the physical and logical link layers of digital telecommunications channels using a packet switching methodology...
.
SMDS was notable for its initial introduction of the 53-byte cell and cell switching approaches, as well as the method of inserting 53-byte cells onto G.703 and SONET.