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Switched Multimegabit Data Service (SMDS) is a high-speed, packet-switched data communication service that was developed in the late 1980s and early 1990s. It is a wide-area networking (WAN) technology designed to transmit data at multimegabit speeds over metropolitan area networks (MANs) and wide area networks.

Key Features and Characteristics:

  1. Packet-Switched Technology: SMDS is based on a packet-switched technology, which means data is broken down into smaller packets before being transmitted over the network. Each packet is independently routed to its destination, and packets can take different paths based on network conditions.
  2. Connectionless Service: SMDS provides a connectionless service, which means that each data packet is treated independently, and no permanent connection is established between sender and receiver before data transmission.
  3. High Speed: SMDS was designed to deliver multimegabit speeds, offering faster data transmission compared to traditional services like Integrated Services Digital Network (ISDN) and T1/E1 lines.
  4. Broadband Service: It is considered a broadband service due to its high-speed data transmission capabilities.
  5. Asynchronous Transfer Mode (ATM) Core: SMDS uses an ATM core network, which allows for efficient data switching and supports various services, including voice, data, and video.
  6. Point-to-Point and Point-to-Multipoint: SMDS supports both point-to-point and point-to-multipoint connections, making it suitable for various networking scenarios.
  7. Scalability: SMDS is designed to be scalable, enabling network operators to expand and upgrade their networks to accommodate growing data demands.

Advantages of SMDS:

  1. High Speed Data Transmission: SMDS offers fast data transmission rates, making it ideal for applications that require large amounts of data to be transferred quickly.
  2. Flexibility: SMDS provides flexibility in network design, allowing users to create custom point-to-point and point-to-multipoint connections as needed.
  3. Cost-Effective for High-Bandwidth Applications: SMDS can be a cost-effective solution for organizations with high-bandwidth requirements, as it can handle significant data loads at relatively lower costs compared to other technologies.

Challenges and Limitations:

  1. Limited Coverage: SMDS was not widely adopted, and its coverage was limited to certain metropolitan areas. As a result, its availability and reach were restricted.
  2. Competition from Other Technologies: As other high-speed networking technologies emerged, such as Asynchronous Transfer Mode (ATM) and Frame Relay, they posed strong competition to SMDS, leading to its decline in popularity.
  3. Legacy Technology: SMDS is now considered a legacy technology, and its use has diminished over the years with the advancement of newer and more efficient networking technologies.


Switched Multimegabit Data Service (SMDS) played a role in the early evolution of high-speed data communication services, offering fast data transmission rates and flexibility in network design. However, with the emergence of more advanced and widely adopted technologies, SMDS has become less prevalent in modern networking environments. Nonetheless, it remains a milestone in the history of broadband data services and the development of wide-area networking technologies.

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