Logical Link Control

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Logical Link Control

Logical Link Control (LLC) is a data link layer protocol used in computer networks to establish, maintain, and terminate logical links between network devices. It encapsulates network layer protocols into data frames, adding addressing and control information for reliable data transmission.

What does Logical Link Control mean?

In computer networking, Logical Link Control (LLC) is a Data Link Layer protocol that provides a way for two devices on the same physical link to establish and maintain a logical connection. LLC is responsible for handling the following tasks:

  • Framing: LLC divides the incoming data stream into frames, which are units of data that can be transmitted over the physical link. Each Frame has a header that contains information about the source and destination devices, as well as the type of data being transmitted.
  • Addressing: LLC assigns unique addresses to each device on the physical link. These addresses are used to identify the source and destination devices of each frame.
  • Flow control: LLC ensures that the flow of data between devices is not interrupted. It does this by using a variety of techniques, such as pausing the transmission of data when the receiver is unable to Process it.
  • Error control: LLC detects and corrects errors that occur during the transmission of data. It does this by using a variety of techniques, such as calculating checksums and using error-correcting codes.

LLC is an important part of the data link layer. It provides the foundation for the higher-layer protocols, such as the Network Layer and the Transport Layer.

Applications

LLC is used in a wide variety of applications, including:

  • Local Area Networks (LANs): LLC is used to connect devices on a LAN. LANs are typically used in homes, offices, and schools.
  • Wide Area Networks (WANs): LLC is used to connect devices on a WAN. WANs are typically used to connect devices in different locations.
  • Wireless networks: LLC is used to connect devices on a wireless network. Wireless networks are typically used in homes, offices, and public places.

LLC is an important part of the data link layer. It provides the foundation for the higher-layer protocols, such as the Network Layer and the Transport Layer. LLC is used in a wide variety of applications, including LANs, WANs, and wireless networks.

History

LLC was developed in the early 1980s as part of the IEEE 802.2 standard. The IEEE 802.2 standard defines the data link layer for local area networks. LLC was designed to be a generic data link layer protocol that could be used with a variety of physical layer technologies, such as Ethernet, Token Ring, and FDDI.

LLC has been widely adopted in the networking industry. It is used in a variety of products, including routers, switches, and network interface cards. LLC is also used in a variety of operating systems, such as Windows, Linux, and Mac OS X.