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Data Link Layer

The second layer of the OSI model, responsible for node-to-node data transfer and error detection on the physical link.

Categorynetwork

Overview

The Data Link Layer (Layer 2) provides a reliable link between two directly connected nodes. It packages data from the Network Layer into frames and handles physical addressing.

Sublayers

  • Logical Link Control (LLC): Manages communication between the network layer and the lower sublayer.
  • Media Access Control (MAC): Controls how devices gain access to the physical medium and uses MAC addresses for identification.

Key Functions

  • Framing: Organizing bits into identifiable units.
  • Physical Addressing: Using MAC addresses to identify source and destination.
  • Error Detection: Using techniques like Cyclic Redundancy Check (CRC).
  • Flow Control: Preventing a fast sender from overwhelming a slow receiver.

Related Terms

OSI ModelMAC AddressSwitch