Data Link Layer (DLL)

Layer 2 of the seven-layer Open Systems Interconnection (OSI) Reference

Model. Software at the Data Link Layer is responsible for addressing, signal formatting (i.e., line encoding and decoding), framing, frame synchronization and sequencing, flow control, error control, and otherwise managing traffic between devices across a link. HDLC, LAP-B, and LAP-D are Data Link Layer protocols, as is frame relay. Local area networks (LANs) operate at the Data Link and Physical Layers. See also error control, flow control, frame relay, HDLC, LAP-B, LAP-D, layer, link, network architecture, OSI Reference Model, protocol, software, and synchronization.

• unicast address
• Unicode Consortium
• Unicode Transformation Format (UTF)
• Unicode (Universal code)
• unified communications
• unified messaging
• unified messaging
• unified messaging
• uniform call distributor (UCD)
• uniform dialing plan (UDP)
• Uniform Resource Identifier (URI)
• Uniform Resource Locator (URL)
• U-NII (Unlicensed National Information Infrastructure)
• uninterruptible power supply (UPS)
• unipolar
• United Nations/Electronic Data Interchange For Administration, Commerce, and Transport
• United Nations (UN)
• United States Computer Emergency Readiness Team (US-CERT)
• United States Digital Cellular (USDC)
• United States Independent Telephone Association (USITA)
• United States Telecom Association (USTA)
• United States Time Division Multiple Access (US TDMA)
• UNI (User Network Interface)
• universal ADSL (universal Asymmetric Digital Subscriber Line Lite)
• Universal Character Set (UCS)