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• CCITT Rec. Q.920 (11/1988) – ISDN USER-NETWORK INTERFACE DATA LINK LAYER – GENERAL ASPECTS
• 1 General
• 2 Concepts and terminology
• 3 Overview description of LAPD functions and procedures
  • 3.1 General
  • 3.2 Unacknowledged operation
  • 3.3 Acknowledged operation
  • 3.4 Establishment of information transfer modes
• 4 Service characteristics
  • 4.1 General
  • 4.2 Services provided to layer 3
  • 4.3 Services provided to layer management
  • 4.4 Administrative services
  • 4.5 Model of the data link service
  • 4.6 Services required from the physical layer
• 5 Data link layer - Management structure
  • 5.1 Data link procedure
  • 5.2 Multiplex procedure
  • 5.3 Structure of the data link procedure
• References