Editing LAPB (section)

[[Image:LAPBstateDiagram.JPG|thumb|200px|LAPB state Diagram]]
'''Link Access Procedure, Balanced''' ('''LAPB''') implements the [[data link layer]] as defined in the [[X.25]] protocol suite. LAPB is a [[bit-oriented protocol]] derived from [[HDLC]] that ensures that frames are error free and in the correct sequence.  LAPB is specified in ITU-T Recommendation X.25 and ISO/IEC 7776.  It implements the connection-mode data link service in the [[OSI Model|OSI Reference Model]] as defined by ITU-T Recommendation X.222.

LAPB is used to manage communication and packet framing between [[Data terminal equipment|data terminal equipment (DTE)]] and the [[Data circuit-terminating equipment|data circuit-terminating equipment (DCE)]] devices in the [[X.25]] protocol stack. LAPB is essentially HDLC in [[Asynchronous Balanced Mode]] (ABM). LAPB sessions can be established by either the DTE or DCE. The station initiating the call is determined to be the primary, and the responding station is the secondary.