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ITU-T Q.931 (05/1998)

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ISDN user-network interface layer 3 specification for basic call control
This Recommendation specifies the procedures for the establishing, maintaining and clearing of network connections at the ISDN user-network interface. These procedures are defined in terms of messages exchanged over the D-channel of basic and primary rate interface structures. The functions and procedures of this protocol, and the relationship with other layers, are described in general terms in Recommendation Q.930/I.450 [1]. Annex M contains the additional basic call signalling requirement for the support of private network interconnection for VPN applications.
Approval date: 1998-05-15
Approval process:TAP
Status: In force
Observation:This Recommendation is also included but not published in I series under alias number I.451
Maintenance responsibility: ITU-T Study Group 11
Further details: Patent statement(s)
Ed. ITU-T Recommendation Status Summary Table of Contents Download
4.1 Q.931 (1998) Amd. 1 (12/2002) In force
4.0 Q.931 (1998) Erratum 1 (02/2003) In force - - here
4 Q.931 (05/1998) In force
3 Q.931 (03/1993) Superseded - - here
2 I.451/Q.931 (11/1988) Superseded -
1 I.451/Q.931 (10/1984) Superseded - - Not available