Integrated Services Digital Network (ISDN) – Signaling Specification of X.25 Packet-Switched Bearer Service for Digital Subscriber Signaling System Number 1 (DSS1)
|Publication Date:||1 November 1991|
The scope of this standard covers the following procedures at the S, T, or U reference point:
a) Circuit-switched access to Packet- Switched Public Data Network (PSPDN) services - case A.
This standard defines the use of the procedures of ANSI T1.602 and ANSI T1.607, when appropriate, on basic rate interfaces and primary rate interfaces for the establishment and release of circuit-switched calls through ISDN to the access port of PSPDN. These circuit-switched calls may be initiated by the user or the access port of PSPDN. Only the B-channel is used in this instance;
b) Packet-switched access to an ISDN virtual circuit service - case B.
This standard defines the use of the procedures of ANSI T1.602 and ANSI T1.607, when appropriate, on basic rate interfaces and primary rate interfaces for the establishment and release of packet-mode access connections to a packet-handling (PH) function provided within the ISDN. These packet- mode access connections may be initiated by the user or the Pl! function within the ISDN. B-channels and D-channels may be used in this instance;
c) X.25 LAPB procedures on the B-channel and LAPD procedures on the D-channel, as described in ANSI T1.602. X.25 LAP procedures are not supported in this standard;
d) X.25 packet level procedures on B-channels and D-channels.
NOTE - Alternative methods of access via any bearer channel to Packet-Switched Public Data Networks are for further study.
This interface standard was written to provide a set of requirements for user-network signaling for ISDN support of packetized data transfer, while conforming, wherever possible, with the I-Series Recommendations of the International Telegraph and Telephone Consultative Committee (CCITT), and while not compromising the principles of evolution expressed therein. Equipment may be implemented with additional functions and procedures.
This standard presents the procedures at the S, T, or U reference point for B-channel, and D-channel access connection on basic rate interfaces and primary rate interfaces to a Packet-Handling (PH) function within the Integrated Services Digital Network (ISDN) to support ISDN virtual circuit service. Procedures at the S, T, or U reference point for B-channel access to a Packet-Switched Public Data Network (PSPDN) are also specified.