ISDN Q.922 Link Access Procedure - Frame Mode (LAPF)

DL

Section: The OpenSS7 Project Devices (4)
Updated: Mon, 22 Dec 2008 00:00:43 GMT
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NAME

dl, lapd, q921, lapf, q922, lapb, x25 - Link Access Procedure (D-Channel, Frame, Balanced) - ISDN Q.921/Q.922 Data Link, X.25

SYNOPSIS

#include <sys/dlpi.h>
#include <ss7/dl.h>
#include <ss7/dl_ioctl.h>
#include <sys/stropts.h>

int hdlc_stream = open(hdlc_device, flags);
int dl_stream = open(dl_device, flags);
int muxid = ioctl(dl_device, I_LINK, hdlc_device);

DESCRIPTION

DL
is an implementation of the Integrated Services Digital Network (ISDN) Data Link (LAPD/LAPF) as specified in ITU-T Recommendation Q.920/921[1, 2], and the Data Communications (LAPB) as specified in ITU-T Recommendation X.25[3].

DL streams can be linked under an isdn(4), iua(4), or other ISDN(4) multiplexing driver using the I_LINK or I_PLINK command of streamio(7), to provide data link services to the Layer 3 protocol. This is normally performed by the ISDN Configuration Daemon, isdnconfd(8).

DL is implemented as a STREAMS(4) multiplexing driver. hdlc(4) streams are linked under the DL multiplexing driver using the I_LINK or I_PLINK commands of streamio(7), to provide physical link services to DL. Once linked, the streams must be configured using dl_ioctl(4).

DL provides the following stream types. The dl_device argument to the open(2) call can be on of the following:

/dev/dl: This devices provides the DL protocol services interface using the DL-primitives of the Data Link Provider Interface (DLPI) described in dlpi(7).

IOCTLS

All interfaces support a set of management IO controls using ioctl(2) and streamio(7) I_STR system calls on the dl_stream. These management IO controls are documented in dl_ioctl(4).

FILES

<sys/dlpi.h>, <ss7/dl.h>, <ss7/dl_ioctl.h>.

MODULES

streams-dl.o.

VERSIONS

The DL module conforms to the DLPI Specification, Revision 2.0.0.

The DL module will first appear in strss7 release 0.8.4.

REFERENCES

[1]: ITU-T Recommendation Q.920, Digital Subscriber Signalling System No. 1 (DSS1) --- ISDN User-Network Interface Data Link Layer --- General Aspects, March 1993, (Geneva), ITU, ITU-T Telecommunication Standardization Sector of ITU. (Previously "CCITT Recommendation") <http://www.itu.int/rec/T-REC-Q.920/>
[2]: ITU-T Recommendation Q.921, Digital Subscriber Signalling System No. 1 --- ISDN User-Network Interface --- Data Link Layer Specification, March 1993, (Geneva), ITU, ITU-T Telecommunication Standardization Sector of ITU. (Previously "CCITT Recommendation") <http://www.itu.int/rec/T-REC-Q.921/>
[3]: ITU-T Recommendation X.25, Interface between Data Terminal Equipment (DTE) and Data Circuit-terminating Equipment (DCE) for terminals operating in the packet mode and connected to the public data networks by dedicated circuit, October 1996, (Geneva), ITU, ITU-T Telecommunication Standardization Sector of ITU. (Previously "CCITT Recommendation") <http://www.itu.int/rec/T-REC-X.25/>
[4]: ITU-T Recommendation Q.921 bis, Digital Subscriber Signalling System No. 1 --- Abstract Test Suite for LAPD Conformance Testing, March 1993, (Geneva), ITU, ITU-T Telecommunication Standardization Sector of ITU. (Previously "CCITT Recommendation") <http://www.itu.int/rec/T-REC-Q.921/>
[5]: DLPI, Data Link Provider Interface (DLPI) Specification, Revision 2.0.0, Draft 2, August 20, 1991, (Parsippany, New Jersey), UNIX. International,Inc., UNIX International Press. <http://www.openss7.org/doc/dlpi.pdf>

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IDENTIFICATION

The OpenSS7 Project: Package OpenSS7 version 0.9.2 released Mon, 22 Dec 2008 00:00:43 GMT.

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Time: 00:00:42 GMT, December 22, 2008