ISDN Q.921-User Adaptation Layer (IUA)

IUA

Section: OpenSS7 STREAMS SIGTRAN Devices (4)
Updated: 2008-10-31
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NAME

iua, dl-iua - ISDN Q.921 User Adaptation Layer (IUA)

SYNOPSIS

#include <sys/stropts.h>
#include <sys/dlpi.h>
#include <sys/dlpi_iua.h>
#include <ss7/iua_ioctl.h>

int iua_stream = open(iua_device, flags);

DESCRIPTION

IUA
is an implementation of the ISDN Q.921 User Adaptation Layer (IUA) defined in RFC 4233[1]. IUA provides a backhaul of the services of the lapd(4) over an IP network using Stream Control Transmission Protocol, sctp(4), as defined in RFC 2960.

IUA is implementated as a STREAMS(4) multiplexing driver. lapd(4) or sctp(4) streams are linked under the IUA multiplexing driver using the I_LINK or I_PLINK commands of streamio(7), to provide transport to remote ASP or SG, or direct LAPD services to IUA. Once linked, the streams must be configured using iua_ioctl(4) IO controls. This is normally performed by the ISDN Configuration Daemon, isdnconfd(8).

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

IUA provides the following lapd(4) devices. The iua_device argument to the open(2) call can be one of the following:

/dev/iua: This device provides the lapd(4) protocol service interface using the DL-primitives of the Data Link Provider knterface (DLPI) described in dlpi(7), with the corrigendum described in dlpi_iua(7). Streams that result from opening this device are directly compatible with lapd(4) streams. This interface is suitable for use with other SS7 modules and drivers or directly by user-level programs using the dlpi(7) interface.

NOTICES

Unlike other OpenSS7 protocol modules and drivers providing transport services, IUA does not provide a sockets(3) interface.

When acting as a Signalling Gateway (SG), streams on this device are not necessarily opened and the SG runs as kernel daemon only.

IUA can be configured on a system as a drop in transparent replacement for lapd(4). In such a configuration, users opening streams or sockets as defined in lapd(4) will be opening iua() streams and sockets, but will be unaware of the difference. In OpenSS7, iua() is used as the primary mechanism of redundancy and distribution at the data link layer, and, when properly configurated (see isdnconfd(8)), iua() functions transparently to the ISDN Layer 3.

Also, opening and binding an iua() stream may result in the opening and binding of a lapd(4) stream on the local or remote host in direct support of the local ISDN user.

IOCTLS

All interfaces support a set of management IO controls using ioctl(2) and the I_STR command to the streamio(7) system call on the iua_stream file descriptor. These management controls are documented in iua_ioctl(4).

In addition, iua supports dl(4) IO controls. See dl_ioctl(4).

FILES

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

DEVICES

/dev/iua.

AUTHOR

Brian F. G. Bidulock <bidulock@openss7.org>
The OpenSS7 Project http://www.openss7.org/

VERSIONS

The IUA driver is specific to the OpenSS7 stack.

The interface conforms to DLPI Revsion 2.

REFERENCES

[1]: RFC 4233, Integrated Services Digital Network (ISDN) Q.921-User Adaptation Layer, January 2006, Ken Morneault, ed., The Internet Society. (Obsoletes RFC 3057) <http://www.ietf.org/rfc/rfc4233.txt>
[2]: 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/>
[3]: 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/>
[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>

TRADEMARKS

OpenSS7tm: is a trademark of OpenSS7 Corporation.
Linux®: is a registered trademark of Linus Torvalds.
UNIX®: is a registered trademark of The Open Group.
Solaris®: is a registered trademark of Sun Microsystems.

Other trademarks are the property of their respective owners.

IDENTIFICATION

OpenSS7 STREAMS SIGTRAN: Package sigtran version 0.9.2.4 released 2008-10-31.

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Time: 09:03:36 GMT, December 12, 2024