(Table 14/Q.711) is used to inform the SCCP management about the status
of the originating user. The
\*QN\(hySTATE indication\*U primitive is used to inform an SCCP user
accordingly.
.bp
.RT
.ce
\fBH.T. [T14.711]\fR
.ce
TABLE\ 14/Q.711
.ce
\fBParameters of the primitive N\(hySTATE\fR
.ps 9
.vs 11
.nr VS 11
.nr PS 9
.TS
center box;
cw(84p) | cw(42p) sw(42p) , ^ | c | c.
Parameter Primitive
N\(hySTATE request N\(hySTATE indication
_
.T&
lw(84p) | cw(42p) | cw(42p) .
Affected subsystem X X
_
.T&
lw(84p) | cw(42p) | cw(42p) .
User status X X
_
.T&
lw(84p) | cw(42p) | cw(42p) .
{
Subsystem multiplicity indicator
} X
_
.TE
.nr PS 9
.RT
.ad r
\fBTableau 14/Q.711 [T14.711], p.\fR
.sp 1P
.RT
.ad b
.RT
.LP
.sp 1
.sp 1P
.LP
2.3.2.3.3
\fIPCSTATE\fR
.sp 9p
.RT
.PP
The \*Q
N\(hyPCSTATE primitive
\*U (Table 15/Q.711) is used to
inform a user about the status of a signalling point.
.RT
.ce
\fBH.T. [T15.711]\fR
.ce
TABLE\ 15/Q.711
.ce
\fBParameters of the primitive N\(hyPCSTATE\fR
.ps 9
.vs 11
.nr VS 11
.nr PS 9
.TS
center box;
cw(72p) | cw(48p) , ^ | c.
Parameter Primitive
N\(hyPCSTATE indication
_
.T&
lw(72p) | cw(48p) .
Affectedd DPC X
_
.T&
lw(72p) | cw(48p) .
Signalling Point Status X
_
.TE
.nr PS 9
.RT
.ad r
\fBTableau 15/Q.711 [T15.711], p.\fR
.sp 1P
.RT
.ad b
.RT
.LP
.sp 1
.sp 2P
.LP
\fB3\fR \fBServices assumed from the MTP\fR
.sp 1P
.RT
.sp 1P
.LP
3.1
\fIDescription\fR
.sp 9p
.RT
.PP
This paragraph describes the functional interface offered by the
MTP to the upper layer functions, i.e.,\ the SCCP and the User Parts. In
order to align the terminology with the OSI\(hyModel, the description uses
the terms
\*Qprimitives\*U and \*Qparameters\*U.
.bp
.RT
.sp 1P
.LP
3.2
\fIPrimitives and parameters\fR
.sp 9p
.RT
.PP
The primitives and parameters are shown in Table\ 16/Q.711.
.RT
.LP
.sp 4
.ce
\fBH.T. [T16.711]\fR
.ce
TABLE\ 16/Q.711
.ce
\fBMessage transfer part service primitives\fR
.ps 9
.vs 11
.nr VS 11
.nr PS 9
.TS
center box;
cw(60p) sw(60p) | cw(60p) , c | c | ^ .
Primitives Parameters
Generic Name Specific Name
_
.T&
lw(60p) | lw(60p) | lw(60p) .
MTP\(hyTRANSFER Request Indication OPC DPC SLS SIO User Data
_
.T&
lw(60p) | lw(60p) | lw(60p) .
MTP\(hyPAUSE (Stop) Indication Affected DPC
_
.T&
lw(60p) | lw(60p) | lw(60p) .
MTP\(hyRESUME (Start) Indication Affected DPC
_
.T&
lw(60p) | lw(60p) | lw(60p) .
MTP\(hySTATUS Indication {
Affected DPC
Cause | ua\d\u)\d
}
.TE
.LP
\ua\d\u)\d
The cause parameter has, at present, two values:
.LP
\fBi\fR
i)
\fISignalling network congested (level)\fR
.LP
This level value is applicable if national option with congestion priorities and multiple signalling link states without congestion priorities as in Recommendation\ Q.704 is implemented.
.LP
ii)
\fIRemote user unavailable.\fR
.nr PS 9
.RT
.ad r
\fBTableau 16/Q.711 [T16.711], p.\fR
.sp 1P
.RT
.ad b
.RT
.LP
.sp 5
.sp 1P
.LP
3.2.1
\fITRANSFER\fR
.sp 9p
.RT
.PP
The primitive \*QMTP\(hyTRANSFER\*U is used between level 4 and level\ 3
(SMH) to provide the MTP message transfer service.
.RT
.sp 1P
.LP
3.2.2
\fIPAUSE\fR
.sp 9p
.RT
.PP
The primitive \*QMTP\(hyPAUSE\*U indicates to the SCCP total inability
of providing the MTP service to the specified destination.
.PP
This primitive corresponds to the destination inaccessible state as
defined in Recommendation\ Q.704.
.bp
.RT
.sp 1P
.LP
3.2.3
\fIRESUME\fR
.sp 9p
.RT
.PP
The primitive \*QMTP\(hyRESUME\*U indicates to the SCCP total ability of
providing the MTP service to the specified destination.
.PP
This primitive corresponds to the destination accessible state as
defined in Recommendation\ Q.704.
.RT
.sp 1P
.LP
3.2.4
\fISTATUS\fR
.sp 9p
.RT
.PP
The primitive \*QMTP\(hySTATUS\*U indicates to the SCCP partial inability
of providing the MTP service to the specified destination, or the
unavailability of the remote peer user. The response of the SCCP for the
latter case is for further study.
.PP
In the case of national option with congestion priorities and multiple
signalling link congestion states without priorities as in Recommendation\
Q.704 is implemented, this \*QMTP\(hySTATUS\*U primitive is also used to
indicate a change of congestion level.
.PP
This primitive corresponds to the destination congested state as
defined in Recommendation\ Q.704.
.RT
.sp 2P
.LP
\fB4\fR \fBFunctions provided by the SCCP\fR
.sp 1P
.RT
.PP
This section is an overview of the functional blocks within the
SCCP.
.RT
.sp 2P
.LP
4.1
\fIConnection\(hyoriented functions\fR
.sp 1P
.RT
.sp 1P
.LP
4.1.1
\fIFunctions for temporary signalling connections\fR
.sp 9p
.RT
.sp 1P
.LP
4.1.1.1
\fIConnection establishment functions\fR
.sp 9p
.RT
.PP
The connection establishment service primitives defined in
\(sc\ 2 are used to set up a signalling connection.
.PP
The main functions of the connection establishment phase are listed
below:
.RT
.LP
\(em
Setup of a signalling connection;
.LP
\(em
Establish the optimum size of NPDUs (Network Protocol Data
Unit);
.LP
\(em
Map network address onto signalling relations;
.LP
\(em
Select functions operational during data transfer phase (for
instance, layer service selection);
.LP
\(em
Provide means to distinguish network connections;
.LP
\(em
Transport user data (within the request).
.sp 1P
.LP
4.1.1.2
\fIData transfer phase function\fR
.sp 9p
.RT
.PP
The data transfer phase functions provide means for a two\(hyway
simultaneous transport of messages between the two endpoints of the signalling
connection.
.PP
The main functions of the data transfer phase as listed below are used
or not used in accordance with the result of the selection performed in
the
connection establishment phase.
.RT
.LP
\(em
Segmenting/reassembling,
.LP
\(em
Flow control,
.LP
\(em
Connection identification,
.LP
\(em
NSDU delimiting (M\(hyBit),
.LP
\(em
Expedited data,
.LP
\(em
Missequence detection,
.LP
\(em
Reset,
.LP
\(em
Receipt confirmation
.FS
The need for this functions is for
further study.
.FE
,
.LP
\(em
Others.
.LP
.sp 1
.bp
.sp 1P
.LP
4.1.1.3
\fIRelease phase functions\fR
.sp 9p
.RT
.PP
These functions provide disconnection of the signalling connection, regardless
of the current phase of the connection. The release may be
performed by an upper layer stimulus or by maintenance of the SCCP itself.
The release can start at each end of the connection (symmetrical procedure).
.PP
The main function of the release phase is the disconnection.
.RT
.sp 2P
.LP
4.1.2
\fIFunctions for permanent signalling connections\fR
.sp 1P
.RT
.sp 1P
.LP
4.1.2.1
\fIConnection establishment phase and connection release\fR
\fIphase functions\fR
.sp 9p
.RT
.PP
The setup and release for permanent signalling connections are for further
study. The stimuli for setup and release of permanent connections are originated
from the Administration function.
.RT
.sp 1P
.LP
4.1.2.2
\fIData transfer phase functions\fR
.sp 9p
.RT
.PP
The functions for the data transfer on permanent signalling
connections correspond to that for temporary connections. Differences may
exist regarding the quality of service. This matter is for further study.
.RT
.sp 1P
.LP
4.2
\fIConnectionless service functions\fR
.sp 9p
.RT
.PP
The functions of the connectionless service are listed
below:
.RT
.LP
\(em
mapping the network address to signalling relations,
.LP
\(em
sequence service classification.
.sp 1P
.LP
4.3
\fIManagement functions\fR | (for further study)\fR
.sp 9p
.RT
.PP
The SCCP provides functions which manage the status of the SCCP
subsystems. These functions allow other nodes in the network to be informed
of the change in status of SCCP subsystems at a node, and to modify SCCP
translation data if appropriate. Subsystem congestion management is for
further study.
.PP
Functions are also provided to allow a coordinated change of status of
replicated SCCP subsystems. At present, this allows a replicated subsystem
to be withdrawn from service.
.PP
When a subsystem is out of service, SCCP test functions are activated at
nodes receiving unavailability information. At periodic intervals the status
of the unavailable subsystem is checked by a SCCP management procedure.
.PP
Broadcast functions within SCCP management broadcast subsystem status changes
to nodes within the network which have an immediate need to be informed
of a particular signalling point/subsystem status change.
.PP
Notification functions to local subsystems within the node (local
broadcast) are also provided.
.RT
.sp 1P
.LP
4.4
\fIRouting and translation functions\fR (for further study)
.sp 9p
.RT
.PP
The SCCP routing provides a powerful address translation function, which
is asked for connectionless and connection\(hyoriented service. Detailed
description of the SCCP routing function can be found in Recommendation\
Q.714, \(sc\(sc\ 2.2 and\ 2.3.
.PP
The basic translation function performed by the SCCP is to transfer
the SCCP address parameter from a global title to a point code and a subsystem
number. Other translation results are also possible. The global title form
of the address could typically be dialed digits (e.g.\ a Freephone (800)
number). Several standardized CCITT numbering plans may be supported by
SCCP; details
are given in Recommendation\ Q.713, \(sc\ 3.4.
.PP
The address translation capabilities of the SCCP in relation to
handling OSI Network Service Access Points (NSAP) are for further study.
.bp
.RT
.ce 1000
ANNEX\ A
.ce 0
.ce 1000
(to Recommendation Q.711)
.sp 9p
.RT
.ce 0
.ce 1000
\fBOSI network layer conformance\fR
.sp 1P
.RT
.ce 0
.PP
The following information should be taken into account when
reading Recommendation\ Q.711 in relation to the provision of an OSI network
layer service.
.sp 1P
.RT
.PP
All references to connectionless classes 0 and 1 are not included in Recommendation\
X.200.
.sp 1P
.LP
\fI\(sc 2.1.1\fR
.sp 9p
.RT
.PP
The Connection identification parameters in the following
primitives are implicit in Recommendation\ X.213:
.RT
.LP
N\(hyCONNECT
.LP
N\(hyDATA
.LP
N\(hyEXPEDITED DATA
.LP
N\(hyDATA ACKNOWLEDGE
.LP
N\(hyDISCONNECT
.LP
N\(hyRESET
.PP
The N\(hyINFORM primitive does not exist within
Recommendation\ X.213.
.PP
The connection establishment interface elements described in
\(sc\ 2.1.1.3.2 is not required to support an OSI network layer
service.
.RT
.sp 1P
.LP
\fI\(sc 2.1.2\fR
.sp 9p
.RT
.PP
Permanent connection services are not defined in
Recommendation\ X.200 and are not required to support an OSI network layer
service. The service is offered by the SCCP for specific No.\ 7
applications.
.RT
.sp 1P
.LP
\fI\(sc 2.2\fR
.sp 9p
.RT
.PP
Connectionless network service is still under study in Study
Group\ VII and is not defined in Recommendation\ X.213.
.RT
.sp 1P
.LP
\fI\(sc 2.3\fR
.sp 9p
.RT
.PP
This section on SCCP management is not defined in
Recommendation\ X.213 and none of the primitives exist in OSI.
.RT
.ce 1000
APPENDIX
.ce 0
.ce 1000
(to Recommendation Q.711)
.sp 9p
.RT
.ce 0
.ce 1000
\fBUnresolved issues in SCCP Recommendations\fR
.sp 1P
.RT
.ce 0
.PP
This appendix lists the topics in SCCP on which study is
continuing in the next study period. It is not an exhaustive list, but does
indicate where the Recommendations might change. In these areas, RPOAs
may need to supplement the Recommendations, but in such a way as not to
conflict with
ongoing work; implementors should consider likely future developments and,
where possible, design to accommodate these.
.sp 1P
.RT
.PP
The topics under study are listed below; the references are to the Blue Book.
.LP
1)
Inter\(hynodal communication model with SCCP connectionless
service (\(sc\ 1.3.3, Rec.\ Q.711);
.LP
2)
Delivery confirmation service (N\(hyDATA ACKNOWLEDGE primitive)
(Table 1/Q.711);
.LP
3)
Transitions caused by N\(hyDATA ACK primitive
(Figure\ 7/Q.711);
.bp
.LP
4)
Facilities causing differences in the called and responding
addresses in N\(hyCONNECT request and response
(\(sc\ 2.1.1.2.2, Rec.\ Q.711);
.LP
5)
The need for Receipt Confirmation Service in SCCP
(\(sc\(sc\ 2.1.1.2.2 and 4.1.1.2, Rec.\ Q.711);
.LP
6)
Connection identification parameter inclusion in Request
types\ 1 and\ 2, and reply primitives between SCCP and ISUP
(\(sc\ 2.1.1.3.2, Rec.\ Q.711);
.LP
7)
Connection identification parameter inclusion in N\(hyCONNECT,
N\(hyDATA, N\(hyEXPEDITED DATA, N\(hyRESET, and N\(hyDISCONNECT primitives
