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- ANNEX A
- (to Recommendation Q.714)
- State diagrams for the signalling connection
- control part of Signalling System No. 7
- A.1 Introduction
- This Annex contains the definitions for the symbols used and defines the
- states of the signalling point X/Y interface and the transitions between states
- in the normal case.
- Annex B contains the full definition of actions, if any, to be taken on
- the receipt of messages by a signalling point.
- A.2 Symbol definition of the state diagrams at the message interface between
- two nodes (signalling points: X and Y) (see Figures A-1/Q.714 and
- A-2/Q.714)
- Figure A-1/Q.714 CCITT 19172
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- Figure A-2/Q.714 - CCITT 73120
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- A.3 Order definition of the state diagrams
- For the sake of clarity, the normal procedure at the interface is
- described in a number of small state diagrams. In order to describe the normal
- procedure fully, it is necessary to allocate a priority to the different figures
- and to relate a higher order diagram with a lower one. This has been done by the
- following means:
- - Figures A-3/Q.714, A-4/Q.714, A-5/Q.714 and A-6/Q.714 are arranged in
- order of priority, with Figure A-3/Q.714 having the highest priority
- and subsequent figures having lower priority. Priority means that when
- a message belonging to a higher order diagram is transferred, that
- diagram is applicable and the lower order one is not.
- - The relation with a state in a lower order diagram is given by
- including that state inside an ellipse in the higher order diagram.
- - The message abbreviations are those defined in Recommendation Q.712.
- Figure A-3/Q.714 - CCITT 19192
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- Fascicle VI.7 - Rec. Q.714 PAGE33
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- Figure A-4/Q.714 - CCITT 19201
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- Figure A-5/Q.714 - CCITT 73131
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- Figure A-6/Q.714 - CCITT 19210
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- ANNEX B
- (to Recommendation Q.714)
- Action tables for the signalling connection
- control part of Signalling System No. 7
- B.1 Introduction
- This Annex contains the definitions for the symbols used and contains the
- full definition of actions, if any, to be taken on the receipt of messages by a
- signalling point (node).
- Annex A contains the full definition of states of the signalling point X/Y
- interface and the transitions between states in the normal case.
- B.2 Symbol definition of the action tables
- The entries given in Table B-1/Q.714 and B-2/Q.714 indicate the action, if
- any, to be taken by a SP on receipt of any kind of message, and the state the SP
- enters, which is given in parentheses, following the action taken.
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- In any state it is possible to receive an Error message (ERR). The
- reaction, if any, depends on the contents (error cause and possible diagnostics)
- of the message and is specified in Q.714, S 3.10.3.
- The reaction on messages received with procedure errors (e.g. too long,
- invalid P(R), not octet aligned, etc.) are normal actions and will be described
- in the text. So they are covered by the actions indicated as NORMAL.
- B.3 Table of contents
- Table B-1/Q.714 Actions taken by SP-Y on receipt of messages.
- Table B-2/Q.714 Actions taken by SP-Y on receipt of messages with known
- message type and containing mismatch information.
- Table B-3/Q.714 Actions taken by SP-Y on receipt of messages during
- connection establishment and release phases.
- Table B-4/Q.714 Actions taken by SP-Y on receipt of messages during the
- data transfer phase in a given state: reset.
- Table B-5/Q.714 Actions taken by SP-Y on receipt of messages during the
- data transfer phase in a given state: data expedited
- data, flow control.
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- TABLE B-1/Q.714
- Action taken by SP-Y on receipt of messages
- State of the interface as perceived by node Any state
- SP-Y
- Message received by node SP-Y
- Any message with unknown message type (see DISCARD
- Note)
- Any message with known message type and: See Table B-2/Q.714
- a)unassigned destination local
- reference number, or
- b)Originating Point Code received
- not equal to the PC stored
- locally, or
- c)source local reference number
- received not equal to the remote
- local reference number stored
- locally
- Any other message See Table B-3/Q.714
- DISCARD: SP-Y discards the received message and takes no subsequent action
- Note - This notion of unknown message type depends upon the protocol class
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- TABLE B-2/Q.714
- Action taken by SP-Y on receipt of messages with known message type and
- containing mismatch information as in Table B-1/Q.714 in any state
- Type of mismatch
- information Unassigned Source local Originating Point
- Message destination local reference number Code received not
- received by node PS-Y reference number received not equal equal to the PC
- to the one stored stored locally
- locally (see Note 1)
- CR (X) N.A. N.A. N.A.
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- CC (Y, X) Send ERR (X) (see N.A. N.A.
- Note 2)
- CREF (Y) DISCARD N.A. N.A.
- RLSD (Y, X) Send RLC (X, Y) Send ERR (X) Send ERR (X)
- (see Note 2) (see Note 2) (see Note 2)
- RLC (Y, X) DISCARD DISCARD DISCARD
- DT1 (Y) DISCARD N.A. C.O.N.P.
- DT2 (Y) DISCARD N.A. C.O.N.P.
- AK (Y) DISCARD N.A. C.O.N.P.
- ED (Y) DISCARD N.A. C.O.N.P.
- EA (Y)
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- DISCARD N.A. C.O.N.P.
- RSR (Y, X) Send ERR (X) Send ERR (X) Send ERR (X)
- (see Note 2) (see Note 2) (see Note 2)
- RSC (Y, X) Send ERR (X) Send ERR (X) Send ERR (X)
- (see Note 2) (see Note 2) (see Note 2)
- ERR (Y) For further study For further study For further study
- IT (Y, X) DISCARD RELEASE C.O.N.P
- DISCARD: SP-Y discards the received message and takes no subsequent action.
- C.O.N.P. Check Optionally Not Performed.
- N.A. Not Applicable
- NAME (d, s): NAME = abbreviation of message
- d = destination local reference number
- s = source local reference number.
- Note 1 - Performing this check is a national option.
- Note 2 - In this situation no action is taken locally on any existing connection section.
- Information in any message sent back is taken from the received message.
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- TABLE B-3/Q.714
- Action taken by SP-Y on receipt of messages during connection establishment and release
- phases
- State of the
- interface Signalling connection control ready: r1
- as perceived by
- node SP-Y
- Message Ready SP-X SP-Y Data SP-X SP-Y
- received connecti connecti transfer disconne disconne
- by note SP-Y c1 on on ct ct
- pending pending c4 pending pending
- c2 c3 c5 c6
- Connexion request NORMAL See Note
- (CR) (c2)
- Connection confirm DISCARD NORMAL DISCARD ERROR 1 DISCARD
- (CC) (c2) (c4) (c4) (c6) (c6)
- Connection refused DISCARD NORMAL DISCARD ERROR 1 DISCARD
- (CREF) (c2) (c1) (c4) (c6) (c6)
- Released (RLSD) See DISCARD ERROR 2 NORMAL DISCARD
- Table (c2) (c3) (c5)
- B-2/Q.71
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- (c5) NORMAL
- (c1)
- Released complete DISCARD ERROR 3 DISCARD ERROR 1 NORMAL
- (RLC) (c2) (c1) (c4) (c6) (c1)
- Other messages DISCARD ERROR 3 See ERROR 1 DISCARD
- (c2) (c1) Table (c6) (c6)
- B-4/Q.71
- 4
- NORMAL: The action taken by SP-Y follows the normal procedures as defined in the
- appropriate sections of the procedure text.
- DISCARD: SP-Y discards the received message and takes no subsequent action.
- ERROR 1: SP-Y discards the received message and initiates a connection release by
- sending a RLSD message with proper invalid type cause.
- ERROR 2: SP-Y returns a Released complete message using information contained in the
- message and takes no subsequent action.
- ERROR 3: SP-Y discards the received message and releases locally.
- Note - Reception of CR in these states is note possible because CR does not contain a
- destination local reference number (no search is performed).
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- Fascicle VI.7 - Rec. Q.714 PAGE33
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- TABLE B-4/Q.714
- Action taken by node SP-Y as receipt of messages during the data transfer state
- State of the interface as Data transfer: c4
- perceived by node SP-Y
- Data SP-X SP-Y
- Message received by node SP-Y control reset reset
- ready request request
- (d1) (d2) (d3)
- Reset request (RSR)(see Note 2) NORMAL DISCARD NORMAL
- (d2) (d2) (d1)
- Reset confirmation (RSC)(see Note 2) ERROR ERROR NORMAL
- (d3) (d3) (d1)
- Other messages See ERROR DISCARD
- Table (d3) (d3)
- B-5/Q.71 (see
- 4 Note 1)
- NORMAL:The action taken by SP-Y follows the normal procedures as defined in
- the appropriate sections of the procedure text.
- DISCARD:Signalling point Y discards the received message and takes no
- subsequent action.
- ERROR:Signalling point Y discards the received message and initiates a reset
- by transmitting a reset request message with the appropriate cause
- indication.
- Note 1 - If signalling point Y issues a reset by transmitting a reset request
- message as a result of an error condition in state d2, it should eventually
- consider the interface to be in the Data control ready state (d1).
- Note 2 - Reception of these messages for a class 2 connection section may
- trigger the sending of an ERR message back if these message types are known by
- the receiving SCCP.
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- TABLE B-5/Q.714
- Action taken by SP-Y on receipt of messages during the data control ready state
- State of the interface
- as perceived by node SP-Y Data control ready: d1
- Normal SP-X SP-Y SP-X and
- data expedite expedite
- Message received by node SP-Y flow d data d data
- e1 e2 e3
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- SP-Y
- expedite
- d data
- e4
- Expedited data (ED) NORMAL ERROR NORMAL ERROR
- (d2) (d3) (d4) (d3)
- Expedited data (EA) acknowledgement DISCARD DISCARD NORMAL NORMAL
- (e1) (e2) (e1) (e2)
- Data (DT), data acknowledgement (AK) and NORMAL NORMAL NORMAL NORMAL
- Inactivity Test (IT) (e1) (e2) (e3) (e4)
- NORMAL:The action taken by signalling point Y follows the normal procedures as defined
- in the appropriate sections of the procedure text.
- DISCARD:Signalling point Y discards the received message and takes no subsequent
- action as direct result of receiving that message.
- ERROR:Signalling point Y discards the received message packet and indicates a reset
- by transmitting a reset request message with the appropriate cause indication
- (e.g. procedure error).
- Note - Reception of an ED, EA, DT2 or AK message for a class 2 connection section will
- cause the receiving SCCP to DISCARD any of these messages. A DT1 message received for a
- class 3 connection section will also be discarded.
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- Fascicle VI.7 - Rec. Q.714 PAGE33
-
- ANNEX C
- (to Recommendation Q.714)
- State transition diagrams (STD) for the signalling connection
- control part
- of Signalling System No. 7
- C.1 General
- This annex contains the description of the main SCCP functions (except
- SCCP management (SCMG) which is contained in annex D to Recommendation Q.714)
- according to the CCITT Specification and Description Language (SDL).
- For the SCCP as a whole, Figure 1/Q.714 illustrates a subdivision into
- functional blocks, showing their functional interactions as well as the
- functional interactions with the other major functions of signalling system No. 7
- (e.g. MTP).
- The functional breakdown shown in this diagram is intended to illustrate a
- reference model, and to assist interpretation of the text of the SCCP procedures.
- The state transition diagrams are intended to show precisely the behaviour of the
- signalling system under normal and abnormal conditions as viewed from a remote
- location. It must be emphasized that the functional partitioning shown in the
- following diagrams is used only to facilitate understanding of the system
- behaviour, and is not intended to specify the functional partitioning to be
- adopted in a practical implementation of the signalling system.
- C.2 Drafting conventions
- Each major function is designated by its acronym (e.g. SCOC = SCCP
- connection-oriented control).
- External inputs and outputs are used for interactions between different
- functional blocks. Included within each input and output symbol in the state
- transition diagrams are acronyms which identify the functional blocks which are
- the source and the destination of the message, e.g.:
- SCRC « SCOC indicates that the message is sent from SCCP routing control to
- SSCP connection-oriented control
- Internal inputs and outputs are only used to indicate control of timers.
- C.3 Figures
- The list of figures is as follows:
- Figure C-1/Q.714 SCCP routing control procedures (SCRC).
- Figure C-2/Q.714 Connection establishment and release procedures at
- originating node for SCCP connection-oriented control
- (SCOC).
- (Sheets 1 to 3: connection establishment, and sheets 4 to
- 6: connection release procedures)
- Figure C-3/Q.714 Connection establishment and release procedures at
- destination node for SCCP connection-oriented control
- (SCOC).
- (Sheets 1 to 2: connection establishment, and sheets 3 to 5:
- connection release procedures)
- Figure C-4/Q.714 Data transfer procedures at originating and destination
- nodes for SCCP connection-oriented control (SCOC).
- Figure C-5/Q.714 Expedited data transfer procedures at originating and
- destination nodes for SCCP connection-oriented control
- (SCOC).
- Figure C-6/Q.714 Reset procedures at originating and destination nodes for
- SCCP connection-oriented control (SCOC).
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- PAGE96 Fascicle VI.7 - Rec. Q.714
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- Figure C-7/Q.714 Connection establishment and release procedures at
- intermediate node for SCCP connection-oriented control
- (SCOC).
- (Sheets 1 to 4: connection establishment, and sheets 5 to 9:
- connection release procedures)
- Figure C-8/Q.714 Data transfer procedures at intermediate node for SCCP
- connection-oriented control (SCOC).
- Figure C-9/Q.714 Expedited data transfer procedures at intermediate node
- for SCCP connection-oriented control (SCOC).
- Figure C-10/Q.714 Reset procedures at intermediate node for SCCP
- connection-oriented control (SCOC).
- Figure C-11/Q.714 Restart procedure for SCCP connection-oriented control
- (SCOC).
- Figure C-12/Q.714 SCCP connectionless control (SCLC).
- C.4 Abbreviations and timers
- Abbreviations and timers used in Figures C-1/Q.714 to C-11/Q.714 are
- listed below.
- Abbreviations
- CR Connection Request
- DPC Destination Point Code
- GT Global Title
- IT Inactivity Test
- MSG Message
- MTP Message Transfer Part
- NPDU Network Protocol Data Unit
- NSDU Network Service Data Unit
- PC Point Code
- SCCP Signalling Connection Control Part
- SCLC SCCP Connectionless Control
- SCMG SCCP Management
- SCOC SCCP Connection-Oriented Control
- SCRC SCCP Routing Control
- SLS Signalling Link Selection
- SS Sub-System
- SSN Sub-System Number
- SSPC Sub-System Prohibited Control
- Timers
- T(conn est) Waiting for connection confirm message.
- T(ias) Delay to send a message on a connection section.
- T(iar) Waiting to receive a message on a connection section.
- T(rel) Waiting for release complete message.
- T(int) Waiting to report abnormal release to maintenance function.
- T(guard) Waiting to resume normal procedures for temporary connection
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- Fascicle VI.7 - Rec. Q.714 PAGE33
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- sections during the restart procedure
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- PAGE96 Fascicle VI.7 - Rec. Q.714
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- Figure C-1/Q.714 (feuillet 1 sur 3) - T1114960-88
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- Figure C-1/Q.714 (feuillet 2 sur 3) - T1114970-88
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- Figure C-1/Q.714 (feuillet 3 sur 3) - T1114980-88
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- Figure C-2/Q.714 (feuillet 1 sur 6) - T1114990-88
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- Figure C-2/Q.714 (feuillet 2 sur 6) - T1115000-88
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- Figure C-2/Q.714 (feuillet 3 sur 6) - T1115010-88
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- Figure C-2/Q.714 (feuillet 4 sur 6) - T1115020-88
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- Figure C-2/Q.714 (feuillet 5 sur 6) - T1115030-88
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- Figure C-2/Q.714 (feuillet 6 sur 6) - T1115040-88
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- Figure C-3/Q.714 (feuillet 1 sur 5) - T1115050-88
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- Figure C-3/Q.714 (feuillet 2 sur 5) - T1115060-88
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- Figure C-3/Q.714 (feuillet 3 sur 5) - T1115070-88
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- Figure C-3/Q.714 (feuillet 4 sur 5) - T1115080-88
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- Figure C-3/Q.714 (feuillet 5 sur 5) - T1115090-88
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