Rec. ITU-T Q.704 (03/1993) � SIGNALLING SYSTEM N. 7 � SIGNALLING NETWORK FUNCTIONS AND MESSAGES
FOREWORD
CONTENTS
1 Introduction
    1.1 General characteristics of the signalling network functions
    1.2 Signalling message handling
    1.3 Signalling network management
2 Signalling message handling
    2.1 General
    2.2 Routing label
    2.3 Message routing function
    2.4 Message discrimination and distribution functions
3 Signalling network management
    3.1 General
    3.2 Status of signalling links
    3.3 Procedures used in connection with link status changes
    3.4 Status of signalling routes
    3.5 Procedures used in connection with route status changes
    3.6 Status of signalling points
    3.7 Procedures used in connection with point status changes
    3.8 Signalling network congestion
4 Signalling traffic management
    4.1 General
    4.2 Normal routing situation
    4.3 Signalling link unavailability
    4.4 Signalling link availability
    4.5 Signalling route unavailability
    4.6 Signalling route availability
    4.7 Signalling route restriction
    4.8 Signalling point availability
5 Changeover
    5.1 General
    5.2 Network configurations for changeover
    5.3 Changeover initiation and actions
    5.4 Buffer updating procedure
    5.5 Retrieval and diversion of traffic
    5.6 Emergency changeover procedures
    5.7 Procedures in abnormal conditions
6 Changeback
    6.1 General
    6.2 Changeback initiation and actions
    6.3 Sequence control procedure
    6.4 Time-controlled diversion procedure
    6.5 Procedures in abnormal conditions
7 Forced rerouting
    7.1 General
    7.2 Forced rerouting initiation and actions
8 Controlled rerouting
    8.1 General
    8.2 Controlled rerouting initiation and actions
9 MTP restart
    9.1 General
    9.2 Actions in a signalling point whose MTP is restarting
    9.3 Actions in a signalling point X, adjacent to a signalling point Y whose MTP restarts
    9.4 Short term isolations
    9.5 TRA messages and timer T19
    9.6 General rules
    9.7 Sequence diagrams
10 Management inhibiting
    10.1 General
    10.2 Inhibiting initiation and actions
    10.3 Uninhibiting initiation and actions
    10.4 Receipt of unexpected management inhibition messages
    10.5 Management inhibited link status and processor recovery
    10.6 Inhibit test procedure
11 Signalling traffic flow control
    11.1 General
    11.2 Flow control indications
12 Signalling link management
    12.1 General
    12.2 Basic signalling link management procedures
    12.3 Signalling link management procedures based on automatic allocation of signalling terminals
    12.4 Signalling link management procedures based on automatic allocation of signalling data links and ...
    12.5 Automatic allocation of signalling terminals
    12.6 Automatic allocation of signalling data links
    12.7 Different signalling link management procedures at the two ends of a link set
13 Signalling route management
    13.1 General
    13.2 Transfer prohibited
    13.3 Transfer-allowed
    13.4 Transfer-restricted (National option)
    13.5 Signalling-route-set-test
    13.6 Transfer-controlled (International network)
    13.7 Transfer-controlled (National option with congestion priorities)
    13.8 Transfer-controlled (National option without congestion priorities)
    13.9 Signalling-route-set-congestion-test (National Option)
14 Common characteristics of message signal unit formats
    14.1 General
    14.2 Service information octet
    14.3 Label
15 Formats and codes of signalling network management messages
    15.1 General
    15.2 Label
    15.3 Heading code (H0)
    15.4 Changeover message
    15.5 Changeback message
    15.6 Emergency changeover message
    15.7 Transfer-prohibited message
    15.8 Transfer-allowed message
    15.9 Transfer-restricted message (national option)
    15.10 Signalling-route-set-test message
    15.11 Management inhibit message
    15.12 Traffic restart allowed message
    15.13 Signalling-data-link-connection-order message
    15.14 Signalling-data-link-connection-acknowledgement message
    15.15 Transfer-controlled message
    15.16 Signalling-route-set-congestion-test message (national option)
    15.17 User Part unavailable message
16 State transition diagrams, abbreviations and timers
    16.1 General
    16.2 Drafting conventions
    16.3 Signalling message handling
    16.4 Signalling traffic management
    16.5 Signalling link management
    16.6 Signalling route management
    16.7 Abbreviations used in Figures 23 onwards
    16.8 Timers and timer values