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
����������������� 2.3.4���� Handling of level 3 messages
����������������� 2.3.5���� Handling of messages under signalling link congestion
������� 2.4���� Message discrimination and distribution functions
�3���� Signalling network management
������� 3.1���� General
������� 3.2���� Status of signalling links
����������������� 3.2.2���� Signalling link failure
����������������� 3.2.3���� Signalling link restoration
����������������� 3.2.4���� Signalling link deactivation
����������������� 3.2.5���� Signalling link activation
����������������� 3.2.6���� Signalling link blocking
����������������� 3.2.7���� Signalling link unblocking
����������������� 3.2.8���� Signalling link inhibiting
����������������� 3.2.9���� Signalling link uninhibiting
������� 3.3���� Procedures used in connection with link status changes
����������������� 3.3.1���� Signalling link failed
����������������� 3.3.2���� Signalling link restored
����������������� 3.3.3 ����Signalling link deactivated
����������������� 3.3.4���� Signalling link activated
����������������� 3.3.5���� Signalling link blocked
����������������� 3.3.6���� Signalling link unblocked
����������������� 3.3.7���� Signalling link inhibited
��������� ��������3.3.8���� Signalling link uninhibited
������� 3.4���� Status of signalling routes
����������������� 3.4.1���� Signalling route unavailability
����������������� 3.4.2���� Signalling route availability
����������������� 3.4.3���� Signalling route restricted1
������� 3.5���� Procedures used in connection with route status changes
����������������� 3.5.1���� Signalling route unavailable
����������������� 3.5.2���� Signalling route available
����������������� 3.5.3���� Signalling route restricted1
����� ��3.6���� Status of signalling points
����������������� 3.6.1���� Signalling point unavailability
����������������� 3.6.2���� Signalling point availability
������� 3.7���� Procedures used in connection with point status changes
����������������� 3.7.1���� Signalling point unavailable
����������������� 3.7.2���� Signalling point available
������� 3.8���� Signalling network congestion
����������������� 3.8.1���� General
����������������� 3.8.2���� Congestion status of signalling links
����������������� 3.8.3 ����Procedures used in connection with link congestion status changes
����������������� 3.8.4���� Congestion status of signalling route sets
����������������� 3.8.5���� Procedures used in connection with route set congestion status changes
�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 restriction1
������� 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
����������������� 9.7.1���� SP with restarting MTP according to subclause 9.2
����������������� 9.7.2���� Actions in SP X adjacent to SP Y whose MTP restarts according to subclause 9.3
10���� Management inhibiting
������ 10.1���� General
������ 10.2���� Inhibiting initiation and actions
������ 10.3���� Uninhibiting initiation and actions
���������������� 10.3.1���� Management-initiated uninhibiting
���������������� 10.3.2���� Signalling routing control initiated uninhibiting
������ 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
���������������� 11.2.1��� �Signalling route set unavailability
���������������� 11.2.2���� Signalling route set availability
���������������� 11.2.3���� Signalling route set congestion (International signalling network)
���������������� 11.2.4���� Signalling route set congestion (National option with congestion priorities)
���������������� 11.2.5���� Signalling route set congestion (National options without congestion priorities)
���������������� 11.2.6���� Signalling point/signalling transfer point congestion
���������������� 11.2.7���� User Part availability control
���������������� 11.2.8���� User Part congestion
12���� Signalling link management
������ 12.1���� General
������ 12.2���� Basic signalling link management procedures
���������������� 12.2.1���� Signalling link activation
���������������� 12.2.2���� Signalling link restoration
���������������� 12.2.3���� Signalling link deactivation
���������������� 12.2.4���� Link set activation
������ 12.3���� Signalling link management procedures based on automatic allocation of signalling terminals
���������������� 12.3.1���� Signalling link activation
���������������� 12.3.2���� Signalling link restoration
���������������� 12.3.3���� Signalling link deactivation
���������������� 12.3.4���� Link set activation
������ 12.4���� Signalling link management procedures based on automatic allocation of signalling data links and signalling terminals
���������������� 12.4.1���� Signalling link activation
���������������� 12.4.2���� Signalling link restoration
���������������� 12.4.3���� Signalling link deactivation
���������������� 12.4.4���� Link set activation
������ 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
���������������� 14.2.1���� Service indicator
���������������� 14.2.2���� Sub-service field
������ 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
���������������� 16.2.5��� �Notations for national operations
������ 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