INTERNATIONAL TELECOMMUNICATION UNION
`
`)45 4
`
`TELECOMMUNICATION
`STANDARDIZATION SECTOR
`OF ITU
`
`1(cid:14)(cid:23)(cid:16)(cid:16)
`(03/93)
`
`30%#)&)#!4)/.3/&3)’.!,,).’
`3934%-.O(cid:14)(cid:23)
`
`).42/$5#4)/.4/##)44
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`
`)45 4Recommendation1(cid:14)(cid:23)(cid:16)(cid:16)
`
`(Previously “CCITT Recommendation”)
`
`Ex. 1012
`YMax Corporation
`Page 1 of 24
`
`

`
`FOREWORD
`
`The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of the International Telecom-
`munication Union. The ITU-T is responsible for studying technical, operating and tariff questions and issuing
`Recommendations on them with a view to standardizing telecommunications on a worldwide basis.
`
`The World Telecommunication Standardization Conference (WTSC), which meets every four years, established the
`topics for study by the ITU-T Study Groups which, in their turn, produce Recommendations on these topics.
`
`ITU-T Recommendation Q.700 was revised by the ITU-T Study Group XI (1988-1993) and was approved by the WTSC
`(Helsinki, March 1-12, 1993).
`
`___________________
`
`NOTES
`
`As a consequence of a reform process within the International Telecommunication Union (ITU), the CCITT
`1
`ceased to exist as of 28 February 1993. In its place, the ITU Telecommunication Standardization Sector (ITU-T) was
`created as of 1 March 1993. Similarly, in this reform process, the CCIR and the IFRB have been replaced by the
`Radiocommunication Sector.
`
`In order not to delay publication of this Recommendation, no change has been made in the text to references containing
`the acronyms “CCITT, CCIR or IFRB” or their associated entities such as Plenary Assembly, Secretariat, etc. Future
`editions of this Recommendation will contain the proper terminology related to the new ITU structure.
`
`In this Recommendation, the expression “Administration” is used for conciseness to indicate both a
`2
`telecommunication administration and a recognized operating agency.
`
`All rights reserved. No part of this publication may be reproduced or utilized in any form or by any means, electronic or
`mechanical, including photocopying and microfilm, without permission in writing from the ITU.
`
` ITU 1994
`
`Ex. 1012
`YMax Corporation
`Page 2 of 24
`
`ª
`

`
`Recommendation Q.700 (03/93)
`
`CONTENTS
`
`1
`
`2
`
`3
`
`4
`
`5
`
`6
`
`7
`
`8
`
`9
`
`10
`
`General ...........................................................................................................................................................
`1.1
`Objectives and fields of application..................................................................................................
`1.2
`General characteristics......................................................................................................................
`1.3
`Components of SS No. 7 ..................................................................................................................
`1.4
`Description techniques in the Q.7xx-Series Recommendations .......................................................
`SS No. 7 signalling network...........................................................................................................................
`2.1
`Basic concepts ..................................................................................................................................
`2.2
`Signalling network components........................................................................................................
`2.3
`Signalling point modes .....................................................................................................................
`2.4
`Signalling routes ...............................................................................................................................
`2.5
`Signalling network structure.............................................................................................................
`SS No. 7 functional blocks.............................................................................................................................
`3.1
`Basic functional division ..................................................................................................................
`3.2
`SS No. 7 architecture ........................................................................................................................
`OSI layering and SS No. 7 .............................................................................................................................
`4.1
`OSI Layering ....................................................................................................................................
`4.2
`Relationship between SS No. 7 layering and the OSI model............................................................
`4.3
`Primitive Interfaces between SS No. 7 Functions ............................................................................
`Addressing .....................................................................................................................................................
`5.1
`Signalling message structure ............................................................................................................
`5.2
`MTP addressing ................................................................................................................................
`5.3
`SCCP addressing ..............................................................................................................................
`5.4
`User Part addressing .........................................................................................................................
`5.5
`Labelling...........................................................................................................................................
`Operations administration and maintenance ..................................................................................................
`6.1
`Management .....................................................................................................................................
`6.2
`Maintenance and testing ...................................................................................................................
`6.3
`SS No. 7 measurements ....................................................................................................................
`Signalling system performance ......................................................................................................................
`7.1
`Hypothetical Signalling Reference Connection (HSRC)..................................................................
`7.2
`MTP ..................................................................................................................................................
`7.3
`SCCP ................................................................................................................................................
`7.4
`TUP...................................................................................................................................................
`7.5
`ISUP..................................................................................................................................................
`Flow control ...................................................................................................................................................
`8.1
`Signalling network flow control .......................................................................................................
`8.2
`Signalling node (congestion) flow control........................................................................................
`Compatibility mechanisms and rules in SS No. 7 ..........................................................................................
`9.1
`Background.......................................................................................................................................
`9.2
`Evolutionary requirements................................................................................................................
`9.3
`Forward and backward compatibility ...............................................................................................
`9.4
`Compatibility rules for SS No. 7 ......................................................................................................
`Glossary..........................................................................................................................................................
`
`Page
`1
`1
`2
`2
`3
`3
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`3
`4
`5
`5
`6
`6
`7
`9
`9
`10
`10
`11
`12
`12
`15
`15
`16
`16
`16
`16
`17
`17
`17
`17
`17
`18
`18
`18
`18
`18
`18
`18
`19
`19
`19
`20
`
`Recommendation Q.700 (03/93)
`
`i
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`Ex. 1012
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`Ex. 1012
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`YMax Corporation
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`Page 4 of 24
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`Ex. 1012
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`Recommendation Q.700
`
`Recommendation Q.700 (03/93)
`
`INTRODUCTION TO CCITT SIGNALLING SYSTEM No. 7
`
`(Melbourne 1988; modified at Helsinki 1993)
`
`1
`
`General
`
`This Recommendation provides an overview of the Signalling System by describing the various functional elements
`of CCITT Signalling System No. 7 (SS No. 7) and the relationship between these functional elements. This
`Recommendation provides a general description of functions and capabilities of the Message Transfer Part (MTP),
`Signalling Connection Control Part (SCCP), Telephone User Part, ISDN User Part (ISUP), Transaction Capabilities
`(TC), and the Operations, Maintenance and Administration Part (OMAP) which are covered elsewhere in the
`Q.7xx-Series Recommendations. (This includes Recommendations Q.700 to Q.787.) However, in the case of
`contradiction between a particular specification and Recommendation Q.700, the particular specification shall apply.
`
`The SS No. 7 ISDN supplementary services are described in the Q.73x-Series Recommendations.
`
`In addition to these functions in the SS No. 7 signalling system, the Q.7xx Series Recommendations describes the
`SS No. 7 network structure, and also specifies the tests and measurements applicable to SS No. 7.
`
`This Recommendation also contains information about other aspects such as SS No. 7 architecture, flow control and
`general compatibility rule which are not specified in separate Recommendations, and are applicable to the overall scope
`of SS No. 7. Recommendation Q.1400 also contains information about architecture and compatibility.
`
`The remainder of this Recommendation describes:
`
`–
`
`–
`
`–
`
`–
`
`–
`
`–
`
`–
`
`–
`
`–
`
`clause 2:
`
`Signalling network concepts components and modes;
`
`clause 3:
`
`The functional blocks within SS No. 7 and the services provided by them;
`
`clause 4:
`
`SS No. 7 protocol layering and its relationship to OSI modelling;
`
`clause 5:
`
`Node, application entity and user part addressing;
`
`clause 6:
`
`Operations, administration and maintenance aspects of SS No. 7;
`
`clause 7:
`
`Performance aspects of the functional blocks within SS No. 7;
`
`clause 8:
`
`Flow control for both the signalling network and within nodes;
`
`clause 9:
`
`Rules for evolving SS No. 7 protocols while preserving compatibility with earlier versions;
`
`clause 10: A cross-reference to a glossary of terms.
`
`1.1
`
`Objectives and fields of application
`
`The overall objective of SS No. 7 is to provide an internationally standardized general purpose common channel
`signalling (CCS) system:
`
`–
`
`–
`
`optimized for operation in digital telecommunications networks in conjunction with stored program
`controlled exchanges;
`
`that can meet present and future requirements of information transfer for inter-processor transactions
`–
`within telecommunications networks for call control, remote control, and management and maintenance
`signalling;
`
`that provides a reliable means for transfer of information in correct sequence and without loss or
`duplication.
`
`The signalling system meets requirements of call control signalling for telecommunication services such as the
`telephone, ISDN and circuit switched data transmission services. It can also be used as a reliable transport system for
`other types of information transfer between exchanges and specialized centres in telecommunications networks (e.g. for
`
`Recommendation Q.700 (03/93)
`
`1
`
`Ex. 1012
`YMax Corporation
`Page 5 of 24
`
`

`
`management and maintenance purposes). The system is thus applicable for multipurpose uses in networks that are
`dedicated for particular services and in multiservices networks. The signalling system is intended to be applicable in
`international and national networks.
`
`The scope of SS No. 7 encompasses both circuit related and non-circuit related signalling.
`
`Examples of applications supported by SS No. 7 are:
`
`–
`
`–
`
`–
`
`PSTN;
`
`ISDN;
`
`Interaction with Network Databases, Service Control Points for service control;
`
`– Mobiles (Public Land Mobile Network);
`
`–
`
`Operations Administration and Maintenance of Networks.
`
`The signalling system is optimized for operation over 64 kbit/s digital channels. It is also suitable for operation over
`analogue channels and at lower speeds. The system is suitable for use on point-to-point terrestrial and satellite links. It
`does not include the special features required for use in point-to-multipoint operation but can, if required, be extended to
`cover such an application.
`
`1.2
`
`General characteristics
`
`Common channel signalling is a signalling method in which a single channel conveys, by means of labelled messages,
`signalling information relating to, for example, a multiplicity of circuits, or other information such as that used for
`network management. Common channel signalling can be regarded as a form of data communication that is specialized
`for various types of signalling and information transfer between processors in telecommunications networks.
`
`The signalling system uses signalling links for transfer of signalling messages between exchanges or other nodes in the
`telecommunication network served by the system. Arrangements are provided to ensure reliable transfer of signalling
`information in the presence of transmission disturbances or network failures. These include error detection and
`correction on each signalling link. The system is normally applied with redundancy of signalling links and it includes
`functions for automatic diversion of signalling traffic to alternative paths in case of link failures. The capacity and
`reliability for signalling may thus be dimensioned by provision of a multiplicity of signalling links according to the
`requirements of each application.
`
`1.3
`
`Components of SS No. 7
`
`SS No. 7 consists of a number of components or functions which are defined in the Q.7xx-Series Recommendations.
`
`SS No. 7 function
`
`Message Transfer Part (MTP)
`
`Recommendations
`
`Q.701-Q.704, Q.706, Q.707
`
`Telephone User Part (TUP) (including some supplementary services)
`
`Q.721-Q.725
`
`Supplementary services
`
`Data User Part (DUP)
`
`ISDN User Part (ISUP)
`
`Signalling Connection Control Part (SCCP)
`
`Transaction Capabilities (TC)
`
`Operations Maintenance and Administration Part (OMAP)
`
`NOTE – Functions of the DUP are fully specified in Recommendation X.61.
`
`2
`
`Recommendation Q.700 (03/93)
`
`Q.73x Series
`
`Q.741 (see Note)
`
`Q.761-Q.764, Q.766
`
`Q.711-Q.714, Q.716
`
`Q.771-Q.775
`
`Q.750-Q.755
`
`Ex. 1012
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`Page 6 of 24
`
`

`
`Other Q.7xx-Series Recommendations which describe other aspects of the signalling system which are not part of the
`SS No. 7 signalling interfaces are:
`
`Title
`
`Signalling Network Structure
`
`Numbering of International Signalling Point Codes
`
`Hypothetical signalling reference connection
`
`PABX application
`
`SS No. 7 Test Specification (General)
`
`MTP Level 2 Test Specification
`
`MTP Level 3 Test Specification
`
`TUP Test Specification
`
`ISUP Test Specification
`
`ISUP Supplementary Service Test Specification
`
`SCCP Test Specification
`
`TCAP Test Specification
`
`Clause 3 describes the relationship between these components.
`
`Recommendations
`
`Q.705
`
`Q.708
`
`Q.709
`
`Q.710
`
`Q.780
`
`Q.781
`
`Q.782
`
`Q.783
`
`Q.784
`
`Q.785
`
`Q.786
`
`Q.787
`
`1.4
`
`Description techniques in the Q.7xx-Series Recommendations
`
`The SS No. 7 Recommendation Series defines the signalling system using prose description which is complemented by
`SDL diagrams and state transition diagrams. Should any conflict arise between the text and the SDL definition, the
`textual description is taken as definitive.
`
`Message sequence charts or arrow diagrams are used to illustrate examples of signalling procedures, but are not
`considered definitive.
`
`Data description are increasingly using ASN.1 method of description.
`
`2
`
`SS No. 7 signalling network
`
`2.1
`
`Basic concepts
`
`A telecommunications network served by common channel signalling is composed of a number of switching and
`processing nodes interconnected by transmission links. To communicate using SS No. 7, each of these nodes requires to
`implement the necessary “within node” features of SS No. 7 making that node a signalling point within the SS No. 7
`network. In addition, there will be a need to interconnect these signalling points such that SS No. 7 signalling
`information (data) may be conveyed between them. These data links are the signalling links of SS No. 7 signalling
`network.
`
`The combination of signalling points and their interconnecting signalling links form the SS No. 7 signalling network.
`
`2.2
`
`Signalling network components
`
`2.2.1
`
`Signalling points
`
`In specific cases there may be a need to partition the common channel signalling functions at such a (physical) node into
`logically separate entities from a signalling network point of view; i.e. a given (physical) node may be defined as more
`than one signalling point. One example is an exchange at the boundary between international and national signalling
`networks.
`
`Any two signalling points, for which the possibility of communication between their corresponding User Part function
`exists, are said to have a signalling relation.
`
`The corresponding concept for a given User Part is called a user signalling relation.
`
`Recommendation Q.700 (03/93)
`
`3
`
`Ex. 1012
`YMax Corporation
`Page 7 of 24
`
`

`
`An example is when two telephone exchanges are directly connected by a bundle of speech circuits. The exchange of
`telephone signalling relating to these circuits then constitutes a user signalling relation between the Telephone User Part
`functions in those exchanges in their role as signalling points.
`
`Another example is when administration of customer and routing data in a telephone exchange is remotely controlled
`from an operation and maintenance centre by means of communication through a common channel signalling system.
`
`Examples of nodes in a signalling network that constitutes signalling points are:
`
`–
`
`–
`
`–
`
`–
`
`exchanges (switching centres);
`
`service control points;
`
`signalling transfer points;
`
`operation, administration and maintenance centres.
`
`All signalling points in a SS No. 7 network are identified by a unique code known as a point code (Recommen-
`dation Q.704 refers).
`
`2.2.2
`
`Signalling links
`
`The common channel signalling system uses signalling links to convey the signalling messages between two signalling
`points. A number of signalling links that directly interconnect two signalling points which are used as a module
`constitute a signalling link-set. Although a link set typically includes all parallel signalling links, it is possible to use
`more than one link set in parallel between two signalling points. A group of links within a link set that have identical
`characteristics (e.g. the same data link bearer rate) is called a link group.
`
`Two signalling points that are directly interconnected by a signalling link are, from a signalling network structure point
`of view, referred to as adjacent signalling points. Correspondingly, two signalling points that are not directly
`interconnected are non-adjacent signalling points.
`
`2.2.3
`
`Signalling modes
`
`The term “signalling mode” refers to the association between the path taken by a signalling message and the signalling
`relation to which the message refers.
`
`In the associated mode of signalling, the messages relating to a particular signalling relation between two adjacent points
`are conveyed over a link set, directly interconnecting those signalling points.
`
`In the non-associated mode of signalling, the messages relating to a particular signalling relation are conveyed over two
`or more linksets in tandem passing through one or more signalling points other than those which are the origin and the
`destination of the messages.
`
`The quasi-associated mode of signalling is a limited case of the non-associated mode where the path taken by the
`message through the signalling network is pre-determined and, at a given point in time, fixed.
`
`SS No. 7 is specified for use in the associated and quasi-associated modes. The Message Transfer Part does not include
`features to avoid out-of-sequence arrival of messages or other problems that would typically arise in a fully non-
`associated mode of signalling with dynamic message routing.
`
`Examples of signalling modes are illustrated in Figure 1.
`
`2.3
`
`Signalling point modes
`
`A signalling point at which a message is generated, i.e. the location of the source User Part function, is the originating
`point of that message.
`
`A signalling point to which a message is destined, i.e. the location of the receiving User Part function, is the destination
`point of that message.
`
`For a particular signalling relation, the two signalling points thus function as originating and destination points for the
`messages exchanged in the two directions between them.
`
`4
`
`Recommendation Q.700 (03/93)
`
`Ex. 1012
`YMax Corporation
`Page 8 of 24
`
`

`
`Associated
`
`Associated
`
`Quasi-associated
`
`Quasi-associated
`
`Associated
`
` Signalling relation
`
`Signalling link set
`
`T1156060-93/d01
`
`Signalling point with at least user function;
`whether or not STP-function is present is irrelevant in the context of the graph
`
`Signalling point with at least STP-function;
`whether or not user function is present is irrelevant in the context of the graph
`
`Signalling point with both user function and STP-function
`
`Signalling point;
`irrelevant whether user function and/or STP-function is present
`
`FIGURE 1/Q.700
`Example of associated and quasi-associated signalling modes
`and definition of signalling network graph symbols
`
`FIGURE 1/Q.700...[D01] = 11 CM
`
`A signalling point at which a message is received on one signalling link and is transferred to another link, i.e. neither the
`location of the source nor the receiving User Part function, is a Signal Transfer Point (STP).
`
`In the quasi-associated mode, the function of a signalling transfer point is typically located in a few signalling points
`which may be dedicated to this function, or may combine this function with some other (e.g. switching) function. A
`signalling point serving as a signalling transfer point functions as an originating and destination point for the messages
`generated and received by the level 3 function of the MTP also in cases when no user functions are present.
`
`2.4
`
`Signalling routes
`
`The pre-determined path, consisting of a succession of signalling points/signalling transfer points and the
`interconnecting signalling links, that a message takes through the signalling network between the origination point and
`the destination point is the signalling route for that signalling relation.
`
`All the signalling routes that may be used between an originating point and a destination point by a message traversing
`the signalling network is the signalling route set for that signalling relation.
`
`2.5
`
`Signalling network structure
`
`The signalling system may be used with different types of signalling network structures. The choice between different
`types of signalling network structures may be influenced by factors such as the structure of the telecommunication
`network to be served by the signalling system and administrative aspects.
`
`In the case when the provision of the signalling system is planned purely on a per signalling relation basis, the likely
`result is a signalling network largely based on associated signalling, typically supplemented by a limited degree of quasi-
`associated signalling for low volume signalling relations. The structure of such a signalling network is mainly
`determined by the patterns of the signalling relations.
`
`Recommendation Q.700 (03/93)
`
`5
`
`Ex. 1012
`YMax Corporation
`Page 9 of 24
`
`

`
`Another approach is to consider the signalling network as a common resource that should be planned according to the
`total needs for common channel signalling. The high capacity of digital signalling links in combination with the needs
`for redundancy for reliability then typically leads to a signalling network based on a high degree of quasi-associated
`signalling with some provision for associated signalling for high volume signalling relations. The latter approach to
`signalling network planning is more likely to allow exploitation of the potential of common channel signalling to support
`network features that require communication for purposes other than the switching of connections.
`
`The worldwide signalling network is structured into two functionally independent levels, namely the international and
`national levels. This structure makes possible a clear division of responsibility for signalling network management and
`allows numbering plans of signalling points of the international network and the different national networks to be
`independent of one another.
`
`Further considerations about the structure of the signalling network are given in Recommendation Q.705, and the impact
`on the message transfer part in Recommendation Q.701.
`
`3
`
`SS No. 7 functional blocks
`
`3.1
`
`Basic functional division
`
`The SS No. 7 comprises the following functional blocks:
`
`– Message Transfer Part (MTP)
`
`–
`
`–
`
`–
`
`–
`
`–
`
`–
`
`Telephone User Part (TUP)
`
`ISDN User Part (ISUP)
`
`Signalling Connection Control Part (SCCP)
`
`Transaction Capabilities (TC)
`
`Application-Entity (AE) (see Note)
`
`Application-Service-Elements (ASEs) (see Note)
`
`NOTE – The glossary shows these as hyphenated terms but the usual convention used in this Recommendation will
`be unhyphenated.
`
`The fundamental principle of the signalling system structure is the division of functions into a common Message
`Transfer Part (MTP) on one hand, and separate User Parts for different users on the other. This is illustrated in Figure 2.
`
`The overall function of the Message Transfer Part is to serve as a transport system providing reliable transfer of
`signalling messages between the locations of communicating user functions.
`
`User functions in SS No. 7 MTP terms are:
`
`–
`
`–
`
`–
`
`–
`
`the ISDN User Part (ISUP)
`
`the Telephone User Part (TUP)
`
`the Signalling Connection Control Part (SCCP)
`
`the Data User Part (DUP)
`
`The term “User” in this context refers to any functional entity that utilises the transport capability provided by the
`Message Transfer Part.
`
`A User Part comprises those functions of, or related to, a particular type of user that are part of the common channel
`signalling system, typically because those functions need to be specified in a signalling context.
`
`The SCCP also has Users. These are:
`
`–
`
`–
`
`–
`
`the ISDN User Part (ISUP)
`
`Transaction Capabilities (TC)
`
`Operations Maintenance and Administration Part (OMAP)
`
`6
`
`Recommendation Q.700 (03/93)
`
`Ex. 1012
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`Page 10 of 24
`
`

`
`Users of SS No. 7
`
`TC user
`
`Transaction Capabilities (TC)
`
`ISDN User Part
`(ISDN-UP)
`(Level 4)
`
`Telephone
`User Part
`(TUP)
`(Level 4)
`
`Signalling Connection
`Control Part
`(SCCP) (Level 4)
`
`Others
`MTP users
`
`MTP (Levels 1-3)
`
`T1156070-93/d02
`
`FIGURE 2/Q.700
`Architecture of SS No. 7
`
`Layers
`
`7
`
`4-6
`(Null)
`
`3
`
`2 1
`
`FIGURE 2/Q.700...[D02] = 11.5 CM
`
`3.2
`
`SS No. 7 architecture
`
`3.2.1
`
`General
`
`From the perspective of an end user, the service provided by a telecommunications network may be regarded as a
`Network Layer service. However, from a signalling network perspective, the service may be provided at a different
`layer/level.
`
`Figure 2 shows the Architecture of SS No. 7 and illustrates the functional relationship between the various functional
`blocks of the SS No. 7 and between the SS No. 7 levels and the OSI Reference Model Layers. This level/layer
`relationship is described in the following subclauses.
`
`The initial specification of SS No. 7 was based on circuit-related telephony control requirements. To meet these
`requirements, SS No. 7 was specified in four functional levels, the Message Transfer Part comprising levels 1-3, and the
`User Parts as level 4.
`
`Figure 3 shows the Functional Levels of SS No. 7. As new requirements have emerged, e.g. for non-circuit related
`information transfer, SS No. 7 has also evolved to meet these new requirements. There has been a need to align certain
`elements in SS No. 7 to the OSI 7 Layer Reference Model (see 4.2).
`
`3.2.2
`
`Message Transfer Part (MTP) levels 1-3
`
`An overview of the MTP is given in Recommendation Q.701. The MTP is defined in Recommendations Q.701-Q.704,
`Q.706 and Q.707.
`
`3.2.2.1
`
`Signalling data link functions (level 1)
`
`Level 1 defines the physical, electrical and functional characteristics of a signalling data link and the means to access it.
`The level 1 function provides a bearer for a signalling link.
`
`The detailed requirements for signalling data links are specified in Recommendation Q.702.
`
`Recommendation Q.700 (03/93)
`
`7
`
`Ex. 1012
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`Page 11 of 24
`
`

`
`ISDN-UP
`(Level 4)
`
`SCCP
`(Level 4)
`
`TUP
`(Level 4)
`
`Signalling network functions
`(Level 3)
`
`Signalling link functions
`(Level 2)
`
`Signalling data link functions
`(Level 1)
`
`Examples of
`Users Parts
`(Level 4)
`
`Message
`Transfer Part
`(Levels 1-3)
`
`T1156080-93/d03
`
`FIGURE 3/Q.700
`SS No. 7 functional levels
`
`FIGURE 3/Q.700...[D03] = 8.5 CM
`
`3.2.2.2
`
`Signalling link functions (level 2)
`
`Level 2 defines the functions and procedures for and relating to the transfer of signalling messages over one individual
`signalling data link. The level 2 functions together with a level 1 signalling data link as a bearer, and provides a
`signalling link for reliable transfer of signalling messages between two points.
`
`The detailed requirements for signalling functions are given in Recommendation Q.703.
`
`3.2.2.3
`
`Signalling network functions (level 3)
`
`Level 3 in principle defines those transport functions and procedures that are common to and independent of the
`operation of individual signalling links. These functions fall into two major categories:
`
`a)
`
`b)
`
`Signalling message handling functions – These transfer the message to the proper signalling link or
`User Part.
`
`Signalling network management functions – These control the current message routing and configuration
`of the signalling network facilities and in the case of signalling network failures, control the
`reconfigurations and other actions to preserve or restore the normal message transfer capability.
`
`The detailed requirements for signalling network functions are given in Recommendation Q.704.
`
`3.2.3
`
`Level 4: MTP User functions
`
`Level 4 consists of the different User Parts. Each User Part defines the functions and procedures of the signalling system
`that are particular to a certain type of user of the system. The following entities are defined as User Parts in SS No. 7.
`
`3.2.3.1
`
`Signalling Connection Control Part (SCCP)
`
`The SCCP is defined in Recommendations Q.711-Q.716. The SCCP provides additional functions to the Message
`Transfer Part to provide connectionless and connection-oriented network services to transfer circuit-related, and non-
`circuit-related signalling information.
`
`The SCCP provides the means to
`
`–
`
`–
`
`control logical signalling connections in a SS 7 network;
`
`transfer Signalling Data Units across the SS 7 network with or without the use of logical signalling
`connections.
`
`8
`
`Recommendation Q.700 (03/93)
`
`Ex. 1012
`YMax Corporation
`Page 12 of 24
`
`

`
`SCCP provides a routing function which allows signalling messages to be routed to a signalling point based on, for
`example, dialled digits. This capability involves a translation function which translates the global title (e.g. dialled digits)
`into a signalling point code and a sub-system number.
`
`SCCP also provides a management function, which controls the availability of the “sub-systems”, and broadcasts this
`information to other nodes in the network which have a need to know the status of the “sub-system”. An SCCP
`sub-system is an SCCP User.
`
`3.2.3.2 Telephone User Part (TUP)
`
`The SS No. 7 Telephone User Part is defined in Recommendations Q.721-725. The TUP Recommendations define the
`international telephone call control signalling functions for use over SS No. 7.
`
`3.2.3.3 Data User Part (DUP)
`
`The Data User Part is referenced in Recommendation Q.741, and the functionality fully defined in Recommenda-
`tion X.61. It defines