Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
INTRODUCTION TO SIGNALING SYSTEM 7 Saad Haj Bakry, Saad Haj Bakry PhD, CEng, FIEE SS7 INTRODUCTION TO SS7 Telecommunications Standards Emergence of SS7 SS7 Structure SS7 Protocols Saad Haj Bakry Introduction to Signaling System 7 TELECOMMUNICATIONS STANDARDS Saad Haj Bakry SS7 TELECOM. STANDARDS Standards ITU & Study Groups ITU Recommendations Saad Haj Bakry ISO-IEC: JTC1 JTC1 Committees Other / Management Organizations SS7 STANDARDS WHY Compatibility Quality Protection Saad Haj Bakry ORGANIZATIONS Interoperability / Efficiency National / Government: e.g. ANSI Open Market International / Governments: e.g. ITU Reliable Products Regional: e.g. ETSI Safe Products Industrial: e.g. EIA Professional: e.g. IEEE For update: www.itu.org SS7 ITU Standards INTERNATIONAL TELECOM. UNION Members: Countries Members: Companies ITU-R: Radio Communications Sector ITU-T: Standardization Sector ITU-D: Development Sector Saad Haj Bakry 189 655 7 Groups Terrestrial Frequencies Satellite Networks Satellite Earth Stations Groups Standards Annual Standards 1,265,000 590 3163 13 2700 210 Groups Support to developing countries 2 For update: www.itu.org SS7 ITU Standards ITU-T Study Groups: 1/2 Reference: Houlin ZHAO, ITU Presentation in Riyadh, March 2004 Study Group 2: Operational aspects of service provision, networks and performance Study Group 3: Tariff and accounting principles including related telecommunications economic and policy issues Study Group 4: Telecommunication management, including TMN Study Group 5: Protection against electromagnetic environment effects Study Group 6: Outside plant Study Group 9: Integrated broadband cable networks and television and sound transmission Study Group 11: Signaling requirements and protocols Saad Haj Bakry For update: www.itu.org SS7 ITU Standards ITU-T Study Groups: 2/2 Houlin ZHAO, ITU Presentation in Riyadh, March 2004 Study Group 12: End-to-end transmission performance of networks and terminals Study Group 13: Multi-protocol and IP-based networks and their internetworking Study Group 15: Optical and other transport networks Study Group 16: Multimedia services, systems and terminals Study Group 17: Data networks and telecommunication software SSG: IMT-2000 and Beyond TSAG: Saad Haj Bakry Telecommunication Standardization Advisory Group (Priorities: IP, Mobility, next generation, security, …) For update: www.itu.org SS7 ITU Standards ITU-T Recommendations Series: 1/3 Houlin ZHAO, ITU Presentation in Riyadh, March 2004 Series AOrganization of the work of the ITU-T Series B Means of expression: definitions, symbols, classification Series C General telecommunication statistics Series D General tariff principles Series E Overall network operation, telephone service, service operation and human factors Series F Non-telephone telecommunication services Series G Transmission systems and media, digital systems and networks Series H Audiovisual and multimedia systems Series I Integrated services digital network Saad Haj Bakry For update: www.itu.org SS7 ITU Standards ITU-T Recommendations Series: 2/3 Houlin ZHAO, ITU Presentation in Riyadh, March 2004 Series J Transmission of television, sound programme and other multimedia signals Series K Protection against interference Series L Construction, installation and protection of cables and other elements of outside plant Series M TMN and network maintenance: international transmission systems, telephone circuits, telegraphy, facsimile and leased circuits Series N Maintenance: international sound programme and television transmission circuits Series O Specifications of measuring equipment Series P Telephone transmission quality, telephone installations, local line networks Saad Haj Bakry For update: www.itu.org SS7 ITU Standards ITU-T Recommendations Series: 3/3 Houlin ZHAO, ITU Presentation in Riyadh, March 2004 Series Q Switching and signalling Series R Telegraph transmission Series S Telegraph services terminal equipment Series T Terminals for telematic services Series U Telegraph switching Series V Data communication over the telephone network Series X Data networks and open system communication Series Y Global information infrastructure and internet protocol aspects Series Z Languages and general software aspects for telecommunication systems Saad Haj Bakry ITU: ISO-IEC: JTC1 For update: www.iso.org SS7 International Standards Organization International Electro-technical Commission Total Membership Number of Main Committees Number of Associated Committees Total Standards Recent Annual Standards IEC ISO 102 143 186 179 552 4820 13544 465 813 ISO-IEC Joint Technical Committee for IT JTC1 Number of Associated Committees 27 Total Standards 1698 Saad Haj Bakry SS7 For update: www.iso.org ITU: ISO-IEC: JTC1 Joint Technical Committee for IT JTC1 International Members 45 Working Members: Participating in the work Saad Haj Bakry 24 Experts 2100 Active Committees 19 Non-Active Committees 8 ISO TC Working with JTC1 20 IEC TC Working with JTC1 10 Recent Annual Standards 106 For update: www.iso.org SS7 ITU: JTC1 Committees ISO / IEC JTC1 Standards Committees: 1/5 SEQ CODE COMMITTEE STATE A/N MEMBERS NO. OF WKG. ATT. STAND. 24 42 565 1 JTC1 Joint Technical Committee for IT A 2 SC01 Vocabulary N 3 SC02 Coded Character Sets A 34 13 48 4 SC06 Telecommunications & Information Exchange Between Systems A 18 23 366 5 SC07 Software Engineering A 28 20 69 6 SC11 Flexible Magnetic Media for Digital Data Interchange A 7 24 87 Saad Haj Bakry For update: www.iso.org SS7 ITU: JTC1 Committees ISO / IEC JTC1 Standards Committees: 2/5 SEQ CODE COMMITTEE STATE A/N 7 SC14 Data Elements Principles N 8 SC15 Volume and File Structure N 9 SC17 Identification Cards and Related Devices A 10 SC18 Document Processing and Related Communication N SC21 Open Systems Interconnection, Data Management and Open Distributes Processing N 11 Saad Haj Bakry MEMBERS NO. OF WKG. ATT. STAND. 32 11 54 For update: www.iso.org SS7 ITU: JTC1 Committees ISO / IEC JTC1 Standards Committees: 3/5 SEQ CODE COMMITTEE STATE A/N MEMBERS NO. OF WKG. ATT. STAND. A 23 20 72 12 SC22 Programming Languages, Their Environments and System Software Interfaces 13 SC23 Optical Disk Cartridges for Information Interchange. A 11 18 33 14 SC24 Computer Graphics and Image Processing A 14 19 55 15 SC25 Interconnection of IT Equipment A 24 13 64 16 SC26 Microprocessor Systems N 17 SC27 IT Security Techniques A 24 42 46 Saad Haj Bakry For update: www.iso.org SS7 ITU: JTC1 Committees ISO / IEC JTC1 Standards Committees: 4/5 COMMITTEE STATE A/N SC28 Office Equipment 19 SEQ CODE MEMBERS NO. OF WKG. ATT. STAND. A 34 13 22 SC29 Coding of Audio, Picture, Multimedia, and Hypermedia Information A 18 23 94 20 SC30 Open Electronic Data Interchange N 21 SC31 Automatic Data Capture A 24 13 64 22 SC32 Data Management Services A 7 24 46 23 SC33 Distributed Application Services N 18 Saad Haj Bakry 8 SS7 For update: www.iso.org ITU: JTC1 Committees ISO / IEC JTC1 Standards Committees: 5/5 SEQ CODE COMMITTEE STATE A/N MEMBERS NO. OF WKG. ATT. STAND. 24 SC34 Document Description and Processing Languages A 32 11 37 25 SC35 User Interfaces A 23 20 19 26 SC36 Learning Technology A 11 18 0 27 SC37 Biometrics A 14 19 0 Total: 1698 Standards Active Committees: 1515 Standards Non-Active Committees: 183 Standards Annual Number of New Standards: Over 100 Saad Haj Bakry 1515 183 SS7 Other Organizations OTHER ORGANIZATIONS: 1/4 Ab. Organization / Address Country ANSI American National Standard Institute: www.ansi.org USA BSI British Standard Institute: www.bsi-global.com UK SCC Standards Council of Canada: www.scc.ca Canada SPRING Singapore Program for Productivity and Innovation: www.stanadards.org.sg Singapore SASO Saad Haj Bakry Saud Arabia Standards Organization: www.saso.org.sa KSA SS7 Other Organizations OTHER ORGANIZATIONS: 2/4 Ab. Organization / Address NISO National Information Standards Organization: www.niso.org (works with ANSI) IEEE Institute of Electrical and Electronics Engineers: www.ieee.org (works with ANSI) BSI British Standard Institute: www.bsi-global.com (special committees) UK ITSC Information Technology Standards Committee: www.cio.gov.on.ca (works with e-Government, Ontario) Canada ITSC Information Technology Standards Committee: www.standards.org.sg (works with SPRING) Singapore SASO Saud Arabia Standards Organization: www.saso.org.sa (special committees) KSA Saad Haj Bakry Country USA SS7 Other Organizations OTHER ORGANIZATIONS: 3/4 Ab. Organization Country ETSI European Telecommunications Standards Institute Europe ATM Forum Industrial: 800 members / HQ California Frame Relay Forum IETF Saad Haj Bakry Industrial: HQ California Internet Engineering Task Force International Singapore KSA SS7 Other Organizations OTHER ORGANIZATIONS: 4/4 Ab. Organization / Address IMTC International Multimedia Telecommunications Consortium: 150 Companies / HQ: California JPEG MPEG IMA MMCF Saad Haj Bakry Joint Photographic Expert Group Motion Picture Expert Group Interactive Multimedia Association Multi-Media Communications Forum Country International: Professional / Industrial SS7 Management Organizations MANAGEMENT ORGANIZATIONS Ab. Organization Country FCC Federal Communication Commission USA CITCC Saudi “Communications and Information Technology Commission” KSA Saad Haj Bakry Introduction to Signaling System 7 EMERGENCE OF SIGNALING SYSTEM 7 Saad Haj Bakry SS7 EMERGENCE OF SS7 Networking Functions Evolution Common Channel Signaling Call Connection Line Signaling Signaling Methods Saad Haj Bakry Intelligence SS7 SS7 Services: Current / Potential SS7 Emergence of SS7 NETWORKING FUNCTIONS User s SS7 Services Chargin g Signaling Switching Transmission Saad Haj Bakry User s SS7 SS7 Emergence of SS7 EVOLUTION OF SIGNALLING SS6 Activating electric current Analog Signals: Over the switched network SS7 Digital messages over packetswitched networks 1960s Time Electrical Current Saad Haj Bakry Analog Signals Digital Signals Emergence of SS7 SS7 CALL CONNECTION 1 Request 2 Dialing / Routing 3 4 Off hook supervisory (ready) signal Dialed digits: destination address Routing: path to destination (using routing information tables) Connection Preparing connections Readiness requirements. Permission Decision On hook supervisory (release) 5 Termination signal Saad Haj Bakry Emergence of SS7 SS7 LINE SIGNALLING Circuit Related Signaling Call Progress Signals Supervisory Signals Caller notifications: ring back, busy signal, “all lines are busy”,… Control Signals Signals (tones) sent from device to another over the route. Status: on-or-off hook (off-hook: request for service). Access Signals Dialing tones provides the address. Alerting Incoming call notification: ringing. Signals Saad Haj Bakry Emergence of SS7 SS7 SIGNALLING METHODS Method In-Band Signaling Out-of-Band Signaling Digital Messages Saad Haj Bakry Concept Problem Within the analog Interference telephone 4kHz with the voice band: 300 – 3800 Hz signal Using: 0-300 & 3800-4000 Still causing distortion Separate path (links) for signaling information (digital messages): signaling and controlling switches and databases (intelligence) Emergence of SS7 SS7 SIGNALLING INTELLIGENCE Emergence: Stored Program Control Storing Information: Databases Processing Information: Example (FCC): Local Using information (static) number portability Autonomous: Less human intervention Saad Haj Bakry Changing information (dynamic) Emergence of SS7 SS7 COMMON CHANNEL SIGNALLING Intelligent Common Channel: Stored Program Control A single channel with suitable capacity that can accommodate all signaling (messages) required Switches / Exchanges Saad Haj Bakry Emergence of SS7 SS7 SIGNALLING SYSTEM 7: 1/2 The heart of: The backbone “signaling and control” of modern communications networks Saad Haj Bakry Telephone companies Long distance providers Cellular providers (intelligence +) Emergence of SS7 SS7 SIGNALLING SYSTEM 7: 2/2 The communications network for communications equipment: Control and signaling information between switches Saad Haj Bakry A data network that uses data messages to allow switches to communicate with other switches and with data bases Emergence of SS7 SS7 SS7 SERVICES: CURRENT (1/2) Service Portability of Local Number Explanation Numbers no longer associated with exchanges (geography). They can be kept fixed. Number translation using databases. Routing to real address 800 & 900 Numbers Saad Haj Bakry Unified area code Translation & Routing (as above) Emergence of SS7 SS7 SS7 SERVICES: CURRENT (2/2) Service Congestion Avoidance Remote Maintenance Others Explanation Automatic re-routing in case of congestion or failure: switch or link Congestion / Failure management Network monitoring Failure detection and correction management: for most cases Intelligence: e.g. diversion of calls Higher “Reliability”, but More “Cost” Saad Haj Bakry Emergence of SS7 SS7 SS7 SERVICES: POTENTIAL Service Configure your own services Explanation Providing customers with access to system switches Customer: activate / deactivate services (dynamic use of services) e.g. Customer can increase his number of lines (800): during sale / peak days Advantages: efficiency / opportunity Future Services Saad Haj Bakry Use of intelligence: new services / less human intervention / higher performance Introduction to Signaling System 7 SIGNALING SYSTEM 7 STRUCTURE Saad Haj Bakry SS7 Structure SS7 STRUCTURE Basic Structure Design Principles Signaling Points Signaling Transfer Points Saad Haj Bakry Links SS7 Structure BASIC STRUCTURE SP SP SCP Transfer Point Mated STPs STP A Regional STP Local STP D B STP SSP A Saad Haj Bakry Service Control Point D Mated STPs C STP STP D A Service Switching Point B A E End Point SP STP C Control Point SCP B B D C Mated STPs A SSP A SP STP Signal Transfer Point F SS7 Structure DESIGN PRINCIPLESP: INTEGRITY Principe Explanation Redundancy STP in pair: Mated STPs Channels in pair: 2 channels to any one node. Common Facility A number of channels in one facility: e.g. channels in T-3 Diversity Channels should be provided on different facility (avoiding failure) Utilization Channel utilization “40 % or less”: to allow for other channel failure Saad Haj Bakry SS7 Structure SIGNALLING POINTS: SP Issue Explanation Generic name: Signaling Point General It is where messages are originated: SSP Where information are available: SCP Service Switching Point (SSP): End Point Specific Mobile Switching Center (MSC): End Point Service Control Point (SCP): Control Point (Database: Intelligence Subsystem) Saad Haj Bakry SS7 Structure SIGNAL TRANSFER POINT: STP Issue Explanation Similar to a “Switch” in PSTN Selects links (route), and directs outgoing traffic (digital signals): Transfer Point Function Local STP: User connection; this is the lowest level in SS7 hierarchy. Regional STP: Connecting local STPs; this is the highest level in SS7 hierarchy. STP Pair Should not be under the same hazard e,.g. Not on the same earthquake fault Saad Haj Bakry SS7 Structure STP: GLOBAL TTITLE Global Title (Dialed Digits): Called Party Address (e.g. Mobile Identification Number: MIN or Telephone Number) Global Title Translation: Looking at Signaling Connection Control Part (SCCP) Use of Database Saad Haj Bakry Routing Decision SS7 Structure STP: ROUTE SELECTION Route Set: Group of routes Routes: Group of Link-sets Link-Sets: Group of Links Use of Database Saad Haj Bakry Links SS7 Structure SS7 LINKS: 1/2 Link Explanation A Access Access to STP B Bridge STP-to-STP: C D Saad Haj Bakry Cross Diagonal Routing Flexibility Pairing STPs: Redundancy STP-to-STP: Additional Routing Strength SS7 Structure SS7 LINKS: 2/2 Link E Extended F Fully Associated Capacity Saad Haj Bakry Explanation Link to Distant STP Pair: Further Routing Strength Bypassing STPs: For Nodes Associated with Same Company Usually “64 kbps” Introduction to Signaling System 7 SIGNALING SYSTEM 7 PROTOCOLS Saad Haj Bakry SS7 Protocols SS7 PROTOCOLS ISO-OSI Layers SCCP Basic SS7 Layers TCAP Message Transfer: Part 1 Message Transfer: Part 2 Message Transfer: Part 3 Saad Haj Bakry ISUP TUP SS7 Protocols ISO-OSI LAYERS Application Interfaces directly with application programs Presentation Provides code conversion and data reformatting. Session Co-ordinates interaction between end-toend application processes. Transport Provides end-to-end data integrity and reliable delivery of data. Network Switches and routes data to the destination node: comm. sub-network. Data Link Transfers units of data point-to-point. Physical Saad Haj Bakry Transmits and receives on the communication medium SS7 Protocols BASIC LAYERS Transaction Capability Control Part Signaling Connection Control Part Integrated Services Digital Network User Part Telephone User Part Message Transfer Part (3): Network Layer Message Transfer Part (2): Data Link Layer Message Transfer Part (1): Physical Layer Saad Haj Bakry SS7 Protocols WHY LAYERS Sophisticated operation: Divide & Rule (Modularity) Layered Modules: Nature of Structure & Operation Integration: of Layered Modules Saad Haj Bakry SS7 Protocols MESSAGE TRANSFER: PART 1 Physical Layer: It deals with hardware and electrical Basic Function configuration Associated with interface cards and multiplexers Software providers should understand its function for Support higher layers Bi-directional links of the Communication same bit rate: Symmetric Links Saad Haj Bakry SS7 Protocols MESSAGE TRANSFER: PART 2 First to handle received messages Last to handle transmitted messages Ensures integrity of messages Acknowledges “good” messages. Function Discards “bad” messages and requests copies of them. Tests links before allowing their use. Places links in service. Gives sequence numbers to messages Interface Reports information to MTP3 Saad Haj Bakry SS7 Protocols MESSAGE TRANSFER: PART 3 Message discrimination. Routing Message distribution. Message routing: Signaling message handling. Traffic & link management. Management Congestion management Signaling network management Saad Haj Bakry SS7 Protocols SIGNALING CONNECTION CONTROL PART Connectionless service: datagram. Basic Connection service: virtual circuit. Services Subsystem management: databases. Special Routing TCAP Saad Haj Bakry Addressing capabilities: Allow locating database information; and invoking features at a switch. Global Title Translation (GTT): 800 / Calling card number / MIN Transport Layer for TCAP SS7 Protocols TRANSACTION CAPABILITIES APPLICATION PART Operations, Maintenance & Administration Basic User Designed Applications Services GSM (Global System Mobile) MAP (Mobility Application Part) Data between applications over SCCP connection-less services. SSPs-SCPs queries and responses Data Exchange Obtain data from databases: e.g. 800 Mobile Switches-Databases: user and equipment identification, roaming,.. Saad Haj Bakry SS7 Protocols ISDN USER PART: ISUP In PSTN: Messaging for setting-up and Function: tearing-down of circuits In Wireless Networks: Establishing Call Connection connections through PSTN (Management) In Telephone Networks: Messages follow the path of voice circuits Basic: Setting-up and Tearing-down calls Types of Passing messages needed Services Supplementary: to maintain and modify calls Signaling Procedure Control / Circuit Procedures Supervision Control / Call Processing Control Saad Haj Bakry SS7 Protocols TELEPHONE USER PART: TUP Function Supporting basic call set-up and tear-down Only for analog circuits ISUP is used instead of TUP ISUP v. TUP for Call Management Saad Haj Bakry SS7 REMARKS Overview Standards: ITU + Emergence of SS7: Intelligence SS7 Structure: Design / Nodes / Links / Protocols: Sub-network / Services Increasing: Future Intelligence / Services Standards / Agreements: Compatibility, Quality Protection Saad Haj Bakry