Download ss7 structure - Home - KSU Faculty Member websites

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