SS7 Overview
Signaling System 7 (SS7)
Definition
Signaling System 7 (SS7) is an architecture for performing out-of-band signaling in support of the call-establishment, billing, routing, and information-exchange functions of the public switched telephone network (PSTN). It identifies functions to be performed by a signaling-system network and a protocol to enable their performance.
Topics
1. What Is Signaling?
2. What Is Out-of-Band Signaling?
3. Signaling Network Architechture
4. The North American Signaling Architecture
5. Basic Signaling Architecture
6. SS7 Link Types
7. Basic Call Setup Example
8. Database Query Example
9. Layers of the SS7 Protocol
10. What Goes Over the Signaling Link
11. Addressing in the SS7 Network
12. Signal Unit Structure
13. What Are the Functions of the Different Signaling Units?
14. Message Signal Unit Structure
Self-Test
Correct Answers
Glossary
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1. What Is Signaling?
Signaling refers to the exchange of information between call components required to provide and maintain service.
As users of the PSTN, we exchange signaling with network elements all the time.
Examples of signaling between a telephone user and the telephone network include: dialing digits, providing dial tone, accessing a voice mailbox, sending a call-waiting tone, dialing *66 (to retry a busy number), etc.
SS7 is a means by which elements of the telephone network exchange information. Information is conveyed in the form of messages. SS7 messages can convey information such as:
•
I’m forwarding to you a call placed from 212-555-1234 to 718-5555678. Look for it on trunk 067.
•
Someone just dialed 800-555-1212. Where do I route the call?
•
The called subscriber for the call on trunk 11 is busy. Release the call and play a busy tone.
•
The route to XXX is congested. Please don’t send any messages to XXX unless they
Definition
Signaling System 7 (SS7) is an architecture for performing out-of-band signaling in support of the call-establishment, billing, routing, and information-exchange functions of the public switched telephone network (PSTN). It identifies functions to be performed by a signaling-system network and a protocol to enable their performance.
Topics
1. What Is Signaling?
2. What Is Out-of-Band Signaling?
3. Signaling Network Architechture
4. The North American Signaling Architecture
5. Basic Signaling Architecture
6. SS7 Link Types
7. Basic Call Setup Example
8. Database Query Example
9. Layers of the SS7 Protocol
10. What Goes Over the Signaling Link
11. Addressing in the SS7 Network
12. Signal Unit Structure
13. What Are the Functions of the Different Signaling Units?
14. Message Signal Unit Structure
Self-Test
Correct Answers
Glossary
Web ProForum Tutorials http://www.iec.org Copyright ©
The International Engineering Consortium
1/29
1. What Is Signaling?
Signaling refers to the exchange of information between call components required to provide and maintain service.
As users of the PSTN, we exchange signaling with network elements all the time.
Examples of signaling between a telephone user and the telephone network include: dialing digits, providing dial tone, accessing a voice mailbox, sending a call-waiting tone, dialing *66 (to retry a busy number), etc.
SS7 is a means by which elements of the telephone network exchange information. Information is conveyed in the form of messages. SS7 messages can convey information such as:
•
I’m forwarding to you a call placed from 212-555-1234 to 718-5555678. Look for it on trunk 067.
•
Someone just dialed 800-555-1212. Where do I route the call?
•
The called subscriber for the call on trunk 11 is busy. Release the call and play a busy tone.
•
The route to XXX is congested. Please don’t send any messages to XXX unless they