SS7 or Signaling System 7 is the dominant protocol used to control the public telephone network. Call routing, number portability, caller-ID, mobile SMS and more are handled using SS7 in the public network. SS7 (along with SIGTRAN for transport), allow application to access public network resources for call control and authentication. During this session, we share some ...

1. Extending the Life of
SS7 Networks
1
with SIGTRAN and STPs

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Today’s Presenters:
Alan D Percy
Chief Marketing Officer
alan.percy@telcobridges.com
Marc St-Onge
Technical Director of Sales
marc.stonge@telcobridges.com

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What to Expect:
Introductions
Background
SS7 Network Elements
Signaling Functions for SS7
The Role of SIGTRAN for transport
SS7 & SIGTRAN Use Cases
Your Questions
A
D
N
E
G
A

4. TelcoBridges Inc.
• Manufacturer of VoIP gateways, signaling
gateways, and SBC software for carriers and
enterprises
• Employee Owned
• Founded in 2002
• Employees: ~40
• Headquarters: Montreal, Canada
• Hardware & software R&D as well as
production of its products in Montreal
• Sales/Support offices:
Montreal, Turkey, Hong Kong
• 24/7 technical support
4
TelcoBridges HQ

5. Worldwide Success
• Global carrier network solutions
• Focus on reliability and service
• Technology innovator
5

6. WHAT IS SS7?
An Introduction to Signaling System 7
6

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SS7 is very much alive!
• It is the core of the global PSTN
• It ensures global voice & SMS connectivity
• And it is growing at 3 to 4% per year
 SMS traffic is increasing
 More roaming
 Increasing number of MVNOs
 Local number portability, 1-800 numbers

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Let’s Start at the Beginning…
Montreal Telephone Exchange (c. 1895)

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The Digital Telephone Network
The 1970s:
• Space Flight
• 1973 Oil Crisis
• Digital Computing Age
• Growth of Telephone Service
• Global Telecommunications
• Adoption of Digital Telephony
• Birth of CCITT SS7

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A Little Background
• Channel Associated Signaling (CAS)
• Signaling is carried with the voice path (analog, T1 RBS, E1 R2)
• Common Channel Signaling (CCS)
• Signaling is carried separate from the voice path (SS7)
Voice
Signaling
Voice
Signaling

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A Little Background
• Common Channel Signaling (SS7) Advantages:
• More efficient use of voice paths/circuit
• More bandwidth available for signaling
• More secure
• More flexible architectures
Voice
Signaling

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SS7 Service Switching Points
SSP
Voice Paths
Signaling Links
SSP
Service
Switching
Point (SSP)
Exchange A Exchange B
Link Set
From: Engineering Networks for Synchronization, CCS 7, and ISDN by P.K. Bhatnager

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Point Codes
Zone
Identification
Area/Network
Identification
Signaling Point
Identification
3 bits 8 bits 3 bits
Format for International Signaling Point Code (14-bits)
Network
Identification
Network Cluster Cluster Member
8 bits 8 bits 8 bits
Format of Point Code for US Network (24-bits)

14. SS7 Signaling Transfer Point
• Signaling Transfer Point
• “Router” for SS7
messages
• Simplifies network
topology
• Allows “Spoke and Hub”
14
SSP
Voice/Data Paths
Signaling Links
SSP
Exchange A Exchange B
STP
Signaling
Transfer
Point SSP
Exchange C

15. SS7 Service Control Point
• SS7 Node that delivers a
service to network
• Database services:
• Caller Name database (CNAM)
• Local number portability
• Home Location Register (HLR)
• Toll Free Number database
• Messaging Services (SMS)
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SCP
SSP
Voice/Data Paths
Signaling Links
SSP
Exchange A Exchange B
STP
Service
Control
Point
SSP
Exchange C

16. SS7 Protocol Stack
16
MTP Level 1
MTP Level 2
MTP Level 3
ISUP
Physical
Data link
Network
Application
Presentation
Session
Transport SCCP
TCAP
SS7

17. SS7 Signaling Example
17
ISDN
User
Originating
Exchange
Transit
Exchange
Terminating
Exchange
ISDN
User
Setup
IAM
Setup ACK
Info
Alert
Connect
SAM
ACM
ANM
IAM
ACM
ANM
Setup
Connect
Access
Signaling
On D-Channel
Interoffice
Signaling
On Signaling Links
Access
Signaling
On D-Channel
From: Engineering Networks for Synchronization, CCS 7, and ISDN by P.K. Bhatnager
(Part of Called
Party Address)
(Remaining Address)

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SS7 Network Architecture
SSP C
STP 1
STP 2
SCP A
STP 3
STP 4 SCP B
SSP A
SSP B
A
A
A
A
C
F
B
D
D
B
C
A
A
A
A
Voice circuit
SS7 link
SSP = Service Switching Point
STP = Signaling Transfer Point
SCP = Service Control Point
A = Access Link
B = Bridge Link
C = Cross Link
D = Diagonal Link
F = Fully Associated
- Class 5 switch
- Class 4 switch
- MSC
- LNP Database
- HLR
- SMSC

19. User
Application
19
SS7 Use Case: CNAM Lookup
Accessing Caller Name ID database
SCP
STP
CNAM
API
Terminating
Service Provider
CNAM
Gateway

20. SIGTRAN
Transport of SS7 signaling over IP
20

21. SS7 Protocol Stacks
21
MTP Level 1
MTP Level 2
MTP Level 3
ISUP
Ethernet
IP
Physical
Data link
Network
Application
Presentation
Session
Transport
SCTP
M2PA
SCCP
TCAP
SIGTRAN
SS7
MTP Level 3
ISUP
SCCP
TCAP
Ethernet
IP
SCTP
M3UA
ISUP
SCCP
TCAP

22. SIGTRAN standards
• Defined by the IETF
• SCTP (Stream Control Transmission Protocol)
• RFC 4960
• Message oriented, reliable, in-sequence delivery
• Supports multi-homing for redundancy
• M2PA (MTP2 User Peer-to-Peer Adaptation Layer)
• RFC 4165
• Equivalent to SS7 TDM links, but over IP
• M3UA (MTP3 User Adaptation Layer)
• RFC 4666
• Enables the transport of higher-layer protocols over IP
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SIGTRAN Use Cases
1. Migrate SS7 TDM links to IP
2. Extend the life your STPs using SIGTRAN
3. Modernize your STPs
4. Bridge old and new SS7 networks
5. SS7 link transport via IP
https://www.youtube.com/watch?v=aUBj4GUFaiM

24. 1. SS7 link migration
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- Eliminates recurring cost of leased line
- 100% transparent for the switch
- Higher reliability due to IP network
IP
network
Transmission
network
STP
STP
SS7
Switch
M3UA
MTP2
TSG800

25. SS7 SOLUTIONS
From TelcoBridges
25

26. Tsig Product Line
26
Confidential
Model TSG800 TSG3200
Applications Signaling Gateways & STP Signaling Gateways & STP
T1/E1
1-16 64
DS3 -
3
OC3/STM-1 -
1
Ethernet Ports 6 5

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Intro: Tsig TSG800
Signaling gateway/STP
• Up to 16 x T1/E1 for SS7 on TDM
• 6 x GigE ports for SIGTRAN, management, SNMP
• Redundant power supplies (DC or AC)
Low-speed
Links
High-speed
links
SIGTRAN
associations
MTP3
routes
SCCP/
GTT
MSU/s
64 2 64 512 384 5,000

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Learn More:
• More on SS7 at:
• https://docs.telcobridges.com/tbwiki/SS7
• Information on TSG800 at:
• https://www.telcobridges.com/products/
tsig-signaling-gateways/tsg800
• Request a consultation at:
• https://www2.telcobridges.com/SS7Consult

29. Video Library on YouTube
• ProSBC Training Modules
• Recorded webinars
• How-to Tutorials
• Customer interviews
• Frequently Asked Questions
• Recorded podcasts
• And more…
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youtube.com/telcobridges

30. Enabling the Migration to
Cloud Communications
30
www.telcobridges.com
www.prosbc.com
sales@telcobridges.com
Youtube.com/telcobridges