Since the late 1970’s SS7 have been the dominant signaling standard for the global PSTN, interconnecting service providers, ILECs, CLECs, and wholesale operators. With the advent of number portability, 800-toll-free, mobile wires and SMS, SS7 had adapted and carried the bulk of the signaling to make all these services possible.

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

2. 2
Today’s Presenters:
Confidential
Alan D Percy
Senior Director of Product Marketing
alan.percy@telcobridges.com
Marc St-Onge
Director of Sales Support
marc.stonge@telcobridges.com

3. 3
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

4. 4
But its evolution is a challenge!
• Aging STP equipment
• Built on proprietary hardware
• Vendors announcing end-of-life and end of support
• Legacy STPs do not support IP
• Carriers are denied the benefit of modern networks
• A forklift upgrade is not desirable
• Need an evolution path to bridge old and new
• Difficult to connect existing infrastructures to new networks

5. SS7 Network Architecture
5
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
A
A
Voice circuit
SS7 link
SSP = Service Switching Point
STP = Signaling Transfer Point
SCP = Signaling Control Point

6. SS7 Network Architecture
6
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
A
A
Voice circuit
SS7 link
- Class 5 switch
- Class 4 switch
- MSC
- LNP database
- 1-800 database
- CNAM database
- HLR, VLR, SMSC

7. SS7 Protocol Stacks
7
MTP Level 1
MTP Level 2
MTP Level 3
ISUP
Ethernet
IP
Physical
Data link
Network
Application
Presentation
Session
Transport
SCTP
M2PA
SCCP
TCAP
MAP,
CAP,
INAP
SIGTRAN
SS7
MTP Level 3
ISUP
SCCP
TCAP
MAP,
CAP,
INAP
Ethernet
IP
SCTP
M3UA
ISUP
SCCP
TCAP
MAP,
CAP,
INAP

8. 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
8

9. 9
Extend the Life of your SS7 Network
1. Migrate SS7 TDM links to IP
2. Keep your STPs, enable them for SIGTRAN
3. Replace your STPs
4. Bridge old and new networks
5. Migrate any SS7 link to IP
Confidential

10. 10
Extend the Life of your SS7 Network
1. Migrate SS7 TDM links to IP
Confidential

11. 1. SS7 link migration
11
Off Net
Leased
line
On Net
Transmission
network STP
STP
SS7
Switch
SS7 link on TDM
(56/64 kbps on T1/E1)
SS7 link on TDM
(56/64 kbps on T1/E1)

12. 1. SS7 link migration
12
- Eliminates recurring cost of leased line
- 100% transparent for the switch
- Higher reliability due to IP network
IP
network
On Net
Transmission
network STP
STP
SS7
Switch
M3UA
MTP2
SGW

13. 13
Extend the Life of your SS7 Network
2. Keep your STPs, enable them
for SIGTRAN
Confidential

14. 2. Enable SIGTRAN for your STPs
14
STP
STP
SS7
Switch
Switch
Switch
STP
STP
SS7 A-links on TDM
B and D-links on TDM
STPs do not support SIGTRAN

15. 2. Enable SIGTRAN for your STPs
15
STP
STP
SS7
Switch
Switch
Switch
STP
STP
B and D-links using M3UA
IP
- Transparent to existing STPs and switches
- Opens the network to new SS7 options
- Maintains current STPs in place
SGW
SGW

16. 16
Extend the Life of your SS7 Network
3. Replace your STPs
Confidential

17. 3. Replace end-of-life STPs
17
STP
STP
SS7
Switch
Switch
Switch
STP
STP
These STPs are
no longer supported

18. 3. Replace end-of-life STPs
18
SS7
Switch
Switch
Switch
STP
STP
IP
B and D-links using M2PA
A-links on TDM
- Provides a supported STP solution
- Enables the use of SIGTRAN protocols
- Transparent to voice switches
- Opens the network to new SS7 providers
STP
STP

19. 19
Extend the Life of your SS7 Network
4. Bridge old and new networks
Confidential

20. 4. Bridge old and new networks
20
STP
STP
SS7
Switch
Switch
Switch
STP
STP
Replace these STPs
with virtual STPs

21. 4. Bridge old and new networks
21
SS7
Switch
Switch
Switch
STP
STP
IP
Virtual
STP
Virtual
STP
A-links on TDM
M2PA
M3UA
SGW
SGW

22. 4. Bridge old and new networks
22
SS7
Switch
Switch
Switch
STP
STP
IP
Virtual
STP
Virtual
STP
HLR SMSC
MSC
IMS/
LTE
- Connects old and new
- Transparent to existing SS7 nodes
- Provides agility to deliver new services
SGW
SGW

23. 23
Extend the Life of your SS7 Network
5. Migrate any SS7 link to IP
Confidential

24. 5. Migrate any link to IP
24
SS7
node
SS7
node
MUX
MUX
Leased line
SS7 on TDM using MTP2

25. 5. Migrate any link to IP
25
SS7
node
SS7
node
M2UA
IP
MTP2 MTP2
- Eliminates expensive leased lines
- Improves network redundancy
- Transparent to existing SS7 nodes
- Highly reliable
Survives up to:
- 5% packet loss
- 7.5 s round trip delay
SGW SGW

26. 26
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

27. 27
Q/A & Next Steps:
• 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
Copyright 2019

28. THANK YOU!
www.telcobridges.com
sales@telcobridges.com
HQ: +1.450.655.8993
HK: +852.3749.9819
28
Confidential