1. Enhanced Services for Converged Networks
The Importance of SS7
Internet Telephony Expo
February 2003

2. Leveraging SS7 for IP Telephony
Before SS7-IN for IP Voice can be discussed….
What is IP Telephony?
Technical Models
Business Models
Where it is going
The Role of SS7 in IP Telephony
PSTN Interconnect
Service Delivery (Existing)
Service Development (New)
Leveraging SS7
Do you have a choice?
Should you have a choice?

3. What is IP Telephony/VoIP?
Well, it’s Telephony using IP…..(duh)?
What is new about it?
Well, it uses IP….(duh)
IP Telephony can mean many things:
Trunking between class 4 switches (arbitrage and intercarrier)
Trunking between class 5 switches (tandem apps)
Replacing Class 5 switches (access)
A new thing? A new form of communication?
IP Telephony is really about three things:
Redefining Access
Redefining Services
Integrating Discrete forms of communications (mobile, voice, visual, information, dialogue, broadcast, entertainment)

4. The Business Drivers for IP Voice
Technology is not the driver
Subscribers don’t care about protocols, codecs or algorithms.
Access
Finding new ways to reach the customer
Increasing accessibility of services to the customer
Mobility of voice
Access through multiple devices
Bypassing ownership of physical plant
Services
Enhanced ability to use existing services
Web provisioning
Voice navigation
Always on, always there
Cool new services
Integrating the four primary communications tools

5. The Business Drivers for IP Voice
New Revenue
Technology is not the driver
Subscribers don’t care about protocols, codecs or algorithms.
Access
Finding new ways to reach the customer
Increasing accessibility of services to the customer
Mobility of voice
Access through multiple devices
Bypassing ownership of physical plant
Services
Enhanced ability to use existing services
Web provisioning
Voice navigation
Always on, always there
Cool new services
Integrating the four primary communications tools
Lower Costs

6. Evolution of IP Voice
Current focus is on re-inventing traditional voice services and architectures on an IP backbone
Incremental improvements and feature enhancements
Integration with PC voice applications like Windows Messenger
Web-based provisioning of service
Mobility
SS7 is the primary mechanism for controlling call states and services
Longer-term, the Services Infrastructure will change
New features, even for traditional voice, will be developed on IP-based systems
New features and services – the “killer apps”
IP (presumably SIP but also something else akin to Parlay) will replace SS7 for services and inter-node signaling

7. SS7 Service Architecture
Billing, Provisioning, Customer Service
Data Repository
Services
Layer
SCP
SCP
Signaling Links
STP
STP
Service
Node
Signaling
Layer
Service
Node
STP
STP
Media
Layer
SSP
SSP
Voice Trunks

8. SS7 Service Architecture
Billing, Provisioning, Customer Service
Data Repository
Services
Layer
SCP
SCP
Signaling Links
STP
STP
Service
Node
Signaling
Layer
Intelligent Network
Centralized core data model for services
0800, LNP, VPN, and mobile
only services widely deployed
Application and data intertwined, making
provisioning and back office difficult and costly
Expensive, proprietary platforms
Service
Node
STP
STP
Media
Layer
SSP
SSP
Voice Trunks

9. SS7 Service Architecture
Service Node
Most common model for PSTN services
Voice mail, calling card, call center
Separate provisioning, billing,
customer service for each platform
Expensive and non-integrated
Billing, Provisioning, Customer Service
Data Repository
Services
Layer
SCP
SCP
Signaling Links
STP
STP
Service
Node
Signaling
Layer
Service
Node
STP
STP
Media
Layer
SSP
SSP
Voice Trunks

10. SS7 Service Architecture
Switch Based (CLASS, Centrex)
Requires local provisioning on each
Class 5 switch
No mobility
Expensive, time consuming for new
feature deployment
Billing, Provisioning, Customer Service
Data Repository
Services
Layer
SCP
SCP
Signaling Links
STP
STP
Service
Node
Signaling
Layer
Service
Node
STP
STP
Media
Layer
SSP
SSP
Voice Trunks

11. Why Migrate Services to IP?
Reduce back office costs
Vendor End of Life of IN platforms
Speed time to market by integrating provisioning systems with Web front end
Reduce customer service call center expenses by automating service delivery and turn up through the Web
Integrate AAA Internet infrastructure with voice services
Provide integrated services for voice and web customers
Provide mobility to subscribers
Integrate VPN, Work at Home and Mobile service offerings
The bottom line: Migration must serve a business purpose and provide new features and end-user benefits. Migration for migration’s sake is a tough case to make

12. VoIP Service Architecture
Application
Server
Services
Layer
Core Services
Platform
Application
Server
Billing, Provisioning, Customer Service
Application
Server
Signaling
Layer
Signaling
SIP Proxy/GK SG
MGC
MGC SG
Media
Layer
STP
STP
STP
Media
STP MG MG

13. VoIP Service Architecture
Handset Based Services
Unlike PSTN, digital signaling right to the
handset
Could be a soft-phone (e.g. XP Client)
Limited to specific local features
Application
Server
Services
Layer
Core Services
Platform
Application
Server
Billing, Provisioning, Customer Service
Application
Server
Signaling
Layer
Signaling
SIP Proxy/GK SG
MGC
MGC SG
Media
Layer
STP
STP
STP
Media
STP MG MG

14. VoIP Service Architecture
Edge Services
Softswtiches (MGCs) and proxy servers
can operate edge oriented services
Potentially difficult to provision and
manage as network scales up
Service parity and consistency difficult
in multi-vendor networks
Application
Server
Services
Layer
Core Services
Platform
Application
Server
Billing, Provisioning, Customer Service
Application
Server
Signaling
Layer
Signaling
SIP Proxy/GK SG
MGC
MGC SG
Media
Layer
STP
STP
STP
Media
STP MG MG

15. VoIP Service Architecture
Application
Server
Services
Layer
Core Services
Platform
Application
Server
Billing, Provisioning, Customer Service
Application
Server
Core Network Services
Contain dial plans, central network routing data
Open, standard platforms, databases
Application servers can share information,
resources
Web-based provisioning enables carrier to
offer subscribers convenience and self
serve customization while maintaining control
Signaling
Layer
Signaling
SIP Proxy/GK SG
MGC
MGC SG
Media
Layer
STP
STP
STP
Media
STP MG MG

16. Services in the Converged Network
Initially…
Existing infrastructure will be used for existing apps
New infrastructure will be used for new apps
Moving Forward…
Service Mediation role is critical but barely understood
SS7 should terminate at the edge of the IP network
New enhanced service infrastructure needs to be defined and developed

17. Leveraging SS7 – Do You Have A Choice?
For PSTN interconnect, ISUP is required for even simple voice termination
This will not change
SS7 interconnect will always be required
For Services, there are alternatives
Use TCAP-AIN as the universal services protocol across IP
Use full AIN from existing infrastructure
Use TCAP-AIN for very basic query response to legacy infrastructure
Forget it – build a new IN based on DNS/SIP/Protocol X

18. 98% of world’s voice traffic
Today’s Networks
PSTN:
98% of world’s voice traffic
GW/SS
VoIP

19. Wither SS7?
Approaches
Provide direct TCAP interfaces to the SoftSwitch layer and have SoftSwitch function as full SSP
Most direct resemblance to PSTN
SoftSwitches are years from having full capability
Performance issues
Too much to build on a single platform
Provide an Service Mediator that maps AIN to IP and holds call state (this is a true SCP implementation)
Requires additional node in the network
Most scaleable
Requires standardization of service delivery profiles in SIP

20. Enabler: Service Mediation Server
To enable migration, a service mediation server must live at the edge of the network
Call states and triggers must map to the existing IN platforms, hold state, and delivery transaction based messaging to SoftSwitches
Porting SoftSwitch SSP to the edge
Transitionary platform? Or permanent?

21. Converged Network Service Delivery
PSTN IP
PSTN OAMP
SMS
App
Server
Services
Layer IP
OAMP
SMS
App
Server
Service
Mediation
App
Server
SCP
TCAP/SCTP
SS7
SIP,
H.323
Signaling
Layer
SIP Proxy/GK
STP
Sig GW
MGC
ISUP/SCTP
MGCP,
MEGACO
Media
Layer
STP
SSP
STP MG
Media: IMT
Media: RTP
PSTN IP

22. SS7 Services for VoIP Networks
PSTN IP
Services
Layer
PSTN OAMP
SMS
App
Server IP
OAMP
SMS
App
Server
Service
Mediation
App
Server
SCP
TCAP/SCTP
SS7
SIP,
H.323
Signaling
Layer
SIP Proxy/GK
STP
Sig GW
MGC
ISUP/SCTP
PSTN services are defined in SCP,
accessed through TCAP/SCTP
0800, LNP, Dialing Plans trigger a query
through TCAP/SCTP to SCP
IP Application platform retrieves data,
translates to SIP, sends to SoftSwitches
MGCP,
MEGACO
Media
Layer
STP
SSP
STP MG
Media: IMT
Media: RTP
PSTN IP

23. VoIP Services for SS7 Networks
PSTN IP
App
Server
Services
Layer
PSTN OAMP
SMS IP
OAMP
SMS
App
Server
Service
Mediation
App
Server
SCP
TCAP/SCTP
SS7
SIP,
H.323
Signaling
Layer
SIP Proxy/GK
STP
Sig GW
MGC
ISUP/SCTP
IP-based services are defined in
Application servers and accessed
Using SIP, DNS or Parlay
SSP issues TCAP query
Service Mediation gateway resolves
query and accesses appropriate servers.
MGCP,
MEGACO
Media
Layer
STP
SSP
STP MG
Media: IMT
Media: RTP
PSTN IP

24. Enabler: DNS
DNS provides the strongest alternative to TCAP for Query-Response applications
Current DNS infrastructure is default address resolver for IP
Many IN apps are address resolution:
Basic Tandem Routing
Carrier Select
LNP
800
CNAM
Problem: Most IN apps require Call Models when anything advanced is delivered.
Very few IN apps are pure query response
Call Model Server + DNS

25. Where We’re Eventually Headed
VoIP:
98% of world’s voice traffic
GW/SS
PSTN

26. Hybrid Network Service Architecture
PSTN
Other Servers
SCP
Service
Mediation
Service Layer
STP/SG
STP
SIP
Call processing Layer
SSP
MGC
SSP
PBX
IP SCP looks like an SSP to the legacy network
Triggers in IP map to SIP

27. Towards a VoIP Service Logic
Real Time Billing
Server/OSP Server
Service Management
System
HP Open View
Access Network
{RADIUS/OSP}
H.323 GK
H323 GW
{XML}
{SNMP}
Access Network
{XML}
{SNMP}
SCP
PBX
SIP GW
{RADIUS
/OSP}
IP STP
{SIP}
{H323}
{SIP}
{H323}
Access Network
{SIP or H.323}
H323 GW
Trunking GW
PSTN

28. Conclusions
Models for SS7 in VoIP will depend on the carrier business model, service set, and installed network infrastructure
Some SS7 service logic is required for PSTN interconnect
Major architectural options:
Where to house the triggers
Where to terminate SS7 and AIN
Service Mediation function
Optimal outcomes will leverage existing SS7 investments but not impose TCAP-AIN on IP components
Service Core must move to IP, even if the IN services remain on the PSTN

29. Michael Gaines +1 (613) 592-2100 michael.gaines@ss8.com
Thank-you!
Michael Gaines
+1 (613)