1. NGN Migration Strategy and Scenarios
Regional Workshop on Assistance to the Arab Region for the implementation of
Next Generation Networks (NGN)
NGN Migration Strategy and Scenarios
Cairo (Egypt), December 2009
Oscar González Soto
ITU Consultant Expert
Spain

2. Agenda Technology migration issues
Migration strategies per network segment
Main steps for IMS and NGSS

3. NGN Migration Strategy Issues for migration planning
Where to start migration?
Which topologies and connectivity are required?
How network segments change in access , local and core?
Which level of protection to assure?
Where to locate new functionalities?
How to ensure service continuity?
Others …..

4. NGN Migration Strategy Modeling issues for NGN design
New models needed to represent multiservice flows
New dimensioning methods for resources handling multimedia services with QoS
New measurement procedures for aggregated multi-service traffics
New procedures to ensure interoperability and end-to-end performance across multiple domains
Redefinition of network segments at the new structure and for QoS quota assignment
New units to define dimensioning and costing for interconnection

5. Network segments: Historical reference configurations
LD circuit Trans
Transmission
circuit AN
Voice
PSTN LE
Customers
CPE
voice
CPE data
data
LD data trans
Data BRAS
Aggreg
DSLAM
PSTN TE
DATA TR
PSTN Transit
DATA Transit
Metro/Regional
Circuit Trans
Metro/Regional data trans
CPE to Transit network
Access network
Local network
Metro/Regional network
Transit network
Double network in circuit and packet modes
Frequently with separated physical media, transmission and energy

6. Network segments: Target full NGN reference configurations
Core NGN net
Transmission
edge
IP Integrated AN
NGN
Edge
Router
Customers
Multiple play
Application servers equipment
IP Multiservice CPE
Access Transmission
LD integrated Trans
Edge/Metro/Aggregation network
Core network
NGN Customer to Transit network
Access network
Home networking
Sense for IP mode deployment in NGN
Integrated network at all layers NGN based on IPv6 network with carrier grade QoS

7. Network segments: Migration from historical to target NGN
LD circuit Trans
Transmission
circuit AN
Voice
PSTN LE
Customers
CPE
voice
CPE data
data
LD data trans
Data BRAS
Aggreg
DSLAM
PSTN TE
DATA TR
PSTN Transit
DATA Transit
Metro/Regional
Circuit Trans
Metro/Regional data trans
CPE to Transit network
Access network
Local network
Metro/Regional network
Transit network
Core NGN net
Transmission
edge
IP Integrated AN
Edge
NGN
Router
Customers
Multiple play
Application servers equipment
IP Multiservice CPE
Access Transmission
LD integrated Trans
Edge/Metro/Aggregation network
Core network
NGN Customer to Transit network
Access network
Home networking

8. Agenda Technology migration issues
Migration strategies per network segment
Main steps for IMS and NGSS

9. Architecture migration: Topology
What changes from current scenario towards target network ?
Other
Networks
DLC
Control
Transport/Media
Distributed Switching
DSL
Wireless gateway
Softswitch
OSS
Services
Packet
Network
IP/MPLS/CAC
Access gateway
Trunk gateway
SCP
TDM
POTS
ISDN
RSU
LEX/TEX
LEX
PCM
Data
ATM/IP
MUX/DSLAM
NMC
SS7
HDSL/XDSL
NAS
Mob IN

10. NGN: Topology migration strategies
Network topology change is more difficult and needs more time that just system substitution
Migration in Overlay :
At transit and international levels
At local level
At access level
Migration in Island (substitution/extension)
Hybrid migration: Overlay and Island combination:
By network levels
By geographical regions
By obsolescence level

11. Network Architecture towards NGN Architecture Consolidation: Topology
TRANSIT NETWORK
NATIONAL LAYER
REGIONAL LAYER RU
LAYER
LEX
Single-layered
TRANSIT NETWORK
NATIONAL/REGIONAL
LAYER RU
LEX/GW
Structure
Simplification

12. Topology reconfiguration for Core
Local Exchanges
Remote Units
LEX Layer
Trunking gateway in each regional site
Packet mode network
IP links
short distance
Regional Level
Softwitches /MGCs
in few sites

13. Topology reconfiguration for Core
Local Exchanges
Remote Units
LEX Layer
Trunking gateway in each local site
Packet mode
network
IP links
Long distance
Regional layer
Softswitches/MGCs located in few sites

14. Dominated by high capacity and protection level
Core: migration strategy
Dominated by high capacity and protection level
Overlay deployment for full coverage in all regions
Quick deployment needed for homogeneous end to end connections (2 to 3 years)
Strong requirements for high quality, protection and survivability
Importance of the optimization for location and interconnection

15. Exchange A subscriber “Growth”
Local/Edge level migration: grow with NGN
Access
gateway
LEX Layer
Packet mode network
Trunking
IP links
Exchange A subscriber “Growth”
Exchange A
TEX Layer
Softwitches/ MGCs located in few sites

16. Local/Edge level migration: substitute with NGN
Obsolete TDM LEXs
Packet mode network
Access
gateway
Access equipment
Rest of
the TDM network
Trunk gateways
gateways
IP links
Softswitches/MGCs

17. Metro-Ethernet
Vision by the Metro Ethernet Forum for LAN to LAN network:
Customer’s
Ethernet
LAN
Telco Central Office
Traditional Telco Network
CSU/DSCs
Routers
Copper Serial Input
Copper Local Loop
ATM
MUX
Sonet ADM
Voice-oriented connectivity
Optical IP Network
Managed Switch located in building telco closet
Optical Gigabit Ethernet throughput
Managed Switch
GB WAN Router
Long Haul Fiber
Metro Fiber Ring
Customer’s
Ethernet
LAN

18. Dominated by functions migration investment and interoperability
Local/Edge network migration
Dominated by functions migration investment and interoperability
Move from joint switching and control to separated control and media GW
Introduce Multimedia Services at all areas
Optimize number, location of nodes and interfaces among existing and new network
Requires longer time and higher investments due to variety of geo- scenarios and geographical distribution

19. Access Network Migration: Physical network today
Structure of the OSP Access Network in most scenarios
SDF
FDF
main cable
branching cables
drop line
MDF .
Regional Exchange
Core/Local network
Primary OSP network
Distribution OSP network
NTBA
Local Exchange
MDF Main Distribution Frame
FDF Feeder Distribution Frame
DSLAM Digital Subscriber Line Access Module
MSAN Multiservive Access Node
SDF Subscriber Distribution Frame
ISDN
basic rate FO
Optical
Interface
AN:DLC
DSLAM
MSAN

20. Access Network Migration: Physical network evolution
Typical trend for Access Network infrastructure evolution
Core/Local
Primary OSP network
Distribution OSP network
SDF AN
branching cables
drop line
Optical
Interface .
NTBA
LEX/GW
LEX Local Exchange
GW Gateway
MDF Main Distribution Frame
AN Access Node
SDF Subscriber Distribution Frame
FO Fiber Optic FO

21. Access dominated by physical infrastructure cost and deployment time:
Network Architecture towards NGN Architecture Consolidation: Access
Access dominated by physical infrastructure cost and deployment time:
“first to start and later to finish”
Quick deployment of DSL and Multimedia Services
FO closer to customer when implementing new outside plant or renovating existing one
New Wireless technologies for low density customer scenarios
Shorter LL length than classical network to be prepared for high bandwidth Multimedia services

22. Where to start and how to co-ordinate migration sequence?
Topology migration: combined segments
Where to start and how to co-ordinate migration sequence?
Network “consolidation” for topology
Cost Optimisation of the network
- Reducing nodes and increase their capacity
- Deployment of ADSL and multiservice access
Network expansion
NGN solution :
- Cap and Grow; this means keeping the existing PSTN network as it is, and grow demand with NGN equipment
Network replacement
Replacement of out-phased (end of life) TDM equipment
- gradual replacement : this means coexistence of the two technologies
- full accelerated replacement with a short transition period
Need to optimize overall network evolution: technically and economically

23. Overall Network Structure Architecture at transition stage

24. Agenda Technology migration issues
Migration strategies per network segment
Main steps for IMS and NGSS

25. Network Architecture towards NGN: IMS Architecture
IMS defines a set of components:
Application Server (AS), which offers value-added services
Home Subscriber Server (HSS) with AAA functionality and unique service profile for each user
Multimedia resource function (MRF) , which controls media stream resources
The “S-CSCF & PSTN emulation” (Serving CSCF) is the serving call state session control function for IMS and PSTN/ISDN simulation system subscribers. Its main function is to control the session states and to invoke services from the data and application system
The Proxy-CSCF supports nomadism and roaming by supporting SIP-based registration of terminals from different accesses
Interconnecting border control function (IBCF) converts signalling protocols when interworking with other application service provider networks is necessary. It also provides the function of information hiding and call filtering to prevent illicit use of the network.
Access gateway control function (AGCF) converts SIP signalling from the S-CSCF to MGCP/H.248 towards an RGW or AGW
Media gateway control function (MGCF) provides interworking between ISUP and other PSTN NNI protocols and SIP used inside the SP network
Border gate function (BGF) is a packet-to-packet gateway ( I- : interconnection / A- Access)
IMS defines 3 types of Application Servers:
SIP Application Server
OSA/Parlay Service Capability Server
Application Server for IN-like services

26. Network Architecture towards NGN: IMS Benefits
First advantage is the higher flexibility of the IMS functionality to adapt to the customer services, irrespective of the technology they use and the access method to reach the network.
Saving in effort and time for the development and deployment of a new service is considerably reduced once the architecture is ready at the network, implying economic savings and better Time to Market for a given service provider in a competitive market.
Efficient introduction on new services at a lower cost will increase the service provider revenues and ARPU which is the major business driver for the healthy operation, market grow and financial results.
- Higher utilization of services and better personalization of functions to specific requirements from the end customers’ point of view, a common use and feel for all services and applications

27. Evolution to IMS: Phases
Convergence to
NGN infrastructure
Current Service
functionality
Partial IMS functionality
and/or coverage
Full IMS coverage
Full HSS, P2P video,
Service broker, Service blending,
RACF, ICD, etc.
IMS services
PSTN
NGN IP core
End to End
NGN
PSTN Architecture
Pre - IMS
PSTN emulation/simulation
Full IMS “SIP” Services
Open Service Architecture, Basic HSS, VoIP, LBS, PBS, IM, PtS, etc.

28. Evolution to converged OSS/BSS: Classical requirements
Typical functions for the OSS and BSS imply a vast set of activities in current networks like:
- Inventory management,
- Network engineering,
- Order management,
- Network elements supervision,
- Application monitoring,
- Traffic measurement and post processing,
- Capacity augmentation,
- Routing planning,
- Trouble ticketing,
Repair management,
Workforce management,
- Service activation,
- Service creation,
- Customer Relations Management (CRM),
- Rating,
- Billing,
Invoicing,
Performance supervision,
- Accounting management,
Pricing agreements,
SLA management
- Support to Marketing & Sales, etc

29. Evolution to converged OSS/BSS: New requirements
- In addition to conventional typical functions, new requirements and higher relevance for existing tasks are needed in the NGN IP mode technology as follows:
Managing support to multimedia services with voice, data, video
and multiple play
- Security policy management,
- Content management,
Managing inter-domain operational activities
Managing functionalities for the coexistence of legacy and new
technologies
Implementing new business procedures associated to bundled
offers
Manage multimedia/multiparty charging application
Service Level Agreements (SLA) management,
- Service creation and upgrading management,
Focus on common processes to all support functions and

30. Evolution to converged OSS/BSS: Phases
Separated OSS, BSS
and Platforms
Integrated OSS/BSS in
Common Platform
BSS
PSTN
DATA
MOBILE
OSS Application 1
OSS Application 2
OSS Application n
BSS/OSS
OSS Applications
OSS Middleware
Integrated IT Platform
Migration from legacy support systems in vertical piles towards integrated OSS/BSS in an IT platform per network type

31. Evolution to converged OSS/BSS: Phases
Integrated OSS/BSS in
Common Platform
Full Integrated NGSS platform interworking with IMS
BSS/OSS
PSTN/DATA
MOBILE
OSS Applications
OSS Middleware
Integrated IT Platform
NGSS
based on
(SOA)
Applications
Transport Stratum
Service Stratum
Third Party Applications
Transport Functions
Transport Control Functions
Service Control Functions
IMS
Applic. Support Functions
IMS Architecture
Migration from IT platforms per network type towards New Generation OSS/BSS for an NGN multiservice network with IMS functionality

32. Matching evolution to NGN, IMS and NGSS
Convergence to
NGN infrastructure
Separated OSS and BSS platforms for PSTN, Mobile,& Data
OSS/BSS Integration for
PSTN and Data
Full Integrated platform
Fixed + Mobile & federated with IMS
Integrated OSS/BSS
PSTN
NGN IP core
End to End
NGN
PSTN Architecture
Pre - IMS
Coexistence for PSTN and NGN
Full IMS “SIP” Services
- Open Service Architecture
- Integration of OSS and BSS functionalities
- NGSS based on “SOA”
Incorporation of new operations for IMS new services

33. NGN Migration Strategy: Conclusions
Network Topology migration is the base for architecture modernization and requires an overall re-design
Different timings apply to 5 network areas: Access, Core, Local/Edge, Services and OSS/BSS
Per country coordination is required for Migration at each area