1. Multi-service Architecture: Evolution of Network Architecture Keith Knightson Khalid Ahmad Carrier Data Networks Nortel Networks, Canada IP-Networking/Mediacom Workshop, 24 -27 April 2001

2. 2 Outline Network Evolution Trends General Architectural Challenges Example of Todays Typical Protocol Architecture Domains of Disruption Architectural Diversity Virtual Services Network / Virtual Transport Network Multi-service Network Multi-service Core Protocol Architecture Interworking Considerations Span of Control / Management Conclusions

3. 3 Network Evolution Trends Optical Infrastructure –Capacity imperative Packet Based Transport & Switching –Multi-service flexibility Location of Intelligence (Core vs Edge) –QoS and Bandwidth Granularity/Control Convergence of Control & Management Aspects –E.g., Dynamic routing vs protection switching Interworking with Legacy Systems

4. 4 General Architectural Challenges (1) Multiple Architectures currently exist – e.g. ISDN, B-ISDN, SS7/AIN, IP, FR, etc Future of Multiple architectures –Are they inevitable due to continual evolution? –Yes, implies interworking will continue to be key issue Move to new single hierarchical architecture –Drivers Functional Simplification, Bandwidth Efficiency Performance, Cost, etc. –Is this realistic in long term? –The ultimate architecture is …All optical, plus….? –Migration issues will be key

5. 5 General Architectural Challenges (2) Position of Intelligence –Edge versus Core Intelligence Edge: Service diversity, QoS Differentiation Core: Survivability, Bandwidth Management, OAM/NM –End-to-End Coherence issues All network aspects, multi-domain applicability Architectural Agility –Customer adaptability –Mix and match technologies –Agile layering (x over y, or y over x) –Seamless Service transparency

6. 6 Example of Todays Typical Protocol Architecture Key Features –Multiple functionally rich layers –QoS Diversity –Rich degree of control/management granularity Optical Layer PDH/SDH ATM/FR IPDataVoice

7. 7 Domain of Disruption: Transport & Switching Layers Layer 1 Functionality Layer 3 Functionality Layer 2 Many Layers Few Layers Issues –Preservation of functionality (service, control & management) –QoS granularity

8. 8 Protocol Architecture Diversity Issues –Interworking between Differently Layered Architectures –Functional Convergence –Common Optical Infrastructure & Packet-based Transport Optical Layer IP Voice Optical Layer MPLS IP VoiceData Optical Layer IPVoice MPLS Data Question: How to deal with Architectural Diversity?

9. 9 Virtual Services Network Virtual Transport Network Virtual Transport Network Virtual Services Y.1311 uses these concepts to describe IP VPN Service Provision Answer: Decouple Customer Services from Transport Facilities Concepts: Virtual Services Network –Customer Service Delivery Platforms Virtual Transport Network –Core Transport & Switching Platforms

10. 10 VSN/VTN Concepts Decoupling of services from Access & Transport technologies allows: Mix and match of various services with any access and core technology Exploitation of different types of technology Agility of service provision and customization Flexibility points for interdiction of interworking functions

11. 11 Multi-Service Network: VSN/VTN Perspectives Packet (e.g. MPLS) Core Virtual Transport Network IWFIWF IWFIWF ATM FR Virtual Service Network ATM FR All Optical Infrastructure LSRLSR LSRLSR LSR IP Network IP Voice VSN/VTN multi-service approach encompasses Network Evolution Trends

12. 12 Multi-Service Core Protocol Architecture Optical Layer MPLS IP Voice ATMFRother Multi-service Layer CoreCore VTNVTN VSNVSN **** * Recursive Architectural Possibility What is preferred packet transport/framing approach? E.g: G.707 Approach Generic Framing Protocol MPLS over Optical (GMPLS)

13. 13 Span of Control/Management IWFIWF IWFIWF Architecture 1Architecture 2Architecture 3 Control 2Control 1Control 3 Span of Control Management 1Management 2Management 3 Span of Management Architecture Diversity implies: Overall capability limited by weakest link in the chain

14. 14 Interworking Considerations Customer investment/preference means multiple architectures Multiple architectures mean interworking Service mapping at equivalent service layers Issues arising: End-to-end coherence (service features, addressing, QoS, security) Coherent Span of Control (signaling, routing, etc) Coherent Span of Management

15. 15 Control Aspects Require End-to-End Coherence Functions for –Addressing –Session Control –Route Control –Feature Selection/Exploitation –QoS Granularity levels, E2E consistency QoS interoperability Consistency with SLAs and availability –Security –Interoperability between signaling gateways Urgent Need for coordination & rationalization of standards efforts in control domain

16. 16 Management Aspects (1) Require End-to-End Coherence Functions for: Configuration Management –Provisioning & Topology Changes Performance Management –Active monitoring –Correlation to SLA & QoS requests –End-to-End consistency Fault Management –End-to-End testing across multiple domains –Fault localization across multiple domains –Recovery/restoration across multiple domains

17. 17 Management Aspects (2) Security –Access control –Authentication –Data Privacy Accounting –Single itemized bill –QoS/SLA correlation –Performance/Fault correlation Boundary between control and management becoming blurred due to change in granularities and response times.

18. 18 Domain of Disruption: Management & Control Many LayersFew Layers Coarse Control Management Domain Fine Control Control Signaling Domain

19. 19 Conclusions (1) Competing architectures will co-exist and must evolve Interworking will continue to be a key issue Unified Multi-Service architectures in VSN/VTN Framework will: –Reduce complexity –Increase flexibility of service provision –Simplify interworking Overarching coherence functions required for integrating control and management –Standards co-ordination rationalization critical

20. 20 Conclusions (2) Two major Domains of Disruption: Layering Implosion –Move from many layers to fewer layers –Fewer levels of granularity –Greater granularity at the lower levels Control and Management –Control and Management converging As granularities converge Automation reduces response times –End-to-End overarching coherence functions required Tectonic Shifts in World of Next Generation Architecture