NOBEL Technical Audit WP5 Objectives & Achievements March 08, 2006

1. NOBEL Technical AuditWP5 Objectives & AchievementsMarch 08, 2006 Workpackage 5 Transmission and Physical Aspects Bernd Bollenz,Herbert Haunstein

2. WP5 - Outline 1) Organisation • Objectives (year 2) • Partners 2) Achievements • Penalty budget based light path design • Static Network Optimization • Transparency regions • Started extension to dynamic traffic demand 3) Conclusion & Outlook for Phase 2 • Rules for physical layer optimization • Continue work in new WP5 (merged WP5/6/7) • Main focus – experimental verification of concepts

3. WP5 – Objectives (year 1 year 2) • Identify the main building blocks for transmission in next generation flexible broadband optical networks as described in WP1 (including intelligent optically transparent crossconnects, configurable OADMs etc) • Build models and simulate network elements with regard to physical constraints in transparent optical networks • Develop algorithms to allow route selection and resource optimisation in intelligent optically transparent (analogue) networks and perform computer simulations to assess their performance. This will include an assessment of the value of wavelength conversion • Derive conclusions on the physical feasibility of transparent optical networks as an input for WP1 / WP4 • Define major design optimisation criteria and identify design rules for transparent transmission in dynamic optical networks and provide input to the international standardization bodies (e.g. ITU-T SG15) • Derive most suitable transport formats (bit rate, modulation, bursts) with respect to cost, distance and robustness against performance impacting functionality in transparent optical networks and for the different network segments (core, metro) • Evaluate and model the impact of all building blocks like optical amplifiers (EDFA, Raman), optical wavelength converters, optical regenerators, adaptive TX/RX interfaces (e.g. for GVD/PMD mitigation) and advanced coding algorithms for further improvement of network efficiency (cost and/or performance) to ensure network wide operation • Model the dynamic behaviour of transparent optical networks, for circuit and burst switched applications, especially with regard to transmission on optical amplified fibre links

4. WP5 - Partners ACREO (ACREO) Alcatel CIT (ACIT) Alcatel SEL (ASEL) British Telecom (BT) France Telecom (FT) Lucent Technologies (LUGmbH) Ericsson GmbH (MCONDATA) Pirelli Labs (PLABS) Siemens (SIEMENS) Telecom Italia (TILAB) TeliaSonera (TS) T-Systems Nova (T-Systems) University of Athens (NTUA) Person months distribution 2005

5. ObjectiveOptimisation of physical layer design Optical transparent transport network Transport Interface Rx Transport Interface Tx Objective Define design rules for 1) Network configuration (equipment placement) for a given topology and static traffic demand under cost constraints (e.g. for reference networks) 2) Operation Dynamic traffic demand: Routing & wavelength assignment under physical constraints Regeneration Required ?

6. ActivitiesOptimisation of physical layer design Network Design Rules Extend to dynamic traffic Network Dimensioning Reference Networks – Traffic demand Cost model on wavelength level Light Path Design Rules Optical monitoring functions “O-E-O vs. Transparency” Requires additional equipment Transmission effects, … Building blocks Modulation format, FEC, Amplifiers Tunable lasers, OADM, OXC

7. Time line & sub teams of WP5 M12 M4 M15 M21 M24 Dynamic Network simulation (Routing) Network Design Rules Optimization Specification of network elements for verification Building Blocks Reference Networks Physical Feasibility Light Path Design Dedicated sub teams: • Carrier‘s group (reference networks, traffic demand estimation) • Optical monitoring group (jointly WP1/4) • Optical transparency cost analysis group (jointly WP2/6/7) • Path computation algorithms group • PMD modelling and mitigation concepts group

8. Achievements Continued activities • PMD mitigation concepts Verification of building blocks • Inline OSNR measurement • Distributed PMD compensation Cost comparison of physical layer alternatives • Relative cost of subsystems Network design • Transparent regions • Optimized equipment placement • Dynamic traffic demands (started) PMDC concepts Slide 11 OSNR Slide 12/13 Dist. PMDC Slide 14 Cost Slide 15 Transparent regions Slide 16 Network design Slide 17-19 Network Optimization Engines Slide 20

9. Summary & outlook Summary (year 2) • Deliverables (D19, D26 & D28) • Penalty budget based light path design • Network design • Equipment placement • Cost optimization for physical layer • Optimized Network design (transparent regions) • Outlook Nobel phase 2 • Apply Design Rules in experiments for verification • Extend network design to dynamic traffic demand

10. Technical details

11. Building blocksPMD mitigation - overview Performance metrics: Q-thresholds vs. DGDfrom literature Q-penalty vs. DGD for different modulation formats Q-penalty vs. PMD incl. equalisation by FFE+DFE Concepts: • optical PMDC • 1stage • 2stage • in-line(distributed) • electronic equaliser • FFE+DFE • MLSE (=VE) back

12. OSA Back-back path EDFA True-OSNR Tester Atten-uator Opt. Filter TX PolCon / Scrambler PMD-Emulator PDL PMD-free path OPM Technology Example: OSNRMeasurement by Polarisation Nulling (I) Experimental Setup: • Technique allows “in-band” measurement of OSNR (no noise floor on either side of signal required) • Commercially available • Good performance, but potential issues with depolarised signal (PMD) and polarised ASE (PDL)

13. OPM Technology Example: OSNRMeasurement by Polarisation Nulling (II) • Measurement with partially polarised ASE noise (emulation of PDL) • Polarisation nulling device does not see ASE co-polarised with signal  measurement inaccuracy depends on PDL in system back

14. PMD-C Measurement results Measurement setup: Measurement results: System parameters: • Modulation format NRZ • Bitrate 10.7 Gbit • BER w/o FEC 1e-6 Conclusion: • Compensation possible with the polarizer approach at 10 Gbit • Can compensate 4.7 ps mean PMD (2 dB OSNR penalty) back

15. Cost comparison studyPhysical layer only • Based on relative cost (750km transponder card = 1) • Opaque vs. transparent/hybrid nodes with broadcast and select architecture for the optical plane (details in D26) • Study partly includes grooming • Transparency limits of 750, 1500 and 3000km • Example for cost formulae opaque transparent/hybrid back

16. Transparent regionsGeneralised transparent domains • flexible partition of a hybrid optical network into a set of smaller Generalised Transparent Domains (GTDs) and a transparent/translucent core • each GTD (and the core) will be engineered separately on the basis of its own inner core size (partitioning avoids any network over-engineering applying different levels of technology) • flexible hybrid nodes at the boundary of each GTD ensure flexibility of the whole network back

17. Traffic Matrix 3 reference networksTraffic matrices Ultra Long Haul Long-Haul Metro

18. Simulated annealing based planningTechnology selection • Heuristic RWA approach  fast computation even for large networks • Fixed-alternate routing (selection of alternative routes from a fixed set) • Reduces computational time by limiting search space • Makes it possible to simulate the critical paths in advance • Wavelength allocation by first fit • Results for the full topology: • Low percentage of paths > 750 km  significant cost reduction by mix of transponder reach

19. Simulated annealing based planningTopology optimization • Cost optimisation of network topology (by removing links): 2005 2006 2007 • Only small cost penalty for keeping 10% of wavelength resources free back

20. General approach Heuristic Exact Shortest Path (SP), heuristic Shortest Widest Path (SWP) Heuristic (Layered Approach) Integer linearprogramming (ILP) Heuristic & incremental ILP for network planning phase Routing and Wavelength Assignment Separate steps: network resources allocated before LPs are set up Layered approach with multiple prioritized criteria Part of ILP with bit-rate dependent length-restriction; unprotected, 1+1 protected Pre-routing as Hamiltonian cycle; RFWA for an incremental connection request Routing Fixed-alternate (for unprotected traffic) Adaptive Adaptive Any path within length-restriction Adaptive, optimized by ILP approach Wavelength Assignment First-Fit with Simulated Annealing & Genetic Algorithm First Fit / Best-Fit / Random-Fit & customizable cost First-Fit Implicit in ILP Adaptive, optimized by ILP approach Sorting of requests Sorted acc. to # of hops (descending) Balanced & adaptive Balanced & adaptive Optimization Goal Minimum used fibres Minimum cost Minimum fibre length (prioritized), lower wavelength numbers preferred Protection “1+1”, protected path: fixed routing None “1+1”, protected path: shortest cycle 1+1 “1+1” Environmental Conditions Static Dynamic Static & Dynamic Static Static Computational effort Medium High Medium Medium Physical layer impairments Maximum length < 1200 km, intrinsic Q-factor, FWM, XPM PMD, Q-factor based on noise Mapped into length restriction intrinsic Preferentially Considered Network 17-nodes German 16-nodes Pan-European 17-nodes German 17-nodes German 17-nodes German SP: Routing and WA simultaneously SWP: First routing and then WA based on criteria Weighted minimum of:# of wavelengths, # of hops, path length SP-Routing: Minimum spans, WA based on spans or Q SWP-Routing: Max # of available continuous wavelengths, cost or Q-based WA High Multi-purpose simulation engines back