1. Scalable Research & Education Networks Dr. Brian Smith, Senior Optical Systems Designer

2. Confidential Content  Introduction.  Review of Requirements for Research and Education Regional Optical Networks.  Comparing Strategies for Regional Optical Networks.  Towards seamless overlay of 10Gbps and 40Gbps traffic.

3. Confidential Introduction  Regional Optical Networks for Research and Education are being built at an increasing rate  Acquisition of dark fiber – lit up as private networks  Some University focused – some joint education/government initiatives.  Large Scale Research Applications are driving the demand for dedicated bandwidth  Real time image sharing between collaborating institutions  Very Large Baseline Interferometry  Distributed supercomputer simulations  Interactive Video Requires a network that can respond quickly to the demands of the Research Community

4. Confidential What features would be required in such a network ?  Dynamic Provisioning  Fully reconfigurable wavelength node  Simple migration from ring to mesh networking.  Ability to switch light-paths using Central/Distributed Management workstation(s).  Single wavelength granularity add and drop.  Seamless switching between DWDM and CWDM providing cost effective multi-grid networks.  Bit rate and protocol transparency – universal interface to higher layers.  Traffic grooming down to ‘STS-1’ level for ultimate flexibility but with GFP for protocol transparency. = Optimum network configuration matched to actual demand.

5. Confidential Other Features ?  Simple and Cost-Effective  Transport platform that integrates WDM transmission, wavelength switching and SDH/SONET grooming.  Central or distributed management of all network elements.  Layer 1 performance monitoring at every node – fault isolation.  Auto discovery of nodes, cards and optical interfaces  Interface directly to existing GigE /10GigE routers/switches (carry 10GigE LAN PHY natively without expensive WAN PHY/SONET encapsulation).  Carry any service (Ethernet, SONET, SAN) at wire speed from Fast Ethernet to 10GigE and beyond. Reduced cost and complexity = Rapid response to new Research Initiatives

6. Confidential  Scalability  Add wavelengths ‘in-service’ with no impact on existing traffic.  Add wavelengths with no adjustments to network provisioning (amplifiers etc).  Seamless overlay of wavelengths carrying traffic up to 2.5G, 10G and 40G over the same fiber.  Allow addition of on-grid alien wavelengths.  Make full use of industry standard technologies such as SFP/XFP to reduce cost and complexity of sparing. All of these features ARE available.....

7. Confidential Fully Managed via the 8600 NMS & 8300 EMS 7200 OADX  Multi-transport platform  Wavelength switching (128 )  STS1 grooming (320G)  CWDM, DWDM & ROADM transmission  Transparent & GFP interfaces  Mesh, ring, star  Scaleable Meriton Product Family 1450 OFA Line  Pre/post/line EDFA  Raman Amplifiers  Intelligent controls  Transient suppression  1510nm OSC  Up to 600 km links without regen 1100 DCMs  Fully passive with low insertion loss Link Extension ProductsMetro Core & Regional 3300 OSU  CWDM & DWDM  Transparent & SRM - Ethernet & SANs - STMx, OCx  Ring, star, & linear  10Gbps supported  Seamless interworking with 7200 OADX Metro Access

8. Confidential OADM vs OADX Network Issues

9. Confidential Typical OADM Transponder- Based Architecture Complicates network planning/engineering. - adding a filter affects the whole network. Serial Filter Design Prevents interconnection of CWDM to DWDM. Dedicated WDM Transponders Results in stranded wavelengths around the ring. - all wavelengths in a band are expected to be dropped at the same site Adding wavelengths requires service outage. - filter insertion, re-cabling, and power re-balancing. Lack of wavelength switching. - limits networking to point-to-point or ring only. Lambda Add/Drop Fixed by Band Can only switch on hard failures eg. fiber cuts. - Cannot switch on data error rate degradation. Protection Switching Limited to LOS. Difficult to isolate faults - no electrical loop- backs. Limited Maintenance & Diagnostic Support. Cannot monitor layer 1 (protocol level) error rate. - Cannot detect data errors and degradation. Performance Monitoring Limited to Optical Level. Truck rolls required to add new service type. - different trib card required per protocol type. Protocol-specific client-side cards.

10. Confidential 7200 OADX – Unique Product Architecture Full 3R Regeneration Simplified network design. - Link based design Wavelength Translation Full CWDM to DWDM connectivity. Wavelength Switching at the Electrical Level Non-blocking add/drop of wavelengths. (any wavelength in to any wavelength out). No stranded wavelengths. Hitless maintenance switches. - of protected lightpaths or cross-connects. Supports up to 16 WDM network interfaces. - allow support of multiple point-to-point, ring, and mesh networks concurrently. Performance Monitoring at the Optical and Electrical Level. Monitoring and detection of layer 1 data errors and degradation. (SONET/SDH, GIGE, FICON, ESCON, Fiber Channel) Protection switching on data error threshold. - protection on loss of signal or error threshold detect Supports Multiple Loopbacks at the Electrical Level. Simplified network troubleshooting. Electronic ROADM Architecture Same trib card supports multiple service types. - simplified sparing, pay as you grow upgrade - SFPs Universal client-side cards.

11. Confidential OADM vs OADX Multi-Degree Support EastWest Typical OADM Meriton 7200 OADX East West 2 WDM Network Interfaces Maximum 16 WDM Network Interfaces Single point-to-point, or single ring network only Multiple point-to-point, multiple ring, multiple mesh network configurations concurrently. Shared network – Not dedicated

12. Confidential OADM vs OADX Multi-WDM Interface Support Typical OADM Meriton 7200 OADX DWDM CWDM DWDM CWDM DWDM CWDM EastWest DWDM OR EastWest CWDM East West CWDM DWDM CWDM AND DWDM CWDM DWDM CWDM WDM network interfaces must match. Any combination of WDM network interfaces.

13. Confidential High error rate initiated protection switching is NOT supported by OADMs. - no level 1 performance monitoring to detect data errors OADM vs OADX High Error Rate Protection Switching DWDM CWDM Fiber Kink Layer 1 performance monitoring detects high error rate and initiates protection switch. OADX layer 1 performance monitoring is used to detect high error rates and automatically trigger protection switching.

14. Confidential OADM vs OADX Adding Wavelengths

15. Confidential Typical OADM capacity upgrade  OADM solutions address fiber exhaust needs but introduce difficult operational and engineering constraints  Serial Architecture Filter Design (Cascaded & Banded)  Result in Stranded Bandwidth  Serious Scaling Pains w/Re-engineering Required Optical Power Output w/No Balancing Maximum Power OEO Filter Loss = L 4L DWDM NE 3L 2L L 1 2 4 3

16. Confidential 7200 OADX capacity upgrade 1 DWDM Mux DWDM band Optical Power Output w/No Balancing 1 DWDM No power balancing or equalization required when adding wavelengths. No re-engineering required simply plug in card / SFP / XFP and your up and running

17. Confidential 7200 OADX Capacity Upgrade – Line Amplifiers OADM Re-provision optical amplifiers to maintain link-budget 1450 OFA amplifiers use gain control – More Gain – No Pain!

18. Confidential OADM vs OADX Adding New Nodes

19. Confidential Existing operational network and service Need to add an additional service, including inserting a new POP/node here. “Bridge” the existing service on-the-fly: using existing capacity, point, click, up and running in seconds. “Roll” the existing connection: hitlessly swing the service to the new path, with no service outage. Break the fibre. No service outages! Bring the new Meriton node into service, into the existing network. No service outages! Establish connections to the new equipment. Provision and activate a new light path. “Roll” the existing service back to its original route. OADM vs OADX – Network Changes Bridge and roll is NOT supported by OADMs. - all switch operations result in service disruptions 7200 OADX bridge-and-roll provides hitless maintenance operations.

20. Confidential OADM vs OADX Multi-Protocols Trib Card Support Typical OADM Meriton 7200 OADX Single Tributary Interface Card. Multiple Protocols Require Multiple Cards More Costly and Complex Upgrades Any port – Any Protocol. Universal Pluggable SFP/XFP Interface SONET OC-12 SONET OC-48 SDH STM-1 SDH STM-4 GigE More expensive Sparing Cost Effective Sparing

21. Confidential Meriton 7200 OADX vs OADM FunctionalityMeriton 7200 OADXTypical OADM Switching Integrated?YesNo Ring Support?Simplified EngineeringComplex Engineering Mesh Support?YesNo Mix CWDM & DWDM?YesNo Wavelength Translation?YesNo Layer 1 Performance Monitoring? YesNo Hitless MaintenanceYesNo; requires services outages ScalabilityYes, cost-effectiveDifficult and expensive

22. Confidential Overlaying 10G and 40G traffic on existing networks

23. Confidential Link Engineering- Challenges 10G OTR 2.5G DWDM DCM OFA Mux 2.5G DWDM 40G Need to understand dispersion tolerance and PMD tolerance to overlay 10G DCM OFA Dispersion tolerance and PMD are much more of an issue when overlaying 40G traffic DCM OFA Lets have a quick look at these issues...

24. Confidential Dispersion Tolerance  The dispersion experienced over any km of fiber segment lies within a range defined by the manufacturer. Wavelength (nm) Compensation (ps/nm)  Similarly, the amount of compensation delivered by a typical DCM is only accurately known within a range. Wavelength (nm) Dispersion (ps/nmkm)

25. Confidential Dispersion Tolerance (cont..)  Taking a 6 span x 80km link with each span compensated 100%, the actual net dispersion can lie between –500 and +500 ps/nm !  So how would this large range in net dispersion affect the eye closure penalty for 2.5, 10 and 40G traffic ?

26. Confidential 6x80kmx26dB - 32 2.5G 40G needs ADCM + enhanced FEC 10G needs FEC

27. Confidential Polarization Mode Dispersion  Using 6x80kmx26dB with 6 EDFA and 6 DCM, the calculated average DGD (assuming fiber is post 1995) = 2.5 ps  The PMD tolerance (and expected outage) for various data rates is: Rate pmd tolerance system outages/yr 2.5G30ps insignificant pmd outages/yr 10G7.6ps insignificant pmd outages/yr 40G(NRZ)1.9ps~ 22 minutes/year uncompensated 40G(RZ)2.7ps~0.5 seconds/year uncompensated 40G scenarios improved using enhanced FEC and/or PMD compensation.

28. Confidential 10G + 40G overlay on existing traffic  With an appropriate adaptive DCM at the receiver and enhanced FEC, 40G traffic can be transmitted over a system designed to support 2.5 and 10G traffic.  With PMD compensation and/or FEC, a 40G(NRZ) system is capable of reaching ~ 500km with no significant outages resulting from PMD.  A 40G(RZ) system with FEC is capable of reaching ~ 700km with no significant outages resulting from PMD

29. Confidential Summary  Reviewed some of the requirements for Research and Education Regional Optical Networks.  Compared OADM vs OADX strategies for Regional Optical Networking.  Analyzed the impact of Chromatic Dispersion and PMD tolerance for migration to 40Gbps traffic over existing networks.

30. Confidential Thank You Dr. Brian Smith brian.smith@meriton.com