State and Future of Advanced Optical Networks

1. The Current State and Future of Advanced Optical Networks July 20, 2004 Rob.Vietzke@uconn.edu Connecticut Education Network University of Connecticut NEREN

2. Agenda • Current State of the Optic Networking • Metro • Regional • New Approaches & Hype • Broken Reasoning • Community Directions

3. Distance scales for U.S. R&E optical networking

4. CT Ed Net “Metro” Experience • Over 1,200 miles of SMF-28 fiber deployed across Connecticut • 160 dark fiber connected K12, Higher Ed sites • All edge sites are GigE • Higher Eds homed to 2 core sites • Up to 4 K12’s daisy chained between pair of core sites • Some CWDM for metro higher ed rings • Considering 10G/1G CWDM combo links

5. CEN Leased Dark Fiber Network

6. Current State: Metro • Typical Scenarios for metro optics • Long Haul GBIC, SFP, XFP, or Xenpak • Occasionally POS or ATM long haul on dark fiber • Integrated pluggable in router/switch • Redundancy through Link State monitoring on multiple paths and L3 routing • Occasionally CWDM or even DWDM added • Almost no other statusing other than up/down of optical layer • Market leaders could do more … • Make basic power telemetry available from pluggables • Make cross-vendor pluggables usable • Encourage higher-power affordable single-channel applications • By example 10G-ER+ to match 1G ZX

7. Current State: Metro • CWDM • Passive nature of OADM’s makes rings livable for customer sites in non-C/O environments • Dedicated, redundant GigE Paths from site • Maintains link state to core • Reasonable Cost / Performance • CWDM OADM packaging adds complexity • No cost effective test gear/approach for CWDM • Complexity of cabling, patching, testing, cleaning can’t be overstated. • Still arguably a great, cheap, disruptive approach

8. CWDM OADM Options

9. Router Router CWDM GBIC & XenPack-EROne Fiber Pair Site B Site A CWDM-MUX-AD-1470 CWDM-MUX-AD-1470 2 λ 1x GE 1x 10GE East LAMBDA XXXX OADM East West West East Xenpak-ER Xenpak-ER East 1470nm West 1470nm West 1470nm East 1470nm Not Used Not Used 1470 GBIC 1470 GBIC

10. Current State: Regional • 3rd Generation DWDM Systems • Market competitors moving very much in step with one another • Planning tools • Power Management • ROADM (Reconfigurable Add/Drop Mux) • Other Evolutions • Dynamic Optical power management across systems, paths, channels, bands • Very manual OADM approaches • Disruptive insertion and balancing • Lots of patch cords within systems & even shelves?? • Highly touted ROADM typically works with limited wavelength windows on transponders & mux-ponders

11. Current State: Regional • 3rd Gen DWDM (Cont’d) • More Flexible transponders and muxponders • Larger agile frequency range for optical output • Larger variety of interfaces and better stuffing of 2.5G and 10G wrappers • Device Management • Increasingly good telemetry and monitoring of optic power, bit error rate, etc. • May need to know TL-1 or CORBA • Always check on XML & SNMP options? • A whole new OSS to learn and support in many cases • Very Much an analog world • Dispersion, loss, balancing, planning more about gain structure than bits. • Still wonder if a good sound engineer or a physicist would understands these things better than a bit head

12. DWDM OADM Site Block Diagram

13. Current State: Regional • Analog World • 99% of designs are fundamentally about how much “noise” can you allow to grow in a system before you won’t be able to see bits anymore and therefore need to regenerate • Faster bit rates are harder to distinguish at shorter distances than slower bit rates

14. Disruptive Thought? OEO everywhere Analog-Optical Systems O-E-O O-E-O O-E-O O-E-O O-E-O O-E-O O-E-O O-E-O • Maximize distance between expensive transponders, muxes, etc • Reduce “noise” by reducing OADM’s, amps, etc wherever possible • Aggregate analog PM data, have some fault isolation capability Digital Optical Network • Regenerate every analog wavelength at every site, make noise problems so far beyond span specs as to become irrelevant • Leverage E in OEO to create electrical add-drop fabric at each site

15. That’s fine, but what would Next Generation Equipment that you wanted look like?

16. Needs & Future Directions • Agile Amplification & Dispersion Approach • Not visit dependant as channel loading increases or fiber ages • Not even to patch an agile transponder in to the right ROADM port • Interruption-free upgrades/changes • Initially affordable & predictable scalability • Allow multi-point exchange of lambdas • Not just rings! Spurs & Aliens necessary • Support RON interconnection • Good growth cost curve (>? Distruptive ?)

17. Observations • We’re spending lots of dollars on separate software licenses, maintenance contracts and O&M systems for optical and L3+ services • Telemetry still lousy for the large enterprise • Am I running a digital optical network or a broadband CATV system • Composite Triple Beat, Carrier to Noise Ratio, Harmonics, Composite Second Order, etc. all things I remember from balancing amplifier cascades. (Telemetry for that stunk too.)

18. Current Approach: • Assume optics and routers are separate • Accept need to purchase/learn new O&M • Look to roll wrappers in to transport layer • Increase complexity there too? • Look for additional flexibility and features to be built in to –both- parts of the equation

19. Approach: OEO w/elec. fabric • Still assume optics and routing is separate • Essentially eliminate analog portion of the problem by doing full conversion and retiming to digital at each site • Continues separation of Optic and Services hardware • Provides switched “wavelengths” cheap • 2.5G based cross fabric may create new barriers for wide-band migration to 40G and 100G • Another highly complex device to understand, manage, troubleshoot and maintain • Idea of a backbone electrical fabric probably increases opportunities for good multi-point junctions at high bandwidth • Replace Line-Card router optics with this technology?

20. Approach: Purify, Simplify O & E • Move digital timing, framing, shaping, etc. in to routers with controllable ITU grid wavelengths out (Large form pluggables?) • Maybe even tunable wavelengths? • Make optical portion pure optic amplification, Dispersion, balancing, etc. Eliminate shaping, timing, framing cards. • Good telemetry and control back to routers for optic control • Can I graph optical performance on Cricket/MRTG? • Need dispersion compensation for 10G or eFEC at day0 • Advance Alien Wavelengths in to Optic platforms • Think about federated optical networks! • Cannibalizes vendor business units & requires current business to do development together • Single wavelength application can actually be router-only with no throw-aways as DWDM is added • Probably still lousy at multi-directional fiber intersections

21. Other thoughts • Drive vendors on telemetry from optics • Anticipate we will need the ability to link RON’s, perhaps with (or even without) a common national backbone for all services • We need to solve Alien Wavelength problem on optical & router platforms • Need ability to monitor and control Power, Wavelength, dispersion, eFEC, etc across the common control plane • Need standardization of signalling and wrappers for alien wavelengths

22. The Current State and Future of Advanced Optical Networks July 20, 2004 Rob.Vietzke@uconn.edu Connecticut Education Network University of Connecticut NEREN