1. SPIE, 9/20/99 We Need the Functions of IP/ATM/SONET/WDM Charlie Rohrs Fellow, Tellabs Research Center Visiting Scientist, MIT

2. Charlie Rohrs, Tellabs Research Center2 Premise: Reliability and Accountable QoS l Currently available public internet service will be improved somewhat as IP evolves to IP++ with some QoS distinction and possibly MPLS trunking. For this service, any pipe structure will do. l There will be a large and increasing class of customers for whom the network is mission critical. These customers will pay $BIG for: »Accountable (Contractual) QoS »Highly reliable uptime for all connections

3. Charlie Rohrs, Tellabs Research Center3 Functions in Today’s Mission Critical Networks l WDM - fat pipes l SONET - reliable pipes - protection, network reprovisioning, granular flow segregation, static reconfigurable QoS l ATM, FR - efficient pipes - accountable flexible QoS, VC Segregation, pipe granularity and flexibility l IP - universal access format and addressing, routing for survivability (not reliability)

4. Charlie Rohrs, Tellabs Research Center4 What Does IP/WDM Really Mean? l Will mission critical network customers be satisfied with IP/MPLS watered-down versions of ATM or FR functions? IP++ = ATM-- l Will WDM take over SONET functions?

5. Charlie Rohrs, Tellabs Research Center5 IP++ QoS and Reliability l Small amounts of downtime affect bottom line and network manager’s careers l Guaranteed service means it can be measured and penalties assessed for failures. l IP efforts intentionally avoiding exactly what mission critical networks need - contractual accountability and traffic segregation

6. Charlie Rohrs, Tellabs Research Center6 IP++ QoS and Reliability l Current public internet shows poor QoS and reliability even though it rides on protected, reliable pipes l Current poor performance is accepted because connectivity and end services are new. As internet services become mission critical, “Time is money” will be applied. l The IPites have usurped the “We have the answer to all the problems” position from the Bellheads.

7. Charlie Rohrs, Tellabs Research Center7 Joining WDM and SONET: Optical Crossconnects and ADMs l SONET functions are almost reconstructable »Optical switching times slow for protection »Problem with wavelength shifting (like crossconnects with no time slot interchange) »Wavelength (OC48, OC192) granularity probably too coarse for pipe management »Fault detection, isolation, alarming need to be reinvented l SONET Crossconnects with WDM ports more likely

8. Charlie Rohrs, Tellabs Research Center8 Why Remove Layers? l Almost everything in the removed layers needs to be reinvented. l Minor improvements in bandwidth efficiency is hardly compelling »SONET dedicated OAM channels »ATM small cell size l If you want to save boxes put two or more functions in a box. l Layering functions is good!!