~
. . ... , .. ....
" _ ~
~F
~
GUESTEDITORIAL
i
ADVANCING OPTICAL TECHNOLOGIES IN SPITE OF THE
TELECOM SLOWDOWN! Sudhir S. Dixit
Philip 1. Lin
igital access crossconnect systems (DACS) are in, and photonic crossconnects are out. Who would have predicted this as the prevailing shift of focus in the telecom industry? The bubble has burst, the VC cash has dried up, and soon we'll be seeing consolidations of companies and even bankruptcies. In the midst of all this, does it make any sense to continue to advance optical technology? In this editorial, we will answer this question with a resounding yes. As we wrap up the final issue of the Lightwave Series for 2002, we need to pause and reflect on the developments this year and anticipate what is to come in the future. We will also make an announcement of an editorial personnel change at the end of this editorial. Cost reduction is king, but not cost reduction at any expense. On the business side, certainly there has been a slowdown in the telecommunications sector in terms of both new deployments and capital investments in emerging companies and carriers. Survival is the key of the game. However, companies will need to have a longer range of view. It would he a shame for a company to survive the telecom winter only to be easily squashed by competition when recovery occurs. Prudent companies spend their efforts on more than survival. They want to be the first out of the gate when this industry turns around. This implies innovation. Innovation allows these companies to offer products that can be differentiated beyond cost. Carriers have now locked up their purse strings. When they are willing to spend again, they will be choosy and select equipment that has higher value and is future-proof. Technological advances are needed in such a stingy market. Technology advancement does not contradict cost reduction; in fact, they are complementary. There has been an increased focus on leveraging existing assets and slashing operating expenses. What better way is there to leverage existing network equipment than hy making them more intelligent? Fast provisioning allows carriers to realize revenues earlier. Traffic management allows them to utilize the existing bandwidth more fully. Auto-provisioning and fault recovery reduces operating expenses by minimizing t h e number and urgency of truck rolls. If we
78
fast-forward into the future, the good news is that any future growth will be measured, rational, and based on solid business principles leading to interoperable solutions with realistic productitechnology life cycles. The temporary pause in the industry will also help minimize the confusion as to which technology to deploy and when. In hindsight the technology developers can concentrate on what they do best (i.e., develop new innovations) rather than be distracted by the financial bonanza. In this issue we take aim at three very important topics: restoration in IP-over-WDM networks, hybrid hierarchical optical cross-connects, and multicasting in optical burst switched networks. Over the past several years IP over WDM using GMPLS signaling has received considerable attention. In such networks failure of a fiber link can bring down a vast number of optical label switched paths (LSPs), which can be catastrophic from a service point of view. Link restoration as quick as possible is critical to the success of any IP-overWDM network. To address this issue, Jian Wang et al. investigate several restoration techniques for fault management in extreme conditions where multiple fibers may fail simultaneously. They compare the various techniques by computing the restoration success rate, average restoration time, availability, and blocking probability. Although network bandwidth is getting cheaper and abundant, optical nodes are becoming complex and could potentially become the bottleneck. Hybrid hierarchical optical crossconnects, both OEO and all-optical types, can deliver the best of both worlds: the OEO part can do the grooming, and the optical part the efficient bypassing of transit traffic. Rauf Izmailov et al. in their article describe the rationale for hybrid hierarchical crossconnects and the various system components that make up such nodes, and discuss their performance and cost implications. Many applications and services are more efficiently served using multicasting (one to many and many to many), where the source selectively broadcasts the information to a set of receivers. It would be only natural to develop techniques at the optical nehvork layer that would be rational and compat-
-
IEEE Communications Magazine November 2002
!
GUESTEDITORIAL
p J
^ _ l l l l _ l l
ible with the requirements of multicasting at the application layer. There has been much research on optical burst switching (OBS) as a switching technology to transport IP traffic directly over WDM networks, but very little has been reported on how IP multicast traffic will be supported. Transporting 1P multicast traffic on an OBS network calls for efficient solutions that will minimize the overhead of control packets and guard bands. Myoungki Jeong el al. address exactly this issue in their article. The authors propose tree-shared multicasting (TS-MCAST) and several tree sharing strategies to reduce the number of control packets generated, resulting in reduction of overhead traffic. Finally, on the editorial front, we would like to inform you of the changes in the editorial makeup of the Lightwave Series. Sudhir Dixit is stepping down from his editorship after having served for about thrce years. The reins are passed on to Dr. Stamatios Kartalopoulos with Philip Lin continuing as a co-editor to provide a smooth transition. As an editor, Sudhir had a great and interesting experience. H e wishes t o thank all who read the series, submitted and reviewed articles on short notice, and provided important comments and feedback. He will cherish your wonderful support for a long time to come. Philip would like to welcome Stamatios and his fresh insight to the Series. Both Philip and Stamatios feel privileged to volunteer their efforts to serve the community this way.
IEEE Communications Magazine
-
November 2002
We hope that the Lightwave Series will continue to provide you with interesting and insightful articles, and continue to enjoy your continued support.
BIOGRAPHIES SUOHIR 5 . DIXIT
ISMI (
[email protected]) is a site manager and heads the
broadband networks department a t Nokia Rerearch Center. Burlington. Marrachurettr. specializing in Internet. optical networks. mabilelwirelerr networks, and content delivery. Prior t o joining Nokia in 1996 he held various engineering and management positions at other major companies. such ar NYNEX (now Verizon). GTE (now Verizon). Motorola. Wang. Harris. and STL (now Nortel Europe). He received a B.E. degree from Maulana h a d College of Tel-hnology, Bhopal. India. an M.E. degree from Birla Inrtitute of Technology and Science. Pilani. India, and a Ph.D. degree from the University of Strathclyde. Glasgow, Scotland. ,all in electrical engineering. He also received an M.B.A. degree from Florida Institute of Technology, Melbourne. He has published or presented about 150 papers, and has 26 patents either granted or pending. He has co-edited a book on Wireless IP (Artech House. December 2002). and edited a book on IP over DWDM (Wiley. January 2003). PHILIP1. LIN (
[email protected]) is a staff research engineer at Tellabs Operations Inc. and a visiting scientist at the Marrachurettr Institute of Technalogy. He received his 8.5. (1989) in engineering from the California Institute of Technology and an S.M. (1991) and a Ph.D. (1996) in electrical engineering from the MaSIaChUIetti lnxtitute of Technology. His Ph.D. thesis work war on all-optical backbone networks. His current research areas include optical network architecture. optical system design, and network aptimization. He has published w e r a l conference and journal papers. and i s a coinventor in three granted and numerous pending patents. He received an honorable mention in the 2001 Eta Kappa Nu Outstanding Young Electrical Engineer Award.
79
