Opportunities and Challenges for Optical Burst- and Packet- switching- Opportunities and Challenges for Optical Burst- and Packet- switching- S. J. Ben Yoo, Fei Xue, et al. Optical Switching and Communications Systems Lab University of California, Davis

2 Progress in Optical Networks Capacity Function RingMesh Dynamic Static Optical Packet Pt-to-Pt Single Channel WDM Optically Amplified Optical Add/Drop Topology Optical Circuit SwitchingOptical Burst SwitchingOptical Packet Switching Optical Label Switching

3 Optical Burst Switching

4 Diff Serve OBS Performance

5 Throughput comparison OBS vs. OCS Under the same network conditions, OBS networks can achieve 20%~30% more throughput than those in OCS networks.

6 Motivations for Optical Packet Switching Data-centric + High-Bandwidth  Packet + Optical Sub-wavelength granularity Cost-effective service delivery and flexibility Avoid electrical RAM and O/E/O bottleneck –DRAM getting faster only by 7%/year –O/E/O conversion consumes power and space Scalability for future bandwidth growths Use optical parallelism for simpler switching fabric From ATM/SONET to IP/WDM paradigm

7 Next Generation Network Overview Wireline O-CDMA LAN Legacy MAN Free Space and Wireline O-CDMA LAN Optical Core Network Edge router Edge router OLS routers OLS switches Star Coupler MAN Star Coupler MAN Edge router Legacy LAN OLS switches SENSOR Networks

8 fiber delay DEMUX NC&M Switching Fabric Label Processing Module-TI (LP-TI) Label Processing Modules-CI (LP-CI) CI OLEOLR OLEOLR OLE OLR IP Router ATM Client Machine UNAS label reader Switch Controller w/ Forwarding Look-up Table OLS Edge Router

9 Buffer Memory MAC controller Buffer, Schedule, and Forward Electronic RAM--Diverse Functions Contention Resolution, Queuing, etc in Time Buffer Memory MAC Buffer Memory MAC Buffer Memory MAC Buffer Memory Buffer Memory Buffer Memory MAC Buffer Memory Buffer Memory Buffer Memory MAC Buffer Memory Buffer Memory Buffer Memory MAC Buffer Memory Buffer Memory Buffer Memory MAC Conventional Electronic Packet Switches SPACE TIME

10 Optical Switch Fabric used in UCDavis OLS core Routers Rapid Tuning (~ 1 nsec) of T_WC to achieve switching in Wavelength, Time, Space domains Scalable to 42 Petabit/sec capacity 32*(256 2 x256 2 ) connectivity T_WC F_WC switch control Tunable Wavelength Converters -router (AWGR) controller TIME WAVELENGTH SPACE Fixed Wavelength Converters

11 Contention Resolution Algorithm packet arrives contention ? cont. res.? time cont. res.? space cont. res.? Send to Edge Router for cont. res. or drop yes no forward no yes S. Yao, S. J. B. Yoo, and B. Mukherjee, “A comparison study between slotted and unslotted all-optical packet-switched network with priority-based routing,” OFC 2001, #TuK2 S. Yao, S. J. B. Yoo, B. Mukherjee, S. Dixit, “Hybrid contention resolution for an optical packet-switched network with self- similar IP traffic,” APOC 2001 # S. Yao, B. Mukherjee, S. J. Ben Yoo, and S. Dixit, “All-optical Packet-switching for Metropolitan Area Networks: Opportunities and Challanges,” IEEE Comm. Magazine, vol.39, p (2001) S. J. B. Yoo, Y. Bansal, Z. Pan, J. Cao, V. K. Tsui, S. K. H. Fong, Y. Zhang, J. Taylor, H. J. Lee, M. Jeon, V. Akella, K. Okamoto, S. Kamei, “Optical-Label Switching based Packet Routing System with Contention Resolution Capabilities in Wavelength, Time, and Space Domains,” OFC 2002, paper #WO2 (2002).

12 OLS Core and Edge Routers

13 Optical Packet Assembly Mechanism Assemble a larger optical packet from IP packets based on destination and QoS The creation of an optical packet: –Reach the Maximum Payload Size (MPS) –Expiration of Assembly Time-out Period (T) MPS

14 Optical Packet Assembly Mechanism MPS Assemble a larger optical packet from IP packets based on destination and QoS The creation of an optical packet: –Reach the Maximum Payload Size (MPS) –Expiration of Assembly Time-out Period (T)

15 Optical Packet Assembly Mechanism MPS Assemble a larger optical packet from IP packets based on destination and QoS The creation of an optical packet: –Reach the Maximum Payload Size (MPS) –Expiration of Assembly Time-out Period (T)

16 Optical Packet Assembly Mechanism MPS Assemble a larger optical packet from IP packets based on destination and QoS The creation of an optical packet: –Reach the Maximum Payload Size (MPS) –Expiration of Assembly Time-out Period (T)

17 Optical Packet Assembly Mechanism MPS Assemble a larger optical packet from IP packets based on destination and QoS The creation of an optical packet: –Reach the Maximum Payload Size (MPS) –Expiration of Assembly Time-out Period (T)

18 Optical Packet Assembly Mechanism MPS Assemble a larger optical packet from IP packets based on destination and QoS The creation of an optical packet: –Reach the Maximum Payload Size (MPS) –Expiration of Assembly Time-out Period (T)

19 Traffic Shaping at the Edge Routers Packet length distribution at the Client and at the Core client transport

20 Packet-loss rates for networks with various number of

21 IP Client-to-IP Client with Cascaded Operation of OLSRs IP Client Network Optical Label Switching Network Core Router Edge Router POS Payload Label POS IP Client Network Edge Router Core Router Payload Label Payload Label Physical Layer Interface Encapsulation Label processing Unit Data bus traffic controller Data Bus SONET PPP Physical Layer Interface Data bus traffic controller AOLS Interface POS Interface Ingress Path Egress Path Edge Router L1 P1 L3 P3 L1, L2 P1, P2 L2 P2 P1,P2, P3 L1, L2, L3 P1

22 Possible Network Evolution Scenario Electronic ATM Network Electronic IP Network LAN Electronic IP Network LAN

23 Electronic MPLS Network Electronic IP Network LAN Electronic IP Network LAN Possible Network Evolution Scenario

24 Electronic MPLS Network MPLambdaS Network LAN Possible Network Evolution Scenario

25 Electronic MPLS Network Optical Label Switched Network LAN Possible Network Evolution Scenario

26 Optical Label Switched Network Electronic MPLS Network LAN Electronic MPLS Network LAN MP S Network Electronic MPLS Network LAN Possible Network Evolution Scenario GMPLS II

27 Optics provides capacity, packet switching provides flexibility and fine granularity Optical Label Switching Provides interoperability in Packet, Burst, and Circuit switching Unified contention resolution in wavelength, time, and space domain. Edge router function critical in performance enhancement and traffic shaping Seamless network evolution from today’s circuit-switching to tomorrow’s burst- and packet- switching Summary