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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 yoo@ece.ucdavis.edu. Progress in Optical Networks. Optical Packet Switching. Optical Burst Switching.
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Opportunities and Challenges for Optical Burst- andPacket- switching- S. J. Ben Yoo, Fei Xue, et al. Optical Switching and Communications Systems Lab University of California, Davis yoo@ece.ucdavis.edu
Progress in Optical Networks Optical Packet Switching Optical Burst Switching Optical Label Switching Optical Circuit Switching Function Optical Packet Optical Add/Drop Capacity Optically Amplified Dynamic WDM Static Single Channel Pt-to-Pt Ring Mesh Topology
Throughput comparison OBS vs. OCS Under the same network conditions, OBS networks can achieve 20%~30% more throughput than those in OCS networks.
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
Next Generation Network Overview Optical Core Network OLS switches OLS switches Edge router Edge router OLS routers Legacy MAN MAN MAN Edge router Star Coupler Star Coupler Legacy LAN SENSOR Networks Wireline O-CDMA LAN Free Space and Wireline O-CDMA LAN
Label Processing Module-TI (LP-TI) label reader Switch Controller w/ Forwarding Look-up Table Switching Fabric fiber delay NC&M DEMUX CI CI CI OLE OLE OLR OLR OLE OLR (LP-CI) Label Processing Modules-CI OLS Edge Router UNAS ATM Client Machine IP Router
Conventional Electronic Packet Switches TIME Buffer Memory Buffer Memory Buffer Memory Buffer Memory Buffer Memory Buffer Memory Buffer Memory Buffer Memory Buffer Memory Buffer Memory Buffer Memory Buffer Memory MAC MAC MAC MAC SPACE controller Buffer Memory Buffer Memory MAC Buffer Memory MAC Buffer Memory MAC MAC • Buffer, Schedule, and Forward • Electronic RAM--Diverse Functions • Contention Resolution, Queuing, etc in Time
Optical Switch Fabric used in UCDavis OLS core Routers WAVELENGTH TIME SPACE controller Fixed Wavelength Converters Tunable Wavelength Converters switch control l-router (AWGR) F_WC T_WC F_WC T_WC F_WC T_WC F_WC T_WC Rapid Tuning (~ 1 nsec) of T_WC to achieve switching in Wavelength, Time, Space domains Scalable to 42 Petabit/sec capacity 32*(2562x2562)connectivity
Contention Resolution Algorithm packet arrives • 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 #4585-04. • 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.142-8 (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). no contention ? yes yes l cont. res.? no yes time cont. res.? no yes space cont. res.? no forward Send to Edge Router for cont. res. or drop
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)
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)
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)
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)
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)
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)
Traffic Shaping at the Edge RoutersPacket length distribution at the Client and at the Core transport client
IP Client-to-IP Client with Cascaded Operation of OLSRs Label Payload Label L1,L2 P1,P2 Label Payload Payload L1 P1 L3 P3 L1,L2,L3 L2 P2 P1,P2,P3 IP Client Network Edge Router Ingress Path Egress Path Optical Label Switching Network Physical Layer Interface Encapsulation AOLS Interface Label processing Unit Core Router Data bus traffic controller Data Bus Core Router Data bus traffic controller PPP POS Interface SONET Physical Layer Interface Edge Router Core Router POS P1,P2,P3 Edge Router P1 POS IP Client Network
Possible Network Evolution Scenario Electronic ATM Network Electronic IP Network Electronic IP Network LAN LAN
Possible Network Evolution Scenario Electronic MPLS Network Electronic IP Network Electronic IP Network LAN LAN
Possible Network Evolution Scenario MPLambdaS Network Electronic MPLS Network Electronic MPLS Network LAN LAN
Possible Network Evolution Scenario Electronic MPLS Network Electronic MPLS Network Optical Label Switched Network LAN LAN
Possible Network Evolution Scenario Electronic MPLS Network MPS Network Optical Label Switched Network Electronic MPLS Network GMPLS II Electronic MPLS Network Electronic MPLS Network LAN LAN LAN
Summary • 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