Burst Transmission, Burst Switching and Dynamic Circuit Switching Prof. Leonid Kazovsky, PNRL Stanford presented by 리준걸 INC Lab. Seoul Nat’l University

SNU INC lab. 2 Outline  Background  Current Status –Long haul –Metro –Access  Optical Burst Switching  Conclusion

SNU INC lab. 3 Background  Optical Network Physical Layer Architecture  LightFlow – part of Stanford Clean Slate Project –End-to-end dynamic connection oriented optical transport layer –Prof. Leonid Kazovsky, PNRL (Photonics Networking Research Lab.) –Prof. Nick McKeown, HPNG (High Performance Networking Group)

SNU INC lab. 4 Current Status of Physical Layer  Long-Haul/ Core (WAN)  Metro  Access

SNU INC lab. 5

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7 Long-haul/ Core  Architecture –SONET/ SDH standard –point-to-point static WDM links  WDM – Wavelength-Division Multiplexing –Multiplex multiple optical carrier signal on a single optical fiber (like TDM, FDM)

SNU INC lab. 8 Long-haul  Problem: –Manual provisioning of wavelengths for new service request  Solution: –Dynamic provisioning of optical circuits with deployment of ROADMs (Re-configurable Optical ADM) –Dynamic Circuit Switching GMPLS – signaling and resource reservation (RSVP)

SNU INC lab. 9 Core – Dynamic Circuit Switching Choose capacity and path/next-hop

SNU INC lab. 10 Metro  SONET/SDH rings – synchronous, self-healing & designed for delay sensitive and fixed-bandwidth traffic  RPR (Resilient Packet Ring) – Metro Packet Rings –IEEE standard for optic fiber ring  Electronic ADM  DCS

SNU INC lab. 11 Metro  Problems: –Multiple overlay networks on static SONET WDM rings  Solution: –Multiple Service Provisioning Platforms (MSPP) –Infrastructure provides multiple services –includes SDH multiplexing, sometimes with add-drop, plus Ethernet ports, sometimes packet multiplexing and switching, sometimes WDM

SNU INC lab. 12 Optical Broadband Access  PON (Passive Optical Network) – point-to-multipoint  Optical splitter – single optical fiber to multiple premise  Tree structure  APON/BPON (ATM/Broadband) – ATM  GPON (Gigabit PON) – Ethernet, ATM  EPON (Ethernet PON) – Ethernet

SNU INC lab. 13 Access – PON architecture

SNU INC lab. 14 Review current status B/E/G PON Tree SONET Ring SONET point- to-point

SNU INC lab. 15 Optical Burst Switching (OBS)  Balance between OCS and OPS  OCS (Optical Circuit Switching) – connection oriented  OPS (Optical Packet Switching) – dynamic  Connection only for the duration of burst

SNU INC lab. 16 OBS  OPS –Need buffers, –need per packet O-E-O conversion, –Switch packet-by-packet  OCS –Unfashionable?  OBS –burst treat a flow of packets collectively –Reducing per-packet cost

SNU INC lab. 17  OBS –separate header from packet, transmit separately –Only header O-E-O conversion –Aggregation at one edge switching in the core assemble at the other edge  Optical Burst Transmission –Access – PON, upstream is TDM-based –Laser ON only during pre-assigned time slot –Laser OFF at other nodes

SNU INC lab. 18 Comparison Optical Switching Bandwidth Utilization Setup Latency Switching Speed Required Proc/Sync Overhead Traffic Adaptive Capability Optical Buffer Main Problem Optical Circuit Switching (OCS) LowHighSlow (ms) Low Not Required Not Very Dynamic Optical Packet Switching (OPS) HighLowFast (ns) High RequiredNo Optical RAM Optical Burst Switching (OBS) HighLowMediumLowHigh Not Required ?

SNU INC lab. 19 Conclusion - LightFlow  Long-haul – Optical Burst Switched mesh network –Dynamic connection oriented optical transport layer  Metro – Optical Burst Transport ring network  Access – Optical Burst Transmission tree network –Re-configurable TDM/WDM-PON

SNU INC lab. 20 LightFlow