Long Term Network Scenarios based on OBS/OPS

1. Long Term Network Scenarios based on OBS/OPS • Partners: - Telecom Italia - Alcatel SEL AG - Alcatel CIT - Lucent Technologies Nederland BV - Marconi Communications ONDATA GmbH - Siemens • - Telefonica - FhG-HHI - IBBT - UCL - IKR - University of Stuttgart - UPC - ICCS Workpackage 3 Advanced Burst/Packet Switching [v1] Gert Eilenberger, Michael Schlosser

2. Agenda The presentation is structured in two parts: • Objectives / Overview (Gert Eilenberger) • TCP over OBS (Michael Schlosser)

3. Agenda • Objectives / Overview (Gert Eilenberger) • TCP over OBS (Michael Schlosser)

4. Targeted Network Architectures PhoneHome PhoneHome Music Gaming Music Gaming Applications Applications SmartBiz SmartBiz Management Management Voice @Home Voice @Home Video Video Service Service TV User User Element Element Interactive Voice Multimedia Services Services Softswitch Control Control Network Capabilities User Location User profile Storage Resource Broker Multicast VPN L3 Packet L3 Packet Security Packet Network Services QOS Charging AAA DSL/FTTU Broadcast L2 Packet / Optical L2 Packet / Optical GigE / SAN SAN/NAS Optical Network Services G-MPLS Ethernet GRID LL Core Core Metro Access Access NOBEL WP3

5. Motivation for Burst/Packet Switching • Goal: Converged multi-service network with end-to-end QoS and multiplexing gain on network level Converged burst/frame switching network (new Layer 2 transport service) Premium Best effort Quasi 2 networks (packet switched) same technology stat. mux. Overprovisioning to get Best effort Premium unused premium quality premium Isolated best effort network Isolated premium network (packet) Status quo: 2 networks 2 technologies (circuit/packet) Premium Best effort Isolated premium network Isolated best effort network (pure TDM)

6. Motivation for Burst/Packet Switching (2) • Architecture options MSN Pure IP IP/OXC IP/DXC Data services TDM services Edge Routers Edge Routers Edge Routers Edge Routers IP router IP router Burstification unit Burst/Frame Switch (service agnostic) Optical Cross Connect Core Router SDH/SONET Cross Connect  Scalability  QoS  Costs  Integrated CP  Scalability  QoS  Costs  Flexibility  QoS  Opt. technology  Flexibility  Multi-layer control

7. Extended long-term scenario The new L2 network service with its hybrid circuit/burst/packet switching capabilities will be fully integrated into the GMPLS control plane (full vertical integration)

8. WP3 Objectives • Network and node architectures for high throughput optical burst/packet core and metro networks • Evolution from wavelength (circuit) switched to burst/packet switched optical networks: exploit improved statistical multiplexing • Exploit transparent opt. wavelength/burst/packet switching to reduce excessive electronic processing for reduced overall cost • Optimal balance between optical and electronic technologies in terms of performance and cost • NovelCP and MP functions adapted for optical burst/packet networks (performance monitoring, protection and restoration). • End-to-End QoS support in opt. burst/packet layer (reservation, allocation, signalling, signal regeneration etc.) • Possible extensions and/or evolution of standards

9. WP3 Key Achievements • Data Plane: Definition of requirements and traffic profiles for burst/packet networks and nodes • Data Plane: Various solutions for burst, packet and hybrid network architectures (dimensioning, performance) • Control Plane: Concepts on architectures and functions specific for burst/packet networks (routing, QoS, GMPLS) • Requirements and assessment of technologies for optical and opto-electronic burst/packet switching solutions • Evolution trends • … contained in >560 pages of deliverables

10. APSON: Adaptive Path Switched ON • Migration concept via APSON to OBS/OPS networks

11. G.709 Frame Switching Concept • Aggregation of client packets into equally sized containers: G.709 Frames • Frame Aggregation Unit at network ingress and egress. • Switching of each individual G.709 frame. • Connection less forwarding. • Connection oriented bandwidth reservation and labeling. • Continuous G.709 OTUx connections on transmission links.

12. 3 1000 DSL users Installed access rates on 1GBit/s 1 concentrator link 2.5 DSL 0.8 Eth 10 Overdimensioning Eth 100 large web server, 2 LAN access 0.6 data center to WAN, Bandwidth efficiency 1000 users 0.4 1.5 super computers 0.2 talking to each other 1 100MBit/s 1GBit/s 10GBit/s 100GBit/s 0 0 2 4 10 10 10 Mean bandwidth on core link Aggregation factor Core Network Dimensioning • Statistical Multiplexing in Core Networks • Aim: Reliable bandwidth estimation in packet based networks • Dimensioning rules for core links • Guidelines for the activity • Use knowledge of installed base andmeasurement of core link occupation • Typical provider knowledge • Avoid assumptions on user behavior and application mix. • Not predictable, outdated before consolidation • Expected result • Modified network dimensioning rules • independent of user behaviour • exploiting statistical multiplexing

13. Virtual Topology Design for OBS/OPS • Motivations for virtual topologies in OBS/OPS • Introduction scenario for OBS/OPS into wavelength-switched networks • Cost-optimal network design: reduce number of burst-switched interfaces by optical bypassing • Exploit lightpaths services for resilience and capacity adaptation • Combination of burst-switched and wavelength-switched networksin client-server hybrid optical network • But: dense virtual topologies also reduce statistical multiplexing gain  Integrative network design needed including effective contention resolution

14. Optical Burst Transport Networks (OBTN) OBTN Components • Use optical bypassing where possible • Allow constraint alternate routing • Assign shared overflow capacityfor alternate routes to improve statistical multiplexing(capacity share is defined by b) • Apply effective contention resolutionin nodes to achieve high QoS Summary • Reduction in burst-switched interfacescompared to OBS • Only small penalty in network resource efficiency • Overall high QoS Burst-switched trunk ports Comparison for COST CN network at 10-5 burst loss

15. ORION: Combining Packets and Circuits • ORION functionality • ORION node architecture

16. OBS node edge router Physical limitations: • Component availability • Signal degradation (BER) • Noise • Crosstalk • Nonlinearities Why physical OBS node design ? What throughput can be achieved with state of the art components?

17. Tune and Select (TAS) Node Architecture

18. 12 256 10 8 148 132 Throughput [Tbps] 6 96 4 2 10 0 0 NRZ NRZ NRZ RZ RZ RZ modulation format SOA type Gain-clamped SOAs have to be used! NRZ modulation is superior Throughput of TAS Nodes with 4 Fibersat 10 Gbit/s maximum throughput due to physical limitations maximum number of wavelengths per fiber allowed throughput to achieve a burst loss rate < 10-6 (effective throughput) Reference SOA Conventional SOA Gain-clamped SOA

19. Buffer limited optical packet network architecture

20. Two Opt. Packet Crossconnect Architectures Class-I Class-II

21. WP3 Migration Scenarios BS over dyn. l WR-OBS APSON ORION G.709 FS OBS/OPS Static l Dyn. l time Field deployment 2015 Product status Research lab status 2010 2005 “From semi-static to dynamically reconfigurable optical networks” technology

22. Agenda • Objectives / Overview (Gert Eilenberger) • TCP over OBS (Michael Schlosser)

23. TCP – Introduction • TCP (Transmission Control Protocol) is the dominating transport protocol in the Internet. • More than 80 % of the IP traffic today uses TCP on the transport layer. • TCP establishes an end to end connection: • Connection oriented • Reliability • Flow control • Congestion Control Application Oriented Layers L 5-7 (e.g. FTP) L 4 (TCP) L 3 (IP) L 2 (OBS) L 1 Transport Layer Network Layer Link Layer Physical Layer

24. H H A1 G1 E1 B1 F1 C1 H H H H H H Burst Blocking due to Collision ElectronicDomain EdgeNode B F D G A E C OpticalDomain CoreNode D1

25. Interaction of TCP and OBS TCP Delay, Delay Jitter Multiple Losses Reordering Aggregation of packets Losses (No buffering) “Aggregated” Losses Deflection Routing Buffering in the Node OBS

26. Research within the TCP Taskforce • Topics: • Impact of different TCP flavors and TCP parameters on TCP performance • Many TCP flows (highly aggregated traffic in metro and core networks) • Dependence of TCP performance on number of TCP segments of one flow in a burst • Performance of TCP with Deflection Routing • Applications: • FTP traffic (long-living TCP connection, bulk transfer) • HTTP traffic (short-lived TCP connections, short transfers ) • Scenarios: • Single Client/Server behaviour • Behaviour of many Clients and Servers

27. Impact of aggregation level on TCP performance blue: lossless red: burst loss rate 1% Application:Heavy Web Browsing x-axis: simulation time y-axis: throughput (bits / sec.) Summary: Higher aggregation level. i.e. higher number of aggregated clients, reduces the negative effect of burst losses on TCP performance, since less TCP segments per flow are affected by loss of a burst 3 Web Browsing Clients 300 Web Browsing Clients

28. Realistic Traffic model for TCP over OBS NOBEL model Classic model • The classic model considers only one TCP client and one TCP server. • The new NOBEL model considers one TCP client, one TCP server and additional traffic sources (fractal traffic). • Real number of TCP segments per burst from a single flow is lower than previously assumed. Simulation with TCP SACK and Reno • Classic model (without additional traffic): An optimal value of the timer can be found. • NOBEL model (with additional traffic): Throughput is similar for the different values. • TCP SACK achieves higher throughput than TCP Reno.

29. Path B Path A Server Client TCP Performance with Deflection Routing • TCP is sensitive to Deflection Routing. • Deflection Routing is useful for contention resolution, as the performance degradation due to deflection routing is considerably smaller than the degradation due to burst losses. • The aggregation of more packets out of one TCP flow in a burst has positive impact on TCP performance with deflection routing.

30. Conclusion • TCP performs well over OBS networks when an appropriate TCP parameter set is used and there is aggregation of multiple TCP flows into bursts. • MSS/MTU size heavily impacts the performance of TCP in OBS networks (at least for greedy sources): high MSS/MTU value results in much lower effect of burst loss. • The advertized receiver window should be set to the maximum value in OBS networks, although the relative effect of burst loss is slightly increasing for high values • The higher the number of active users, the lower is the effect of burst loss on the throughput in the network • TCP SACK achieves higher throughput than TCP Reno. • Real number of TCP segments from a single flow is lower than previously assumed • Deflection Routing has a negative impact on the TCP performance, but it is useful for contention resolution, as the performance degradation due to deflection routing is considerably smaller than the degradation due to burst losses.

31. Outlook for NOBEL 2 • Taskforce will continue work • New TCP flavours • Traffic source models derived from measurements fromNOBEL partners • Influence of new application mixes • Influence of traffic asymmetry and burstiness (metro networks) • Burst loss due to collisions • Dependency on network load • Dependency on network topology • Dependency on burst distribution (length, interarrival times) • Derivation of optimized traffic dependent parameter sets(e.g. max. burst timer/sizes) • Evaluation of hybrid solutions (Circuit / OBS) • Generalization of burst reordering problem in high-speed core networks

32. WP3 Thank you for your attention!

33. Additional slides (could be shown in strongly compressed form if time allows) - Will be presented as poster

34. Connection-oriented OPS scenario • Main Property: Shared WDM links • Several wavelengths to choose from on the same output fibre • Problem: • Algorithm to map the Optical Virtual Circuits (OVCs) into the output wavelengths • Solution: • At OVC set up: Assign the OVC to the optimum wavelength • Using a dynamic wavelength assignment during the OVC life: In case of congestion, move the OVC to another wavelength using a Wavelength Selection(WS) algorithm

35. 10-1 TSWS LBWS SKWS 10-2 10-3 Packet Loss Rate (PLR) 10-4 10-5 10-6 0.4 0 0.5 1 1.5 2 2.5 Granularity D 1.2 QoS provisioning: Different WS Algorithm per Service Category • ATM like scheme: Provide K different categories of service based on K different WS algorithms • Each WS algorithm presents different performance • Thus, we can map the service categories into the WS algorithm according to the QoS requirements of these service categories • Case study: • 3 Categories of service • 3 WS algorithms • Problem: • The WS algorithms do not have performance alignment with the optical buffer granularity (D) • D = (FDL-size / Average IPpacket-size) x (Vt / Vp) • Our solution: • Redesigning the Optical Buffer architecture TSWS: Two State WS LBWS: Loss Bounded WS SKWS: Sequence Keeping WS

36. 1 RT LS 10-1 BE 10-2 10-3 Packet Loss Rate (PLR) 10-4 10-5 10-6 10-7 10-8 0 0.2 0.4 0.6 0.8 1 Granularity D QoS provisioning: Proposed Optical Buffer Architecture • Non consecutive FDL • FDL sequence: multiples of 1.2 / 0.4 = 3 • Example: • Optical buffer with 6 FDLs: Sequence: 0, 1, 2, 3 (1 x 3), 6 (2 x 3), 9 (3 x 3) • With this Optical Buffer Architecture we got: • The alignment of the WS algorithms performance • The aimed QoS provisioning: • Real Time (RT) • Very low PLR and no out of sequence packet • Loss Sensitive (LS) • Bounded PLR • Best Effort (BE) • Acceptable PLR

37. QoS provisioning: Proper Optical Buffer Architecture • Consistency of the solution: • Such a non-consecutive Optical Buffer Architecture depends on two design parameters, namely the propagation rate (Vp) and the transmission rate (Vt), an on the average IP (MPLS) packet size • The average IP packet size measured at the Catalan Academic Network over one day in September 2003 was 582 Bytes. • This measure done one year later (in October 2004) raised to 641 Bytes • And this year (in October 2005) we obtained an average IP packet size of 662 Bytes

38. QoS provisioning: Proper Optical Buffer Architecture • Consistency of the solution: • Impact of the Average_IP-packet-size variation: • In our simulations we used: Vt = 2.5 Gbps, Vp = 2 108 mps and an Average_IPpacket-size = 500 Bytes  To fix the working point at D = 0.4, the required FDL-size = 128 m • If the Average_IP-packet-size = 582 Bytes  To fix the working point at D = 0.4, the required FDL-size = 155 m  With a FDL-size = 128 m, the obtained performance will be that for D = 0.34 • If the Average_IP-packet-size = 641 Bytes  To fix the working point at D = 0.4, the required FDL-size = 171 m  With a FDL-size = 128 m, the obtained performance will be that for D = 0.31 • If the Average_IP-packet-size = 662 Bytes  To fix the working point at D = 0.4, the required FDL-size = 176 m  With a FDL size = 128 m, the obtained performance will be that for D = 0.30

39. Backup slides (will not be shown)

40. Motivation for Burst/Packet Switching (x) Pure IP (IP backbone with big, fat routers) • Features: • No dedicated aggregation function (done in the router line card) • Point to point links • Best packet multiplexing and routing flexibility • Main issues = complexity and costs • Network Processor: Mio packets/s to handle • Many and complex protocols (control plane) • High speed memory + scheduling • High line card cost • Will reach scalability limits (equipment critical size/capacity) • Transit traffic has to be processed in each node Pure IP Edge Routers Core Router Future proof scenario?? (used here as reference)

41. Motivation for Burst/Packet Switching (y) Current generation crossconnects (SDH, OXC) • Features: • Aggregation router (traffic sink) • Packet over SONET (POS) interfaces • Point to point links, circuit switched • Sub-wavelength granularity switching (VC SONET/SDH hierarchy) • Main Issues: • Connectivity limitations (N2 problem; N= nb of nodes) • Low filling of the resources due to traffic partitioning • Virtual concatenation • Multi-hopping  rerouting of traffic in the IP layer • Need for finer granularities and dynamic reconfiguration IP/OXC Edge Routers IP router Cross Connect Difficult trade-off: connectivity vs. resource efficiency when choosing the granularity

42. OPXC Nodes - Preliminary Conclusions • Modeling work has already started and will continue in the second year • Preliminary results indicate the following with respect to the aforementioned architectures: • Class-I, Total Transported Capacity (BER: 10-15no FEC): • 20 nodes x10Tb/s all-optical WCs • 10 nodes x10Tb/s o/e WCs • Class-II, Total Transported Capacity (BER: 10-15no FEC): • 5 nodes x10Tb/s all-optical WCs • 20 nodes x10Tb/s o/e WCs • Class-II o/e outperforms the O-O due to the inherent noise emission of the XPM-MZI of the latter. Class-I O-O has stepper non-linear transfer function.

43. WP3: Advanced Packet/Burst Switching Deliverables • D4: “Requirements for burst/packet networks in core and metro supporting high quality broadband services over IP” (M6)  • D16: “Preliminary definition of burst/packet network and node architectures and solutions” (M14)  • D23: “Definition of hybrid opto-electronic burst/packet switching node structures and related management functions” (M20)  • D32: “Preliminary report on feasibility studies on opto-electronic burst/packet switching nodes” (M24)  under finalization

44. WP3: Advanced Packet/Burst Switching Activities • A3.1 Optical core & metro burst/packet network & node architecture & evolution • A3.2 Optimal balance of opt. and el. technologies (transparency vs. O/E/O) • A3.3 Novel control & management functions for optical burst/packet networks • A3.4 QoS in optical burst/packet layer (reservation, allocation, signalling, regeneration) • A3.5 Contribution to possible extensions and/or evolution of standards

45. WP3 Data Plane Aspects Network & node architectures, solutions for core and metro (1) • OCS network scenarios and solutions: • Multi-granular OXCs combine wavelength switching, waveband switching, and fibre switching to reduce port count • New network architecture to converge circuit, packet and flow switching • Burstification by concatenation of packets (slotted approach) • Buffer limited network concept • New techniques for the best effort traffic to improve the packet loss rate • Several optical packet cross-connect architectures are under study and benchmarking against other architectures (e.g. IST-DAVID). Study on both opto-electronic and all-optical solutions. • Optical Node architectures • Comprehensive analysis of SOA based broadcast and select architecture • Impact of noise, crosstalk, SOA saturation and dynamics on node size, cascadability • Impact of modulation formats (NRZ, RZ, RZ-DPSK) • Limits of effective throughput due to physical impairments and burst losses • Analysis of AWG based architecture

46. WP3 Data Plane Aspects Network & node architectures, solutions for core and metro (2) • Hybrid circuit/burst switching solutions • APSON concept (Adaptive Path Switched Optical Network) • Design options and QoS concepts for APSON (preliminary analysis and evaluation) • Migration concept via APSON to OBS/OPS networks • ORION: combining packet and circuit switching • Node level simulations with different traffic statistics • Re-ordering when overspilling on packet-per-packet basis • Overspill per flow • Develop and evaluate different algorithms • Planned: lightpath re-entry (Even less packet handling, more complex control) • G.709 Frame Switching concept • Opto-electronic approach for circuit and burst switching in the same node • Reduced processing effort for packet type traffic • New L2 functionalities: Bypass switching of transit traffic, protection, restoration, QoS • Good scalability towards Terabit/s nodes for future IP dominated transport networks • WR-OBS architecture • Wavelength routing of bursts • Centralized control node employing two-way reservation • Providing QoS guarantees

47. WP3 Data Plane Aspects Traffic aggregation and performance of OBS networks • Traffic models for OBS networks • Different aggregation levels • Single wavelength per burst assembly queue • Multiple wavelengths per burst assembly queue • Impact of long-range dependence in OBS traffic • Analysis of burst aggregation strategies in OBS networks • Extension of studies and analysis on • Burstification algorithms and resulting burst size distributions and burst arrival rates • Traffic models and traffic characterization in OBS edge nodes • First concepts for reduction of blocking probabilities in OBS networks • End-to-end performance analysis for OBS networks • Preliminary analytical study assuming full wavelength conversion capability • Analysis of QoS differentiation techniques for OBS • Offset time based and preemption based • Impact of OBS on TCP performance • Impact of deflection routing • Effect of reordering and influence on different TCP flavours • Effect of burst loss probability on TCP performance, depending on the number of users generating traffic

48. WP3 Control and Management Aspects • Control Plane for Burst/Packet networks (GMPLS applied to OBS) • Existing CP and MP architectures and functions, potential extensions of standards • Study of potential solutions for the Control Plane in OBS networks: Adaptation of current routing and signaling protocols (GMPLS) to OBS. • Labeled optical burst switching • Signaling issues • Analysis of one-way and two-way reservation techniques • Effect of reservation techniques on TCP throughput • Novel control & management functions for optical burst/packet networks • Routing in OBS networks: Development of a burst routing strategy on top of a MPLS like connection-oriented optical network (under study). • Routing in OPS networks: Design and evaluation of two different routing algorithms for OPS networks, namely the Flow-multipath routing (MPLS like, connection-oriented) and the Packet-adaptive routing (connectionless) (under study). • QoS in optical burst/packet layer (reservation, allocation, signalling...) • A method for providing QoS in OBS networks was proposed. The method is called Burst Class Differentiation and consists of assigning different burst lengths and different burst contention resolution rules to the different classes of traffic (under study). • A scheme of different Service Categories (ATM like) for connection-oriented (MPLS like) OPS networks was proposed and evaluated.

49. WP3 Technology Aspects • Potential building blocks for OBS nodes • Assessment of switching techniques • MEMS (only for large bursts) • Fast optical switches (SOAs, LiNbO3 switch array, AWG + tunable lasers) • Realizations in optics • Requirements of optical devices for OBS networks • Assessment of technologies (optics vs. electronics) • All-optical OADM and OXC offer less functionality compared to O-E-O • Optical performance monitoring still unresolved • Upgrading from low-cost/slow reconfiguration to fast reconfiguration when advanced optical components become available • Opto-electronic Multi-Terabit packet switching • Electronic technologies for signal processing • Optical technologies for space switching (e.g. 40 Tbit/s optical space switching matrix, based on an integrated optical technology • Exploitation of WDM techniques to minimise the number of in line buffers

50. WP3 Interaction with other WPs • WP1: Provide inputs on burst/packet network scenarios and layering aspects to the NOBEL network vision. • WP2: Exchange info on Routing Management for burst/packet networks. • WP4: CP requirements/concepts to provide QoS in the new L2 burst/packet transport service. • WP6: Harmonization of burst/packet network and node architectures to be implemented by WP6. • WP7: Exchange of technology requirements and specifications for burst/packet nodes