1 / 21

Optical burst and packet switching (the long term goal of optical networking !/?) Lars Dittmann,

Optical burst and packet switching (the long term goal of optical networking !/?) Lars Dittmann, NET • COM • DTU, Technical University of Denmark ld@com.dtu.dk. Two areas addressed in this talk: Optical network in general (short and long term)

jase
Download Presentation

Optical burst and packet switching (the long term goal of optical networking !/?) Lars Dittmann,

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Optical burst and packet switching (the long term goal of optical networking !/?) Lars Dittmann, NET•COM•DTU, Technical University of Denmark ld@com.dtu.dk www.com.dtu.dk

  2. Two areas addressed in this talk: • Optical network in general (short and long term) • Optical switching (the E-Photon/ONE perspective) www.com.dtu.dk

  3. Optical networking – what is that? • Optical networking and optical transmission is often confused !! • Generic SDH/SONET is often called “first generation optical networks” – but optics is in no respect involved in any networking function i.e. only static point-to-point connection (but first time optical transmission was standardised). • Optical networks contains elements where the optical signal (in the optical domain) can be routed/switched in several directions. - and due to that, is optical network typically analogue networks and as such very simple. www.com.dtu.dk

  4. Transport network rather than optical networks • Current evolution of transport network (short term 0-5 years) • Next generation SDH/SONET (VCAT/LCAS – flexible and dynamic bandwidth, circuit switched capacity below a wavelength) • PBT – proprietary Ethernet extension to MAC-in-MAC (driven by NORTEL and BT) – Circuit oriented packet switching • T-MPLS – standardised extension to Ethernet (driven by ALCATEL/LUCENT) – circuit oriented packet switching. • Ethernet based – extended with routing functions and resource reservation. • No transport network – just pure transmission (driven by Cisco and Juniper) www.com.dtu.dk

  5. Trends in optical networking • Today the optical network technology is (slowly) evolving (in many domains) and is getting more mature for use in operational network. • WDM enabled the used of wavelength routed network • With or without wavelength conversion (studies indicates that wavelength converters are mainly an advantage when traffic is highly dynamic) • The Internet and migration towards packet mode handling of services pushed for time-domain operation in all layer – including the optical layer. • IP over DWDM – slim layered structure with optics taking over all functionalities below the IP layer (high bandwidth, efficient bandwidth management and QoS, network resilience etc.) www.com.dtu.dk

  6. Trends in optical networking • Long terms wavelength assignment • Fast wavelength assignment (wavelength switching) • Burst switching (or very fast wavelength switching) • Packet (or cell) switching (fixed or variable packets) • Overall trend: more time domain dynamics driven by changes in application demands and better optimization and utilization of bandwidth resources) www.com.dtu.dk

  7. Key problems in optical networking • Technological problems are many – a number of things proven in lab or in small scale, but hard to move into reliable operational networks. Including the optical flip/flop and 3R that is first step to make optical networking digital) • Administrative problems (in addition of getting access to the signal) is also hugely addressed – specially for wavelength routed networks, but also for OBS and OPS networks. • However – optical networking only make sense in relation to a transport networks as an optical packet router is not a one-to-one replacement for an IP router. www.com.dtu.dk

  8. Service/application layers Control Integrated Control/Management Transport network layers Management Trends in network administration (network resources) • Classic split in network control (realtime operation) and network management (off-line). • Network control being automated and based on algorithms and local knowledge • Network management based on manual interaction and global knowledge. • Trend: Stronger integration of control and management – dynamic operation in all layers www.com.dtu.dk

  9. MPLS e.g. ASON/ASTN e.g. GMPLS Trends in network administration (network resources) Integrated system vs. segmented systems. Higher layer Service/application oriented (Packet/cell switched) Higher loop Integrated loop Lower layer Physical media oriented (Circuit switched ??) Lower loop www.com.dtu.dk

  10. OBS&GMPLS PROPOSAL for OBS and GMPLS integration Integration of GMPLS and OBS function – hybrid control plane Source: Anna Vasileva Manolova COM-DTU, ” Contention Resolution in OBS Networks with GMPLS Control” www.com.dtu.dk

  11. Comments • Despite it is said that the optical technology provides unlimited resources – most trends in different areas of optical networking is focusing on resource optimization._____________________________________ • Both OBS and OPS aim at better resource granularity and higher utilization compared to pure WDM networks. • Control systems aim a having a direct related modification of resource assignment in lower layers (potentially having more stable routing table in application layers)_____________________________________ • Why do we care about resource optimization in the optical layer, when cables usually contains tens or hundreds of fibers that with cheap CWDM easily provides a small (and typical) number of wavelength per fiber. (For the access we aim at ulimited bandwidth.) www.com.dtu.dk

  12. VD-S: Optical Switching Systems Overview of Research in Optical Switching (VD-S: Virtual Department Switching)

  13. Key issues identified by partners as scope of work: • Optical Packet Switching • Optical Buffering • Wavelength Converter Usage Reduction • Optical Signal Monitoring • Packet Compression Techniques • Recovery Switching • Quality of Service in Switches • Physical Impairment Based Switching • Optical Clock Recovery • Wavelength Conversion by Nonlinear Effects • Optical Flip-Flops • Hybrid Optical Switch Architectures • GMPLS Optical Switch Nodes • Contention Resolution Schemes • OTDM Time-slot Switching • Multi-wavelength Regeneration • Optical Cross Connect • 2R Regeneration • OCDM encoders/decoders • Optical Multicast Architecture www.com.dtu.dk

  14. Signaling Protocol Extensions forConverter-saving Wavelength Assignment in GMPLS Optical Networks N. Andriolli1, J. Buron2, S. Ruepp2, F. Cugini3, L. Valcarenghi1, P. Castoldi1 1: Scuola Superiore Sant’Anna di Studi Universitari e di Perfezionamento, Pisa, Italy 2: Department of Communications, Optics & Materials, DTU, Copenhagen, Denmark 3: CNIT, National Laboratory of Photonic Networks, Pisa, Italy IEEE Workshop on High Performance Switching and Routing HPSR 2006 – Poznań

  15. The wavelength assignment process performed by GMPLS signaling can be optimized • Use standard and novel signaling extensions to collect information on the label preference from the nodes along the path • Design node-local algorithms exploiting these extensions to reach the specific target Minimize wavelength converterutilization in wavelength-routed optical networks Motivations GMPLS framework strong candidate to control next generation data networks • Extends connection-oriented, traffic-engineered MPLS approach to multiple switching layers • Defines specific protocol extensions to simplify operation in WDM optical networks • Converter waste increases: • the network cost • the blocking probability, with a limited amount of WC www.com.dtu.dk

  16. PATH message: l1 l3 l1 l3l4 l1 l2 l4 • From source to destination • May carry additional objects, such as the Label Set Label Set = PATH PATH PATH Not designed to avoidunnecessary WC l1 Asource B WC C WC Ddest l2 l3 RESV message: l4 • From destination to source • Carries the wavelength selected by each upstream node for its previous hop RESV RESV RESV RESV RESV RESV l3 l1 l1 l2 l1 l3 LSP setup procedure • Routing: shortest path on the sub-graph with links having at least an available wavelength • Wavelength assignment: signaling session along the found path WavelengthConversion www.com.dtu.dk

  17. Suggested Vector l1 l3 l1 l2 l4 l1 l3 l4 Label Set = PATH PATH PATH In this scenario SV contains the number of conversions needed to use the corresponding label l1 Label reservation algorithm Asource B C Ddest l2 SV computing algorithm • At destination, reserve the label with minimum received SV and propagate it as far as possible • If a conversion is needed, reserve the label with minimum received SV l3 l4 • Source node: 0 for any label (no WC) • Intermediate nodes: same value for labels available on the previous hop, otherwise minimum received SV + 1 RESV RESV RESV l1 l1 l1 Label preference with Suggested Vector • Novel optional object included in PATH message • Indicates the preference level for each wavelength within the Label Set • General purpose: allows to rank wavelengths according to a given preference metric 0 1 0 0 0 0 1 0 www.com.dtu.dk

  18. Optical flip-flop based on Erbium-Ytterbium doped fibre Mirco Scaffardi, SSSUP, Pisa www.com.dtu.dk

  19. Operating principle stimulated emission absorption t Fibre transparent Fibre not transparent Reset pulses t Set pulses Pulsewidth: 10 ns Rep. Frequency: ~ 900 kHz Pulse energy: 19.82 nJ t Read Signal (1541 nm) Reset Pulses (1565 nm) circulator out 1 CW 1541 nm 2 50/50 3 coupler Er3+/Yb fiber t Set Pulses (1535 nm) t 1,5 m t Pulsewidth: 10 ns Rep. Frequency: ~ 900 kHz Pulse energy: 18.48 nJ =1541 nm out www.com.dtu.dk

  20. Experimental results Pread=-12dBm PSet =9dBm Set pulses Reset pulses 422 ns 1102 ns Input (a.u.) Output (a.u.) 1.25 mV 1102 ns 680 ns Time (µs) Time (µs) Pread=-4dBm PSet =12dBm • Transition time of 10 ns measured. • Transition time reduced increasing set and reset power and decreasing their width. • High level memorization time up to dozens of µs is possible Output (a.u.) 3.2 mV Time (µs) www.com.dtu.dk

  21. Thank you for listening! Questions and comments! www.com.dtu.dk

More Related