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Ways and means of seeing the light

Ways and means of seeing the light. Valentino Cavalli TERENA. Technical opportunities and problems of optical networking. Background. Study on developments of equipment for optical transmission, switching and routing Technical sessions at: Initial Workshop Operator’s Workshop

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Ways and means of seeing the light

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  1. Ways and means of seeing the light Valentino CavalliTERENA Technical opportunities and problems of optical networking Workshop, Bad Nauheim, 16-17 June 2003

  2. Background • Study on developments of equipment for optical transmission, switching and routing • Technical sessions at: • Initial Workshop • Operator’s Workshop • NREN’s Workshop • TF-NGN/ASTON group: • Direct involvement in meetings with vendors, Discussion at TF-NGN meetings, white paper of lower layer research areas Workshop, Bad Nauheim, 16-17 June 2003

  3. Index • Current networking environment, emerging factors and challenges for NRENs • Technology facts and developments concerning fibres, transmission equipment, switches and routers • Consequences in terms of network management and network architecture • Conclusions Workshop, Bad Nauheim, 16-17 June 2003

  4. Current Environment • Shared IP, basically best-effort and ubiquitous any-to-any service • Networks currently over-provisioned (with exceptions in some countries and generally at the campus level) • Guaranteed performance and traffic engineering mostly at the IP routing layer • Simple and transparent model, easy management Workshop, Bad Nauheim, 16-17 June 2003

  5. Emerging factors • Access to fibre much easier than in the past: universities and NRENs exploring a DIY approach towards network infrastructure • Developments of WDM equipment, opto-electronics and all-optical devices. • Increased availability of bandwidth but also increased need • Changes in traffic patterns • Need for high-bandwidth p2p connectivity between a limited number of locations to support large data flows • Dynamic, on-demand bandwidth management, requiring network-aware middleware Workshop, Bad Nauheim, 16-17 June 2003

  6. What are NRENs facing? • DIY approach towards network infrastructure, but to what extent? Campus, National, International? • Depends on reach, but is actually happening at Campus and National level. • More complex internationally, not only because of distance, but also need to provide services end-to-end across multiple administration domains • New expertise also required • Change of traditional customer-supplier relationship with carriers, more collaboration is possible and needed Workshop, Bad Nauheim, 16-17 June 2003

  7. Technology • Physical transmission layer (Optical fibre) • WDM equipment: • End-points, add-drop multiplexers, regenerators, amplifiers • Switches • Routers Workshop, Bad Nauheim, 16-17 June 2003

  8. Optical transmission • Wide availability of fibre but limited to certain locations (even within a country) • Need for amplification, signal regeneration, dispersion compensation: limitations of existing fibre plants • Different access options: • leased connectivity, managed fibre, long-term lease, fibre ownership • Cost effectiveness: Dark fibre vs managed wavelength • Issue: Operation might require install and maintain equipment at remote locations for NRENs Workshop, Bad Nauheim, 16-17 June 2003

  9. WDM equipment • transmission technology allowing today (DWDM) up to 40 Gbit/s on a single wavelength, up to 160-190 wavelength per fibre, up to several Tbit/s per fibre • Analogue technology, standardisation limited to ITU Wavelength Grid, limited interoperability • Lot of dependency on fiber type and quality, dispersion, etc., needs to be tailored to each specific situations Workshop, Bad Nauheim, 16-17 June 2003

  10. Capacity and reach • Transmission capacity at 40Gbit/s per wavelength (channel) available, multiples of 40Gbit/s being tested • Costs of the electronics impact on interfaces, router line-cards, etc. • Market demand not clear yet • Depending on fibre type current 2.5-10Gbit/s systems require regeneration after 4-5 amplification spans (spans varying between 80-120km) so 400-600km, new generation ULH systems can reach up to 4000km • Experiences with NIL up to 230km (GE and 2.5Gbit/s), 180km at 10GE Workshop, Bad Nauheim, 16-17 June 2003

  11. Optical switching • Wavelength termination and signal regeneration require OEO conversion, transponders are very expensive, but OOO Switching equipment terminates only local traffic and does not impact on express traffic • OOO switches are signal-transparent, lower unit cost, footprint and lower operational costs • Generally support a variety of framing interfaces SONET/SDH, GE, 2.5, 10 GE, G.709, GFP • Electrical technology still needed at user interface for multiplexing and bandwidth grooming Workshop, Bad Nauheim, 16-17 June 2003

  12. Routing • Wide range of functionality supported: IPv6, multicast, QoS, MPLS • G-MPLS already available, but little interoperability • Support for multiple 10Gbit/s, 40Gbit/s bit-rate interfaces is available, but line-rate interfaces exploiting the full capacity of transmission links are not there yet • Cost of ASICs – mass production • Driving introduction of 40Gbit/s Workshop, Bad Nauheim, 16-17 June 2003

  13. Management • A mix of networking elements requiring a unified control plane and sophisticated management systems to seamlessly manage network and transport layer • several signalling protocols being standardised by IETF and ITU-T • Inter-operability, and multi-domain management still represent a challenge • More cooperation among network operators to provide e2e services across domains Workshop, Bad Nauheim, 16-17 June 2003

  14. Network architecture • Shared IP model,higher meshing? Gigabit core routers increasingly expensive at higher speed • Circuit switching addressing “heavy” user needs? • Over-provisioning is no longer a cost effective solution • Simple extension of shared IP model does not scale, need to explore hybrid network architecture solutions • Routers and switches can be combined in providing a flexible network architecture • Limited cost saving but more efficient way of serving users • Engineering traffic not only at layer 3 but also at layers 2 and 1 Workshop, Bad Nauheim, 16-17 June 2003

  15. Conclusions • Simple extension of shared IP model does not scale, need to explore hybrid solutions • Circuit/lambda switching coexisting with IP routing • 40Gps/s will happen soon • Exploitation of dark fibre depend on economics and reach • At less than 250km NIL solutions seem viable • Management functions crossing multiple domains are being developed, but: • more work needed in standardisation of signalling protocols • Need to address complexity of providing end-to-end services in multi-domain (and multi-vendor) environment Workshop, Bad Nauheim, 16-17 June 2003

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