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Valentino Cavalli TERENA Ways and means of seeing the light Technical opportunities and problems of optical networking Workshop, Bad Nauheim, 16-17 June 2003 Valentino Cavalli <[email protected]> 1 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 Valentino Cavalli <[email protected]> 2 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 Valentino Cavalli <[email protected]> 3 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 Valentino Cavalli <[email protected]> 4 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 Valentino Cavalli <[email protected]> 5 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 Valentino Cavalli <[email protected]> 6 Technology • Physical transmission layer (Optical fibre) • WDM equipment: – End-points, add-drop multiplexers, regenerators, amplifiers • Switches • Routers Workshop, Bad Nauheim, 16-17 June 2003 Valentino Cavalli <[email protected]> 7 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 Valentino Cavalli <[email protected]> 8 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 Valentino Cavalli <[email protected]> 9 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 Valentino Cavalli <[email protected]> 10 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 Valentino Cavalli <[email protected]> 11 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 Valentino Cavalli <[email protected]> 12 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 Valentino Cavalli <[email protected]> 13 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 Valentino Cavalli <[email protected]> 14 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 Valentino Cavalli <[email protected]> 15