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IP over Intelligent Optical Networks. Kumar N. Sivarajan CTO, Tejas Networks kumar@tejasnetworks.com www.tejasnetworks.com. Optical Access. IP. ATM. Optical Network. SONET/SDH. Higher Layer Networks. Optical Networks. Fiber Provides the physical transport medium
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IP over Intelligent Optical Networks Kumar N. Sivarajan CTO, Tejas Networks kumar@tejasnetworks.com www.tejasnetworks.com January 5, 2001
Optical Access IP ATM Optical Network SONET/SDH Higher Layer Networks Optical Networks • Fiber • Provides the physical transport medium • Optical networks: Create the pipes • WDM: Fast pipes for voice/data • Optical amplification: Long pipes • IP Routers, ATM switches, SDH equipment: Fill the pipes • Operations Support System (OSS) • Manage all aspects of the network
Evolution of Transmission Technology • 1st Generation: Copper is transmission medium • 2nd Generation: Optical Fiber (late 80s) • Higher data rates; longer link lengths • Dense Wavelength-Division Multiplexing (DWDM, 1994) • Fiber exhaust forces DWDM • Erbium-doped fiber amplifiers (EDFAs) lower DWDM transmission cost • 3rd Generation: Intelligent optical networking (1999) • Routing and signaling for optical paths
DWDM Evolution • Faster (higher speed per wave), • 40 Gb/s on the horizon • Thicker (more waves), • 160 waves possible today • Longer (link lengths before regeneration) • A few thousand km possible today • 160 waves at 10 Gb/s = 1.6 Tb/s • 25 million simultaneous phone calls • 5 million books per minute
Optical Pass-Through (Routing) Node A Node B Node C Node A Node B Node C IP/ATM/ SDH IP/ATM/ SDH IP/ATM/ SDH IP/ATM/ SDH IP/ATM/ SDH IP/ATM/ SDH No optical pass-through With optical pass-through
Intelligent Optical Networking • Optics is not merely a transmission technology • Optics provides a flexible layer upon which to deliver network service • DWDM provides enormous link capacities • DWDM: Physical layer of Intelligent Optical Network • Routing and signaling of optical paths • Provides significant economies over conventional network architectures • Enables revolutionary new services • 2.5 Gb/s path from Bangalore to Boston, on demand!
IP over Intelligent Optical Networks • Establish high-speed optical layer connections (lightpaths) • IP routers connected through lightpaths rather than fiber • Switching (WDM crossconnects) add flexibility to the optical layer • Flexible, potentially rich, topology at IP layer
Intelligent Optical Networking Developments • Incorporate SONET/SDH multiplexing capability into interface cards of DWDM equipment • Connect IP routers with STM-1/4 interfaces directly to DWDM equipment transporting STM-16/64 wavelengths • Move protection function from SONET/SDH to optical layer • Rerouting all wavelengths affected by a fiber cut is more efficiently done by optical switches than SDH equipment at ends of lightpaths • Add intelligence to optical layer • Borrow algorithms/protocols from data (IP) networks • Routing: OSPF, Signaling: MPLS
Optical Network Architectures • Ring • Simplest topology with redundant paths • Interconnected Rings • Mesh • More efficient routes • Mesh with Switching • Efficient routing • Flexibility in demand management
IP over Intelligent Optical Networks: Summary • Application traffic predominantly IP-based • Perhaps including voice in the near future • Intelligent optical networks: physical layer of all high-bandwidth networks • IP over intelligent optical networks is the natural evolution • Incorporate QoS functionality of ATM in IP • Incorporate reliability functions of SDH within DWDM • IP protocols (OSPF, MPLS) basis for intelligent algorithms in optical networks • OSPF for autodiscovery • OSPF for routing circuits • MPLS for signalling circuit setup