IP over Intelligent Optical Networks Kumar N Sivarajan

IP over Intelligent Optical Networks Kumar N. Sivarajan CTO, Tejas Networks kumar@tejasnetworks. com www. tejasnetworks. com January 5, 2001

Optical Networks § Fiber • Provides the physical transport Optical Access 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 IP ATM Optical Network SONET/SDH Higher Layer Networks

Evolution of Transmission Technology • 1 st Generation: Copper is transmission medium • 2 nd Generation: Optical Fiber (late 80 s) 4 Higher data rates; longer link lengths • Dense Wavelength-Division Multiplexing (DWDM, 1994) 4 Fiber exhaust forces DWDM 4 Erbium-doped fiber amplifiers (EDFAs) lower DWDM transmission cost • 3 rd Generation: Intelligent optical networking (1999) 4 Routing and signaling for optical paths

Dense Wavelength-Division Multiplexing (DWDM)

DWDM Evolution • Faster (higher speed per wave), 440 Gb/s on the horizon • Thicker (more waves), 4160 waves possible today • Longer (link lengths before regeneration) 4 A few thousand km possible today • 160 waves at 10 Gb/s = 1. 6 Tb/s 425 million simultaneous phone calls 45 million books per minute

IP over ATM

ATM over SONET

IP over ATM over SONET

Optical Pass-Through (Routing) Node A IP/ATM/ SDH Node B IP/ATM/ SDH Node C IP/ATM/ SDH No optical pass-through Node A IP/ATM/ SDH Node B IP/ATM/ SDH Node C IP/ATM/ SDH 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 4 2. 5 Gb/s path from Bangalore to Boston, on demand!

SONET over Optical Layer

IP over SONET over Optical Layer

IP over Optical Layer

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 highbandwidth networks § IP over intelligent optical networks is the natural evolution • Incorporate Qo. S 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