Optics In Routers Isaac Keslassy, Da Chuang, Nick McKeown

1. R R In In Input Output Linecard Rack 1 Out Out Fixed Laser/Modulator Detector Out Out 1 1 2 3 2 2R/N In In L = 16 160Gb/s linecards L = 16 160Gb/s linecards l l 1 1 Out Out 1 N 1 1 l l l l , , l l 1 2 1 2 Linecard 1 Linecard 1 2 2 2 1 l l … … N N In In l l N Out Out N Input Output l l 1 1 2 1 l l 2 2 , l l , l l Linecard 2 Linecard 2 1 2 1 2 2 2 2 3 Out Out … l l … In In NxN AWGR N N l l Out Out N N Input Output l l 1 1 N N-1 N N l l l l , , l l 1 2 1 2 Linecard N Linecard N 2 2 1 N l l … … Out Out N Optics N l l N N 2 N 2 3 4 1 N 4 3 1 1 1 1 L 2 2 L L 2 L 2 1 Electronics Electronics Switch Fabric R R R R R R Scheduler R R R/N R/N In R/N R/N R/N R/N R/N R/N R R In R/N R/N R/N R/N R/N R/N R/N R R R/N In R/N R/N Uniform Multiplexing Uniform Demultiplexing Uniform Demultiplexing Uniform Multiplexing Linecard Rack G = 40 Switch Rack < 100W Group/Rack 1 Group/Rack 1 Uniform Spreading 40 x 40 static MEMS L = 16 160Gb/s linecards 1 2 Static MEMS Switch Static MEMS Switch Group/RackG Group/RackG 55 56 Optics In RoutersIsaac Keslassy, Da Chuang, Nick McKeown Wireline Thrust Router Wish List Stanford 100Tb/s Router Typical Router Architecture Scale to High Linecard Speeds • No Centralized Scheduler • Optical Switch Fabric • Low Packet-Processing Complexity Scale to High Number of Linecards • High Number of Linecards • Fault-Tolerance to Linecard Failures Provide Performance Guarantees • 100% Throughput Guarantee • Delay Guarantee • No Packet Reordering • “Optics in Routers” project • http://yuba.stanford.edu/or/ • Some challenging numbers: • 100Tb/s • R=160Gb/s linecard rate • N=640 linecards • Should provide performance guarantees A Single Combined Mesh AWGR-Based Solution Load-Balanced Switch R R R/N R/N In R/N R/N R/N R/N R/N R/N R R In R/N R/N R/N R/N R/N R/N R/N R R R/N In R/N R/N Bounding Reordering by Bounding Δ High Number of Linecards: Use Hierarchical Mesh FOFF (Full Ordered Frames First) Algorithm • Property 1: FOFF maintains packet order. • Property 2: FOFF maintains an average packet delay within constant from ideal output-queued router. • Corollary:FOFF has 100% throughput for any adversarial traffic. • Property 3: FOFF has O(1) complexity. • Property 4: FOFF is distributed. Fault-Tolerance to Linecard Failures: Use MEMS Switches Implementation of a 100Tb/s Load-Balanced Router Summary • The load-balanced switch • Does not need any centralized scheduling • Can use a mesh • Using FOFF • It keeps packets in order • It guarantees 100% throughput • With the electro-optical architecture • It scales to high port numbers • It tolerates linecard failure