| Title | : | Scheduling in Data Center Networks with Optical Traffic Grooming |
| Speaker | : | C S Ganesh (IITM) |
| Details | : | Tue, 10 Feb, 2015 3:00 PM @ BSB 361 |
| Abstract: | : | This talk presents our work on transmission scheduling in an optically groomed data center network (OGDCN) - a hierarchical and hybrid optical-packet data center network architecture that uses optical combiners, optical wavelength routers and packet switching components. In this architecture, each compute and storage node (CSN) is equipped with one or more tunable optical transceivers. A source-destination pair has to tune to the same wavelength at a given time, to establish communication. Multiple transmitters that share a link segment cannot use the same wavelength at the same time on the link since this would result in collisions. Hence, transmission scheduling is required to prevent collisions and to allot time slots to satisfy transmission requests. We show that this scheduling problem is NP-complete and then present two sets of heuristics to solve this problem in a centralized server. The first set of heuristics, classified as (CE), assumes continuous time and computes the earliest free time duration for communication. Based on time synchronization mechanisms used, a software-based (CES) and a hardware-based (CEH) variant are defined. The second set of heuristics, called (SL), uses slotted time and intersecting time within the allotted time slot for communication. The SL schemes are affected by variation in propagation delay and unused slot duration. Three different variants that address propagation delay variance and two variants that address unused slot duration are defined. The proposed variants are evaluated theoretically and using discrete event simulations. Based on simulations, CEH variant performs better than the rest of the heuristics. Among SL variants, the delay compensation scheme (SLD) with variable slot durations (SLV) performs better. |
