LightFDG: An Integrated Approach to Flow Detection and Grooming in Optical Wireless DCNs

Abstract

LightFDG is an integrated approach to flow detection (FD) and flow grooming (FG) in optical wireless data center networks (DCNs), which is interconnected via wavelength division multiplexing (WDM) based free-space optical (FSO) links. Since forwarding bandwidth-hungry elephant flows (EFs) and delay-sensitive mice flows (MFs) on the same path can cause severe performance degradation, the LightFDG optically grooms flows of each class into rack-to-rack (R2R) flows. Then, R2R-MF and R2R-EF flows are separately forwarded over lightpaths of separate MF and EF virtual topologies, respectively. Lightpaths are provisioned by jointly determining the capacity and route based on flows' arrival rate, size, and completion time request. To prevent EFs from congesting the MF lightpaths, high speed and accurate flow-detection mechanisms are also necessary for classifying EFs as soon as possible. Therefore, a fast-lightweight-andaccurate flow detection framework is developed by leveraging the transmission control protocol (TCP) behaviors. The proposed FD scheme has the flexibility of being implemented as in-network or centralized to classify flows of modifiable and unmodifiable hosts, respectively. Since the centralized scheme incurs considerable overhead, the processing and communication overhead is also mitigated by proposed techniques. Numerical results show that LightFDG outperforms traditional load balancers by about 3f or EFs and 10ˆfor MFs. Along with the developed overhead mitigation methods, the centralized scheme is shown to provide up to 62ˆlower overhead with 100% accuracy and with about 224ˆhigher detection speeds than the existing centralized solutions.

FSO Communication: Benefits, Challenges and Its Analysis in DWDM Communication System

“…The proposed system supports very limited distances. The simulation results for the FSO system at different parameters such as high distance, bit rate, transmitting power and wavelength are evaluated in [2]. In outdoor communication, atmospheric attenuation is a critical factor that affects the quality of the signal.…”

“…Optical wireless systems such as FSO provide large data rate solutions to bandwidth dependent applications. However, weather constraints on such technologies pose a great challenge to their deployment in the areas where high reliability cannot be tolerated due to their adverse effects [2], [3].…”

F4Tele: FSO for Data Center Network Management and Packet Telemetry

“…The digital micromirror device can direct FSO beams toward tens of thousands directions, while it needs 12µs to switch between these directions. In [17], [18], [13], [9] the authors utilized FSO-WDM and traffic grooming to augment the DCN bandwidth and exploit the FSO-WDM agility to build two isolated virtual topologies: one for delay-sensitive flows and another for throughput-hungry flows. The results have demonstrated that the proposed method provides superior performance in both throughput and flow completion times.…”

“…Although it entails significant modifications for every network switch to maintain low communication and processing overhead, it needs 2.3Gbps per switch to send the collected statistics, and encoded flowsets to the NMS. Other researchers have introduced alternative solutions at the expense of the necessary performance figures, (e.g., accuracy, and speed), and features (e.g., routing loops and blackhole detection) [5], [6], [7], [8], [9].…”

“…When using wireless FSO links between the server-racks and the NMS-rack(s) three features are enabled: re-configurable topologies, high link capacity, and low cabling complexity and maintenance overhead. The previous researches [11], [12], [13], [9] used FSO technology to transmit data traffic. However, they suffered from several challenges (e.g., switching speed, FSO alignment, and LoS congested horizon).…”