1. Title and keywords
Title:
VLCcube: A VLC Enabled Hybrid Network Structure for Data Centers
VLCcube: a data center hybrid network structure that supports VLC
Keywords:
data center networks;
inter-rack network ; inter-rack network;
visible Visible light communication;
throughput;
packet loss rate.
2. Summary
Recent results have made a promising case for offering oversubscribed wired data center networks (DCN) with extreme costs. Inter-rack wireless networks are drawing intensive attention to augment such wired DCNs with a few wireless links. Inspired by the promise of easy deployment and plug-and-play, we present VLCcube, a novel inter-rack wireless solution that extends the design of wireless DCN into three further dimensions: (1) all inter-rack links are wireless; (2) there is no imposition of any infrastructure-level alteration on wired production data centers; and (3) it should be plug-and-play, without any need of additional mechanical or electronic control operations. This vision, if realized, will lead to increased flexibility, reduced reconstructing cost, simplified configuration and usage, and outstanding compatibility with existing wired DCNs. Previous proposals, however, are opposed to the last two design rationales. To achieve this vision, the proposed VLCcube augments Fat-Tree, a representative DCN in production data centers, by organizing all racks into a wireless Torus structure via the emerging visible light links. We further present the topology design, hybrid routing, and flow scheduling schemes for VLCcube. Extensive evaluations indicate that VLCcube outperforms Fat-Tree significantly under the existing ECMP flow scheduling scheme, irrespective of the undergoing traffic pattern. Moreover, the performance of VLCcube can be significantly promoted by our congestion-aware flow scheduling scheme. More precisely, compared to ECMP, our flow scheduling scheme makes VLCcube achieve ×1.50 throughput under batched flows, ×2.21 and ×2.59 throughput under two different kinds of online flows.
Recent research results provide a promising case for providing oversubscribed wired data center networks (DCNs) at extreme costs. Inter-rack wireless networks are attracting widespread attention, and a small number of wireless links are used to expand this type of wired DCN. Inspired by the promise of easy deployment and plug-and-play, we proposed VLCcube, a novel inter-rack wireless solution that extends the design of wireless DCN to three deeper levels: (1) All machines The inter-rack links are all wireless; (2) There is no infrastructure-level transformation of the wired production data center; (3) It should be plug and play, without any additional mechanical or electronic control operations. If this idea is realized, it will increase flexibility, reduce reconstruction costs, simplify configuration and use, and maintain excellent compatibility with existing wired DCN. However, the previous proposal is contrary to the latter two design principles. In order to realize this vision, the proposed VLCcube organizes all racks into a wireless ring structure through the emerging visible light link, thereby enhancing the representative DCN fat tree in the production data center. We further proposed VLCcube's topology design, hybrid routing and flow scheduling solutions. A large number of evaluations show that no matter which stream mode is selected, the performance of VLCcube is significantly better than fat tree under the existing ECMP (Equal-Cost Multi-Path) stream scheduling scheme. In addition, through our congestion-aware flow scheduling scheme, the performance of VLCcube can be significantly improved. More precisely, compared with ECMP, our stream scheduling scheme enables VLCcube to achieve a throughput of 1.50 under batch streams, and a throughput of 2.21 and 2.59 under two different types of online streams.
3. Innovation and academic value
Contributions:
We design VLCcube, a hybrid DCN structure, which employs VLC wireless links to interconnect all racks in a Fat-Tree data center as a wireless Torus. The topology construction strategy is well designed to ensure high connectivity and low average path length. As an easy-deployable and plug-and-play hybrid DCN, VLCcube realizes the three design rationales at the same time.
(1) This paper designs a hybrid DCN structure VLCcube, which uses VLC wireless chain The road interconnects all racks in the fat tree data center into a wireless ring. The topology structure strategy is reasonably designed to ensure high connectivity and low average path length. As a hybrid DCN that is easy to deploy and plug and play, VLCcube implements three design patterns at the same time.
To fully exploiting the topological properties, we present a hybrid routing scheme for VLCcube to jointly utilize both wired and wireless links. To further improve the network performance, we design a light-weight method to address the optimized flow scheduling problem. The method can efficiently derive an outstanding solution for batched as well as online flows.
(2) In order to make full use of the topological characteristics, this paper proposes a hybrid VLCcube routing scheme, which can use wired and wireless links at the same time. In order to further improve network performance, the paper designs a lightweight method to solve the problem of optimized flow scheduling. This method can effectively solve batch processing and online streaming.
Comprehensive experiments are conducted to measure the performance of VLCcube. The results indicate that VLCcube outperforms Fat-Tree significantly under the existing ECMP flow scheduling scheme, irrespective of the used traffic pattern. Compared to ECMP, our congestion-aware flow scheduling scheme make VLCcube achieve better performance, ie, ×1.50 throughput under batched flows, ×2.21 and ×2.59 throughput under two kinds of online flow patterns.
(3) Tested the performance of VLCcube through comprehensive experiments. The results show that no matter which stream mode is selected, under the existing ECMP stream scheduling scheme, the performance of VLCcube is significantly better than the fat tree. Compared with ECMP, the congestion-aware stream scheduling scheme proposed in this paper enables VLCcube to be implemented in batch streams. A throughput of 1.50 was achieved, and throughputs of 2.21 and 2.59 were achieved under two different types of online streams.
4. Understanding of conclusions and inspiration for learning work
In this paper, we present VLCcube, an easy-deployable, and high-performance hybrid DCN architecture. VLCcube introduces the emerging VLC technique to interconnect all racks together with a wireless Torus network, so as to augment the wired Fat-Tree network. The introduced VLC links can decrease the APL and enhance the network bandwidth. To exploit the benefits of VLCcube, we furtherdesign dedicated flow scheduling methods for both batched and online flows. The evaluations indicate that VLCcube Always outperforms Fat-Tree, and our scheduling methods can significantly promote its performance.
This article proposes an easy-to-deploy high-performance hybrid DCN architecture-VLCcube. VLCcube introduces the emerging VLC technology to interconnect all racks through a wireless torus network to expand the wired fat tree network. The introduction of VLC links can reduce APL and increase network bandwidth. In order to give full play to the advantages of VLCcube, we further designed a dedicated stream scheduling method for batch processing and online streaming. The results show that the performance of VLCcube is better than fat trees, and our scheduling method can significantly improve its performance.
Future work:
The future work is mainly of two folds. On one hand, we will consider the design and evaluation of other hybrid DCNs using VLC links, in the settings of other wired DCNs (eg, BCube,MDcube, Jellyfish, etc). New challenges will occur when integrating the VLC wireless links with other existing wired topologies. On the other hand, we envision a complete wireless data center based on VLC links only.
There are two main aspects of future work. On the one hand, we will consider the use of VLC link design and evaluation of other hybrid DCNs in the settings of other wired DCNs (such as BCube, MDcube, hyllfish, etc.). When VLC wireless links are integrated with other existing wired topologies, new challenges will arise. On the other hand, we envision a complete wireless data center based on VLC links.