Browsing by Subject "802.11ad"

Now showing 1 - 3 of 3

Open Access
60 GHz wireless data center networks: A survey
(Elsevier BV * North-Holland, 2021-02-11) Terzi, Çağlar; Körpeoğlu, İbrahim
Data centers (DCs) became an important part of computing today. A lot of services in Internet are run on DCs. Meanwhile a lot of research is done to tackle the challenges of high-performance and energy-efficient data center networking (DCN). Hot node congestion, cabling complexity/cost, and cooling cost are some of the important issues about data centers that need further investigation. Static and rigid topology in wired DCNs is an other issue that hinders flexibility. Use of wireless links for DCNs to eliminate these disadvantages is proposed and is an important research topic. In this paper, we review research studies in literature about the design of radio frequency (RF) based wireless data center networks. RF wireless DCNs can be grouped into two as hybrid (wireless and wired) and completely wireless data centers. We investigate both. We also compare wireless DCN solutions in the literature with respect to various aspects. Open areas and research ideas are also discussed.
Open Access
Fly-path: Traffic-based multi-hop routing approach for hybrid wireless data centers
(Elsevier BV, 2021-03-15) Mergenci, Cem; Körpeoğlu, İbrahim
High data transfer rates achieved by 802.11ad at 60 GHz ISM band enables use of wireless communication in data centers. In this paper, we investigate the possibility of offloading traffic from wired to wireless network in hybrid data centers. By understanding the capabilities of the wireless network, we can design the hybrid data center network accordingly, to achieve better construction and operating efficiency. First, we propose a system model in which each top-of-the-rack switch is equipped with two radios, so that three non-overlapping channels of 802.11ad that are available worldwide can be assigned in an interference-free manner to any configuration of wireless links. Then, we propose multi-hop routing algorithms that assign traffic to wireless infrastructure. These algorithms consist of two families. SP family of algorithms route traffic only over shortest-paths between source and destination pairs. LP algorithms relax this restriction and assign traffic to longer paths when necessary. In order to evaluate the performance of our routing algorithms, we also propose a random data center traffic generation method, based on an analysis of a real-world data center traffic pattern. We evaluate the performance of our allocation methods in terms of different metrics for various network sizes. Results show that our methods can offload significant amount of traffic from wired to wireless network, can achieve quite high throughput, and can utilize wireless links very well.
Open Access
Server and wireless network resource allocation strategies in heterogeneous cloud data centers
(2020-08) Mergenci, Cem
Resource allocation is one of the most important challenges in operating a data center. We investigate allocation of two main types of resources: servers and network links. Server resource allocation problem is the problem of how to allocate virtual machines (VMs) to physical machines (PMs). By modeling server resources (CPU, memory, storage, IO, etc.) as a multidimensional vector space, we present design criteria for metrics that measure the fitness of an allocation of VMs into PMs. We propose two novel metrics that conform to these design criteria. We also propose VM allocation methods that use these metrics to compare allocation alternatives when allocating a set of VMs into a set of PMs. We compare performances of our proposed metrics to the ones from the literature using vector bin packing with heterogeneous bins (VBPHB) benchmark. Results show that our methods find feasible solutions to a greater number of allocation problems than the others. Network resource allocation problem is examined in hybrid wireless data centers. We propose a system model in which each top-of-the-rack (ToR) switch is equipped with two radios operating in 60-GHz band using 3-channel 802.11ad. Given traffic flows between servers, we allocate wireless links between ToR switches so that the traffic carried over the wireless network is maximized. We also present a method to randomly generate traffic based on a real data center traffic pattern. We evaluate the performance of our proposed traffic allocation methods using randomly generated traffic. Results show that our methods can offload significant amount of traffic from wired to wireless network, while achieving low latency, high throughput, and high bandwidth utilization.