CHAPTER 4 DATACENTER NETWORKS AND RELEVANT STANDARDS

Datacenters are the core of cloud computing, and their network is an essential component to allow distributed applications to run efficiently and predictably [17]. However, not all datacenters provide cloud computing. In fact, there are two main types of datacenters: production and cloud. Production datacenters are often shared by one tenant or among multiple (possibly competing) groups, services and applications, but with low rate of ar-rival and departure. They run data-analytics jobs with relatively little variation in demands, and their size varies from hundreds of servers to tens of thousands of servers. Cloud dat-acenters, in contrast, have high rate of tenant arrival and departure (churn) [75], run both user-facing applications and inward computation, require elasticity (since application de-mands are highly variable), and consist of tens to hundreds of thousands of physical servers [12]. Moreover, clouds can be composed of several datacenters spread around the world. As an example, Google, Microsoft and Amazon (three of the biggest players in the market) have datacenters in four continents; and each company has over 900, 000 servers. This chapter presents a in-depth study of datacenter networks (DCNs), relevant stan-dards and operation. Our goal here is three-fold: i) provide a detailed view of the net