Topology switching for data center networks

Abstract

Emerging data-center network designs seek to provide physical topologies with high bandwidth, large bisection capacities, and many alternative data paths. Yet, existing protocols present a one-size-fits-all approach for forwarding packets. Traditionally, the routing process chooses one “best ” route for each end-point pair. While some modern protocols support multiple paths through techniques like ECMP, each path continues to be selected using the same optimization metric. However, today’s data centers host applications with a diverse universe of networking needs; a single-minded forwarding approach is likely to either let paths go unused, sacrificing reliability and performance, or make the entire network available to all applications, sacrificing needs such as isolation. This paper introduces topology switching to return control to individual applications for deciding best how to route data among their nodes. Topology switching formalizes the simultaneous use of multiple routing mechanisms in a data center, allowing applications to define multiple routing systems and deploy individualized routing tasks at small time scales. We introduce the topology switching abstraction and illustrate how it can provide both network efficiency and individual application performance, and admit flexible network management strategies. 1