Constructing dual-CISTs of DCell data center networks.

The k-dimensional data center network with n port switches, denoted by Dk,n, has been proposed as a structure of the server-centric network and it was required to have a high reliability on data transmission. A set of t spanning trees in a graph G are called completely independent spanning trees (CISTs for short) if for every pair of nodes x, y ∈ V(G), the paths joining x and y in any two trees have neither node nor edge in common, except for x and y. In particular, if t=2, the two CISTs are called a dual-CIST. Although it has been proved that determining if a graph G admits t CISTs is an NP-complete problem even for t=2, the construction of multiple CISTs on the underlying graph of a network has applications in the fault-tolerance of data transmission. In this paper, we provide a recursive construction for building a dual-CIST on Dk,n for k ≥ 0 and n ≥ 6.