Diagnosability Evaluation of the Data Center Network DCell

With the rapid development of cloud computing, many large-scale data centers are being built to provide increasingly popular online application services. This leads to the proposal of data center networks (DCNs) supporting millions of servers with high-network capacity by using only commodity switches. The k-dimensional DCell with n-port switches and tk, n servers, D-k,D- n, has been proposed as a model for a large-scale DCN with a server-centric structure. In this paper, we study the diagnosability and the g-good-neighbor conditional diagnosability of Dk, n. We prove that: (i) D-k,D- n is(n+ k-1)-diagnosable under the precise diagnosis strategy and (2k + n-2)/(2k+ n -2)diagnosable under the pessimistic diagnosis strategy; (ii) the g-good-neighbor conditional diagnosabilities of D-k,D- n under the PMC model and the MM* model are both (g+ 1) k+ n-1(resp. (n+ k-g) t(g-n+ 1, n) -1) with 0 <= g <= n-1 (resp. n pound g pound n+ k-2), which is almost (g + 1) (resp. tg-n+ 1, n) times of the traditional diagnosability. These results provide a quantitative evaluation for a large-scale DCN's reliability and availability.