RWADMM: Routing and Wavelength Assignment for Distribution-Based Multiple Multicasts in ONoC

Abstract

Multicast communication widely exists in cache coherence protocols for Chip Multiprocessors (CMPs) in various parallel applications. The system performance can be significantly deteriorated if no effective routing method is supported for multicast.,,,, Optical Network-on-Chip (ONoC) has become the mainstream for CMPs design because of its unique merits of high bandwidth density and low energy consumption. Although existing multicast routing and wavelength assignment methods have improved system performance, such as reducing packets delay and wavelengths, they only consider one multicast request in their design. In this paper, we target on dealing with multiple multicasts problem regarding to fully utilizing the network resources.,,,, We propose a Routing and Wavelength Assignment method for Distribution-based Multiple Multicasts, RWADMM, in which routing and wavelength assignment are determined by the distribution of the nodes involved in the multicasts. We first derive 4 Routing Theorems for particular scenarios according to the distribution of source and destination nodes, which need only a minimum of one wavelength. Then, a Group-partitioning routing algorithm for general cases is proposed by decoupling all multicast nodes into several small groups and each group can be routed by one of the 4 Routing Theorems. As a result, the number of wavelengths is equal to the number of groups. Simulation results show that our proposed scheme outperforms other routing methods in terms of the number of wavelengths used, especially being effective in the case of large number of multicast requests.