Improving the Scalability of Distributed Network Emulations: An Algorithmic Perspective

Abstract

By deploying virtualized network elements (hosts, switches, routers, links, etc.) on clusters of commodity machines, distributed network emulations (DNE) closely mimic the behaviors of network systems and provide real-time interactions and analysis for network service management. However, DNE encounters scalability challenges when faced with large network topologies. These challenges can be boiled down to the assignment problem: to which physical machine each virtualized network element should be assigned so that the largest possible network topology can be emulated? In this paper, we tackle this problem from an algorithmic perspective. We first propose TBR (topology balancing relaxation) as the relaxation of the assignment problem. TBR tries to maintain a balance of the hardware resource consumption, by minimizing the maximum inter-machine bandwidth. We further develop TBS (topology balancing solver), which combines mathematical techniques with multi-level algorithms to solve TBR efficiently. We integrate TBR and TBS into MaxiNet, a famous distributed network emulator. Experimental results show that with the same available physical resources, TBR and TBS can improve emulation scalability by up to 4.7× compared to baselines.