Collaborative Traffic Measurement in Virtualized Data Center Networks

Data center network monitoring can be carried out at hardware networking equipment (e.g., physical routers) and/or software networking equipment (e.g., virtual switches). While software switches offer high flexibility to deploy various monitoring tools, they have to utilize server resources, especially CPU and memory, that can no longer be reserved fully to service users' traffic. In this paper we closely examine the costs of ( i) sampling packets on a virtual switch for monitoring purposes; (ii) sending them to a user-space program for measurement; and (iii) forwarding them to a remote server where they will be processed in case of lack of resources locally. Starting from empirical observations, we derive an analytical model to accurately predict (R ² = 99.5%) the three aforementioned costs, as a function of the sampling rates, and pave the way for a collaborative monitoring approach where servers delegate monitoring tasks to each other via port mirroring in case they lack resources.