A New Available Bandwidth Measurement Technique for Service Overlay Networks

We introduce a new measurement algorithm for the available bandwidth in a network path between two endhosts. This algorithm is an adaptation from existing active measurement methods for the purpose of being applied in inline network measurement. Inline network measurement method measures the available bandwidth by using packets which an active TCP connection transmits, instead of using probe packets, as in the existing methods. The measurement is performed by inferring network characteristics information from transmitting and receiving intervals of TCP data and ACKnowledgement packets. Inline network measurement is useful in service overlay networks, in which up-to-date information on the available bandwidth in the underlying IP network should be known as early as possible. In this paper, we first introduce the measurement algorithm and then discuss the problems with applying the proposed measurement algorithm to an active TCP connection. We evaluate the proposed measurement algorithm using simulation experiments and show that it can provide an estimation of available bandwidth every 2-4 RTTs. Moreover, the accuracy of measurement results can be maintained considerably well while the number of packets in a measurement is reduced by approximately 90% in comparison with existing methods.