Data traffic now represents the majority of traffic carried in transport networks. Due to the very bursty nature of users' data traffic, the aggregated traffic will be also bursty in metro networks as well as in the core. If mean data rates alone are considered in network design, the bursty nature of the traffic leads to underdimensioning the networks and could result in congestion. However, ignoring statistical multiplexing, which reduces the impact of bursts by only considering peak data rates, leads to overdimensioning and excessive costs. Guérin's equivalent bandwidth model takes into account the statistical multiplexing of aggregated variable traffic flows in an accurate and very simple way, enabling the realistic dimensioning and simulation of data-aware transport networks.