A treadmill includes a tread board, two uprights mounted on two opposite sides of the tread board, two handlebars each pivotally mounted on a respective one of the uprights, and two vibration damping devices each mounted between a respective one of the uprights and a respective one of the handlebars to provide a vibration damping effect to the respective handlebar. Each modules includes a fully encapsulated function which is typically called from another module. Each service offering of the set of feasible service offerings and the set of candidate service offerings is defined by a price and a service level. In accordance with the label information, the device transports L2 communications between the first and second customer networks through the one or more intermediate networks.