An eyewear structure combinable with an accessory glasses unit comprises a main glasses unit and an accessory glasses unit each having assembly bores drilled at a bridge thereon wherein attracting elements with insert grooves and attracted elements with insert rod are respectively combined with magnetic elements and embedded to the assembly bores of the main and accessory glasses units. The chassis includes a chassis bottom wall, a chassis front wall and a chassis rear wall. By enabling the flow sources to regulate their data traffic based on the QCN messages from a congestion control component, the queue length at the bottleneck link may converge to an equilibrium queue length rapidly and TCP throughput performance may be enhanced substantially in a TCP incast circumstance.