摘要：T hroughout its relatively brief history, the Internet has continually challenged our preconceptions about networking and communications architectures. For example, the concepts that the network itself has no role in management of its own resources, and that resource allocation is the result of interaction between competing end-to-end data flows, were certainly novel innovations, and for many they have been very confrontational. The approach of designing a network that is unaware of services and service provisioning and is not attuned to any particular service whatsoever—leaving the role of service support to end-to-end overlays—was again a radical concept in network design. The Internet has never represented the conservative option for this industry, and has managed to define a path that continues to present significant challenges.
