Title: Why Path-Based Adaptation? Performance Implications of Different Adaptation Mechanisms for Network Content Delivery (NYU-CS-TR843) Authors: Xiaodong Fu and Vijay Karamcheti Abstract: Because of heterogeneous and dynamic changing network environments, content delivery across the network requires system support for coping with different network conditions in order to provide satisfactory user experiences. Despite the existence of many adaptation frameworks, the question that which adaptation approach performs the best under what network configurations still remains unanswered. The performance implication of different adaptation approaches (end-point, proxy-based and path-based approaches) has not been studied yet. This paper aims to address this shortcoming by conducting a series simulation-based experiments to compare performance among these adaptation approaches under different network configurations. In order to make a fair comparison, in this paper approach-neutral strategies are proposed for constructing communication paths and managing network resources. The experiment results show that there are well-defined network environments under which each of these approaches delivers its best performance; and among them, the path-based approach, which uses the whole communication path to do adaptation, provides the best and the most robust performance under different network configurations, and for different types of servers and clients.