Research On The Key Technologies Of End-to-End Multipath Transfer

With the rapid development of the Internet, the emergence of the new access technologies and the overlapped coverage of the heterogeneous networks, the terminals of the Internet present the multihoming trend. Multihomed terminals are potentially capable to access the network at anytime, anywhere and with any access technology. However, due to the original design drawbacks of the Internet on the using of multi-homing, the multihoming feature is hard to be utilized effectively. Though designed to make use of the multihoming, the current technologies in the Internet bring side effects in both the network routing and transmission performance. Therefore, how to utilize the multihoming feature to transfer data without introducing additional cost to the network attracts significant research attention recently.On the basis of in-depth analysis of the current multihoming and multipath transport technologies, this dissertation presents the End-to-End Multipath Transfer (E2EMPT) scheme, in order to improve the aggregate bandwidth of the multihoming host, the utilization of the network resource, the reliability of the service, the privacy of the data transferred and carry out the traffic engineering at the edge of the network. This dissertation mainly studies the key technologies of E2EMPT in three aspects, the data transfer, the path selection and path discovery, by following a top-down order. The main work of this dissertation can be summarized as follows:1. Through performing in-depth analysis of the multipath transfer schemes based the transport layer protocols, the design principles of the E2EMPT are summarized. A new end-to-end multipath transfer design, E2EMPT, is proposed. E2EMPT adopts the dual sequence space mapping scheme, sending schedule algorithm, and receiver buffer management to eliminate the unnecessary fast retransmission caused by the reordering packets, which improves the reordering robustness of the multihomed terminals and consequently the aggregate bandwidth.2. Modeling and analyzing the steady-state throughput and data privacy. A data transport model based Drop-tail Queue of the E2EMPT is proposed, with the consideration of the SCTP congestion control algorithm. By analyzing the average throughput of the congestion avoidance phase and the timeout retransmission phase, the E2EMPT steady-state throughput model is constructed, and a function of the E2EMPT throughput about the path loss ratio and path delay is derived. A relation model about the data privacy and the number of the path used in the E2EMPT is built. By making a tradeoff between the memory resource consumption and the data privacy, the model suggests the optimal number of the path used in E2EMPT heuristically.3. Modeling the receiver buffer blocking problem of the E2EMPT and proposing a path selection algorithm. A mathematic model to analyze the relationship between the maximum amount of the reordering packets and the path loss ratio and delay is estab-lished, when E2EMPT using the diverse path. Based on the model, this dissertation proposes a path selection algorithm to choose a set of paths with similar path delay and relatively low path loss ratio. The algorithm attempts to eliminate the influence of the diverse path character to the overall performance of the E2EMPT. Through simulations, the optimal path selection parameters are chosen, and the performance of the E2EMPT with path selection is evaluated.4. Proposing a source-directed path diversity in the interdomain routing to provide the best effort link disjointed end-to-end path for the E2EMPT. The iBGP that adopts the route reflection architecture has the path hiding problem. Through modifying the function of the route reflector to the route relay which could advertise multiple paths towards the same destination to the neighbors, the iBGP could recover the path redundancy. This dissertation presents the Source-Directed Path Diversity (SDPD). The SDPD makes the source specify the path used and express the preference on the path to the network, by inserting a path selection hint in the packets. The SDPD also could make the BGP routers forward the packets based the source hint, to exploit the path diversity at the best effort. The path similarity and path stretch of the diverse paths exploited by the source are measured in the simulation.This dissertation researches the E2EMPT, which has practical significance for the utilization of the multihomed terminals. Furthermore, this dissertation contributes to expand the ideas about the network researching, by trying to solve the relative issues of the Internet from the view of the terminals, and provides a useful guideline for the evolving of the Internet and the designing of the next generation networking.