Congestion control of TCP flows in Internet routers by means of index policy

Abstract

In this paper we address the problem of fast and fair transmission of flows in a router, which is a fundamental issue in networks like the Internet. We model the interaction between a source using the Transmission Control Protocol (TCP) and a bottleneck router with the objective of designing optimal packet admission controls in the router queue. We focus on the relaxed version of the problem obtained by relaxing the fixed buffer capacity constraint that must be satisfied at all time epoch. The relaxation allows us to reduce the multi-flow problem into a family of single-flow problems, for which we can analyze both theoretically and numerically the existence of optimal control policies of special structure. In particular, we show that for a variety of parameters, TCP flows can be optimally controlled in routers by so-called index policies, but not always by threshold policies. We have also implemented the index policy in Network Simulator-3 and tested in a simple topology their applicability in real networks. The simulation results show that the index policy achieves a wide range of desirable properties with respect to fairness between different TCP versions, across users with different round-trip-time and minimum buffer required to achieve full utility of the queue.

Study on Westwood Algorithm Optimization

“…And equation (3) and (4) will be integrated to be equation (5) Actual N RTT RTT c   min (5) As can be seen, the additional latency of RTTc compared to RTTmin is caused by the packets backlog in cache.…”

“…Meanwhile, TCPW and Reno algorithm share the identical additive increase mechanism at congestion avoidance stage, so the network has been saturated in additive increase phase and about to enter network congestion state. The same increment mechanism of TCPW and Reno will enlarge congestion window rapidly, which will induce the recongestion of network [5].…”

Whittle index policy for crawling ephemeral content

“…This has been a very successful heuristic for restless bandits, which, while suboptimal in general, is provably optimal in an asymptotic sense [26], [27] and has good empirical performance. It and its variants have been used extensively in logistical and engineering applications, some recent instances of the latter in communications and control being for sensor scheduling [19], multi-UAV coordination [20], congestion control [3], [4], [13], channel allocation in wireless networks [14], cognitive radio [17] and real-time wireless multicast [23]. Book length treatments of indexable restless bandits appear in [12], [24].…”

Time Delayed Feedback Control of Internet Congestion Control Model with Compound TCP under RED

“…Transport Control Protocol (TCP) [1] has been widely used in the current Internet for reliable end-to-end transmission of data. As time goes, several variations of the basic congestion control mechanism of TCP have been proposed during the last several years for efficient transmission of data over high-speed long-distance networks.…”