Conference Paper

CHOKeW: bandwidth differentiation and TCP protection in core networks

Dept. of Electr. & Comput. Eng., Florida Univ., Gainesville, FL
DOI: 10.1109/MILCOM.2005.1605882 Conference: Military Communications Conference, 2005. MILCOM 2005. IEEE
Source: IEEE Xplore


Both bandwidth differentiation and TCP protection is important for implementing quality of services (QoS) in TCP/IP networks. To the best of our knowledge, no other schemes have combined these two tasks together so far. In this paper we present a stateless active queue management (AQM) algorithm called CHOKeW. CHOKeW uses "matched drops" created by CHOKe to control the bandwidth allocation, but excludes the RED module. Based on the congestion status and the priority of the arriving packet, CHOKeW adjusts the maximum number of packets drawn from the buffer for matched drops. Using simulations, we show that CHOKeW is capable of working in different congestion scenarios, supporting multiple bandwidth priority levels by giving high priority flows with high throughput, and restrict the throughput of high-speed unresponsive flows to protect TCP flows

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    ABSTRACT: Although differentiated services (DiffServ) networks have been well discussed in the past several years, a conventional Active Queue Management (AQM) algorithm still cannot provide low-complexity and cost-effective differentiated bandwidth allocation in DiffServ. In this paper, a novel AQM scheme called CHOKeR is designed to protect TCP flows effectively. We adopt a method from CHOKeW to draw multiple packets randomly from the output buffer. CHOKeR enhances the drawing factor by using a multistep increase and single-step decrease (MISD) mechanism. In order to explain the features of CHOKeR, an analytical model is used, followed by extensive simulations to evaluate the performance of CHOKeR. The analytical model and simulation results demonstrate that CHOKeR achieves proportional bandwidth allocation between different priority levels, fairness guarantee among equal priority flows, and protection of TCP against high-speed unresponsive flows when network congestion occurs.
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    ABSTRACT: In order to find a cost-effective solution for combining pricing, admission control, buffer management and scheduling in DiffServ networks, we propose the ConTax-CHOKeW framework. ConTax is a distributed admission controller that works in edge routers, while CHOKeW, designed in our previous research for core networks, is a buffer management scheme. Since a user in a higher priority class requests more bandwidth that is differentiated by CHOKeW, this user is likely to generate more network load. ConTax uses the sum of priority values for all admitted users to measure the network load. When the network load is heavier, ConTax charges a higher price for each priority class. The price includes a basic price and an extra price called congestion tax. By using simulations, we show that ConTax is capable of controlling the network load as well as the number of users that are admitted into the network. In addition, by employing ConTax, network providers can gain more profit, and users have greater flexibility that in turn meets the specific performance requirements of their applications
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