A time-dominated TCP congestion control over heterogeneous networks

The traditional transmission control protocol (TCP) suffers from performance problems such as throughput bias against flows with longer packet roundtrip time (RTT), which leads to burst traffic flows producing high packet loss, long delays, and high delay jitter. This paper proposes a TCP congestion control mechanism, TD-TCP, that the sender increases the congestion window according to time rather than receipt of acknowledgement. Since this mechanism spaces out data sent into the network, data are not sent in bursts. In addition, the proposed mechanism reduces throughput bias because all flows increase the congestion window at the same rate regardless of their packet RTT. The implementation of the mechanism affects only the protocol stack at the sender; hence, neither the receiver nor the routers need modifications. The mechanism has been implemented in the Linux platform and tested in conjunction with various TCP variants in real environments. The experimental result shows that the proposed mechanism improves transmission performance, especially in networks with congestion and/or high packet loss rates. Experiments in real commercial wireless networks have also been conducted to support the proposed mechanism's practical use. Copyright © 2008 John Wiley & Sons, Ltd.     

Trunk congestion control in heterogeneous circuit switched networks

A circuit-switched network with two types of traffic is modeled as a finite two-dimensional Markov chain. The problem of trunk congestion under different routing schemes is analyzed. It is shown that the trunk reservation technique can be used to alleviate trunk congestion in this heterogeneous traffic environment. It is also shown that two control schemes, namely, the restricted access and preemption, when properly applied, may minimize the blocking of one type of traffic while keeping that of the other at a certain level. Some numerical examples are presented     

Efficient congestion control mechanism for flow‐aware networks

Transmission based on flows becomes more and more popular in teleinformatics networks. To guarantee proper quality of service, to enable multipath transmissions, or just to increase transmission effectiveness in a network, traffic should be sent as flows. Flow‐aware networking architecture is one of the possible concepts to realize flow‐based transmissions. In this paper, the efficient congestion control mechanism (ECCM) is proposed to improve transmission in flow‐aware networks (FAN). The mechanism makes it possible to minimize acceptance delay of streaming flows (served with high priority) without deteriorating other transmissions in the network. It is confirmed by simulation experiments that the implementation of FAN with the ECCM mechanism is a promising solution for the Future Internet. Copyright © 2015 John Wiley & Sons, Ltd.     

A novel congestion control model for interworking AAA in heterogeneous networks

In the 3rd generation partnership project (3GPP) and wireless local area network (WLAN) interworking networks, 3GPP authentication, authorization, accounting (AAA) server located in 3GPP core network will be responsible for the AAA request from WLAN access network (AN). However, centralized AAA deployment is bound to give rise to the single point failure, resulting in system congestion. In order to solve this problem, this paper presents a novel congestion control model for AAA. In addition, through analyzing the model, the conclusion can be drawn that the average congestion rate of extensible authentication protocol (EAP) user request is related with factors, such as the arrival rate of EAP request, the number of EAP re-authentication, and the system buffer queue length. Finally, the simulation results show that EAP request arrival rate is directly proportional to the congestion rate, and when the number of EAP re-authentication and system buffer queue length are fixed, the number of corresponding user authentication vectors should be directly proportional to the EAP request arrival rate, so as to ensure the average congestion rate of EAP request is less than 0.005.     

A simple adaptive routing scheme for congestion control inShuffleNet multihop lightwave networks

The authors describe a simple adaptive routing scheme for datagram (connectionless) and virtual circuit (connection-oriented) transmission that relieves congestion resulting from nonuniform traffic patterns and network failures. The authors describe a fixed-routing algorithm for dedicated channel ShuffleNets. Based on the fixed routing algorithm, an adaptive routing scheme for datagram transmission is presented followed by performance results for uniform and nonuniform traffic patterns and fault tolerance. The adaptive routing of datagrams uses only the local queue size information available at the network interface units (NIUs) and redistributes the load as congestion develops. Since datagrams are individually routed through the network, they may not arrive at their destination in the order they were generated and may need to be resequenced. The authors compute an upper estimate on the resequencing buffer size for stream traffic. A virtual circuit version of the adaptive routing algorithm eliminates the need for resequencing buffers     

A globally stable adaptive congestion control scheme for Internet-style networks with delay

In this paper, we develop, analyze and implement a congestion control scheme in a noncooperative game framework, where each user's cost function is composed of a pricing function proportional to the queueing delay experienced by the user, and a fairly general utility function which captures the user demand for bandwidth. Using a network model based on fluid approximations and through a realistic modeling of queues, we establish the existence of a unique equilibrium as well as its global asymptotic stability for a general network topology, where boundary effects are also taken into account. We also provide sufficient conditions for system stability when there is a bottleneck link shared by multiple users experiencing nonnegligible communication delays. In addition, we study an adaptive pricing scheme using hybrid systems concepts. Based on these theoretical foundations, we implement a window-based, end-to-end congestion control scheme, and simulate it in ns-2 network simulator on various network topologies with sizable propagation delays.     

Stability analysis and design of the second-order congestion control for networks with heterogeneous delays

This paper addresses the problem of the stability of congestion control for networks with heterogeneous round-trip communication delays. We present a frequency-domain approach to this problem. The approach is based on the analysis of the clockwise property of system transfer functions, generalized Nyquist stability criterion, and a recent lemma of Vinnicombe. We point out that a prerequisite for establishing decentralized stability criteria for distributed congestion control is that the Nyquist plots of time-delayed transfer functions corresponding to price (rate) dynamics at links (sources) satisfy clockwise property in certain frequency intervals. Based on the detailed investigation of global geometric properties of the frequency response of price dynamics at links, we derive sufficient conditions for the local asymptotic stability of a kind of the second-order active queue management algorithm-REM algorithm. A simple design procedure is also proposed for guaranteeing the asymptotic stability of the control algorithm.     

QoS-driven adaptive congestion control for voice over IP in multiservice wireless cellular networks

This work establishes a QoS-driven adaptive congestion control framework that provides QoS guarantees to VoIP service flows in mixed traffic scenarios for wireless cellular networks. The framework is composed of three radio resource management algorithms: admission control, packet scheduling, and load control. The proposed framework is scalable to several services and can be applied in any current or future packet-switched wireless system. By means of dynamic system-level simulations carried out in a specific case study where VoIP and Web service flows compete for shared access in an HSDPA wireless network, the proposed framework is able to increase the overall system capacity twofold depending on the traffic mix, while keeping the system operating optimally in its target QoS profile.     

Efficient call admission control for heterogeneous services inwireless mobile ATM networks

An efficient call admission control scheme for handling heterogeneous services in wireless ATM networks is proposed. Quality-of-service provisioning of jitter bounds for constant bit rate traffic and delay bounds for variable bit rate traffic is used in the CAC scheme to guarantee predefined QoS levels for all traffic classes. To reduce the forced handoff call dropping rate, the CAC scheme gives handoff calls a higher priority than new calls by reserving an appropriate amount of resources for potential handoff calls. Resource reservation in the CAC scheme makes use of user mobility information to ensure efficient resource utilization. Simulation results show that the proposed CAC scheme can achieve both low handoff call dropping rate and high resource utilization     

Opportunistic media access control and routing for delay-tolerant mobile ad hoc networks

In delay-tolerant mobile ad hoc networks, motion of network nodes, network sparsity and sporadic density can cause a lack of guaranteed connectivity. These networks experience significant link delay and their routing protocols must take a store-and-forward approach. In this paper, an opportunistic routing protocol is proposed, along with its compatible media access control, for non-real-time services in delay-tolerant networks. The scheme is mobility-aware such that each network node needs to know its own position and velocity. The media access control employs a four-fold handshake procedure to probe the wireless channel and cooperatively prioritize candidate nodes for packet replication. It exploits the broadcast characteristic of the wireless medium to utilize long-range but unreliable links. The routing process seizes opportunities of node contacts for data delivery. It takes a multiple-copy approach that is adaptive with node movements. Numerical results in mobile ad hoc networks and vehicular ad hoc networks show superior performance of the proposed protocol compared with other routing protocols. The mobility-aware media access control and routing scheme exhibits relatively small packet delivery delay and requires a modest amount of total packet replications/transmissions.     

Error and congestion control for wireless sensor networks

In the wireless sensors network (WSN) field, a wide variety of sensors produce a heterogeneous traffic mix, targeting diverse applications with different reliability requirements. We focus on emergency response scenarios, where a mobile rescuer moves through a, possibly disconnected, network, trying to talk to diverse sensors. We assume two types of sensors, event sensors triggered by an event and periodic sensors activated at predefined time intervals, as well as two types of transmission, either using the highest bit rate available or using predefined bit rates. Our reliable transport protocol for sensor networks with mobile sinks (RT‐SENMOS) takes into account all these parameters and tries to provide the best possible user experience under the current circumstances of the network, using a sink‐driven approach where an application‐specific sink is combined with generic sensors. RT‐SENMOS was implemented and tested over a real network with emulated losses and compared against rate‐controlled reliable transport (RCRT), a well‐known sink‐driven protocol. The results show that RT‐SENMOS fully exploits the available bandwidth in all cases, while RCRT only manages to exploit 60% to 90% of it. Furthermore, RT‐SENMOS adapts much faster to prevailing network conditions, while its protocol overhead, in terms of control messages exchanged, is much lower than that of RCRT.     

A congestion control framework for ATM networks

The authors propose a congestion control framework for ATM networks that requires simple protocols and that provides guaranteed grade of service The authors suggest that the network provides two different services: express service and first-class service. Express service is appropriate for real-time applications, whereas first-class service is appropriate for nonreal-time applications. To provide such services, the proposed congestion control scheme prevents congestion inside the network by controlling the congestion at two levels: VC (virtual circuit) level and cell level. The VC-level control takes place during the call setup in the form of (logical) bandwidth reservation for individual VCs. The cell-level control is exercised across the network interface in the form of the choking/relieving of only first-class VC traffic in case of congestion. The authors analyze the performance of the proposed scheme, and show how to engineer various parameters to satisfy cell-level performance requirements (e.g., cell delay and loss)     

Adaptive congestion control for DSRC vehicle networks

Dedicated short range communications (DSRC) was proposed for collaborative safety applications (CSA) in vehicle communications. In this article we propose two adaptive congestion control schemes for DSRC-based CSA. A cross-layer design approach is used with congestion detection at the MAC layer and traffic rate control at the application layer. Simulation results show the effectiveness of the proposed rate control scheme for adapting to dynamic traffic loads.     

An effective congestion control scheme for ATM networks

Congestion control is considered one of the most challenging issues of ATM. Simulation results are presented which show the performance superiority of the proposed scheme as compared to the conventional leaky bucket scheme. © 1998 John Wiley & Sons, Ltd.     

On-board closed-loop congestion control for satellite-based packet-switching networks

NASA Lewis Research Center is currently investigating a satellite architecture that incorporates an on-board packet-switching capability. Because of the statistical nature of packet switching, arrival traffic may fluctuate, and thus it is necessary to integrate the congestion control mechanism as part of the on-board processing unit. This study focuses on the closed-loop reactive control. We investigate the impact of the long propagation delay on the performance, and propose a scheme to overcome the problem. The scheme uses a global feedback signal to regulate the packet arrival rate of the ground stations. In this scheme, the satellite continuously broadcasts the status of its output buffer and the ground stations respond by selectively discarding packets or by tagging the excessive packets as low-priority. The two methods are evaluated by theoretical queueing analysis and simulation. The former is used to analyse the simplified model and to determine the basic trends and bounds, and the latter is used to assess the performance of a more realistic system and to evaluate the effectiveness of more sophisticated control schemes. The results show that the long propagation delay makes the closed-loop congestion control less responsive. The broadcast information can only be used to extract statistical information. The discarding method needs carefully-chosen status information and a reduction function, and normally requires a significant amount of ground discarding to reduce the on-board packet loss probability. The tagging method is more effective since it tolerates more uncertainties and allows a larger margin of error in status information. It can protect the high-priority packets from excessive loss and fully use the down-link bandwidth at the same time.     

基于相遇时长的时延容忍路由

移动用户和无线设备终端已成为大量数据的源节点。在如此数据密集型的移动的无线通信网络中,时延容忍网络(DTNs)在数据路由、分发和收集阶段扮演着重要作用。为此,提出基于相遇时长的时延容忍路由(CDR)。先分析了数据密集型路由问题：仅凭一次相遇机会无法完成大数据量的传输。再通过相遇频率、相遇时长和缓存区的可用空间三项信息,计算路径的权重,将具有最大权重的路径作为最短路径,并依此路径传输数据。仿真结果表明,相比于等待路由(SW),CDR路由有效地提高了数据包传递率。     

基于消息传输率的时延容忍网络路由

针对时延容忍网络(DTNs),提出基于消息传输率的路由(DTRR).将每条消息划分若干个消息块.当源节点遇见合适的转发节点就传输消息块,否则就将消息块存于缓存区中.同时,DTRR路由结合相遇频率、相遇时长和缓存区的可用空间,推导链路的消息传输率.再依据消息传输率,选择下一跳转发节点.仿真结果表明,提出的DTRR路由在消...     

MaxNet: a congestion control architecture for scalable networks

MaxNet is a distributed congestion control architecture. This paper analyzes the stability properties of MaxNet. We show that MaxNet is stable for networks with arbitrary delays, numbers of sources, capacities, and topologies. Unlike existing proposals, MaxNet does not need to estimate the number of bottleneck links on the end-to-end path to achieve these scaling properties.     

混合网络下的ECLN拥塞控制跨层优化算法

针对有线网络中的拥塞控制机制ECN进行改进,引入网络负荷因子的概念来更准确、有效的更新发送方的窗口大小,并将它和无线网络中的WELN机制相结合,提出了ECLN机制来提高在混合网络下的网络性能,并用NS2仿真工具在物理层引入无线信道错误模型来模拟无线链路上的丢包现象.仿真结果表明,该算法能够有效降低丢包数,明显提高网络的吞吐量.