684 research outputs found
Energy-efficient wireless communication
In this chapter we present an energy-efficient highly adaptive network interface architecture and a novel data link layer protocol for wireless networks that provides Quality of Service (QoS) support for diverse traffic types. Due to the dynamic nature of wireless networks, adaptations in bandwidth scheduling and error control are necessary to achieve energy efficiency and an acceptable quality of service. In our approach we apply adaptability through all layers of the protocol stack, and provide feedback to the applications. In this way the applications can adapt the data streams, and the network protocols can adapt the communication parameters
Dynamic Bandwidth Allocation in ATM Networks
Today's new applications such as World Wide Web, video conferencing and
multimedia have introduced a large amount of traffic into the network. Additionally
new applications are also heading towards real time process. Instant access to the
network, greater level of performances and higher degree of satisfaction has
become the main concerns of users using these new applications. Although current
transmission mediums have advanced in capacity through means such as optical
fiber and Gigabit Ethernet, future and unknown new services tend to consume up
the available bandwidth. ATM network is the new technology used to support a
wide variety of services including data, voice, video and most possibly other future
applications. Its flexibility, efficiency and high throughput have gained popularity
but with greater complexity due to different approaches in handling different type
of services.A high-speed network such as ATM networks must have an effective traffic
management scheme in order to gain high data throughput with the least cost of
operation. Thus, simulation and modeling are the effective methods used to design
the trade-off between network parameters and their performances. Effective sharing
of network resources such as bandwidth and buffer are studied through the dynamic
allocation method. Static allocation scheme has been proven inefficient to provide
high resources utilization as can be seen in STM networks compared to A TM
networks. However, ATM networks should provide different dynamic allocation
methods according to its different services and traffic characteristics. Four dynamic
allocation strategies have been designed, evaluated and compared for their
performances. They are called Static Bandwidth Allocation, Bandwidth Allocated
Proportional to Expected Queue Length, Bandwidth Allocated Proportional to
Expected Queue Length with Threshold Value and Bandwidth Allocated with
Threshold Interrupt. Bandwidth Allocated with Threshold Interrupt is proven to be
the most effective strategy as it could response to congestion immediately
Quality of Service over Specific Link Layers: state of the art report
The Integrated Services concept is proposed as an enhancement to the current Internet architecture, to provide a better Quality of Service (QoS) than that provided by the traditional Best-Effort service. The features of the Integrated Services are explained in this report. To support Integrated Services, certain requirements are posed on the underlying link layer. These requirements are studied by the Integrated Services over Specific Link Layers (ISSLL) IETF working group. The status of this ongoing research is reported in this document. To be more specific, the solutions to provide Integrated Services over ATM, IEEE 802 LAN technologies and low-bitrate links are evaluated in detail. The ISSLL working group has not yet studied the requirements, that are posed on the underlying link layer, when this link layer is wireless. Therefore, this state of the art report is extended with an identification of the requirements that are posed on the underlying wireless link, to provide differentiated Quality of Service
Dynamic bandwidth allocation in ATM networks
Includes bibliographical references.This thesis investigates bandwidth allocation methodologies to transport new emerging bursty traffic types in ATM networks. However, existing ATM traffic management solutions are not readily able to handle the inevitable problem of congestion as result of the bursty traffic from the new emerging services. This research basically addresses bandwidth allocation issues for bursty traffic by proposing and exploring the concept of dynamic bandwidth allocation and comparing it to the traditional static bandwidth allocation schemes
Recommended from our members
Apparatus and method for congestion control in high speed networks
An adjustable bit rate (ABR) feedback control scheme is provided where the effects of multiloop delays and high priority traffic transmission are built into the control model. The data traffic is filtered by a low pass filter. Then, the low frequency bandwidth of the filtered traffic is measured and compared to a predetermined threshold. If the measured value exceeds the threshold, the ABR traffic flow is reduced. If the measured value is less than the threshold, the ABR traffic flow is increased. In addition, a General Prediction Control (GPC) method may be applied to the control model for optimal performance. An object of the invention is to minimize the unused link capacity subject to no congestion, where the ABR traffic is adapted to the low frequency variation of high priority traffic flow for high efficiency.Board of Regents, University of Texas Syste
- …