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Concern over the accurate evaluation of QoS requirements has been one of driving forces in the development of QoS management architectures. This paper presents an architectural approach to QoS evaluation and admission control, based on the modelling of both system behaviour and QoS requirements. Two aspects are considered. The first refers to QoS m...
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Context 1
... us consider a Personal Area Network (PAN) that consists of a Wireless router connected to the Internet. Figure 3 depicts a number of users (Stations), namely two PCs (PC1, PC2) and a Laptop (L1), which access the Internet via the router (Access Point). L2 is not part of the initial configuration. ...
Context 2
... stations are competing with each other to acquire bandwidth and to achieve a better QoS. Now, consider a laptop L2, which wants to join the PAN as depicted in Figure 3. The task of the QoS manager is to determine the effect of a provision of service to L2 on the existing components. ...
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Citations
... These models are based on the timed automata as suggested by Bordbar et. al [3] [4].The interaction with the access point, which makes use of PCF, is modelled as state transition for PCF. At the start of a contention free period, the medium gets busy as inFig 3.1, and this is shown with the signal access of state mode for PCF. ...
The international standard IEEE 802.11 wireless LAN protocol is a popular standard for wireless local area networks. Its medium access control layer (MAC) is a carrier sense multiple access with collision avoidance (CSMA/CA) design, although collisions cannot always be prevented, randomized exponential backoff rule is used in the retransmission scheme to minimize the likelihood of repeated collisions. To work around this problem, we identify state transition of the protocol that can be used to simplify the models and make verification feasible. This paper explains the state transition model of two way handshake mechanism of IEEE 802.11 standard for MAC DCF. Using these observations, a time variant generalized state transition model for channel, sender and destination station has been described. The proposed model has been validated using network simulator ns-2.
... Timed Automata models can be used at design time to compute performance and/or reliability metrics [81,82,83], but also for run-time monitoring of services [84,85]. Recently, timed automata have been used to model and analyze timeliness properties of embedded system architectures [80]. ...
... QoS evaluation and admission control, based on the modeling of both system behavior and QoS requirements, in a TA framework, has been investigated [81]. Two aspects are considered. ...
This document introduces and describes the prediction models which support the estimate of the quality attributes considered in the Q-ImPrESS project. Models are discussed within the Model Driven Development frame-work and their points of strength and weakness are analyzed. An example of use of the models with respect to the client-server architecture introduced in Q-ImPrESS Deliverable D2.1 is also provided and the interrelationships among the model parameters and the Q-ImPrESS Service Architecture Meta-Model is analyzed.
There has been a phenomenal increase in the demand of quality-of-service (QoS)
in wireless networks over the years due to rapid growth in the number of wireless
and mobile devices. Such devices are in use to access Internet and QoS aware
applications such as video conferencing, voice-over IP, interactive video-on-demand
and many other multimedia applications. wireless local area networks (WLANs)
confirming to the IEEE 802.11 standard have become extremely popular at an
unprecedented rate. As a result, WLAN networks are gaining the momentum and
making their way into residential, commercial, industrial and public areas. These
trends are more and more accelerated in places like airports, hotels and coffee
shop, this typically has many floating end users. The time stringent applications
are delay sensitive that require throughput and delay bound creates an urgent
need for QoS support in WLANs.
