A Dynamic Multimedia User-Weight Classification Scheme for IEEE_802.11 WLANs

In this paper we expose a dynamic traffic-classification scheme to support multimedia applications such as voice and broadband video transmissions over IEEE 802.11 Wireless Local Area Networks (WLANs). Obviously, over a Wi-Fi link and to better serve these applications - which normally have strict bounded transmission delay or minimum link rate requirement - a service differentiation technique can be applied to the media traffic transmitted by the same mobile node using the well-known 802.11e Enhanced Distributed Channel Access (EDCA) protocol. However, the given EDCA mode does not offer user differentiation, which can be viewed as a deficiency in multi-access wireless networks. Accordingly, we propose a new inter-node priority access scheme for IEEE 802.11e networks which is compatible with the EDCA scheme. The proposed scheme joins a dynamic user-weight to each mobile station depending on its outgoing data, and therefore deploys inter-node priority for the channel access to complement the existing EDCA inter-frame priority. This provides efficient quality of service control across multiple users within the same coverage area of an access point. We provide performance evaluations to compare the proposed access model with the basic EDCA 802.11 MAC protocol mode to elucidate the quality improvement achieved for multimedia communication over 802.11 WLANs.Comment: 15 pages, 8 figures, 3 tables, International Journal of Computer Networks & Communications (IJCNC

IWQoS 2017

Producción CientíficaThe promises of SDN and NFV technologies to boost innovation and to reduce the time-to-market of new services is changing the way in which residential networks will be deployed, managed and maintained in the near future. New user-centric management models for residential networks combining SDN-based residential gateways and cloud technologies have already been proposed, providing flexibility and ease of deployment. Extending the scope of SDN technologies to optical access networks and bringing cloud technologies to the edge of the network enable the creation of advanced residential networks in which complex service function chains can be established to provide traffic differentiation. In this context, this paper defines a novel network management model based on a user-centric approach that allows residential users to define and control access network resources and the dynamic provision of traffic differentiation to fulfill QoS requirements.Ministerio de Economía, Industria y Competitividad (context of GREDOS project TEC2015 -67834- R, TEC2014-53071- C3 -2P and Elastic Networks TEC2015-71932- REDT

Setting the parameters right for two-hop IEEE 802.11e ad hoc networks

Two-hop ad-hoc networks, in which some nodes forward traffic for multiple sources, with which they also compete for channel access suffer from large queues building up in bottleneck nodes. This problem can often be alleviated by using IEEE 802.11e to give preferential treatment to bottleneck nodes. Previous results have shown that differentiation parameters can be used to allocate capacity in a more efficient way in the two-hop scenario. However, the overall throughput of the bottleneck may differ considerably, depending on the differentiation method used. By applying a very fast and accurate analysis method, based on steady-state analysis of an QBD-type infinite Markov chain, we find the maximum throughput that is possible per differentiation parameter. All possible parameter settings are explored with respect to the maximum throughput conditioned on a maximum buffer occupancy. This design space exploration cannot be done with network simulators like NS2 or Opnet, as each simulation run simply takes to long.\ud The results, which have been validated by detailed simulations, show that by differentiating TXOP it is possible to achieve a throughput that is about 50% larger than when differentiating AIFS and CW_min.\u

Providing proportional TCP performance by fixed-point approximations over bandwidth on demand satellite networks

In this paper we focus on the provision of propor- tional class-based service differentiation to transmission control protocol (TCP) flows in the context of bandwidth on demand(BoD) split-TCP geostationary (GEO) satellite networks. Our approach involves the joint configuration of TCP-Performance Enhancing Proxy (TCP-PEP) agents at the transport layer and the scheduling algorithm controlling the resource allocation at the Medium Access Control (MAC) layer. We show that the two differentiation mechanisms exhibit complementary behavior in achieving the desired differentiation throughout the traffic load space: the TCP-PEPs control differentiation at low and medium system utilization, whereas the MAC scheduler becomes the dominant differentiation factor under high traffic load. The main challenge for the satellite operator is to appropriately configure those two mechanisms to achieve a specific differentiation target for the different classes of TCP flows. To this end, we propose a fixed-point framework to analytically approximate the achieved differentiated TCP performance. We validate the predictive capacity of our analytical method via simulations and show that our approximations closely match the performance of different classes of TCP flows under various scenarios for the network traffic load and configuration of the MAC scheduler and TCP-PEP agent. Satellite network operators could use our approximations as an analytical tool to tune their network

Managing delay in the access

17th European Conference on Networks and Optical Communications and 7th Conference on Optical Cabling and Infrastructure,took place 2012-Jun-20-22, Vilanova i la Geltrú (Catalonia, Sapin). The web to event http://www.craax.upc.edu/noc2012/So far latency has been regarded as a minor issue in Passive Optical Networks (PONs). However it may become a key factor for the commercial success of PON and WDM-PON. In this work we review the relevance of very-low latency in the access as the enabler of new higly-interactive cloud services. Then, we propose an approach for delay-based differentiation in PON that causes the delay variance to become smaller than in regular IPACT, featuring a reduction of jitter for high-priority traffic. Then we analyse the impact of setting a maximum delay guarantee to high-priority traffic, on low-priority traffic.This work has been funded by the MEDIANET project and the FIERRO thematic network.Publicad

Bandwidth allocation in cooperative wireless networks: Buffer load analysis and fairness evaluation.

In modern cooperative wireless networks, the resource allocation is an issue of major significance. The cooperation of source and relay nodes in wireless networks towards improved performance and robustness requires the application of an efficient bandwidth sharing policy. Moreover, user requirements for multimedia content over wireless links necessitate the support of advanced Quality of Service (QoS) features. In this paper, a novel bandwidth allocation technique for cooperative wireless networks is proposed, which is able to satisfy the increased QoS requirements of network users taking into account both traffic priority and packet buffer load. The performance of the proposed scheme is examined by analyzing the impact of buffer load on bandwidth allocation. Moreover, fairness performance in resource sharing is also studied. The results obtained for the cooperative network scenario employed, are validated by simulations. Evidently, the improved performance achieved by the proposed technique indicates that it can be employed for efficient traffic differentiation. The flexible design architecture of the proposed technique indicates its capability to be integrated into Medium Access Control (MAC) protocols for cooperative wireless networks

Improving energy efficiency and quality of service in an integrated wireless-optical broadband access network

Exponential growth in the volume of wireless data, boosted by the growing popularity of mobile devices such as smart phones and tablets, is forcing telecommunication industries to rethink network design, and focus on developing high capacity mobile broadband networks. Accordingly, researchers have undertaken developmental work for an integrated wireless-optical broadband access network (WOBAN). Passive optical networks (PONs) and fourth generation (4G) wireless networks are two major candidate technologies for the WOBAN. PON is a wired access technology, well-known for its high capacity, whereas 4G is a wireless broadband access technology, popular for its ease of deployment and ability to offer mobility. Integration of PON and 4G technologies, as a wireless-optical broadband access network, offers advantages such as extension of networks in rural areas, support for mobile broadband services, and rapid deployment of broadband networks. However, these two technologies have different design architectures for handling broadband services which require Quality of Service (QoS), for example, 4G networks use traffic classification for supporting different QoS demands whereas PON does not differentiate between traffic types. This integrated network must also be energy efficient, as a green broadband access network, without hindering QoS. While these technologies both use sleep mode, they differ in their power saving mechanisms. This thesis first addresses a QoS solution for the incompatibility between these technologies. Service class mapping is proposed in Chapter 3 for the integrated WOBAN, based on the M/G/1 queuing model supported by an innovative priority scheduler. Once class mapping is deployed, a power saving mechanism can be devised by exploiting traffic differentiation. Specifically, a class-based strategy is proposed which helps optimise the sleep period for the terminal units of the optical network, without compromising QoS. Since the optical network involves control and terminal nodes, both of which consume power, this thesis proposes an energy efficient mechanism that involves both components. In contrast, other published strategies (Chapter 2) have only considered the terminal units. Chapter 4 presents the mechanism for enabling global sleep (control and terminal nodes) and local sleep (terminal nodes), based on the available traffic\u27s class structure. This mechanism enables sleep for different components within the bandwidth allocation by adapting the switching between predefined polling cycle lengths. As the WOBAN is comprised of both wireless and optical parts, a dynamic resource management mechanism is needed which responds to changing daily traffic patterns across a green integrated network. Consequently, Chapter 5 proposes a mechanism which dynamically adapts the polling cycles, of the optical and wireless parts of the network, to the changing traffic volume and class composition. Tailored sleep durations for the components of the WOBAN are facilitated within the resource management regime, as these components differ in their ability to function efficiently if management of the sleep periods is not responsive to the changing traffic volumes and class composition. This dissertation creates new knowledge by seamlessly integrating the two parts of WOBAN and introducing differentiated, class-based sleep for the components of the hybrid network to help realise a green WOBAN

Quality of Service Differentiation in Heterogeneous CDMA Networks : A Mathematical Modelling Approach

Next-generation cellular networks are expected to enable the coexistence of macro and small cells, and to support differentiated quality-of-service (QoS) of mobile applications. Under such conditions in the cell, due to a wide range of supported services and high dependencies on efficient vertical and horizontal handovers, appropriate management of handover traffic is very crucial. Furthermore, new emerging technologies, such as cloud radio access networks (C-RAN) and self-organizing networks (SON), provide good implementation and deployment opportunities for novel functions and services. We design a multi-threshold teletraffic model for heterogeneous code division multiple access (CDMA) networks that enable QoS differentiation of handover traffic when elastic and adaptive services are present. Facilitated by this model, it is possible to calculate important performance metrics for handover and new calls, such as call blocking probabilities, throughput, and radio resource utilization. This can be achieved by modelling the cellular CDMA system as a continuous-time Markov chain. After that, the determination of state probabilities in the cellular system can be performed via a recursive and efficient formula. We present the applicability framework for our proposed approach, that takes into account advances in C-RAN and SON technologies. We also evaluate the accuracy of our model using simulations and find it very satisfactory. Furthermore, experiments on commodity hardware show algorithm running times in the order of few hundreds of milliseconds, which makes it highly applicable for accurate cellular network dimensioning and radio resource management