Path signalling in a wireless back-haul network integrating unidirectional broadcast technologies

The black-haul infrastructures of today's wireless operators must support the triple-play services demanded by the market or regulatory bodies. To cope with increasing capacity demand, in our previous work, we have developed a cost-effective heterogeneous layer 2.5 wireless back-haul (WiBACK) architecture, which leverages the native multicast capabilities of broadcast technologies such as DVB to off-load high-bandwidth broadcast content delivery. Furthermore, our architecture provides support for unidirectional technologies on the data and the control plane. This adopts a centralized coordinator approach, in which coordinator nodes install so-called management and data pipes. No routing state is kept at plain WiBACK nodes, which merely store QoS-aware pipe forwarding state. Consequently, the architecture requires a reliable protocol to push resource allocation and pipe forwarding state into the network, considering possibly unidirectional connectivity. Such a protocol, whose task is related to MPLS label distribution, is essential during the initial forming of WiBACK topologies and during regular network operations to reliably manage the data pipes. In this paper, we present a novel approach to extend our IEEE 802.21-inspired WiBACK TransportService and, based upon this, the design of an RSVP-TE-style pipe signalling protocol using nested hop-by-hop request/response MIH transactions that supports signalling over unidirectional technologies. A thorough evaluation and successful testbed deployments show that this protocol reliably signals pipe state even under high loss conditions

Network level performance of differentiated services (diffserv) networks

The Differentiated Services (DiffServ) architecture is a promising means of providing Quality of Service (QoS) in Internet. In DiffServ networks, three service classes, or Per-hop Behaviors (PHBs), have been defined: Expedited Forwarding (EF), Assured Forwarding (AF) and Best Effort (BE). In this dissertation, the performance of DiffServ networks at the network level, such as end-to-end QoS, network stability, and fairness of bandwidth allocation over the entire network have been extensively investigated. It has been shown in literature that the end-to-end delay of EF traffic can go to infinity even in an over-provisioned network. In this dissertation, a simple scalable aggregate scheduling scheme, called Youngest Serve First (YSF) algorithm is proposed. YSF is not only able to guarantee finite end-to-end delay, but also to keep a low scheduling complexity. With respect to the Best Effort traffic, Random Exponential Marking (REM), an existing AQM scheme is studied under a new continuous time model, and its local stable condition is presented. Next, a novel virtual queue and rate based AQM scheme (VQR) is proposed, and its local stability condition has been presented. Then, a new AQM framework, Edge-based AQM (EAQM) is proposed. EAQM is easier to implement, and it achieves similar or better performance than traditional AQM schemes. With respect to the Assured Forwarding, a network-assist packet marking (NPM) scheme has been proposed. It has been demonstrated that NPM can fairly distribute bandwidth among AF aggregates based on their Committed Information Rates (CIRs) in both single and multiple bottleneck link networks

Research challenges on energy-efficient networking design

The networking research community has started looking into key questions on energy efficiency of communication networks. The European Commission activated under the FP7 the TREND Network of Excellence with the goal of establishing the integration of the EU research community in green networking with a long perspective to consolidate the European leadership in the field. TREND integrates the activities of major European players in networking, including manufacturers, operators, research centers, to quantitatively assess the energy demand of current and future telecom infrastructures, and to design energy-efficient, scalable and sustainable future networks. This paper describes the main results of the TREND research community and concludes with a roadmap describing the next steps for standardization, regulation agencies and research in both academia and industry.The research leading to these results has received funding from the EU 7th Framework Programme (FP7/2007–2013) under Grant Agreement No. 257740 (NoE TREND)