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On the Scalability of Carrier-grade Mesh Network Architectures
Get PDFISBN: 978-1-905824-23-6The increasing popularity of multi-hop wireless mesh networks, augmented with specific mechanisms required to support carrier-grade services, makes them an attractive alternative to classical backhaul solutions for network operators. However, current mesh deployments are typically small-sized, and, under real-time service requirements, it is yet unclear if they could scale to realistic network sizes. In this paper we present a carrier-grade mesh network architecture and conduct a thorough study of its scalability. In particular, we identify the main bottleneck problems and evaluate by means of simulations and practical experiments the costs induced by the modules that provide self-configuration, resource handling, routing and mobility
support capabilities. The obtained results confirm that the control overhead of the proposed modules is low enough to permit mesh deployments spanning a network size of 100 nodes. Furthermore, our architecture and all proposed modules support dividing the whole network into sub-domains, which allows operating even larger networks.TRUEpu
A Simple Analytical Model for Energy Efficient Ethernet
Get PDFThe recently approved Energy Efficient Ethernet standard IEEE 802.3az achieves energy savings by using a low power mode when the link is idle. However, those savings heavily depend on the traffic patterns, due to the overhead inherent in transitions between active and low power modes. This makes it impractical to estimate energy savings through measurements or simulations in all relevant scenarios. In this letter we present an analytical model to estimate the energy consumption of an Energy Efficient Ethernet link, based on simple traffic parameters. The model is validated through simulation and experimental data.TRUEpu
Impact of Prefix Hijacking on Payments of Providers
Get PDFWhereas prefix hijacking is usually examined from
security perspectives, this paper looks at it from a novel economic
angle. Our study stems from an observation that a transit AS
(Autonomous System) has a financial interest in attracting extra
traffic to the links with its customers. Based on real data about the
actual hijacking incident in the Internet, we conduct simulations
in the real AS-level Internet topology with synthetic demands for
the hijacked traffic. Then, we measure traffic on all inter-AS links
and compute the payments of all providers. The analysis of our
results from technical, business, and legal viewpoints suggests
that hijacking-based traffic attraction is a viable strategy that
can create a fertile ground for tussles between providers. In
particular, giant top-tier providers appear to have the strongest
financial incentives to hijack popular prefixes and then deliver
the intercepted traffic to the proper destinations. We also discuss
directions for future research in the area of hijacking-based
traffic attraction.TRUEpu
IEEE 802.21: A shift in the Media Independence
Get PDFISSN 978-1-4577-0928-9In this paper we present our vision on future uses of the Media Independence paradigm developed within the IEEE 802.21. We argue that this specification is an excellent starting point for future applications that require the handling of heterogeneous technologies. The current IEEE 802.21 standard facilitates media independent handovers by providing higher layer mobility management functions with common service primitives for all technologies, thus hiding the technology specifics of the lower layers. In this paper we claim that such a media independent abstraction can be useful for functions other than handovers and advocate for extending the IEEE 802.21 standard to cover these additional functions. We concentrate on a particular scenario currently being discussed in the 802.21 WG, the Spectrum Optimization & White Spaces. We first identify the key challenges that need to be addressed in order to satisfy the requirements of these scenarios by means of a media independence abstraction. Then, based on the requirements identified, we outline a proposal for a media independent service layer architecture.TRUEpu
CIPT: Using Tuangou to Reduce IP Transit Costs
Get PDFISBN: 978-1-4503-1041-3A majority of ISPs (Internet Service Providers) support connectivity to the entire Internet by transiting their traffic via other providers. Although the transit prices per Mbps decline steadily, the overall transit costs of these ISPs remain high or even increase, due to the traffic growth. The discontent of the ISPs with the high transit costs has yielded notable innovations such as peering, content distribution networks, multicast, and peer-to-peer localization. While the above solutions tackle the problem by reducing the transit traffic, this paper explores a novel approach that reduces the transit costs without altering the traffic. In the proposed CIPT (Cooperative IP Transit), multiple ISPs cooperate to jointly purchase IP (Internet Protocol) transit in bulk. The aggregate transit costs decrease due to the economies-of-scale effect of typical subadditive pricing as well as burstable billing: not all ISPs transit their peak traffic during the same period. To distribute the aggregate savings among the CIPT partners, we propose Shapley-value sharing of the CIPT transit costs. Using public data about IP traffic of 264 ISPs and transit prices, we quantitatively evaluate CIPT and show that significant savings can be achieved, both in relative and absolute terms. We also discuss the organizational embodiment, relationship with transit providers, traffic confidentiality, and other aspects of CIPT.TRUEpu
Probabilistic Bounds on the Length of a Longest Edge in Delaunay Graphs of Random Points in d-Dimensions
Get PDFMotivated by low energy consumption in geographic routing in wireless networks, there has been recent interest in determining bounds on the length of edges in the Delaunay graph of randomly distributed points. Asymptotic results are known for random networks in planar domains. In this paper, we obtain upper and lower bounds that hold with parametric probability in any dimension, for points distributed uniformly at random in domains with and without boundary. The results obtained are asymptotically tight for all relevant values of such probability and constant number of dimensions, and show that the overhead produced by
boundary nodes in the plane holds also for higher dimensions. To our knowledge, this is the first comprehensive study on the lengths of long edges in Delaunay
graphs.TRUEpu
Optimized IPv6 Internet access from vehicles in multi-hop and heterogeneous environments
Get PDFIn order to provide efficient Internet connectivity
from vehicles, three fundamental functionalities are needed:
IP address autoconfiguration, enhanced routing and mobility
support. This extended abstract provides a brief view of the
work done so far in this research work, that aims at providing a solution for these three open issues. An analytical model for an address autoconfiguration mechanism and a routing protocol have been already proposed, with accepted contributions. A third line analyzing mobility aspects is currently being developed. Another accepted contribution is a statistical framework for studying the interarrival time between vehicles, that has been elaborated using real traffic measurements.TRUEpu
Resilient data gathering and communication algorithms for emergency scenarios
Get PDFFrom the issue entitled "Wireless and Mobile Networking"A typical application field of Wireless Sensor Networks (WSNs) is the collection of environmental data, which is sent to a base station. Routing protocols are needed to efficiently direct the information flows to the base station. Since sensor nodes have strict energy constraints, data gathering and communication schemes for WSNs need to be designed for an efficient utilization of the available resources. An emergency management scenario is investigated, where a sensor network is deployed as virtual lifeline for fire fighters entering a building. Besides of supporting their navigation, the virtual lifeline is also used for two further purposes. First it enables the exchange of short voice messages between fire fighter and command post. For this, a fast and reliable routing protocol (EMRO) has been developed based on a broadcasting scheme. Second,measuring data, like temperature and gas, in the environment and informing fire fighters and command post about it, is of high importance. For this purpose a network coding based data gathering algorithm has been designed. The feasibility of simultaneously using the virtual lifeline for data gathering and communication and thus the coexistence of a classical routing protocol with a network coding scheme is studied in this paper by means of simulation and real experiments. The resilience to packet loss and node failure, as well as the transmission delay are investigated
by means of short voice messages for the communication
part and temperature readings for data gathering.TRUEpu
Bisection Bandwidth of Product Networks with Application to Data Centers
Get PDFThe bisection width of interconnection networks has always been important in parallel computing, since it bounds the amount of information that can be moved from one side of a network to another, i.e., the bisection bandwidthFinding the exact value of the bisection width has proven to be challenging for some network families. For instance, the problem of finding the exact bisection width of the multidimensional torus was posed by Leighton [1, Problem 1:281] and has remained open for almost 20 years. In this paper we provide the exact value of the bisection width of the torus, as well as of several d-dimensional classical parallel topologies that can be obtained by the application of the Cartesian product of graphs. To do so, we first provide two general results that allow to obtain upper and lower bounds on the bisection width of a product graph as a function of some properties of its factor graphs. We also apply these results to obtain bounds for the bisection bandwidth of a d-dimensional BCube network, a recently proposed topology for data centers.Telematics EngineeringUniversidad Carlos III de Madrid, Spainpu