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Special section on Networked Electronic Media - The new internet experience (Editorial)
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LFA applicability in SP networks
Get PDFLFA Applicability: Pierre Francois was the editor of RFC 6571 [2], "LFA applicability in SP networks", co-edited with Clarence Filsfils, distinguished engineer at Cisco Systems. This RFC presents an analysis of the applicability of an IP Fast Reroute technique called "Loop-free alternates" in Internet Service Provider Networks. This work has been performed in collaboration with Cisco Systems, France Telecom - Orange, AT&T, and Deutsche Telekom.In this document, we analyze the applicability of the Loop-Free Alternates method of providing IP fast re-route in both the core and the access parts of Service Provider networks. We consider both the link and node failure cases, and provide guidance on the applicability of LFA to different network topologies, with special emphasis on the access parts of the network.Internet Engineering Task Force (IETF)pu
Impact of mobility models on clustering based routing protocols in mobile WSNs
Get PDFThis paper presents comparison of different hierarchical (position and non-position based) protocols with respect to different mobility models. Previous work mainly focuses on static networks or at most a single mobility model. Using only one mobility model may not predict the behavior of routing protocol accurately. Simulation results show that mobility has large impact on the behavior of WSN routing protocols. Also, position based routing protocols performs better in terms of packet delivery compared to non position based routing protocols.TRUEpu
On designing next generation MAC for cellular networks using the FLAVIA paradigm
Get PDFImplementing a flexible and modular architecture for scheduled systems will speed-up the deployment of novel and adjustable MACs for cellular systems. Such an architecture will be of great benefit for researchers, vendors and operators by enabling off-the-shelf devices to be used for testing modified MACs, by allowing fast upgrade of existing devices, and by drastically reducing the time-to-market of MAC products, which ultimately turns into enhanced services for the users. In this paper, we show how the architecture proposed in the FLAVIA project can enable the paradigm
shift towards open, modular and flexible scheduled MAC architectures, thus allowing cellular operators to use up-to-date research results to augment and promptly update
the capabilities of the cellular network by creating and instantiating MAC services.TRUEpu
High-performance hardware monitors to protect network processors from data plane attacks
Get PDFhttp://dx.doi.org/10.1145/2463209.2488832The Internet represents an essential communication infrastructure that needs to be protected from malicious attacks. Modern network routers are typically implemented using embedded multi-core network processors that are inherently vulnerable to attack. Hardware monitor subsystems, which can verify the behavior of a router's packet processing system at runtime, can be used to identify and respond to an ever-changing range of attacks. While hardware monitors have primarily been described in the context of general-purpose computing, our work focuses on two important aspects that are relevant to the embedded networking domain: We present the design and prototype implementation of a high-performance monitor that can track each processor instruction with low memory overhead. Additionally, our monitor is capable of defending against attacks on processors with a Harvard architecture, the dominant contemporary network processor organization. We demonstrate that our monitor architecture provides no network slowdown in the absence of an attack and provides the capability to drop attack packets without otherwise affecting regular network traffic when an attack occurs.TRUEpu
Lossless Migrations of Link-State IGPs
No full textNetwork-wide migrations of a running network, such as the replacement of a routing protocol or the modification of its configuration, can improve the performance, scalability, manageability, and security of the entire network. However, such migrations are an important source of concerns for network operators as the reconfiguration campaign can lead to long, service-disrupting outages. In this paper, we propose a methodology that addresses the problem of seamlessly modifying the configuration of link-state Interior Gateway Protocols (IGPs). We illustrate the benefits of our methodology by considering several migration scenarios, including the addition and the removal of routing hierarchy in a running IGP, and the replacement of one IGP with another. We prove that a strict operational ordering can guarantee that the migration will not create any service outage. Although finding a safe ordering is NP-complete, we describe techniques that efficiently find such an ordering and evaluate them using several real-world and inferred ISP topologies. Finally, we describe the implementation of a provisioning system that automatically performs the migration by pushing the configurations on the routers in the appropriate order while monitoring the entire migration process.TRUEpu
Quantize-and-Forward Schemes for the Orthogonal Multiple-Access Relay Channel
Get PDFThe multiple-access relay channel with two sources,
a single relay, and one destination is considered. Under the
assumption of noisy source–relay links causing the relay to be unable to decode without error, we propose a framework for designing one- and two-dimensional quantizers for quantizing the soft information at the relay. These quantizers are mutualinformation preserving. Simulation results show a) that mutualinformation preserving quantization schemes outperform techniques in which the soft information is forwarded in an analog fashion to the destination, b) that two-dimensional quantization outperforms one-dimensional quantization for source–relay links of different quality, and c) that diversity order of two can be gained in block Rayleigh fading channels by having the relay adaptively select a two-dimensional quantizer from a fixed set of quantizers shared with the destination, depending on the channel state on the source–relay linksTRUEpu
Energy Saving in Optical Operator Networks: the Challenges, the TREND Vision, and Some Results
Get PDFWe discuss how to save energy in IP-over-WDM networks, presenting the vision of TREND, the FP7 NoE, and the saving that can be obtained with adaptive routing solutions that put network interfaces of various granularities to sleep in periods of low traffic. Results refer to two operator networks, considering power and traffic forecasts for 2020.TRUEpu
A SOFT Way for OpenFlow Switch Interoperability Testing
Get PDFThe increasing adoption of Software Defined Networking, and OpenFlow in particular, brings great hope for increasing extensibility and lowering costs of deploying new network functionality. A key component in these networks is the OpenFlow agent, a piece of software that a switch runs to enable remote programmatic access to its forwarding tables. While testing high-level network functionality, the correct behavior and interoperability of any OpenFlow agent are taken for granted. However, existing tools for testing agents are not exhaustive nor systematic, and only check that the agent’s basic functionality works. In addition, the rapidly changing and sometimes vague OpenFlow specifications can result in multiple implementations that behave differently. This paper presents SOFT, an approach for testing the interoperability of OpenFlow switches. Our key insight is in automatically identifying the testing inputs that cause different OpenFlow agent implementations to behave inconsistently. To this end, we first symbolically execute each agent under test in isolation to derive which set of inputs causes which behavior. We then crosscheck all distinct behaviors across different agent implementations and evaluate whether a common input subset causes inconsistent behaviors. Our evaluation shows that our tool identified several inconsistencies between the publicly available Reference OpenFlow switch and Open vSwitch implementations.European Research CouncilTRUEpu
Opportunistic Information Dissemination in Mobile Ad-hoc Networks: The Profit of Global Synchrony
Get PDFThe topic of this paper is the study of Information Dissemination in Mobile Ad-hoc Networks by means of deterministic protocols. We characterize the connectivity resulting from the movement, from failures and from the fact that nodes may join the computation at different times with two values, α and β, so that, within α time slots, some node that has the information must be connected to some node without it for at least β time slots. The protocols studied are classified into three classes: oblivious (the transmission schedule of a node is only a
function of its ID), quasi-oblivious (the transmission schedule may also depend on a global time), and adaptive.
The main contribution of this work concerns negative results. Contrasting the lower and upper bounds derived, interesting complexity gaps among protocolclasses are observed. More precisely, in order to guarantee any progress towards solving the problem, it is shown that β must be at least n − 1 in general, but
that β ∈ Ω(n 2/ log n) if an oblivious protocol is used. Since quasi-oblivious protocols can guarantee progress with β ∈ O(n), this represents a significant gap,
almost linear in β, between oblivious and quasi-oblivious protocols. Regardingthe time to complete the dissemination, a lower bound of Ω(nα + n 3/ log n) is proved for oblivious protocols, which is tight up to a polylogarithmic factor
because a constructive O(nα + n 3 log n) upper bound exists for the same class. It is also proved that adaptive protocols require Ω(nα + n 2), which is optimal given that a matching upper bound can be proved for quasi-oblivious protocols. These results show that the gap in time complexity between oblivious and quasioblivious, and hence adaptive, protocols is almost linear. This gap is what we call the profit of global synchrony, since it represents the gain the network obtains from global synchrony with respect to not having it.TRUEpu