Performance analysis of general backoff protocols

In this paper, we analyze backoff protocols, such as the one used in Ethernet. We examine a general backoff function (GBF) rather than just the binary exponential backoff (BEB) used by Ethernet. Under some mild assumptions we find stability and optimality conditions for a wide class of backoff protocols with GBF. In particular, it is proved that the maximal throughput rate over the class of backoff protocols is a fixed function of the number of stations (N) and the optimal average service time is about Ne for large N. The reasons of the instability of the BEB protocol (for a big enough input rate) are explained. Additionally, the paper introduces novel procedure for analyzing bounded backoff protocols, which is useful for creating new protocols or improving existing, as no protocol can use unbounded counters

How Penalty Leads to Improvement: a Measurement Study of Wireless Backoff

Despite much theoretical work, different modifications of backoff protocols in 802.11 networkslack empirical evidence demonstrating their real-life performance. To fill the gap we have set out to experiment with performance of exponential backoff by varying its backoff factor. Despite the satisfactory results for throughput, we have witnessed poor fairness manifesting in severe capture effect. The design of standard backoff protocol allows already successful nodes to remain successful, giving little chance to those nodes that failed to capture the channel in the beginning. With this at hand, we ask a conceptual question: Can one improve the performance of wireless backoff by introducing a mechanism of self-penalty, when overly successful nodes are penalized with big contention windows? Our real-life measurements using commodity hardware demonstrate that in many settings such mechanism not only allows to achieve better throughput, but also assures nearly perfect fairness. We further corroborate these results with simulations and an analytical model. Finally, we present a backoff factor selection protocol which can beimplemented in access points to enable deployment of the penalty backoff protocol to consumer devices.Non Peer reviewe

06441 Abstracts Collection -- Naming and Addressing for Next Generation Internetworks

From 29.10.06 to 01.11.06, the Dagstuhl Seminar 06441``Naming and Addressing for Next-Generation Internetworks\u27\u27 was held in the International Conference and Research Center (IBFI), Schloss Dagstuhl. During the seminar, several participants presented their current research, and ongoing work and open problems were discussed. Abstracts of the presentations given during the seminar as well as abstracts of seminar results and ideas are put together in this paper. The first section describes the seminar topics and goals in general. Links to extended abstracts or full papers are provided, if available

PAuthKey: A Pervasive Authentication Protocol and Key Establishment Scheme for Wireless Sensor Networks in Distributed IoT Applications

Wireless sensor Networks (WSNs) deployed in distributed Internet of Things (IoT) applications should be integrated into the Internet. According to the distributed architecture, sensor nodes measure data, process, exchange information, and perform collaboratively with other sensor nodes and end-users, which can be internal or external to the network. In order to maintain the trustworthy connectivity and the accessibility of distributed IoT, it is important to establish secure links for end-to-end communication with a strong pervasive authentication mechanism. However, due to the resource constraints and heterogeneous characteristics of the devices, traditional authentication and key management schemes are not effective for such applications. This paper proposes a pervasive lightweight authentication and keying mechanism for WSNs in distributed IoT applications, in which the sensor nodes can establish secured links with peer sensor nodes and end-users. The established authentication scheme PAuthKey is based on implicit certificates and it provides application level end-to-end security. A comprehensive description for the scenario based behavior of the protocol is presented. With the performance evaluation and the security analysis, it is justified that the proposed scheme is viable to deploy in the resource constrained WSNs

On the Disaster Resiliency within the Context of 5G Networks:The RECODIS Experience

Network communications and the Internet pervade our daily activities so deeply that we strongly depend on the availability and quality of the services they provide. For this reason, natural and technological disasters, by affecting network and service availability, have a potentially huge impact on our daily lives. Ensuring adequate levels of resiliency is hence a key issue that future network paradigms, such as 5G, need to address. This paper provides an overview of the main avenues of research on this topic within the context of the RECODIS COST Action