2,948 research outputs found
Options for Securing RTP Sessions
The Real-time Transport Protocol (RTP) is used in a large number of
different application domains and environments. This heterogeneity
implies that different security mechanisms are needed to provide
services such as confidentiality, integrity, and source
authentication of RTP and RTP Control Protocol (RTCP) packets
suitable for the various environments. The range of solutions makes
it difficult for RTP-based application developers to pick the most
suitable mechanism. This document provides an overview of a number
of security solutions for RTP and gives guidance for developers on
how to choose the appropriate security mechanism
Frame Based Precoding in Satellite Communications: A Multicast Approach
In the present work, a multibeam satellite that employs aggressive frequency
reuse towards increasing the offered throughput is considered. Focusing on the
forward link, the goal is to employ multi-antenna signal processing techniques,
namely linear precoding, to manage the inter-beam interferences. In this
context, fundamental practical limitations, namely the rigid framing structure
of satellite communication standards and the on-board per-antenna power
constraints, are herein considered. Therefore, the concept of optimal frame
based precoding under per-antenna constraints, is discussed. This consists in
precoding the transmit signals without changing the underlying framing
structure of the communication standard. In the present work, the connection of
the frame based precoding problem with the generic signal processing problem of
conveying independent sets of common data to distinct groups of users is
established. This model is known as physical layer multicasting to multiple
co-channel groups. Building on recent results, the weighted fair per-antenna
power constrained multigroup multicast precoders are employed for frame based
precoding. The throughput performance of these solutions is compared to
multicast aware heuristic precoding methods over a realistic multibeam
satellite scenario. Consequently, the gains of the proposed approach are
quantified via extensive numerical results.Comment: Accepted for presentation at the IEEE ASMS 201
Issues in designing transport layer multicast facilities
Multicasting denotes a facility in a communications system for providing efficient delivery from a message's source to some well-defined set of locations using a single logical address. While modem network hardware supports multidestination delivery, first generation Transport Layer protocols (e.g., the DoD Transmission Control Protocol (TCP) (15) and ISO TP-4 (41)) did not anticipate the changes over the past decade in underlying network hardware, transmission speeds, and communication patterns that have enabled and driven the interest in reliable multicast. Much recent research has focused on integrating the underlying hardware multicast capability with the reliable services of Transport Layer protocols. Here, we explore the communication issues surrounding the design of such a reliable multicast mechanism. Approaches and solutions from the literature are discussed, and four experimental Transport Layer protocols that incorporate reliable multicast are examined
IETF standardization in the field of the Internet of Things (IoT): a survey
Smart embedded objects will become an important part of what is called the Internet of Things. However, the integration of embedded devices into the Internet introduces several challenges, since many of the existing Internet technologies and protocols were not designed for this class of devices. In the past few years, there have been many efforts to enable the extension of Internet technologies to constrained devices. Initially, this resulted in proprietary protocols and architectures. Later, the integration of constrained devices into the Internet was embraced by IETF, moving towards standardized IP-based protocols. In this paper, we will briefly review the history of integrating constrained devices into the Internet, followed by an extensive overview of IETF standardization work in the 6LoWPAN, ROLL and CoRE working groups. This is complemented with a broad overview of related research results that illustrate how this work can be extended or used to tackle other problems and with a discussion on open issues and challenges. As such the aim of this paper is twofold: apart from giving readers solid insights in IETF standardization work on the Internet of Things, it also aims to encourage readers to further explore the world of Internet-connected objects, pointing to future research opportunities
Maximum Production Of Transmission Messages Rate For Service Discovery Protocols
Minimizing the number of dropped User Datagram Protocol (UDP) messages in a network is regarded as a challenge by researchers. This issue represents serious problems for many protocols particularly those that depend on sending messages as part of their strategy, such us service discovery protocols. This paper proposes and evaluates an algorithm to predict the minimum period of time required between two or more consecutive messages and suggests the minimum queue sizes for the routers, to manage the traffic and minimise the number of dropped messages that has been caused by either congestion or queue overflow or both together. The algorithm has been applied to the Universal Plug and Play (UPnP) protocol using ns2 simulator. It was tested when the routers were connected in two configurations; as a centralized and de centralized. The message length and bandwidth of the links among the routers were taken in the consideration. The result shows Better improvement in number of dropped messages `among the routers
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