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Summary: Over the next decade, most devices connected to the Internet will not be used by people in the familiar way that personal computers, tablets and smart phones are. Billions of interconnected devices will be monitoring the environment, transportation systems, factories, farms, forests, utilities, soil and weather conditions, oceans and resources. Many of these sensors and actuators will be networked into autonomous sets, with much of the information being exchanged machine-to-machine directly and without human involvement. Machine-to-machine communications are typically terse. Most sensors and actuators will report or act upon small pieces of information - 'chirps'. Burdening these devices with current network protocol stacks is inefficient, unnecessary and unduly increases their cost of ownership. This must change. The architecture of theInternet of Things must evolve now byincorporating simpler protocols toward at the edges of thenetwork, or remain forever inefficient. Rethinking the Internet of Things describes reasons why we must rethink current approaches to the Internet of Things. Appropriate architectures that will coexist with existing networking protocols are described in detail. An architecture comprised of integrator functions, propagator nodes, and end devices, along with their interactions, is explored.

It is necessary to introduce WSN (Wireless Sensor Network) into IB (Intelligent Building), so as to promote the intelligent monitoring and control level of building environment. As one of ISO standards, BACnet(a data communication protocol for Building Automation and Control NETworks) is a leading protocol of automation control networks in IB. BACnet defines a device type named B-SS (BACnet Smart Sensor) for WSN, but there is no implementation program on B-SS and no scheme of B-SS connected with IPv6 till now. In order to achieve a kind of WSN based on B-SS which can interconnect with IPv6, this paper analyzed the 6LoWPAN (IPv6-based Low-power Wireless Personal Area Networks) protocol put forward by 6LoWPAN WG in IETF and designed an integrated model which integrates BACnet and 6LoWPAN in TinyOS2.0. The integrated model was tested in TOSSIM and the result shows that the integration technology is reasonable and feasible. [ABSTRACT FROM AUTHOR]

Wireless communications using microwaves are increasingly important, e.g. Wi-Fi. Performance is a very relevant issue, resulting in more reliable and efficient communications. Laboratory measurements are made about several performance aspects of Wi-Fi (IEEE 802.11a, b, g) point-to-point links using available access points from Enterasys Networks (RBT-4102). Through OSI levels 3, 4 and 7, detailed results are presented and discussed, namely: latency, ICMP packet loss, TCP throughput, jitter, percentage datagram loss and FTP transfer rate. [ABSTRACT FROM AUTHOR]

an increase number of wireless applications consist of a network of mobile nodes moving together in high velocity, existing protocols focused on roaming of single node, and there are no mature solutions to keeping uninterrupted high-speed mobile communications for roaming the entire subnet with a moving velocity as high as a vehicle. In this paper, firstly we propose the idea of the new handover scheme based on mobile IP, and then introduce the principle and key issues for subnet mobility in networks. The station (STA), a wireless communications equipments in mobile wireless subnet, taking the access point (AP) as the gateway, implements the multiple-hop subnet mobile IP by cooperation of the home agent, the foreign agent, interior network routing agent and reused tunneling, thus to overcome the limitation of one hop between the movement node (MN) to the exit of the tunnel. A dynamic next AP scanning and finding model and a handover trigger model named Well-time is designed to provide low latency. We implement the scheme on re-designed STA and AP, the experiment shows that the new scheme enables a mobile subnet to handover seamlessly across heterogeneous wireless networks and maintains all ongoing high-speed communications with the nodes in fixed networks, when moving at a high velocity up to 50km/h. [ABSTRACT FROM AUTHOR]

Nowadays, high computing demands are often tackled by clusters of computers, each of which is basically an assembly of a growing number of CPU cores and main memory; these nodes are connected by some kind of communication network. With the growing speed and number of CPU cores, the network becomes a severe bottleneck limiting overall cluster performance. High-speed interconnects like SCI and Dolphin DX are good for alleviating this communication bottleneck, when the communication software is either based on IP or specifically adapted to the interconnect. Software written to communicate directly via Ethernet frames can not be used this way, though. In this article, we present ETHOM, a driver that implements an Ethernet interface on top of the Dolphin Express software stack. It enables the Dolphin networks SCI and DX to be used as high-speed replacement for Ethernet. Offering an Ethernet and with that an IP interface, it enhances their functionality and allows usage of layer-2 kernel functionality like interface bonding and bridging. This driver is an improvement of ETHOS, the Ethernet over Sockets driver, delivering lower latencies at the cost of higher CPU load. By means of various measurements, we show that ETHOM with SCI or DX offers a two-fold increase in communication performance over Gigabit Ethernet. [ABSTRACT FROM AUTHOR]

This working prototype system can detect handwritten digits from a scanned image of an input form by using Neural network technique. Hand writing recognition and Image detection through this methodology is very fast and effective as compared to old fashioned image pixel comparison methodology, which is comparably slow. In the initial phase for handwritten digit input we have designed a form which can take hand writing samples from different people. The form must have specific format so user can give multiple input in 10 rows, and hand write 0,1,2,3,4,5,6,7,8,9 in the corresponding sampling cells ( rows* columns). The cell must also have width according to your requirement (e.g set it to 20*2 pixels). Once the blank forms have been manually filled by different people then scan these forms with the help of scanner. So now we have images of hand writing samples of digits. In the 2nd phase, we use image slicing technique to slice sample image of size 16*16 pixel for each digit from the scanned form [1]. Each scanned form image will make nearly 100 images of 16*16 pixels. Repeat the same step for all scanned sample forms and place all these 16*16 pixel images ( sample pool) into one location. In the detection phase, a three-layered neural network is used: After training, the obtained weight and bias are stored for each digit sequence(signature). It is now possible to identify the meaning of any hand written digit with the help of AI engine. So now when ever any handwritten digit will be given as sample input in to the system , the output array will automatically give the digit whose corresponding match value is detected. The above process is a blueprint of human cognitive thinking process. [ABSTRACT FROM AUTHOR]

This paper examines the bit-error rate (BER) for an optical direct-detection code-division multiple-access (OCDMA) system employing a novel prime code family, hereby referred to as 'Double-Padded Modified Prime Code (DPMPC)' for the spreading and de-spreading operations in addition to coherent homodyne dual-balanced detection. As a coherent modulation, binary phase-shift keying (BPSK) format is deployed where the phase is modulated by either an external phase-modulator or injection-locking methods. The phase limitation and the performance for both phase-modulations including multiple access interferences (MAI) in a shot-noise limited regime are studied and moderate penalty associated with the limited phase excursion is revealed. [ABSTRACT FROM AUTHOR]

Several conferences have been regularly organized worldwide each year. The organizing process consists of many major steps including call for papers, paper submission, article reviews, author notification and participant registration. The networking computer system could facilitate managing the activities that involve plenty of remote stakeholders. This paper therefore presents an approach to implementing a conference management system using web service technology fused with the concept of business process modeling to support the workflows of conference management tasks. In this work, the REST protocol is selected for invoking the defined conference managing services, whereas Windows Workflow Foundation is exploited for binding all activities into the process flow. The approach enhances the stateless process to the stateful process. Moreover, the process flow is easily reorganized or customized for the subsequent conferences. The component activities, implemented as a service, within the process flow can be reused as well. The fact that services exchange data through XML standard, the implemented system is platform and language independent. [ABSTRACT FROM AUTHOR]

Today, the network bandwidth increased and hardware devices have continuously to enhanced, resulting the vigorous development of the internet. Nowadays, cloud computing is using the lowpower hosts to achieve high reliability that will be to ensure the ability to be better. However, the high capability most with high fault-tolerant by distributed systems, consensus problems will have an impact on the system node to complete the task of it. In previous works, consensus as a variety of connected networks is discussed with fallible components and is proposed a protocol to solve the consensus problem. In this paper, the consensus problem in topology of cloud computing is revisited. The proposed protocol, Dual Consensus Protocol for Cloud Computing (DCPCC), is supported to solve the consensus with malicious and dormant fault with transmission media. The DCPCC protocol can reach consensus with minimal rounds of message exchange and tolerate the maximal number of allowable components. [ABSTRACT FROM AUTHOR]

Swamp poisoning in BitTorrent corrupts files sharing between peers. The worst case causes the swamp unusable as the protocol does not provide sufficient data integrity checking. This paper proposes two solutions in order to resolve this attack. [ABSTRACT FROM AUTHOR]

Current advances in wireless communication, microelectronics, semiconductor technologies, and intelligent sensors have contributed to the development of unobtrusive WBANs. These networks provide long term health monitoring of patients without any constraint in their normal activities. Traditional MAC protocols do not accommodate the assorted WBAN traffic requirements in a power efficient manner. In this paper, we present a brief discussion on the development process of a low power MAC protocol for WBANs. We observe the behavior of a beacon-enabled IEEE 802.15.4 for on-body sensor networks. We further propose a low power technique called traffic based wakeup mechanism for a WBAN that exploits the traffic patterns of the BAN Nodes to ensure power efficient and reliable communication. [ABSTRACT FROM AUTHOR]

An intelligent transportation system (ITS) incorporates a variety of equipment and devices that all work in mutual harmony. However, each piece of equipment or device has its data format and protocol. Therefore, they cannot directly exchange data with each other. In this research, a unified framework for data exchange in an ITS is proposed. The proposed mechanism serves to receive data from several equipments outside of cars, repackages the received data and then dispatches the data to devices inside the cars. Based on this framework, data in equipment and devices can be interchanged (with each other) to accomplish data sharing in an ITS. [ABSTRACT FROM AUTHOR]

Chapter 6 of the book "GPS Handbook for Professional GPS Users" by Huibert-Jan Lekkerkerk is presented. It discusses a specific aspect of global positioning system (GPS) which is the nature of a navigation satellite. It details the elements of transmitted messages which consists a code used for the actual positioning and the navigation messages itself. It emphasizes the use of the protocol, NMEA 0183 for real transmission and the Receiver Independent Exchange (RINEX) for post-processing.

The Reference Model for Open Distributed Processing (RM-ODP) defines a framework within which support of distribution, interoperability and portability can be integrated. An ODP system is defined in terms of five viewpoints. The ODP engineering specification consists of a set of engineering objects which communicate via a channel object. The engineering viewpoint defines the ODP transparencies and ODP functions. We focus in this paper on the language of the channel engineering object. We associate to each component state of a global state a set of words that may be contained in channels. We define, for each object, a grammar 'like' context free in which, each rule is of the form X→ u-1Yv, where u-1Yv stand for the residual of the language (L(Y)v) with regard to u. We use context-free grammar properties to make transformations and appear a symbol X in the right member of each X-production to express loop and cycle transitions in the CFSM. The algebraic property of context-free languages is then used to calculate these languages which are minimal solution of a system of equations. These languages can be used to verify some protocol properties such as reachability and deadlock problems. [ABSTRACT FROM AUTHOR]

Wireless Sensor Network is Multihop Self-configuring Wireless Network consisting of sensor nodes. The patterns of movement of nodes can be classified into different mobility models and each is characterized by their own distinctive features. The significance of this study is that there has been very limited investigations of the effect of mobility models on routing protocol performance such as Packet Delivery Ratio, Throughput and Latency in Wireless Sensor Network. In this paper, we have considered the influence of pursue group and random based entity mobility models on the performance of Ad Hoc On-Demand Distance Vector Routing Protocol (AODV) routing protocol. The simulation results show that Pursue Group Mobility model is better than Random Based Entity model. [ABSTRACT FROM AUTHOR]

An ad hoc network is a collection of wireless mobile nodes, frequently forming a network topology without the use of any existing network infrastructure or centralized administration. we compare the performance of the three prominent routing protocols for mobile ad hoc networks, Ad hoc On Demand Distance Vector (AODV), Destination Sequenced Distance Vector(DSDV) and Temporally Ordered Routing Protocols (TORA). We have chosen four performance metrics, such as Average Delay, Packet Delivery Fraction, Routing Load and Varying MANET Size, simulation for the popular routing protocols AODV, DSDV and TORA. The simulations are carried out on NS-2. The performance differentials are analyzed using varying network size and simulation times. The simulation results confirm that AODV performs well in terms of Average Delay, Packet Delivery Fraction. As far as Routing Load concerns TORA performs well. [ABSTRACT FROM AUTHOR]

Due to the increasing multicast applications and high desire for its deployment, it seems that any new technology should support multicast. However, Mpls (Multiprotocol Label Switching) technology which enhances IP packet forwarding capability by using layer 2 switching still does not offer any special solution for multicast support. In this paper, we propose a new mechanism for multicast over Mpls. We separate labels for unicast and multicast traffic. Our method use one label for each multicast tree. Therefore, consumes fewer labels compared to existing proposals and has smaller forwarding tables. [ABSTRACT FROM AUTHOR]

The purpose of this paper is to present a coalition Multi-Agent based model for Real-Time Distribution System (RTDS). This model is based on Contract-Net Protocol (CNP), and an Agent Communication Model is also provided. A two-stage approach is introduced to solve the real time problems: the initial solutions will be generated in stage 1, and its objective is to design least cost routes from one depot to a set of customers, and to service all the customers, while respecting capacity and time window constraints. In stage 2, the Vehicle Agents would decide whether to service new order through negotiation with Scheduling Agent. Finally, the proposed model is detailed, illustrated through a numerical example, experimented on the base of Solomon's benchmark and compared to the optimal solution. [ABSTRACT FROM AUTHOR]

Information on network protocols from a chapter of the book "Network Protocols Handbook," Fourth Edition is presented. The Bandwidth Allocation Protocol (BAP) defines datagrams to coordinate adding and removing individual links in a multi-link bundle. Developed by Cisco Systems, the Director Response Protocol (DRP) refers to a simple User Datagram Protocol (UDP)-based application. Gateway-to-Gateway Protocol (GGP) specifies how core routers should exchange reachability and routing information.

This paper mainly studies the data communication protocols of control area network (CAN) for the vehicle information systems. The objective is to create the environment of the line replaceable unit (LRU) in these systems. The data transmitted from CANBus are one of the valuable resources. There are 8 bytes of them in each transmission. If they are appropriately planned, the data communication protocol can improve the efficiency of the communication, e.g., arbitrations, masks, filters of nodes for CAN can be assigned arbitrarily on line. Even the software of CAN unit can be upgraded and downloaded on line, too. Upon the above concept, this paper will propose a feasible configuration of the vehicle information systems as well as a kind of possible data communication protocols. [ABSTRACT FROM AUTHOR]

This paper proposes the Channel Hopping with Negotiated Pattern (CHNP) protocol, a MAC protocol specially designed for industrial Wireless Sensor Networks (WSN) applications. CHNP tries to achieve the reliable communication under the harsh industrial radio environment in an energy and bandwidth efficient way by fully take advantage of the multi-channel capability of radio chips. To the best of our knowledge, CHNP is the first multi-channel MAC protocol specially designed for industrial WSN applications, which pays special attention to the reliability performance, and makes comprehensive optimization on energy, delay, and throughput performance at the same time. The following contributions are made in CHNP: first, a novel MAC framework based on synchronized channel hopping mechanism is proposed, which provides a good platform to perform the comprehensive performance optimization; second, an effective interference domain division mechanism is designed to achieve higher performance; third, an adaptive transmission mechanism is designed, which can sidestep the bad channels and realize reliable communication even under harsh RF environment ; last, a sniffing mechanism is provided to achieve low energy operation. Simulation results show that the performance of CHNP achieves a significant improvement over the previous related work in the context of industrial WSN applications. [ABSTRACT FROM AUTHOR]

In recent year, Peer-to-Peer (P2P) approach for media streaming has been studied extensively. In comparison to on-demand media streaming, P2P live media streaming faces a much stringent time constraint. In order to improve the performance metrics, such as startup delay, source-to-end delay, and playback continuity, we present PALMS, a P2P approach for live media streaming where node employs gossip based pull and push protocols to receive and forward media data among connected nodes. We present a simple heuristic mechanism for the pull protocol in the selection of media segments and peers. Besides the pull method, a push method is deployed to increase the streaming quality. We also adopt a randomized push protocol in order to increase the probability of media data delivered to connected nodes. We know that the presence of free-riders could degrade the delivered streaming quality. In PALMS, a simple tit-for-tat incentive mechanism is adopted to discourage the existence of free-riders. We conducted simulations and performance comparisons for PALMS. Experimental results demonstrate that PALMS can deliver better streaming quality and more resilience towards the heterogeneity of network bandwidths as compared to some of the existing protocols. [ABSTRACT FROM AUTHOR]

In MAS, agent interaction protocol has become the basis of coordination, cooperation and communication among agents. Since the semantics of agent interaction protocol in UML or AUML faces ambiguous and inconsistent problems, the paper presents an Extended Colored Petri Net(ECPN) as agent protocol modeling mechanism. By means of ECPN techniques presented in the paper, we can model agent interaction mechanism, validate the model's properties, and implement feasible transition to executable processes. The relevant techniques are demonstrated by a FIPA Protocol example in details. [ABSTRACT FROM AUTHOR]

Peer-to-Peer (P2P) systems and Grids share the same focus on harnessing resources across large-scale multi-administrative domains though having many different characteristics. The way of using P2P approaches to realize decentralized P2P Grid system extends the resource scalar exponentially. This paper presents a layered resource space model that has a good feature in expansibility, autonomy, modularity and loose coupling. In terms of this model a Bootstrap based on Distributed Hashing Table (DHT) is added into P2P Grid and a Peer Service is implemented in every node. The semantic-based resource management architecture and RPC protocols are discussed. A prototype experiment is realized with BT tracker functionality. This model could be used in P2P Grid systems and heterogeneous P2P systems as a reference for resource sharing and collaboration. The contribution of this paper is to provide a semantic-based solution to resource discovery, search and integration that will enable the SOA revolution in P2P Grid. [ABSTRACT FROM AUTHOR]

In recent years, there has been a growing interest in wireless sensor networks. One of the major issues in wireless sensor network is developing an energy-efficient routing protocol. Since the sensor nodes have limited available power, energy conservation is a critical issue in wireless sensor network for nodes and network life [1]. LEACH is very effective in enhancing nodes' lifetime from routing's aspect. In this paper we propose a novel routing algorithm, pseudo LEACH, which copes with limited transmission range of each node and brings in a pseudo cluster header to improve the energy efficiency of LEACH. The simulation results are shown at the end to verify the performance of our pseudo LEACH. [ABSTRACT FROM AUTHOR]

Internet Protocol Next Generation Label Switching (IPngLS) is seen as another interesting approach satisfying the ever-increasing Internet users' multimedia demands as well as the future IPv6 addressing. With the concept of mapping the MPLS shim header into the IPv6 header, IPngLS provides the decrease of packet overhead which results in the better network performance. We have modified MPLS network simulator (MNS) extended from network simulator (ns) for IPngLS network simulator. The validation of our simulator is carried out by comparing with result from the approximate calculation with the timing diagram. After that, the performance study of IPngLS in comparison with MPLS is done by simulation. We evaluate the performance of multiple traffic sources based on throughput, bandwidth utilization, dropped packet and mean end-to-end delay. Our simulation results show that IPngLS provides better performance 1.695 %, based on throughput and bandwidth utilization, than MPLS at the very high traffic load, while the average of dropped packet and mean end-to-end of IPngLS is lower than MPLS 2.049 % and 1.491 %, respectively. [ABSTRACT FROM AUTHOR]

An ad hoc network is a collection of wireless mobile nodes dynamically forming a temporary network without the use of any existing network infrastructure or centralized administration. Due to the limited transmission range of wireless network interfaces, multiple networks "hops" may be needed for one node to exchange data with another across the network. In recent years, a variety of new multicasting routing protocols targeted specifically at this environment have been developed, but little performance information on each protocol and no realistic performance comparison in different network scenarios are available .The multicast operation of the Ad hoc On-Demand Distance Vector (AODV) routing protocol (MAODV) is intended for use by mobile nodes in an ad hoc network. The protocol behavior is unpredictable and changes drastically with respect to change in the network scenarios. In this detailed packet-level simulation study is carried out using network simulator 2 and show when the network is stabilized under varying mobility and traffic scenarios. Our simulation results shows that change in network scenario will impact the performance of routing protocols in ad hoc networks. [ABSTRACT FROM AUTHOR]

Devices in mobile ad hoc networks depend on the cooperation of other nodes for relaying of packets in the network. Medium Access Control protocols such as IEEE 802.11 are efficient with upper layer protocols only if the nodes adhere to the protocol and cooperate. Non-cooperating nodes may delay forwarding of frames or drop the frames altogether. This might be advantageous for individual nodes (from the point of view of saving energy) but it hampers the network as a whole. Such non-cooperating nodes disrupt communication between the cooperating nodes. We present a solution with a part modification of the IEEE 802.11 protocol to detect and penalize such non-cooperating nodes and thus making it unattractive to deny cooperation. For this we associate each node with an index, the Fairness Index, which is dynamically mapped to the behavior of the associated node. We not only penalize them but also ensure reliable routing throughout. In our scheme we also allow a convicted node to return to the mainstream if it shows its eagerness to cooperate. We prove the same using simulation results. [ABSTRACT FROM AUTHOR]

The aim of this paper is twofold. On the one hand, it aims to shed light on the influence of electronic technology and media (World Wide Web and hypertext) on a particular genre, through the analysis of a small corpus of 80 book reviews taken from online sources. Attention is focused on the use made by an established genre of hypertext technology and its implications for the evolution and diversification of this particular type of discourse activity. On the other hand, this analysis draws attention to the problems involved in regarding the book review as a recognisable genre rather than a group of writing practices that might be regarded as genres in their own right. The use of hypertext technology highlights divergences already existing in these practices and propels them into new life. A particularly revealing aspect in this regard is the system of links used by the online reviews in the corpus, which are discussed in relation to two central parameters of genre -- audience and communicative purpose -- and are found to play a similarly significant rhetorical goal in hyperdiscourse interaction. [ABSTRACT FROM AUTHOR]

This work describes ongoing multidisciplinary research which aims to analyse and to apply connectionist architectures to the interesting field of computer security. In this paper, we present a novel approach for Intrusion Detection Systems (IDS) based on an unsupervised connectionist model used as a method for classifying data. It is used in this special case, as a method to analyse the traffic which travels along the analysed network, detecting anomalous traffic patterns related to SNMP (Simple Network Management Protocol). Once the data has been collected and pre-processed, we use a novel connectionist topology preserving model to analyse the traffic data. It is an extension of the negative feedback network characterised by the use of lateral connections on the output layer. These lateral connections have been derived from the Rectified Gaussian distribution. [ABSTRACT FROM AUTHOR]

The article focuses on features of transmission control protocol (TCP) as a reliable transport protocol. TCP provides a reliable, connection-oriented, byte stream service between applications. TCP provides reliability and ensures end-to-end delivery of data by adding services on top of IP. TCP treats the actual data it sends as an unstructured stream of bytes. TCP keeps track of each byte that is sent/received. TCP enables many application processes within a single device to use the TCP services simultaneously, this is termed TCP multiplexing.

The article describes the design challenges and technical hurdles facing successful deployment of wireless Internet Protocol (IP) telephony. New wireless network architecture will take advantage of the service and management flexibility offered by IP, allowing service providers to offer multimedia and data content to their wireless subscribers. The greatest challenges facing the successful deployment of wireless IP telephony are threefold: securing reliable guarantees of service quality on par with traditional cellular systems, obtaining spectral efficiencies over the wireless channel that will not hinder system capacity or service quality, and effectively providing seamless connections to mobile users.

The article focuses on the combination of wireless communications and asynchronous transfer mode (ATM), referred to as wireless ATM, which aims at providing freedom of mobility with service advantages and quality-of-service guarantees. Wireless ATM is mainly considered for wireless access to a fixed ATM network, in this sense, it is applicable mostly to wireless LANs. The article describes the basic issues and solutions for the medium access control. It also discusses some important protocols and their effectiveness in servicing ATM traffic. The article analyzes the required signaling enhancements for call and mobility control.

The article focuses on transport protocols for optical networks. The term "transport protocol," as used in the article and in the context of computer communication systems, refers to an end-to-end protocol. The article presents features of optical networks that are particularly salient to transport protocols. It provides an overview of the generic functions that transport protocols are expected to provide, and discusses how these functions are affected by the use of optical networks. The article describes specific transport protocols that have been used with optical networks.

The article provides an overview of digital transport formats, synchronous optical network (SONET) and synchronous digital hierarchy (SDH). SONET and SDH are similar digital transport formats that were developed for the specific purpose of providing a reliable and versatile digital structure to take advantage of the higher bit rate capacity of optical fiber. SONET is based on a synchronous digital signal comprised of 8-bit octets, which are organized into a frame SDH bit rates are built on the basic rate of synchronous transport module 1 of 155.520 Mbps.

The article focuses on session initiation protocol (SIP). SIP is a signaling protocol for setting up, tearing down and modifying multimedia sessions. These sessions can consist of any number of media, such as audio, video and shared applications and can be either unicast or multicast. SIP was originally designed to be used with multicast multimedia conferences in the Internet, allowing participants to invite others to join the multicast group. Cable carriers can also use SIP as the signaling protocol in the Distributed Call Signaling version of the PacketCable specification.

The article focuses on importance of satellites in IP networks. Satellites have been an important element of telecommunications networks for many years in providing long-distance telephony and television broadcasting. This article will review the satellite communications systems and introduce a new era for satellite communications toward broadband satellite systems and satellite-for-the Internet systems. This means that the satellite is changing its traditional role as being simply a relay in space into becoming an active element similar to a switch or a router in terrestrial networks.

The article focuses on optical synchronous code-division multiple access (CDMA) systems. CDMA is a multiple access protocol that is efficient with low traffic and has zero access delay. Especially direct detection optical CDMA systems have been investigated widely to apply for highspeed local area networks, because they allow multiple users to access the network simultaneously. In the transmitter and receiver, low-cost devices with high cost performance and high reliability, such as Fabry-Perot laser diode and avalanche and pin photodiodes, are available.

This article presents information on multiprotocol label switching (MPLS) in communication systems. MPLS allows the setup of label-switched paths (LSPs) between Internet Protocol (IP) routers to avoid the IP forwarding in the intermediate routers. IP packets are tagged with labels. The initial goal of label-based switching was to increase the throughput of IP packet forwarding. In regular non-MPLS IP networks, packets are forwarded in a hop-by-hop manner. This means that the forwarding decision of a packet traversing the network is based on the lookup of the destination in the local routing table.

This article presents information on communication networks. A number of communication networks use a broadcast (or multiaccess) transmission, medium, where the signal transmitted by a node (station) is received by every other node that is in the listening area of the transmitting node. The constraints vary by technology and also by network type. The general task of the medium access control (MAC) protocol is to organize the transmissions such that under the given constraints successful communication takes place over the broadcast transmission medium. A large number of MAC protocols have been proposed in the literature, and quite a few of them are standardized and widely deployed in different commercial networks.

The article presents information related to the Internet protocol (IP) telephony. IP telephony systems are designed to transmit packetized voice using the Internet Protocol (IP). IP telephony networks can offer video, high-quality audio, and directory services, in addition to services traditionally offered by the public switched telephone network (PSTN). Enterprises implement IP telephony networks to avoid the cost of supporting both a circuit switched network and a data network. Individual users save money by using IP telephony software to bypass long distance charges in the PSTN. IP telephony makes use of statistical multiplexing and voice compression to support increased efficiency over circuit-switched networks. However, many IP networks do not support quality-of-service guarantees.

The article presents an overview of the traditional functional areas associated with network management and examines the established sets of standards that have been applied in the search for one that delivers real-time monitoring of applications' response times. Remote network monitoring 2 (RMON2) represents the only attempt to categorize the characteristics of applications traffic and breaks it down by protocol. The RMON2 specification does not calculate application response time, and some proprietary extensions are limited to round trip time measurements based on delta values of observed traffic. Packet Internet groper has been a tool traditionally used to test response times, but this relates only to its own protocol and has been proven to be woefully inadequate when dealing with applications traffic.

The article focuses on fixed Internet protocol networks (IP) and analyzes why their original mechanisms for dealing with congestion needed a radical overhaul to support the real-time, multimedia applications of today. If mobile devices are to become a gateway or portal to be able to access such applications, a consistent method of getting packet A to location B in a regular and timely fashion is entirely necessary. The IP network, as originally conceived, was designed to be a dumb network with intelligent peripherals. Applications were conversations that took place between a server and its clients, and routers simply forwarded packets between one sub-network and another, using their shared knowledge of all destination networks to complete its main task of finding a route from A to B.

The article examines the service level expectations of mobile network's applications and services when transmitted across a wireless network in order to gauge whether mobile devices can truly be a portal to multi-service networks. The article first considers two other examples of testing that have been carried out using different models and methods and the conclusions they drew. After an overview of the simple test laboratory topology, it focuses on specific applications and what happens to them under the stress conditions of having other applications compete for the same bandwidth in a simulated wireless environment. The reticence in taking up wireless application protocol services was in part due to its monotone screen and low-resolution display.

Chapter 6 portrays the issues and advantages related to implementing VoIP service in corporate communication environments. It is possible to roll out easily VoIP service in single-location Enterprises where the network is highly reliable and available-that is supporting multiple LAN segments with backups of servers and power supply-using either IP phones or traditional POTS phones with adapters. Multimedia communication server and IP-PBX can be easily deployed in such a scenario, which provide an opportunity to integrate the corporate Datacom and Telecom departments. For multi-site medium to large Enterprises, access and transmission level security and quality of service may pose real implementation challenges. [ABSTRACT FROM PUBLISHER]

Chapter 5 reviews the architecture, and hardware and software elements of a recently developed testbed that can be used for subjective and objective evaluation of VoIP services. By using suitable routing configuration of the access switch (e.g., a PBX), it is possible to route a telephone call either over a circuit-switched (PSTN) network or over a packet-switched, e.g., an IP-based network. The services include real-time voice transmission and DTMF based interaction with IVR units for completing transaction. [ABSTRACT FROM PUBLISHER]

Chapter 8 illustrates how IP based voice communication can be deployed in Global Enterprises. In traditional PSTN networks, various countries of the World use their own version of the ITU-T standards, be it for signaling or for bearer or information transmission. When IP based networks, protocols, interfaces, and terminals (PCs, IP phones, Web clients, etc.) are used, unification of transmission, signaling, management, and interfaces can be easily achieved. We discuss one possible hierarchical architecture for control of IP based Global communication for a hypothetical multi-national organization. [ABSTRACT FROM PUBLISHER]

In Chapter 9, a series of "dos" and "don'ts" are offered to guide in the design of VoIP services using any operational IP network. Some concluding remarks, and list a few of the most challenging future research topics are also presented in his chapter. Although VoIP promises low-cost implementation of telephony and many other feature-rich services, managing the legacy or PSTN style security, reliability, availability, service-completion statistic, customer satisfaction, etc. are posing realistic challenges to the network designer, and operators alike. [ABSTRACT FROM PUBLISHER]

Chapter 2 discusses the existing and emerging Internet technologies that are making the implementation of voice over an Internet protocol (IP) a reality. These include development of (a) low-bit-rate voice coding algorithms, (b) efficient encapsulation and transmission of packetized voice signal, (c) novel call setup, routing, and management protocols, (d) quality of service delivery mechanisms, etc. [ABSTRACT FROM PUBLISHER]

Chapter 3 presents evolution of the VoIP signaling protocols beginning from the ones which assume interworking with the traditional switch-based infrastructure (PSTN) in mandatory to those which use totally Internet based protocols and paradigms (server-router based network architecture). We put special emphasis on the activities which are focusing on making the PSTN domain enhanced telephone call features available to the IP domain clients like PC based soft phones or hardware based IP phones. [ABSTRACT FROM PUBLISHER]