Voice over IP (VoIP) systems are gaining in popularity as the technology for transmitting voice traffic over IP networks. While VoIP technology is set to revolutionize communications, and is already being used by a number of traditional telephone companies to connect their regional offices, on a smaller scale it can also be a useful solution for businesses looking to trim their telephone expenses. As the popularity of VoIP systems increases, they are being subjected to different kinds of intrusions, some of which are specific to such systems, and some of which follow a general pattern. There have been enormous strides made in the field of intrusion detection systems (IDS) for different components of the information technology infrastructure. Some of the IDSs are generic in nature and can be customized with detection rules specific to the environment in which they are deployed (e.g., Snort  and Prelude ), and some are tools specifically targeted to an environment or to specific classes of intrusions, such as IBM Tivoli Intrusion Manager for MQSeries products . VoIP systems pose several new challenges to IDS designers. First, these systems employ multipleprotocols for call management and data delivery. Second, the systems are distributed in nature and employ distributed clients, servers, and proxies. Third, the attacks against such systems span a large class, from denial of service to billing fraud. Finally, the systems are heterogeneous and typically under several different administrative domains, e.g., the proxy server may be provided by the service provider and the client managed by the home organization.
Enterprise integration within and beyond the data center begins with an enterprise service bus (ESB). With support for multipleprotocols such as MQTT, XMPP, JMS, etc., an ESB can drive data transformation, handling the large volumes of data being generated at the edge of the network, and processing summary data to send back to the data center for deep analysis.
The notion of agent has of late become popular in the Grid community, as exemplified by several workshops on the use of agents in the Grid. What are agents for the Grid? What is the difference between agents and Web-services? These are questions that we address by describing a port of the S o FAR agent framework to Web services in the context of a bioinformatics Grid. In this first paper, we focus our dis- cussion solely on issues at the transport layer. Through an agent communication language (ACL) and an abstract com- munication model, we have been able to define a generic API to communications, and are able to support multipleprotocols, including the XML protocol, the transport mech-
An increasing number of enterprise applications are requiring the speed and power of centralized storage environments to consolidate IT assets, handle dramatic storage growth, support virtualized environments, and meet backup and disaster recovery requirements. Although multipleprotocols and architectures are available to achieve a centralized storage infrastructure, a SAN is the preferred architecture for enterprises that require high speed, availability, and scalability, with Fibre Channel or FCoE the current SAN protocols of choice due to its speed, reliability, and flexibility to meet various application and networking requirements.
Isometric exercise involves sustaining contraction against resistance without altering the length of the muscle. Recent studies confirm that isometric handgrip training is able to effectively reduce blood pressure with a large magnitude effect on systolic pressure, although more modest on diastolic and mean pressures. Likewise, the hypotensive efficacy of isometric training seems to be more strongly observed in hypertensive individuals over 45 years old who undergo training for more than 8 weeks. Inder et al.8 did meta-analysis of eleven studies, totaling 302 participants. Six studies used handgrip and five studies used leg exercise. None of the studies reported any adverse events from isometric exercise. Despite the multipleprotocols used, those studies involving unilateral upper limb training and involving 4 sets of 2 min contraction at 30% of maximal voluntary contraction (MVC), separated by 4 minutes of rest, seem to obtain the best results8.
The nonexclusive IN protocol provides consistency only when the IN operations are non-interfering. Other READs can try to read it simultaneously. This protocol uses fewer messages than the strict protocol but guarantees a weaker consistency. The ‘delete’ messages are sent only once, and replies to them are returned. To make this protocol sequentially consistent, it can be combined with the Primary Copy Replication protocol. In Primary copy replication, one of the tuple copies is considered as the primary. Before an IN operation is successfully returned over any of the replicas, ownership over the primary is required. Thus, the primary acts as a serialization point for concurrent, interfering IN operations. Figure 2.5 illustrates a scenario of the Primary copy replication. In this protocol changes to the primary are immediately propagated to the other replicas. We can relax this tight implementation by propagating changes in batches and performing multiple changes at the primary tuplespace.
Abstract— Mobile ad hoc network (MANET) is composed of a collection of mobile nodes which are movable. Therefore, dynamic topology, unstable links, limited energy capacity and absence of fixed infrastructure are special features for MANET when compared to wired networks. MANET does not have centralized controllers, which makes it different from traditional wireless networks (cellular networks and wireless LAN). An adhoc network is self-organizing and adaptive. Device in mobile ad hoc network should be able to detect the presence of other devices and perform necessary set up to facilitate communication and sharing of data and service. Ad hoc networking allows the devices to maintain connections to the network as well as easily adding and removing devices to and from the network. The set of applications for MANETs is diverse, ranging from large-scale, mobile, highly dynamic networks, to small, static networks that are constrained by power sources. Then we discuss the security criteria of the mobile ad hoc network and present the main attack types that exist in it then address the possible solution to protect the security mechanism, which involve Availability, integrity, authentication and non-repudiation. Finally a comparison of various routing protocols in MANETs is presented.
These two sensing polices are then incorporated into the p-Persistent Carrier Sense Multiple Access (CSMA) mechanism to make sensing error aware CR MAC protocols. We analyze the proposed CR MAC protocols with respect to the interference and throughput performance and derive closed-form expressions. Primary user protection is achieved via tunning the channel access probability p of p- Persistent CSMA according to the interference analysis. The CR MACs also aims to maximize the CR network throughput while satisfying the primary user protection constraints. Through simulations, we find that the analysis is highly accurate as compared to simulation results. In addition, the proposed sensing error aware CR MAC protocols outperform two existing schemes with considerable gain margins, which justify the importance of considering channel sensing errors in CR MAC design.
input/multiple output (MIMO) communication environment that supports up to 8 streams. The channel bandwidth in 802.11ac is up to 80 MHz while the maximum channel bandwidth in 802.11n is 40 MHz . IEEE 802.11ac standard operates in the 5 GHz band. After a period Wi-Fi operating in 2.4 GHz bands, their limitations became apparent, mainly due to interference. Interference between 2.4 GHz neighbors can reduce the network performance .
If multiple neighbors want to talk to a node at the same time, they will try to send when the node starts listening. In this case, they need to contend for the medium. Among contention protocols, the 802.11 does a very good job on collision avoidance. S-MAC follows similar procedures, including virtual and physical carrier sense, and the RTS/CTS exchange for the hidden terminal problem. There is a duration field in each transmitted packet that indicates how long the remaining transmission will be. If a node receives a packet destined to another node, it knows how long to keep silent from this field. The node records this value in a variable called the network allocation vector and sets a timer for it. Every time when the timer fires, the node decrements its NAV until it reaches zero. Before initiating a transmission, a node first looks at its NAV. If its value is not zero, the node determines that the medium is busy. This is called virtual carrier sense.
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The routing protocols are classified as follows on the basis of the way the network information is obtained in these routing protocols The main class of routing strategy reactive proactive and hybrid. We work on the reactive protocol Ad hoc On- demand Distance Vector (AODV) Routing; an attempt has been compare the performance of single path Vs multipath simulation of prominent on demand reactive routing procedure for MANET.
AH protocol furnishes authentication, data integrity and protects against relay attacks. But it does not provide Confidentiality. In addition to what AH offers, ESP provides confidentiality. It uses various cryptographic techniques to achieve data integrity and authentication. Security Association (SA) is integral component of IPsec architecture. Security Association contains data needed for IPsec to function. It includes IP address of source, authentication keys, encryption key, key lifetime etc. Security association is unidirectional i.e. Two separate associations are required for inbound and outbound packet transfer. Key management is done by protocols like Internet Key Exchange. IPsec was designed for ipv6 but can be used for systems using ipv4.
Many types of power system protection have very stringent requirements for communications, specifically: low latency, symmetrical latency, and low jitter . Conventionally, time- division multiplexing (TDM) has been used to minimise jitter and to provide dedicated bandwidth. These systems typically also offer resilience to link failure. However, TDM systems are inherently inflexible and make inefficient use of available bandwidth, particularly when multiple services – such as phasor measurement unit data, supervisory control and data acquisition (SCADA), voice telephony, and video surveillance – must be supported .
high-quality templates should be seen as a corruption of the client. This might be a valid argument in certain use cases, however, for the purpose of generality, it seems more appropriate to assume that biometric data is public and resort to the liveness assumption, when modeling security of biometric-based protocols. Since biometric data is used in many different domains (e.g. e-passports, personal computers, entry access systems, etc.) leakage of high-quality templates is not unlikely. In contrast to private keys, biometric characteristics are produced by nature and are bound to a specific person. From this perspective, their modeling via liveness assumption, aiming at user’s physical presence seems to be more appropriate. Liveness assumption has also been in the focus of recent standardization initiatives, e.g. ISO/IEC WD 30107 Anti-Spoofing and Liveness Detection Techniques.
1. Introduction. Recently, the problem of collaborative control in networked multi- agent systems  has received signiﬁcant attention due to its important application, such as multiple mobile robots, multi-intelligent vehicles, and multiple unmanned aerial vehi- cles. At the beginning, it is used to be a single agent to complete the task. However, as the task size and task complexity increased, the traditional agent can hardly meet the need of some complex tasks. Besides, the algorithm of relevant controller will become very complex with the task diﬃculty increased. So it has practical signiﬁcance to study the cooperative work of multi-agents, especially the formation control [2-6].
Most Local Area Networks have migrated to a Gigabit or at least a Fast Ethernet backbone with switched 10/100 connections to clients, printers and file servers. Fast on the inside, but slow on the outside, many U. S. businesses rely on copper T-1 and T-3 connections, or fiber ATM / SONET circuits for WAN connectivity. These connections were designed for voice but were never intended to handle the exponentially growth of Internet and data traffic, applications or the protocols typically used in today's LAN. What's more, provisioning and maintaining these circuits, or upgrading from a T-1 to a T-3 connection is an expensive and time-consuming proposition for both the service provider and the customer. It also requires significant capital investment at both the Point of Presence (POP) and the customer premises.