Connection-oriented Networks Research Articles

Connection-oriented computer network secure communication and encryption algorithm

This paper studies the data encryption model and encryption method of the connection-oriented computer network communication system. Firstly, the application and security analysis of digital certificate and big integer decomposition encryption algorithm in connection-oriented are studied. Secondly, in the design of encryption communication module, a new hybrid encryption mechanism is proposed, that is, a strong and fast encoding algorithm is used to encrypt the plain text, Rivest-Shamir-Adleman (RSA) algorithm is used to encrypt the key, and Secure Hash Algorithm (SHA) algorithm is used to generate the digital abstract. Finally, an improved cryptographic model of elliptic curve cryptosystem is constructed, and an effective exclusive form of node private key is obtained. The experimental results show that the improved algorithm can simplify the deployment and improve the efficiency of the cryptographic system in large-scale public key certificate system.

Connection-oriented computer network secure communication and encryption algorithm

This paper studies the data encryption model and encryption method of the connection-oriented computer network communication system. Firstly, the application and security analysis of digital certificate and big integer decomposition encryption algorithm in connection-oriented are studied. Secondly, in the design of encryption communication module, a new hybrid encryption mechanism is proposed, that is, a strong and fast encoding algorithm is used to encrypt the plain text, Rivest-Shamir-Adleman (RSA) algorithm is used to encrypt the key, and Secure Hash Algorithm (SHA) algorithm is used to generate the digital abstract. Finally, an improved cryptographic model of elliptic curve cryptosystem is constructed, and an effective exclusive form of node private key is obtained. The experimental results show that the improved algorithm can simplify the deployment and improve the efficiency of the cryptographic system in large-scale public key certificate system.

A Review on Bandwidth Utilization for Bursty Traffic in Asynchronous Transfer Mode Networks

ATM (Asynchronous Transfer Mode) network is connection-oriented high speed multiservice network. Now a days ATM networks are used as backbone networks in Telecom industry. ATM network supports different service classes, include ABR (Available Bit Rate), rt-VBR (real time Variable Bit Rate), nrt-VBR (non real time Variable Bit Rate), CBR (Constant Bit Rate), UBR (Unspecified Bit Rate), and GBR (Guaranteed Bit Rate)to handle multiple services like data, voice, video and so on. But burtsy traffic handled by ABR, rt-VBR, nrt-VBR, GBR service classes, but all have their own limitations. This paper presents an overview of different Traffic shaping, Congestion Control mechanisms to handle bursty traffic in ATM networks.

Design of Miniaturized Triplexers via Sharing a Single Triple-Mode Cavity Resonator

A novel approach for design of a miniaturized cavity triplexer is proposed in this paper by using triple-mode resonator (TMR) as a common feeder of three frequency channels in a triplexer. Three frequency channels are generated by three fundamental modes of a single rectangular triple-mode cavity resonator. Without installing any connection-oriented junction network, i.e., T-junction or star junction, only coupling slots are adopted herein to achieve required coupling coefficients and external quality factors toward the specified Chebyshev responses in the three passbands simultaneously. High isolation among these three separated bands can be effectively achieved owing to the modal orthogonality via sharing a common TMR structure as a feeder. Two triplexers are then designed and fabricated using varied topologies. The hybrid resonator triplexer method is presented as the first approach by using a TMR as a feeder to feed three sets of single-mode cavity bandpass filters. As the second approach, the triple-mode triplexer (TMT) method is developed by cascading a few TMRs to form a multistage higher order TMT. Finally, two fabricated triplexer prototypes are tested for experimental verification of the proposed design methodology. Good agreement between measurement and simulation is achieved.

Analysis and Tools for Improved Management of Connectionless and Connection-Oriented BLE Devices Coexistence.

With the introduction of low-power wireless technologies, like Bluetooth Low Energy (BLE), new applications are approaching the home automation, healthcare, fitness, automotive and consumer electronics markets. BLE devices are designed to maximize the battery life, i.e., to run for long time on a single coin-cell battery. In typical application scenarios of home automation and Ambient Assisted Living (AAL), the sensors that monitor relatively unpredictable and rare events should coexist with other sensors that continuously communicate health or environmental parameter measurements. The former usually work in connectionless mode, acting as advertisers, while the latter need a persistent connection, acting as slave nodes. The coexistence of connectionless and connection-oriented networks, that share the same central node, can be required to reduce the number of handling devices, thus keeping the network complexity low and limiting the packet’s traffic congestion. In this paper, the medium access management, operated by the central node, has been modeled, focusing on the scheduling procedure in both connectionless and connection-oriented communication. The models have been merged to provide a tool supporting the configuration design of BLE devices, during the network design phase that precedes the real implementation. The results highlight the suitability of the proposed tool: the ability to set the device parameters to allow us to keep a practical discovery latency for event-driven sensors and avoid undesired overlaps between scheduled scanning and connection phases due to bad management performed by the central node.

Link fault identification using dependent failure in wireless communication networks

The study of various communication networks has attracted many researchers from various academic fields in recent years. It is a major research to identify the faulty links in communication networks. A dependent failure approach is presented to identify the faulty links in wireless communication networks. The node importance evaluation is introduced to overcome the limitations of traditional independent failure methods. Faulty nodes effect on their direct links in the network. The dependent failure topology graph (DFTG) model and faulty link identification method take into consideration the failure probability of different nodes. The management node can autonomously identify, in real time, the most probable failed network links through building the DFTG model. Experimental validation and actual application are carried out separately. The identification method of faulty links applies to satellite networks with the connection-oriented network structure. From the simulation analyses and the actual satellite network, the test results demonstrate that this proposed method is valid, efficient, and suitable for wireless communication network applications.

Strategies for optical transport network recovery under epidemic network failures

The current trend in deploying automatic control plane solutions for increased flexibility in the optical transport layer leads to numerous advantages for both the operators and the customers, but also pose challenges related to the stability of the network and its ability to operate in a robust manner under different failure scenarios. This work evaluates two rerouting strategies and proposes four policies for failure handling in a connection-oriented optical transport network, under generalized multiprotocol label switching control plane. The performance of the strategies and the policies are evaluated under multiple correlated large-scale failures. We employ the Susceptible---Infected---Disabled epidemic failure spreading model and look into possible trade-offs between resiliency and resource efficiency. Via extensive simulations, we show that source rerouting outperforms on-site rerouting, and that there exist a clear trade-off between policy performance and network resource consumption, which must be addressed by network operators for improved robustness of their transport infrastructures. Applying proactive methods for avoiding areas where epidemic failures spread results in 50 % less connections requiring recovery, which translates in improved quality of service to customers and lower recovery expenses for the network operator.

Finite-time sliding mode flow control design via reduced model for a connection-oriented communication network

This paper addresses the flow control design of a connection-oriented communication network from the robust control theory perspective. Network is modelled as a nth order discrete system whose first order model is obtained using the two-time scale property associated with the process. The proposed scheme is characterised by an equivalent control based discrete sliding mode design for the first order model which is applied to nth order systems through aggregation. Besides its design simplicity, the proposed method exhibits finite time convergence property for the states while applied to the full order system emulating the characteristics of terminal sliding mode in a certain way. Simulation results via Matlab and ns-2 validate the efficacy of the proposed algorithm as an effective flow controller for connection-oriented networks.

Applications of Industrial Ethernet in Smart Substation: Problems and Solutions

In view of the current network structure of the Smart Substations in China, the industrial Ethernet is analyzed with respect to the presence of long latency that may be found in the communication of Smart Substation, the configuration complexity that is not conducive to repair and the maintenance involving relatively high economic costs. A connection-oriented switching network technology is then proposed on similar issues, with a leaky bucket model being built up based on the substation information flow. Subsequently, the service classification and priority scheduling mechanism are placed to introduce the network calculus to calculate the delay bound of each of information flows. Conclusively, based on the IEC62439, a network communication method for Smart substation is established to solve the problems with the Industrial Ethernet application in smart substation.

An optimal sliding mode congestion controller for connection-oriented communication networks with lossy links

Abstract A new discrete-time sliding-mode congestion controller for connection-oriented networks is proposed. Packet losses which may occur during the transmission process are explicitly taken into account. Two control laws are presented, each obtained by minimizing a different cost functional. The first one concentrates on the output variable, whereas in the second one the whole state vector is considered. Weighting factors for adjusting the influence of the control signal and appropriate (state or output) errors are incorporated in both the functionals. The asymptotic stability of the closed-loop system is proved, and the conditions for 100% bottleneck node bandwidth utilization are derived. The performance of the proposed algorithm is verified by computer simulations.

연결지향형 패킷교환 처리기의 스케줄링 성능평가 및 시험 방안 연구

In a connection-oriented packet switching network, the data communication starts after a virtual circuit is established between source and destination. The virtual circuit establishment time includes the queue waiting times in the direction from source to destination and the other way around. We use this two-way queueing delay to evaluate scheduling policies of a packet switching processor through simulation studies. In this letter, we also suggest user testing functions for the packet switching processor to manage virtual circuits. By detecting error causes, the user testing helps the packet switching processor provide reliable connection-oriented services.

Multivariable Approach to Bandwidth Sharing in a Multi-source Connection-Oriented Network with Heterogenous Delays

Abstract This paper deals with the bandwidth sharing and dynamic rate control in a connection-oriented multi-source network from the multivariable control theory perspective. Multi-source networks are characterised by heterogenous delays associated with their flows. General methodology in such cases involves design of a single input control (based on the upper bound of the delay) which is shared among the participating sources with the help of fairness algorithms. However, most of these fairness algorithms are iterative procedures and do not take into account the impact of variable delays on bandwidth allocation. By approaching this task from the multivariable control theory base, proposed method gives the flexibility to design optimal rate control in correspondence to the delays and removes the requirement of an explicit fairness algorithm. A novel discrete multivariable model of network is derived by segregating the sources according to their delays which leads to the property that the rank of input matrix and the system dimension are determined by the number of distinct delays and the upper bound of the delay respectively. With suitable choice of weighing matrices in the optimal control design, required fairness and throughput are ensured in the network.

Applications and Status of Path Computation Elements [Invited

In any dynamic control plane architecture targeting connection-oriented networks, the path computation function can be defined as the one that deals with obtaining a route for a given request or, equivalently, with finding appropriate resources to be allocated to new incoming flows within the network, given the knowledge of the network status, its topology and resource availability, and the applicable constraints and policies. The path computation function can be located in a network management system or in one or more network elements. In the scope of a distributed control plane such as multiprotocol label switching (MPLS) and generalized MPLS, such a function is commonly located either in a process running on each node controller (referred to as source routing) or deployed using a dedicated entity. To this end, the Internet Engineering Task Force defines a path computation element (PCE) as a control plane functional component which is able to perform constrained path computation on a graph representing a network. This paper provides an overview of PCEs and elaborates on selected aspects regarding the deployment and use of PCEs as a functional element in the framework of control and management of optical networks, highlighting the motivations behind their adoption, common deployment models, and related testbed experimentation. The paper also briefly explores new trends such as the extensions for the so-called stateful PCEs and the role of PCEs in software defined networks.

Runtime connection-oriented guaranteed-bandwidth network-on-chip with extra multicast communication service

This paper presents a flexible runtime connection-oriented guaranteed-bandwidth Network on Chip (NoC). Comparing with a standard time-division multiplexing (TDM) method, our local ID-based method provides better flexibility to establish dynamic runtime connections. A specific pre-designed algorithm for finding a conflict-free scheduling, as commonly used in the TDM-based method, is not needed. The contention problem is solved with the hardware solution based on the locally organized message identity (ID), in which flits belonging to the same stream packet will have the same unique/local identity-tag (ID-tag) on each communication link. The ID-tags of each stream will vary locally over communication links and are updated. The updating is organized by ID-tag mapping management units. The routing is organized using runtime programmable routing reservation table. In addition, the proposed methodology supports also a deadlock-free multicast routing service.

Discrete Time Sliding Mode Flow Controllers for Connection-Oriented Networks with Lossy Links

Abstract In this paper we propose two discrete-time sliding mode flow controllers for multisource connection-oriented networks. Each connection in the considered networks is characterized by a time delay and a packet loss ratio. The proposed controllers take advantage of appropriately designed sliding hyperplanes, which ensure the closed-loop system stability and finite-time error convergence to zero. Moreover, the proposed controllers ensure full utilization of the bottleneck link available bandwidth, guarantee bounded transmission rates, and eliminate the risk of buffer overflow in the bottleneck node. Since the primary controller may lead to excessive values of the transmission rate at the beginning of the control process, the modified controller is designed using the concept of the reaching law, which helps the removing of the undesirable effect.

Energy-aware traffic engineering: A routing-based distributed solution for connection-oriented IP networks

The present paper deals with energy saving in IP networks and proposes a distributed energy-aware traffic engineering solution, named DAISIES, for switching off network links according to traffic variations. DAISIES works in a connection-oriented network, e.g. an IP/MPLS network, and follows a routing-based approach, i.e. it acts on the routing algorithm whilst link switch-off/on are consequence of routing decisions. The basic idea is to re-compute the path of each traffic demand when its requested capacity changes. A specific cost function is used to compute link weights into the shortest path routing algorithm with the goal of keeping unused as many links as possible. The main advantages of DAISIES can be summarized as follows: (i) no changes are required to current routing and signaling protocols, (ii) packet loss is completely avoided, (iii) both traffic decreasing and increasing and changing network conditions are automatically managed, and (iv) link switch-off/on take place transparently to the routing protocol and to other nodes. The performance of the proposed solution is evaluated in terms of energy saving relative to a static network optimized to support the peak traffic. Results show that DAISIES is able to save about 30% of energy in several traffic conditions. Moreover, it is shown that it is possible keeping the additional complexity low and still reaching high energy efficiency.

DEMONSTRATING THE SYNERGY BETWEEN CAC AND SCHEDULING IN WIRELESS NETWORKS

Wireless technology is now an integral part of communication network infrastructure. From their first beginnings, such as connection-oriented General System Mobile networks for voice traffic only and connectionless wireless local area networks for data traffic, new generation wireless networks are connection-oriented and provide differentiated services to the user. With the arrival of more sophisticated services and mobility, have arisen the need for Connection Admission Control and traffic scheduling in the network to enhance the quality of experience (QoE) of the user and optimizing the revenue in dynamic workload environments. A great deal of research effort has gone into the study of the performance of one such network standard, namely the IEEE 802.16 networks. Most optimization studies focus on scheduling (a very mature subject in computing) and ignore connection admission (a very mature subject in telephone engineering) or vice versa. In this paper we claim that one should not study the two in isolation and provide empirical evidence to prove our claim.

Quantity-based flow control strategy for connection-oriented communication networks

Abstract. In this paper a new flow control strategy for connection-oriented communication networks is presented. It utilises methods of control theory, in particular the Smith predictor and dead-beat control, to achieve desirable dynamics of the considered network. In contrast to a number of earlier proposals in which the controller command is interpreted as the rate transmission, in our solution it is interpreted as the quantity of data that the controlled node is expected to send. This allows us to model a single virtual connection with non-persistent data source as a time-delay system in which the delay may temporarily exceed its assumed boundary. Favourable properties of the proposed control strategy are formulated as mathematical theorems and thoroughly discussed.

Fast Service Recovery Under Shared Protection in WDM Networks

In this paper, we investigate the problem of survivable routing of static demands in connection-oriented WDM networks with shared protection. We first discuss conditions and characteristics of a typical backup path sharing approach with respect to the average length of backup paths, and the values of connection restoration time. Next we propose a new method of sharing the backup paths, called SPGC, which is the first one that does not increase the length of backup paths (thus providing fast restoration of broken connections). The respective ILP model has been introduced. Owing to the complexity of the SPGC problem, an efficient heuristic algorithm designed for the general case of limited wavelength conversion capability has been also proposed. Extensive numerical experiments have shown that the proposed backup path sharing approach provides values of service recovery time which are up to 50% shorter on average, compared to the typical sharing technique. These results were achieved together with a significant reduction of the total link capacity utilization ratio of up to 40%.

A self-adapting connection admission control solution for mobile WiMAX: Enabling dynamic switching of admission control algorithms based on predominant network usage profiles

WiMAX is a connection-oriented wireless network that provides QoS in metropolitan broadband communications. One important component in WiMAX QoS provisioning and management is the Connection Admission Control (CAC), which must be aware of the network conditions (e.g., user traffic demands and physical aspects). In our research, we define the association between a particular user traffic demand and a specific physical condition as a network usage profile. State-of-the-art proposals focus on optimizing CAC algorithms considering a single network usage profile; the adaptation of CAC algorithms when the predominant network usage profile changes is partially or fully neglected. In this article, we introduce a self-adapting CAC solution that, using a library of CAC algorithms, is able to switch the running algorithm according to the current network usage profile. The evaluation results, obtained through simulations, demonstrate that our self-adapting CAC solution is able to detect the changes on the predominant network usage profile. In addition, the results show how much different profiles can impact on the efficiency of CAC algorithms, thus confirming the need of switching the running CAC algorithm so that QoS can be guaranteed for the ongoing connections.