The exhaustion of IPv4 addresses has forced the deployment of the new version of the Internet Protocol (IPv6). However, the migration to the new protocol is done gradually and with the due care for many reasons that include: cost, inclusion of support for IPv6 in existing applications, training of technical staff, lack of web content available over IPv6 from important providers, and obsolete devices not anymore supported by manufacturers. For those reasons, many transition mechanisms have been proposed, each one to fill distinct requirements, with different operational theory and availability according to the network environment. A performance evaluation of these mechanisms can help network administrators and researchers in their selection of the best transition technology for their environment. In this paper, we present a performance comparison of some transition mechanisms such as ISATAP, 6to4, and NAT64 in real testbeds with Debian, Windows 7, Windows 8, and Windows 10. For NAT64, two different tools were tested: TAYGA and Jool. We measure the OWD and the throughput for UDP and TCP for every mechanism, for both Ethernet and Fast Ethernet technologies. From this research, we can conclude that all the modern operating systems for PCs already have good support for IPv6, and a very similar network performance. Also, we can infer from our work that in controlled environments, native IPv4 has the best performance, closely followed by native IPv6. The difference is essentially due to the length of the IP header (20 bytes in IPv4 and 40 bytes in IPv6). The tunneling solutions chosen for this research (ISATAP and 6to4) have a similar performance, which is the lowest of the studied technologies, because of the additional IPv4 header in the tunnel.

Secure Socket Layer (SSL) and Transport Layer Security (TLS) protocols use cryptographic algorithms to secure data and ensure security goals such as Data Confidentiality and Integrity in networking. They are used along with other protocols such as HTTP, SMTP, etc. in applications such as web browsing, electronic mail, and VoIP. The existing versions of the protocols as well as the cryptographic algorithms they use have vulnerabilities and is not resistant towards Man-In-The- Middle (MITM) attacks. Exploiting these vulnerabilities, several attacks have been launched on SSL/TLS such as session hijacking, version degradation, heart bleed, Berserk etc. This paper is a comprehensive analysis of the vulnerabilities in the protocol, attacks launched by exploiting the vulnerabilities and techniques to mitigate the flaws in protocols. A novel taxonomy of the attacks against SSL/TLS has been proposed in this paper.

Encryption is a way to secure and verify data that are traded through public communication channels in the presence of intruder party called antagonists. Consequently, the transmitted or stored message can be converted to unreadable form except for intended receivers. The decryption techniques allows intended receiver to reveal the contents of previously encrypted message via secrete keys exchanged exclusively between transmitter and receiver. The encryption and decryption techniques can be applied equally to a message in any form such as text, image, audio or video. The current paper applies and evaluate two different encryption/decryption algorithms to the real-time audio signal. The first one is the well-known RSA encryption and decryption technique, while the second one is a new suggested algorithm based on symmetric cryptography concept. The Matlab Simulink simulator tool is used for acquiring the real-time audio signal and simulating the proposed algorithms. Considering the mathematical nature of the audio signal, the experimental results showed that the RSA method yields an audio signal with low quality while the suggested algorithm yields audio signal with high quality as exact signal as the original one.

The selection of cluster heads is of immense importance in the cluster based protocols which are widely used in wireless sensor networks. However, for the random selection of cluster heads when the distance of cluster heads is also taken into account such as in LEACH-DT algorithm, the lifetime of the network is improved. In this paper, a new algorithm for selection of cluster heads is proposed where the residual energy of the cluster heads is also considered along with the distance to the base station. The proposed approach ensures better energy balance of the network nodes. The performance of the proposed algorithm is measured at various stages of network lifetime and a significant improvement over LEACH-DT has been observed. Also, a two-level heterogeneous hierarchical architecture of the proposed algorithm is investigated which further enhances the performance of the proposed algorithm.

Cloud computing has become buzzword today. It is a digital service where dynamically scalable and virtualized resources are provided as a service over internet. Task scheduling is premier research topic in cloud computing. It is always a challenging task to map variety of complex task on various available heterogenous resources in scalable and efficient way. The very objective of this paper is to dynamically optimize task scheduling at system level as well as user level. This paper relates benefit-fairness algorithm based on weighted-fair Queuing model which is much more efficient than simple priority queuing. In proposed algorithm, we have classified and grouped all tasks as deadline based and minimum cost based constraints and after dynamic optimization, priority of fairness is applied. Here different priority queue (high, mid, low) are implemented in round-robin fashion as per weights assign to them .We recompile the CloudSim and simulate the proposed algorithm and results of this algorithm is compared with sequential task scheduling and simple constraints (cost and deadline) based task scheduling algorithm. The experimental results indicates that proposed algorithm is, not only beneficial to user and service provider, but also provides better efficiency and fairness at priority level, i.e. benefit at system level.

Vehicular Ad hoc Network involves the movement of vehicles and the communication between them for their security. VANETs have many application areas. One of main applications of VANETs is to improve the driving safety. In various safety related applications, vehicular nodes constantly communicate with roadside equipments. Road Side Units (RSUs) can sense the real time information about road conditions, animals straying and road blocks and passes all this hazardous related information to the vehicles approaching in its range. These alert messages enable the driver to take timely decisions in preventing from accidents or delays in information delivery. In this paper, Enhanced Direction based Hazard Routing Protocol and Ad Hoc On-demand Distance Vector protocols are used to avoid prevent vehicles from collision and to increase the coverage range of VANETs. These issues are resolved by bypass routing and a synchronized clock maintained with the RSUs respectively. To solve the issues and make the system more reliable we propose the roadside wireless sensor nodes along with vehicular nodes in the network. The RSUs are fixed at some distances and communicate with wireless sensors attached at vehicular nodes.

In recent years, the Internet has incremented the several incipient applications that rely on multicast transmission. This paper discusses the challenges of scheduling algorithms for multicast in high-speed switches that reduces the overhead of adaptation by selecting a HOL (Head of Line Cell) using Round Robin pointer. The objective of this paper is to design a scheduling algorithm called MDDR (Multicast Due Date Round-Robin) scheduling to achieve maximum throughput and low delay that has two phases request and grant. In request phase, MDDR assigns a Due Date (Request Time Slot) for HOL cells of each queue in the input port. Round Robin Pointer is utilized in the grant phase to select a request if HOL occurs. MDDR achieves more preponderant performance than MDRR (Multicast Dual Round-Robin), since the request shall be made when the Due Date is reached. MDDR mainly minimizes many requests made for output ports and time complexity. The simulation results show that the proposed algorithm has good switching performance in throughput and average time delay under Bernoulli and bursty traffic conditions.

A MANET is a set of mobile nodes which works in a dynamic changing network and it is capable of communicating with each other efficiently where all the nodes perform a dual role as that of a transmitter and a receiver. Hence MANETs do not use any centralized administration for communication due to this reason they are more vulnerable to attacks. So MANET uses special technique called EAACK, which uses special acknowledgment messages to avoid intruder communication. So due to this type of authentication, more acknowledgment messages are transferred in between two nodes, which increases delay in communication. Hence this drawback reduces system performance.
In this paper we propose a new clustering technique in EAACK called CEAACK. Our proposed technique shows better performance when compare to the normal EAACK technique, which drastically reduces the number of acknowledgment packets during authentication process which achieves a good energy efficiency network and better data transmission.
Further, this technique consumes low energy and in the process provides better efficiency in data transmission in MANETs.