Vehicular Ad hoc Network (VANET) is formed to share information on a temporary basis between the vehicular nodes in a wireless medium. The routing information is used to discover the vehicles and the route has to be maintained to transfer the data. It may lead to link failure or breakage in the communication, if there is high network mobility and constrained topology arrangement. In case of failure, it may cause loss of data and delay in the network. So, to avoid breakage, the routing information is stored in traditional protocols like CBAODV and CS-CBAODV. Instead of storing routing information in client side, the idea of storing data in the remote side is taken into consideration to backup permanently. This remote server manages the data in client server which is to be delivered to vehicular node. After analyzing related protocols and simulators, a new reactive based routing protocol is designed in this research work and it is named as RS-CBAODV is used to handle routing information between vehicular node, Client side node (RST i.e. Road Side Terminals) and also in Remote side storage node. To analysis the performance of the proposed protocol, MOVE and NS2 simulator is used to compare both CS-CBAODV and RS-CBAODV protocols.

PACTS (Parallelized Adaptive Cipher with Transposition and Substitution) is a new class of Symmetric Cryptographic Algorithm designed using traditional techniques to efficiently utilize the parallel computing capabilities of the modern computing systems. It overcomes the performance inconsistencies prevalent in conventional cryptographic algorithms when they are implemented in different computing systems with different processing capabilities. The size of the key and the plain text blocks of PACTS are each 1024-bits. The adaptive nature of this algorithm is achieved by incorporating flexibility in the size of the key and plain text sub-blocks and the number of rounds. Level of Intra-packet parallelization, variety in grain size and the required security strength are achieved by suitably deciding the sub-block size. Flow of the algorithm is made dynamic by determining the execution steps at runtime using the value of the key. In spite of these advantages PACTS always produces the same cipher text block for a particular plain text block when the same key is used. CBC mode along with 2-way and 4 way Interleaved CBC modes are employed to overcome this problem. The performance of the PACTS in ECB, CBC and Interleaved CBC modes are analyzed with implementations in shared memory parallel computing environment using OpenMP, Java Threads and MPI.

Exchange of data over the internet is increasing day by day. Security is the main issue in communication over a network. Protection must be given against intruders. Hence Cryptography plays a vital role in providing security. There are two basic types of cryptography: Symmetric Key and Asymmetric Key. Symmetric Key uses same or single key for encryption and decryption whereas Asymmetric Key uses separate keys for encryption and decryption. The most commonly used are the Symmetric Key algorithms. The strength of these algorithms is based on the difficulty to break the original messages. In this paper, a new Symmetric Key algorithm called as KED (Key Encryption Decryption) using modulo69 is proposed. Here not only alphabets and numbers are used, but special characters have also been included. Two keys are used in which one is a natural number which is relatively prime to 69 and finding the inverse modulo69 of it and the other key is a random number generated by the proposed key generation method. The proposed algorithm is used for Encryption and Decryption.

Wireless links are characterized by high error rates and intermittent connectivity. TCP congestion control has been developed on the assumption that network congestion is the only cause for packet loss. Upon detecting a packet loss, TCP drops its transmit window resulting in an unnecessary reduction of end-to-end throughput which results in suboptimal performance.The sender has to be made aware by some feedback mechanism that some of the losses reported are not due to congestion. The Active Queue Management algorithms (AQM) are used to reduce congestion, and in this paper, we have analysed four AQM algorithms, Random Early Deduction (RED), Wireless Explicit Congestion Notification (WECN), Queue Management Backward Congestion Control Algorithm (QMBCCA) and its enhanced version Extended Queue Management Backward Congestion Control Algorithm (EQMBCCA). WECN, QMBCCA & EQMBCCA algorithms make use of feedback mechanisms. WECN gives feedback using the CE bit. QMBCCA and EQMBCCA make use of ISQ notifications and also the CE bit whenever the average queue size crosses minimum threshold value. EQMBCCA reduces the reverse ISQ traffic by introducing a configurable intermediate threshold value IntThres. The comparison is made in terms of Delay, HTTP packet loss percentage and fairness for FTP flows in a wireless environment. It is found that the performance of EQMBCCA is almost equal to that of QMBCCA and better than RED and WECN.

Uncontrollable development of wireless and mobile communication technology aims to provide the seamless continuous connection to access various wireless technologies and to have connection with the best network which provides the best quality of service (QoS). Each application requires different QoS, so the network selection may vary accordingly. To achieve this goal and to select the best network for a mobile terminal when moving from one network to another, it is necessary to have a good decision making algorithm which decides the best network for a specific application that the user needs based on QoS parameter. This paper presents an overview of handoff types, handoff process, and classification of vertical handoff, parameters required, existing work and the comparison table.