Maghrib Abidalreda Maky AL-Rammahi

Voice over Internet Protocol (VoIP) is currently one of the fastest spreading telephone technologies. In recent years, VoIP has been widely used in wired and wireless networks because of its compatibility with and adoption in IEEE 802.11 devices. This technology works in the second layer of data link layer, and thus, is compatible with the carrier-sense multiple access with collision avoidance protocol (CSMA/CA), which works in IEEE 802.11 networks. The operation of this protocol depends on various algorithms, including the distributed coordination function (DCF) algorithm. This algorithm is governed by the transmission of packets at any time without considering the priorities of other stations. A collision of packets may occur when transmitting simultaneously with the rest of the stations. Another algorithm is the enhanced distributed channel access (EDCA), which sets a priority when sending packets between stations. Thus, if more than one station is transmitting simultaneously, then one of the stations will have higher priority and the remaining stations in the transmitter will have to wait depending on the order of priority. Consequently, collisions do not occur. In this regard, EDCA is better than DCF. The parameters of these algorithms are modified to produce a new algorithm, called M_EDCA. The three algorithms are applied using a simulation program, i.e. OPNET. The final results are obtained, and the results of the new algorithm are compared with those of the existing algorithms. The best results are achieved using the new algorithm, and consequently, the best voice quality in transmission and reception, and the best performance and service in VoIP applications.

In case of detector network the nodes loss some quantity of energy once performing the communication. To boost the lifetime of network a energy economical communication approach is needed. In case of multicast network an collective approach is employed by LEACH protocol by creation of chain of nodes. The given work is the improvement over the LEACH protocol individual to some parameter. Here we are proposing the three call parameters to pick following node in network .These parameters embrace the space, energy and also the residual energy. The projected work can improve the potency even in case of engorged and congested network and improve the network life. Sensing element network is the large set of small sensors that transfer small piece of data. As it forms a huge range of sensors it suffers from the matter of QOS. Every sensing element node consumes some energy with totally different communication operations. If no external energy is provided to them, a sensing element can be dead because it participates for long-standing within the communication. The planned work is proposed to improve the network life- time in case of LEACH protocol. It's a Cluster based protocol and transfer information to at least one of its neighbor node supported distance. During this planned work we are going to take the choice primarily based on the remaining energy on transmission. If the remaining energy is a smaller amount than the threshold, it'll communicate to some compromising node rather than effective distance node. The work is about to provide higher utilization of energy and to enhance the node and network life.

Today all organizations generally rely on wireless networks for ease of movement and less expensive than wired networks but also wireless networks suffer from some of the disadvantages is the presence of some of the threats to the security of networks penetrate through passwords for Wi-Fi networks by hacker and this is a big problem and resolve this issue and during the development and improvement of some of the algorithms used encryption in wireless networks and increase protection and help to the difficulty of penetrating passwords, at the present time there are different types of encryption algorithms to provide protection for wireless networks as well as the help of these algorithms to provide information security and the health of the user, and operate these algorithms to achieve three priorities encryption such as integrity, confidentiality and authentication. This can be achieved with these three priorities, and promote the development of the encryption algorithm AES.