ZigBee Wireless Technology is the leading global standard for implementing low-cost, Low-data-rate, short-range wireless networks with extended battery life. The ZigBee standard provides network, security, and application support services operating on top of the IEEE 802.15.4 Medium Access Control (MAC) and Physical Layer (PHY) wireless standard. It employs a suite of technologies to enable scalable, self-organizing, and self-healing networks that can manage various data traffic patterns, The low cost allows the technology to be widely deployed in wireless control and monitoring applications, the low power-usage allows longer life with smaller batteries, and the mesh networking provides high reliability and larger range. ZigBee has been developed to meet the growing demand for capable wireless networking between numerous low power devices. In this paper , we will try to give a complete picture about ZigBee technology including the structure of this technology, the layers where this technology works referred to the OSI model, how this technology works, the main components that use to create a ZigBee network, The objective of this simulation is to establish tree topology networkby; using an OPNET Modeller 14.5 program, and to investigate the performance of the network model, and see the effect on data when we change the time of transmission and finally we will investigate the performance of some network models that employ IEEE 802.15.4 protocol using different scenarios. arabic 19 English 91
Mariam Abojela Msaad, Almoatasem Aboaisha , Ahmed Eshoul(12-2019)

A denial of service attacks are usually employed to interrupt the system's activity by getting a large number of fake requests, which leads to slowing down and stopping information system or network operations. This paper outlines the basic principles of DDoS attacks, explains how DDoS attack works. The paper presents an experimental using OPNET simulation tool in which traffic from three different applications VoIP, FTP, and HTTP is used to make the practical model with a firewall shield to model and simulate DDoS over Internet. However, three scenarios have been developed to illustrate different aspects of the DDoS over networks. The results clearly demonstrate how firewalls can be configured to mitigate DDoS attacks
Azeddien M. Sllame, Reema A. Saed, Mariam Abojella Msaad(5-2021)

This paper describes a Fat tree based Network-on- Chip system using MPLS networking technique. A discrete-event simulator has been developed in C++ in in order to demonstrate the applicability of the MPLS to Network-on-Chip systems. The correctness and the efficiency of the MPLS based Fat networkon- chip system is measured against well-known wormhole with virtual channels technique. The results of the MPLS-based NoC in terms of throughput and latency are clearly proves the applicability of the MPLS to implement future NoC designs arabic 8 English 38
Azeddien M. Sllame, Nagwa Abobaker Salama(11-2016)