in wireless networks, mobility is an important issue because Internet connectivity can only be effective if it is available during the movement of a node. To enhance mobility, the IEEE802.16e standard has set procedures to design wireless access systems to operate on the move without any disruption of services. The major difference between mobile WiMAX and fixed WiMAX is mobility support. However, speed and trajectory of nodes are unpredictable and can vary even in identical circumstances. In this paper mobile node trajectory is studied under different codecs schemes in order to evaluate the effect of node movement, towards or away from the base-station, on end to end delay, jitter, mean opinion score and throughput of a VoIP application. The results showed that trajectory inward improves network performance since mobile node gets closer to the base-station and hence signal is improved and less power is required. arabic 12 English 67
I. Almerhag, N. Aboalgasem(5-2017)

Successful companies know that network management is crucial for the proper support and maintenance of network infrastructure. When it comes to managing a large-scale or highly complex network, you’ll need a powerful network management system that will meet your challenging business needs. There are several programs suggested different types of solutions. PRTG and SolarWinds are an excellent solution, since they have many features that help the network engineer, administrator or technician to easily control, manage and monitor the devices comprehensively. Moreover, PRTG and SolarWinds can integrate with monitoring and management protocols such as SNMP and NetFlow to provide an excellent integrated unified management solution. That being said, PRTG and SolarWinds will facilitate the management of network devices throughout performing configuration, Security, Fault, Performance and Accounting management which will increase productivity, Quality, Revenue and lower the cost. arabic 9 English 66
Mariam Abojela Msaad, Mohamed Fathi Almograbi , Anas Moftah Alshoukri (12-2019)

This paper describes the usage of OPNET simulation tool to evaluate VoIP over MPLS networks which employs RSVP protocol as QoS mechanism with SIP or H.323 as signaling protocols for setting up VoIP calls over the Internet. The results showed that the H.323 with RSVP over MPLS networks produced minimal end-to-end delay than SIP protocol; making it a good choice as a signaling protocol with VoIP over MPLS networks for places requiring minimal end-to-end delay, while SIP reported lowest delay jitter with minimal call setup time
Azeddien M. Sllame, Asra Hema, Huda Alnajem(3-2018)