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a new feature of services in Nagios has been added to the existing system which has no such services. The bandwidth monitoring and notification system are configured for alerting the network administrators when the bandwidth of the network in an organization hits a certain threshold settings. The system sent an email alert and sms notification to the network administrator for taking further action in order to maintain the Quality of Service (QoS) in the network. All the logs file of the Nagios actions is saved in the Nagios File Logs. The analysis was conducted from the case study and problem statements. Network Development Life Cycle (NDLC) was chosen as a methodology for implementing this system in the network. Nagios is installed inside Ubuntu 10 Operating System along with Multi-Router Traffic Grapher (MRTG) and Mail Postfix. MRTG and Mail Postfix were configured to be integrated with the Nagios System. On the client side, NSClient++ has been installed, for monitoring the bandwidth and performance of windows based on operating system. The Nagios services have been improved with the implementation of sms and emails notifications since the existing services have no such utilities. With the implementation of these services to Nagios, the performance could be even better for the future.

This paper proposed a method of allocating additional TXOP duration to replenish the bandwidth used during the retransmission of frames at link layer in audio-video transmission by IEEE 802.11e HCCA. In the proposed scheme, the HC monitors the number of retransmission at link layer and utilize the surplus bandwidth to allocate additional TXOP duration on the basis of number of retransmission performed during the last transmission. The proposed scheme also reduces the polling overhead to gain surplus bandwidth by polling only a station in a polling interval. By simulation, we compare the application-level QoS of the TGe scheme and the proposed scheme. Numerical results show that the proposed scheme can keep the QoS of audio and video high under lossy wireless channel especially when the number of multimedia stations is small. Furthermore, the proposed scheme can admit more traffic flows than the TGe scheme.

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