Admission control mechanism for quality of service and security in H.323 voice gateway

摘要

The rapid demand on the VOIP communication lead to the increase of the development of information security and the offered quality. Therefore, information technology has increased the deepening and developing of call admission control (CAC). In which, admission decisions and resource reservations are taken at the edge voice gateway, rather than resources or individual routers within the network. This means that, CAC decision is made before a voice call is established and it depends on the availability of the required call resources to provide suitable quality of service (QoS) for the new call. In this article, a new model for voice network, in order to achieve QoS along with security, is proposed. In the proposed model, the admission control decision is taken place at H.323 voice gateways using resource reservation protocol. It is shown that the admission control decision should be taken at edge H.323 voice gateways. This will lead to provide the accepted security for both, source and destination nodes which were previously authenticated through the identity services engine. It is concluded from the simulation results that the packet loss rate of call flows after implementing the mechanism is almost 0%. In addition, there is no jitter although there is some delay for packet delivery "Latency." The latency observed by the proposed model is still accepted according to the ITU G.114 standard which recommends a maximum of a 150 ms one-way latency. All results are tested in GNS3 based simulation to evaluate the performance of voice gateway based upon CAC.