Research On Probing Methods Of Topology-aware Overlay Network Based On IMS Core Network

Traditional mobile network which is based on circuit switch technology can becapable of exchanging voice anytime and anywhere. It can provide flexible access fordifferent terminals. Since it does not support IP technology, the businesses can onlybe expanded vertically, thus the communication rate between different applicationsbecomes lower and it may need more operations between different business gatewaysto get access to the mobile communications network. Therefore, evolution fromcommunication network to IP-based network architecture has become an inevitabletrend in this case.Therefore IMS emerged. IMS (IP Multimedia Subsystem) is a networkarchitecture defined by3GPP. It supports both fixed access and mobile access, and itutilizes SIP protocol to support network communications. The main feature is that itcan be independent of the access of terminals.However, it is needed to ensure the quality of service (QoS) of IMS core networkif IP technology is to be utilized in telecommunication industry. To solve the relatedissues, the International Organization for Standardization (ISO) has developed apolicy-based QoS framework. But such a policy-based framework has not taken thenetwork resource utilization into account sufficiently, which may easily lead to issuesrelated to the concentration of resources. Such issues could be resolved by deployingoverlay network on IMS core network. However, generally, overlay network couldnot perceive the topology of underlying network, which often cause the issues oflong-distance transmission. Therefore, in order to solve the related issues, this articleproposes two probing methods of topology-aware overlay network based on IMS corenetwork.Innovation work in this article is summarized as follows:1. A passive probing method of topology-aware overlay network based on IMSis proposed. This algorithm mainly utilizes related attributes in BGP and OSPF toprobe the network distance between a candidate node and a service node, in order to achieve the goals of deploying a topology-aware network. This algorithm especiallyapplies to the situation that the network topology stays relatively stable.2. A combinative passive and active probing method of topology-aware overlaynetwork based on IMS is proposed. This algorithm combines the probing methodmentioned above with the existing active probing method to probe the networkdistance between a candidate node and a service node, in order to achieve the goals ofdeploying a topology-aware network. This algorithm has a wide application. It canapply to the situation that the network topology changes frequently or the networktopology stays stable relatively.This article describes in detail about the implementation of these two methods.The simulation results prove that they can reduce the network distance oftransmission and improve the utilization of resources, thus improve the QoS of IMScore network.