Design and Implementation of an OSA Service Capability Server for mobile devices
Application Servers (ASs) are the entities responsible for hosting multimedia services/applications in the IP Multimedia Subsystem (IMS). The services in the IMS network could be basic network services provided by network operators or external value added services by third party service providers. 3GPP proposes the Open Service Architecture (OSA) as a standardized way of introducing external services by third parties in the operator’s network. The type of ASs used to provide OSA services are called OSA framework Application Servers (OSA ASs) in the IMS network. An OSA AS does not involve in the control signaling (SIP-signaling) with the S-CSCF directly but through the OSA Service Capability Server (SCS). The SCS is the entity which directly involves in control signaling and provides mapping of SIP messages into invocations of the OSA API. Additionally, the SCS ensures network security and integrity by an authorization mechanism for the OSA AS. Typically, like other ASs such as SIP AS and IM-SSF ASs, an OSA SCS is implemented on high-tech server machines. From the mobile end’s perspective, research has shown that mobile devices today are capable of becoming IMS SIP AS through the support of REST-based Mobile Web Services. However, a concept of mobile OSA SCS and AS is still in question.
This thesis presents the design and implementation of OSA SCS architecture for mobile devices. The solution will be based on standardized interfaces and protocols proposed by 3GPP. The proposed design will enable peer-to-peer mobile multimedia communication in the operator’s IMS network. A proof-of-concept prototype will be envisaged to demonstrate OSA services provisioning among mobile peers in the IMS. In the final phase of thesis, the performance aspects of transport protocol and media transmissions will be evaluated.