An all-IP network infrastructure
The next-generation mobile systems will be mainly based on IP protocol, offering innovative end-user services such as voice telephony, multimedia conferencing or mobile web access. Such an evolution necessitates the development of an all-IP network infrastructure access which would be possible via heterogeneous technologies anywhere and anytime. Thus, the EVOLUTE project, seamless multimedia services Over alL IP-based infrastructures, implemented an all IP network infrastructure, which ensures the provisioning of real-time and non-real-time multimedia services among heterogeneous environments. It essentially provides seamless multimedia services to roaming users. In the context of the project, the Universal Mobile Telephone Service (UMTS) and Wireless Local-Area Network (WLANs) technologies have been considered. In addition, the main features and capabilities of existing and emerging protocols have been examined and utilized in order to design and develop an efficient multilayer mobility management scheme. Using as a base the Session Initiation Protocol (SIP), a protocol often used to establish voice over IP calls or maintain other sessions such as games and chats, the SIP Express Router was designed and realized. The SIP Express Router, designed in modular manner, offers functional components ranging from receiving and forwarding messages to programming interfaces for different communication modes such as audio, video or gaming. Furthermore a multi-layer and hierarchical mobility management scheme has been proposed, resulting from the synergy and the extract of the existing protocols such as Mobile IP and SIP. The resulting IP-based architecture has been tested in a both laboratory environment and in a close to real environment. Demanding scenarios were used in order to prove its efficiency in delivering seamless multimedia services to users that move among heterogeneous networks.