Main results of the Evolute project are the following;
- SIP based service provision components.
- Implementation of two multimedia service scenarios on top of the EVOLUTE infrastructure. One scenario is Instant Messaging (IM) and Video Streaming based, however the second deals more with instant messaging and roaming between WLAN and GPRS (or GSM) network.
- Implementation of the RTSP mobility.
To make the service provision possible in EVOLUTE, the SIP proxy -- the SIP Express Router (SER)-- was enhanced by some components such as IM and presence platform, SIP/SMS Gateway, CPL script. Some enhancements on the client side were performed as well, for instance, the SIP client (KPhone) was extended to support roaming and dynamic changing of the used IP address. It was also enhanced to interwork with an RTSP server in order to allow the explained below scenario.
The multimedia service based on both Instant Messages and Video Streaming can be considered as an example of the location based services that can be deployed in a WLAN hot spot or in the 3G Network by a Service Provider. The service is based on the assumption that the SIP and RTSP protocols are used. A user enters in the WLAN hot spot, he gets access to the network using the Evolute AAA procedure and then he registers at the SIP proxy. The SIP proxy sends him an Instant Message with a list of RTSP URLS from which the user can choose a movie trailer (for example). He clicks on the selected URL and the RTSP player starts. The movie will be provided if the user is authorized to get access to the RTSP service.
This service is fully integrated in the Service Authentication and Authorization architecture proposed and implemented in the project, allowing an ISP to directly deploy it in its network.
Keeping a multimedia session alive while roaming in a heterogenous environment was also addressed in EVOLUTE and a multimedia service scenario was developed for that purpose: a user accessing the internet with a GPRS technology, starts a text chat session with a friend, then he moves to a hotspot and keeps the multimedia session. Afterwards, he moves to a GSM network, closes his laptop but still keeps chating by receiving SMS messages on his mobile. The components used in this scenarios were mentioned earlier.
At the moment the RTSP standard doesn�t contain any reference to mobility and till now there is no implementation of both RTSP client and server that is able to manage the mobility of the user. The state of art is the proposal of H. Schulzrinne�s in which he suggests a solution for RTSP mobility based on the SIP mobility approach.
The multilayer mobility management architecture proposed in the EVOLUTE project, even if it is based on a hybrid SIP/Mobile IP/micromobility protocols solution can be applied also to RTSP. In an intra-domain handoff, the RTSP signaling traffic is exchanged between the RTSP server and the client using Mobile IP, instead of the RTP media stream that is redirected to the RTSP client new position, without using Mobile IP. The redirection of the RTP traffic has been done sending a PAUSE message, then a new SETUP message from the client to the server, followed by a PLAY message. This solution, agreed with the MMUSIC working group has been successfully tested in the laboratory: the RTSP client interacted with the Cellular IP client, the Mobile IP client and the RTSP server in the correct way during the handoff. The tests show that, even if few seconds are required for the handoff, the freezing of the images and the restarting of the images have a good effect on the user perception of the handoff. This solution has been implemented in the MPEG4IP client and in the Darwin streaming server, without any header addition to the RTSP standard, but using the great flexibility of the RTSP protocol.
Since the EVOLUTE mobility solution involves also Network Address Translator, the implementation of the RTSP mobility includes also the addition of the STUN protocol support in the MPEG4IP client. This will allow the RTSP client not only to support the RTSP mobility, but also the NAT and firewall traversal.
All these results have been developed in Linux and tested both in a laboratory environment and in a close to real environment: they can be considered prototypes of multimedia services. These results can interest 2G/3G/4G telecom operators, WLAN network service providers, Service providers and Content Providers.
They can use the multimedia service provisioning architecture, proposed in the EVOLUTE project, to offer a wide range of services because there is the support of AAA functionalities. Even if the results have been demonstrated and evaluated with a 2G network, they could be extended to a 3G/4G network without any changes and without any impact on the exploitation results, because the multimedia service provisioning architecture has been designed for being used in a 3G networks.