Individuals are nowadays surrounded by several personal multimedia capable devices. On the other hand, the popularity of the multimedia applications is increasing and new application domains are constantly emerging. In this kind of development, users can benefit and quality of experience can increase if their applications can move while executing among all the multimedia devices that surround them. These factors are some of the main driving forces to research application mobility. In this Master s thesis we design, implement and evaluate a module called negotiation and data transfer module for application mobility. This module is an important part of application mobility because it encompasses two of its crucial functionalities: the resource negotiation and the application data transfer. During the negotiation process, the hosts that are involved exchange resource capabilities in order to determine whether the application migration can take place. The protocol used for negotiation needs to be able to carry any type of resource description, then it has to be able to distinguish between multiple negotiation sessions and finally it has to be efficient. This protocol is coupled with two other systems, which together facilitate the negotiation process. The first, called the resource variable presentation system, is used to represent and store the negotiated resources which are then conveyed with the negotiation protocol. The second, called the negotiation algorithm, is an algorithm that takes the resources described with the resource variable presentation system and calculates whether the migration conditions are met. Based on the results provided by this algorithm, we decide whether the application migration can take place. In this Master s thesis, we analyze the Session Initiation Protocol (SIP) as a candidate for the negotiation protocol in the context of application mobility. If the migration is possible, the data transfer protocol is used to transfer migrating application data to the host that continues execution. This protocol needs to be efficient and it has to be able to provide feedback to the user about the current amount of transferred data. Feedback is sent to the user only if the time span from the beginning of the migration till the moment when the migrating application is continued on the remote host exceeds the pre-established time value for that migrating application. The mechanism that calculates this value and then, if needed, configures the data transfer protocol to send feedback is in this Master s thesis called precopy. We analyze the Message Session Relay Protocol (MSRP) protocol as a candidate for the data transfer protocol in this context. The results show that the negotiation and data transfer module performs correctly and according to design. The results also show that performance of the resource negotiation depends on the size and the content of the conveyed payload, while the performance of the data transfer is influenced by the size of the transferred payload and the configuration of the data transfer protocol. Both processes are influenced by the type of network as well.