REACH: A Roaming-Enabled Architecture for Multi-Layer Capturing

Modern mobile PCs have different kinds of network access technologies, such as wire-based interfaces (Ethernet) or wireless adapters (IEEE 802.11 WLAN, GPRS/GSM or UMTS). Ongoing research deals with the problem of performing a "vertical handover", that allows switching your currently used network access technology on-the-fly without interruption of the application sessions. The "Roaming-Enabled Architecture" (REACH) presented in this paper is a middleware-based approach that does not use IP mobility extensions and does not depend on modifications of the infrastructure. In fact, it is related to the already published mechanisms MSOCKS and the Universal Seamless Handoff Architecture (USHA). However, REACH is designed plugin-driven in order to support multiple coexistent schemes to perform vertical handovers on different layers of the Internet protocol suite. Each relay plugin is able to intercept data coming from the applications, which is necessary to route all data through the protection schemes in order to make the mobile nodes handover-aware. Hard and soft handovers are supported by REACH as well as softer handovers and channel bundling. A mobile node can connect to multiple proxy servers simultaneously in order to utilize different services, take care of some forms of performance degradation that are related to triangle routing and to do load balancing.