Handover-aware SIP-based VoIP provided by a roaming-enabled architecture (REACH). - In: IEEE Sarnoff Symposium, 2008, ISBN 978-1-4244-1843-5, (2008), insges. 6 S.
The protocols of Voice-over-IP (SIP, RTP and RTCP) have several issues, for example the NAT and the firewall problem. They lead to solutions such as "Back-to-back User Agents" (B2BUA), "Session Border Controllers" and helper-protocols such as "Simple Traversal of UDP through NATs" (STUN) and "Traversal Using Relay NAT" (TURN). - This paper focusses on a different challenge, a problem that arises when a user becomes mobile and his IP-enabled telephone is forced to change its network access technology due to network coverage issues ("perform a vertical handover"). We present a middleware-based solution that makes SIP-based VoIP handover-aware and effectively solves the NAT and firewall problem. - This approach builds on the "Roaming-Enabled Architecture" (REACH), a plugin-driven middleware that uses proxy servers. REACH offers for multiple data capturing schemes required to provide an easy-to-use handover-aware solution, but VoIP was not supported yet. Here, we present a self-implemented "Session Border Controller" for SIP and RTP that was divided into two designed to be used within the infrastructure of REACH. - This mechanism adds full support for VoIP to the REACH software suite, allowing telephony in combination with any kind of vertical handover such as hard-, soft and softer handovers in IP-based networks of any kind.
http://dx.doi.org/10.1109/SARNOF.2008.4520062
REACH: a roaming-enabled architecture for multi-layer capturing. - In: IEEE Wireless Communications and Networking Conference, 2008, (2008), S. 2699-2704
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.
http://dx.doi.org/10.1109/WCNC.2007.473
Media-push technology in multimedia mobile environment. - In: 4th IEEE Consumer Communications and Networking Conference, 2007, ISBN 978-1-4244-0667-8, (2007), S. 1182-1183
http://dx.doi.org/10.1109/CCNC.2007.243
Architektur für die Verarbeitung von Kontextinformationen - Architekturkonzept : interner Forschungsbericht. - Ilmenau : Techn. Univ., Fachgebiet Kommunikationsnetze. - 27 S. = 936 KB, TextLiteraturverz. S. 27
kontextsensitiv, Kontextsensitivität, kontextsensitive Dienste, kontextsensitive Telekommunikationsdienste, Kontext, Kontextinformation
http://www.db-thueringen.de/servlets/DocumentServlet?id=9077
Kontextsensitives Routing - Architekturkonzept : interner Forschungsbericht
überarb., interner Forschungsbericht vom 20. Juni 2007. - Ilmenau : Techn. Univ., Fachgebiet Kommunikationsnetze. - IV, 34 S. = 1,13 MB, Text
http://www.db-thueringen.de/servlets/DocumentServlet?id=8439
Digitale Sprach- und Datenkommunikation : Netze - Protokolle - Vermittlung. - München [u.a.] : Fachbuchverl. Leipzig im Carl Hanser Verl., 2007. - 361 S. ISBN 3-446-22979-5
Literaturangaben
Service discovery modelling for intelligent building network. - In: Information technology and electrical engineering - devices and systems, materials and technologies for the future, (2006), insges. 9 S.
http://www.db-thueringen.de/servlets/DocumentServlet?id=13076
A VPN-driven infrastructure for vertical handovers. - In: IEEE Sarnoff Symposium, 2006, ISBN 978-1-4244-0002-7, (2006), insges. 4 S.
Mobile PCs are equipped with a multitude of network access technologies, such as IEEE 802.11 WLAN, GPRS over GSM or wire-based Ethernet. If the user wants to access the Internet he has to choose one of the technologies and has to use it for the whole duration of the session. But this is problematic when the user wants to be mobile and has to change network access technologies. It was quite problematic so far to start a session using Ethernet and then perform a seamless vertical handover to WLAN when the user becomes mobile. The protocols used in the Internet were not designed with mobility in mind. Some proposals were made to circumvent these problems, for example by using enhancements like Mobile IP or IPv6 , but a solution that could easily be applied to a multitude of different "real-world systems" has not been presented yet. We developed a method that implements a data transfer mechanism that is able to handle the problems caused by mobility and vertical handovers. Our first approach made use of the universal proxy protocol SOCKSv5 (RFC 1928) to relay all data to a central proxy server using a handover-capable transport mechanism. Here, "socksified" applications were needed, which was not feasible in all possible scenarios˜{Evers2004}. This paper presents our latest enhancement that makes use of a Virtual Private Network (VPN) in combination with our handover capable transport mechanism. This offers a full VPN-based network access to all applications running on the mobile node and is able to do all handover related work transparently. VPN-clients are available for all relevant operating systems. The handover management software was implemented using C++ and runs on GNU/Linux, Mac OS and Microsoft Windows. The architecture offers full mobility to the end user without the need of modifications to the applications or the operating system itself.
http://dx.doi.org/10.1109/SARNOF.2006.4534787
Digital television in the near future. - In: Information technology and electrical engineering - devices and systems, materials and technologies for the future, (2006), S. 19-21
Definition and implementation of context information. - In: Joint 2nd Workshop on Positioning, Navigation and Communication 2005 (WPNC '05) & 1st Ultra-Wideband Expert Talk 2005 (UET '05), (2005), S. 63-68