Fast Adaptive Routing Supporting Mobile Senders in Source Specific Multicast

IP multicast deployment recently progresses, but group services often remain restricted to limited domains and fail to comply with route-optimizing mobility management of the next generation Internet. Source Specific Multicast (SSM) facilitates transparent inter-domain routing and is expected to globally disseminate to many users and services. However, mobility support for Source Specific Multicast is still known to be a major open problem. In this paper, we propose the Enhanced Tree Morphing (ETM) protocol for extending SSM routing to mobile multicast sources. The scheme dynamically adapts SSM forwarding states to sender mobility, and transforms (morphs) source specific distribution trees into new, optimal trees rooted at a relocated source. ETM is simple, robust and secure, while it admits superior performance in packet forwarding at a low signaling overhead. Extensive evaluations based on a full protocol implementation, and simulations based on real-world topology data are performed, granting full insight into the properties of packet loss and delay stretch, protocol convergence times and router state evolution during single and rapidly repeated handovers. In a constant bit rate scenario, an ETM source handover typically leads to a slightly increasing delay of the first data packet, only. When operating on realistic network topologies, the protocol uniformly converges within less than 50 ms, thereby sustaining robustness under rapid source movement at all speeds common to our mobile world. Further optimizations are identified for FMIPv6 and for multihomed nodes

ETM - An Optimized Routing Protocol for Mobile SSM Sources

Mobility is considered a key technology of the next generation Internet and has been standardized within the IETF. Rapidly emerging multimedia group applications such as IPTV, MMORPGs and video conferencing increase the demand for mobile group communication, but a standard design of mobile multicast is still awaited. The traditional Internet approach of Any Source Multicast (ASM) routing remains hesitant to spread beyond walled gardens, while the simpler and more selective Source Specific Multicast (SSM) is expected to globally disseminate to many users and services. However, mobility support for Source Specific Multicast is still known to be a major open problem. In this paper we introduce the Enhanced Tree Morphing (ETM), an optimized multicast routing protocol for transforming (morphing) source specific distribution trees into optimal trees rooted at a relocated source. Following up on previous results for the initial Tree Morphing, we present enhancements that lead to a simpler protocol with significantly optimized performance values in both, forwarding performance and protocol robustness. Extensive evaluations based on real-world topology data are part of this work

QoS Performance Study of One Way Link Characteristics in an IEEE 802.16d TDD System

WiMAX systems are beginning to spread as a wide-area wireless access technology that provides QoS support for future multimedia applications. Vendors have started to ship off-the-shelf hardware that addresses the market of broadband Internet coverage in sparsely populated areas. Facing a potentially large deployment of 802.16-based end-system connectivity, it is of vital interest to experimentally evaluate the capabilities of WiMAX systems in real-world setups. The main objective of our current paper is to quantify QoS performance of the one way wireless service flows in a 3.5 GHz band carrier utilizing the time division duplexing mode of the IEEE802.16 standard. We evaluate performance dependencies of the time division duplexing system on modulation and load, and show that the link latency is asymmetric.Unknow