The rate at which the Internet is becoming mobile is unprecedented. This has increased the demand for continuous connectivity even while moving from one network to another at very high speeds. Moving from one network to another gives rise to a handoff process which often incurs packet losses and severe end to end transport protocol performance degradations for the Mobile Node. Most research on IP mobility has focused on minimizing the delays of the handoff process with network infrastructure based approaches. A different way of minimizing the impact of the handoff is to enable the Mobile Node to connect to multiple access networks simultaneously, allowing it to perform Make-Before-Break handoffs. In this paper, we compare the performance of these two alternatives, focusing on the use of Fast Handovers for Mobile IPv6 framework on the infrastructure side and on the other hand Make-Before-Break handoffs using two network interfaces. Both of these schemes require proactive handoffs for optimal performance. The results show that the use of two interfaces for Make-Before-Break handoffs provides increased handoff performance over Fast Handovers for Mobile IPv6.

Measuring the performance of an implementation of a set of protocols and analyzing the results is crucial to understanding the performance and limitations of the protocols in a real network environment. Based on this information, the protocols and their interactions can be improved to enhance the performance of the whole system. To this end, we have developed a network mobility testbed and implemented the network mobility (NEMO) basic support protocol and have identified problems in the architecture which affect the handoff and routing performance. To address the identified handoff performance issues, we have proposed the use of make-before-break handoffs with two network interfaces for NEMO. We have carried out a comparison study of handoffs with NEMO and have shown that the proposed scheme provides near-optimal performance. Further, we have extended a previously proposed route optimization (RO) scheme, OptiNets. We have compared the routing and header overheads using experiments and analysis and shown that the use of the extended OptiNets scheme reduces these overheads of NEMO to a level comparable with Mobile IPv6 RO. Finally, this paper shows that the proposed handoff and RO schemes enable NEMO protocol to be used in applications sensitive to delay and packet loss

The growth of wireless networks is inevitable. The Mobile Router is an inherent part of wireless networks and provides mobility management of an entire network. A Mobile Router implementation has been successfully completed on our network mobility test bed and is currently being employed to test various mobility scenarios. The performance of such an integral component of a system would undoubtedly come under close scrutiny. One of the methods to establish the quality of the implementation is to compare it to an industry standard implementation. This paper presents the on going work that is being done to evaluate the performance of the lab implemented Mobile Router by comparing it to a router available commercially.

The inherent difficulty in faithfully modeling wireless channel characteristics in simulators has prompted researchers to build wireless network testbeds for realistic testing of protocols. While previous testbeds are mostly designed to provide a research environment of static wireless networks, our work is aimed to assess protocols used for mobile wireless networks (such as an on-board network on public transport vehicles). In this work, we describe our on-going efforts in designing and implementing a network mobility testbed for network mobility (NEMO) protocol. This paper attempts to provide an initial reference to identify the feature set necessary for a network mobility testbed. We first describe the architecture of our testbed. Next, we present some preliminary results to demonstrate the use of our testbed in evaluating the performance of NEMO protocol under different scenarios.

Abstract — The proliferation of the increasing number of devices and technologies has brought about the extension of the concept of roaming users to roaming networks. This has inspired many researchers to investigate optimal mechanisms to enable communications for such roaming networks. Within the European 6th Framework Ambient Networks Project, we identify such roaming networks as dynamic Routing Groups, which consist of a number of different types of nodes with different capabilities. External communications from nodes within the routing group can be done via selected Gateway nodes. In this paper we present the Gateway Selection Architecture (GSA) which provides support for Gateway identification, management and selection for nodes within a RG. We describe the benefits of this architecture and compare it to other known approaches.