In this paper, we evaluate a low latency handoff protocol for MIPv4, the post-registration handoff method. This mechanism proposed by the IETF tries to improve the performance of hierarchical mobile IP by decreasing the handoff latency. We give a detailed description of the protocol behavior by means of an ns simulation and propose a simple queuing model to study the influence of various parameters on the protocol performance.

A statistical multiplexer is a basic model used in the design and the dimensioning of communication networks. The multiplexer model consists of a single server queue with constant service time and a more or less complicated arrival process. The aim is to determine the packet loss probability as a function of the capacity of the buffer. In this paper, we show how rational approximation techniques may be applied to compute the packet loss efficiently. The approach is based on the knowledge of a limited number of sample values, together with the decay rate of the probability distribution function. A strategy is proposed where the sample points are chosen automatically. The accuracy of the approach is validated by comparison with both analytical results obtained using a matrix-analytic method and simulation results.

Mobile IP allows node mobility involving changes of point-of-attachment to the Internet. In order to reduce the impact on the performance and the signaling overhead, hierarchical mobility management schemes have been introduced. These schemes define protocols that allow movements within a domain to be handled locally, without involvement of the mobile node's home network. In order to reduce more the packet losses during handoff, new schemes have been defined, such as smooth handoff. By storing packets temporarily in the access point after the mobile host has left and forwarding them to the new access point as soon as the mobile has connected to it, it is possible to reduce significantly the packet loss. In this paper we develop an analytical model and a simulation program using OPNET Modeler to evaluate the packet loss and packet delay for UDP streams and the throughput for TCP streams that are involved in a handoff. We show that, in spite of the buffering capabilities of the previous access point, packets may still get lost. The reason for this loss is identified and solutions to this problem are proposed.