Numbat - extensible simulation environment for mobile, IPv6 capable IEEE 802.16 stations

Numbat is a new simulation environment, developed with IPv6 mobile stations supporting WiMAX in mind. To provide near real-time capabilities (required for VoIP or video streaming) in a mobile environment, full handover procedure has to be as fast as possible. Both investigated components - IEEE 802.16 based networks and IPv6 capable nodes - are rapidly gaining acceptance. Therefore it appears essential to perform full scale analysis of the handover procedure in such an environment. Numbat allows simulation and analysis of various mobility related issues. It offers support for multiple base stations with groups of subscribers, both fixed and mobile. Also support for tight integration with higher layers (IPv6, DHCPv6, Mobile IPv6) is usable, but still under development. This paper presents the purpose, functional requirements and architecture of the simulation environment. The current state of implementation, validation, future areas of improvement and an example simulation results are also discussed in detail. Obtained results clearly show that most significant delays are caused by the IPv6 layer. Some of the possible areas of improvement in several auto-configuration mechanisms are identified. Some optimization proposals are also discussed.