QoS-Aware Architecture for FHMIP Micromobility Nuno Vasco Lopes ∗ , Maria João Nicolau † , Alexandre Santos ∗ ∗ Department of Informatics, † Department of Information Systems University of Minho, Braga 4710-057, Portugal email: vascolopes@di.uminho.pt, joao@dsi.uminho.pt, alex@di.uminho.pt Abstract—Wireless networks will certainly run applica- tions with strict QoS requirements and so, micro-mobility protocols such as Fast Hierarchical Mobile IPv6 (FHMIP) are useful tools to accomplish this new feature. The FHMIP is an effective scheme to reduce Mobile IPv6 handover disruption, however it does not support application’s QoS requirements. Therefore, in order to provide QoS guarantees for real-time applications it is necessary to develop new traffic management schemes; this implies the optimization of network mobility support and also some network congestion control. A traffic management scheme of this type should take into account the QoS requirements of handover users and should implement a Resource Management (RM) scheme in order to achieve this. In this paper, a new RM scheme for the DiffServ QoS model is proposed. This new scheme is implemented by access routers as an extension to FHMIP micromobility protocol. In order to prevent QoS degradation of the existing traffic, access routers should evaluate the impact of admitting a new Mobile Node (MN), previously to the handover. This evaluation and sequent decision on wether admitting or refusing MN’s traffic is based on a Measurement-Based Admission Control (MBAC) algorithm. This architecture, that has been implemented and tested using ns-2, includes a simple signaling protocol, a traffic descriptor and exhibits an adaptive behavior to traffic QoS requirements. All the necessary measurements are aggregated by Class-of- Service, thus avoiding maintaining state on the individual flows. Index Terms—Quality of Service, mobility support, ad- mission control, signaling. I. I NTRODUCTION Providing the QoS levels suited to real-time applica- tions needs is, in itself, a big challenge for the research community. IETF community has been working, for some years now, in order to define Internet QoS models able to meet this need but the task still challenges researchers. Integrated Services (IntServ) and Differen- tiated Services (DiffServ) are the primary QoS models developed within IETF. The Diffserv QoS model has also Nuno V. Lopes was partially supported by an FCT Grant (SFRH/BD/35245/2007) been used as the QoS Model able to overcome some well known scalability and complexity problems of IntServ, pushing up complexity and processing load to border routers and keeping core routers as simple as possible. However, IntServ and DiffServ models were developed to provided QoS guarantees in wired networks, where user mobility and wireless-constrained bandwidth are not a problem. On the other hand, current Mobile IP standard lacks on QoS provisions, on scalability, robustness and on an unified RM function. Mobile IP is a macro-mobility solution and generally is not sufficient for handling micro-mobility scenarios, where cell size is small and high frequency handovers are common. There are few proposals for micro-mobility, such as Hierarchical Mo- bile IP, Fast Handover, Cellular IP and HAWAII but a detailed comparation of these protocols can be found, as a survey, in P. Reinbold and O. Bonaventure paper [1]. However, micro-mobility and Mobile IP are Best-Effort (BE) and do not provide QoS guarantees, so, currently, the mobility management and the QoS models work independently. Contrary to the fixed network environ- ments, in wireless networks mobile users can potentially change their point of attachment to the network many times during a session, thus changing to a new Access Router (nAR) that may affect the applications’ QoS. Moreover, wireless links have a less predictable behavior than wired links. Therefore, when the MN changes its point of attachment, active applications on mobile should negotiate their QoS requeriments in the nAR as a part of the handover procedure. Micromobility mechanisms such as FHMIP, during handovers, use tunnels to forward packets between previous Access Router (pAR) and nARs. This helps to reduce packet losses and registration time; however this is not enough because applications should also be provisioned with appropriate QoS ensur- ing that packets will reach the mobile node in accordance with the QoS contract. Wireless networks are more dy- namic and current cell resource availability is constantly changing, either because other users moved into the cell, or because the user leaved the cell. Therefore, user mo- bility will require a signalization for dynamic resource 9781-4244-3941-6/09/$25.00 ©2009 IEEE