tailieunhanh - Wireless Mesh Networks 2010 Part 7

Tham khảo tài liệu 'wireless mesh networks 2010 part 7', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 5 A Layered Routing Architecture for Infrastructure Wireless Mesh Networks Glêdson Elias Daniel Charles Ferreira Porto and Gustavo Cavalcanti Federal University of Paraiba Brazil 1. Introduction Wireless Mesh Networks WMN is a new technology that promises improved performance flexibility and reliability over conventional wireless networks. WMNs are easy to deploy and have self-configurable and self-healing capabilities. In essence a WMN is a dynamic multi-hop wireless network in which the nodes automatically establish and maintain connectivity among them. Thus routing protocols have a fundamental role by providing paths to allow communication between non-neighbor nodes and so keep up best routes. One of the most important goals for routing protocols developed for WMNs is to reduce the routing overhead and improve network scalability. The WMN s architecture defines two types of nodes mesh client MC and mesh router MR . They can play different roles in the network forwarding packets in behalf of other ones or just using the network resources. Depending on such roles three types of WMNs can exist client infrastructure and hybrid Akyldiz et al. 2005 . A client WMN is just an ad hoc network built only by MCs. The infrastructure WMN IWMN is the most common type being formed by a fixed dedicated group of MRs which builds a wireless backbone providing a coverage area for keeping connected mobile MCs even when they are moving Fig. 1 . In IWMNs MCs cannot forward packets and besides cannot communicate directly with each other. Finally in a hybrid WMN the backbone is built by mobile and fixed devices. Hence both MCs and MRs can forward packets although only MRs can connect the backbone to other networks. The routing facilities required by WMNs are already present in protocols developed for ad hoc networks. So ad hoc routing protocols like DSR Johnson et al. 2004 AODV Perkins C. et al. 2003 and OLSR Clausen T. Jacquet P. 2003 have been applied in several WMN projects Chen J. .