tailieunhanh - the_handbook_of_ad_hoc_wireless_networks_6

Tham khảo tài liệu 'the_handbook_of_ad_hoc_wireless_networks_6', công nghệ thông tin, quản trị mạng phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Simpo PDF Merge and Split Unregistered Version - http Bordercast-Based Global Reactive Interzone Routing Route discovery in the Zone Routing framework is distinguished from standard broadcast-based route discovery through a message distribution service known as bordercasting 14 . Rather than blindly broadcasting a route query from a neighbor to a neighbor bordercasting allows the query to be directed outward toward regions of the network specifically toward peripheral nodes that have not yet been covered by the query. A covered node is one that belongs to the routing zone of a node that has received a route query . The query control mechanisms reduce route query traffic by directing query messages outward from the query source and away from covered routing zones as illustrated in Fig. . A node can determine local query coverage by noting the addresses of neighboring nodes that have forwarded the query. In the case of multiple channel networks a node can only det ect query packets that have been directly forwarded to it. For single channel networks a node may be able to detect any query packet forwarded within the node s radio range . through eavesdropping in promiscuous reception mode . When a node identifies a query forwarding neighbor all known members of that neighbor s routing zone . those members that belong to both the node s and neighbor s routing zones are marked as covered. When a node is called upon to relay a bordercast message it again uses its routing zone topology to construct a bordercast tree which is rooted at itself and spans its uncovered peripheral nodes. The message is then forwarded to those neighbors in the bordercast tree. By virtue of the fact that this node has forwarded the query all of its routing zone members are marked as covered. Therefore a bordercasting node will not forward a query more than once. Query detection can be enhanced by introducing a random delay prior to construction of the bordercast