| 摘要 |
The invention provides a method of admission control at an intermediate node between a source node 20 and a destination node 90 in an ad hoc network, e.g. a wireless ad hoc network, preferably a mobile ad hoc network (MANET). The source node 20 sends a route request message including quality of service requirement information to discover at least one route to a destination node 90 via one or more intermediate nodes 30, 40, 50, 60, 70. The destination node 90 then generates for at least one discovered route between the source node 20 and the destination node 90, a route reply message which includes the quality of service requirement information. The route reply message is sent to the source node 20 via the intermediate nodes defined in the discovered route (e.g. 50, 60). On receipt of a route reply message, each intermediate node determines whether it can meet the requirements specified by the quality of service requirement information and, if so, transmits the route reply message to the next node in the route; the node does not forward the route reply message if it determines that it cannot meet the requirement. Thus the source node 20 only receives replies from discovered routes which have recently determined that they satisfy the quality of service requirement information, which is advantageous in highly mobile ad hoc networks where up-to-date information is essential. A similar determination based on the forward transmission of the route request message (see fig. 2) may be used to ensure the destination node 90 only replies along routes that meet the quality requirements. The quality of service requirement determination may be based on more than one quality metric, e.g. the maximum available bandwidth at a node may vary depending on a MAC delay (fig. 5). |
