Link Quality Source Routing (LQSR) is a routing protocol for wireless mesh networks. The protocol was developed by Microsoft for use with their Mesh Connectivity Layer (MCL) technology, which facilitates the interconnection of computers into a mesh network using WiFi or WiMax wireless service. The LQSR protocol is based on Dynamic Source Routing (DSR).
LQSR identifies all the nodes in a wireless mesh network and assigns relative weights to the links among the nodes. In addition, the channel, the bandwidth, and the loss are determined for every possible link. This information is sent to all the nodes. Based on this information, LQSR uses a routing metric called Weighted Cumulative Expected Transmission Time (WCETT) to define the best path for the transmission of data from a given source to a given destination. The route between two nodes during communication can consist of more than one hop. That is, there may be one or more intermediate nodes between the source and destination. If the optimum path between a particular source and destination changes, LQSR modifies the route accordingly, without interrupting the link between the nodes. The LQSR protocol, like DSR, works automatically with a minimum of administrator oversight.
Wireless mesh networks using MCL technology hold promise for people in remote areas who have not previously had access to high-speed Internet services. Such a network can be connected to the Internet by a single leased, broadband T-1 or satellite connection, thereby providing Internet access over a significant geographical area without the need for an existing cable or wire infrastructure among the nodes.