Blocking-EDS

  Since RREQ packets are flooded throughout the network, this algorithm does not scale well to large networks. If the destination node is located relatively near the source, issuing a RREQ packet that potentially pass through every node in the network is wasteful. The optimization AODV uses is the expanding ring search algorithm, which works as follows. The source node searches successively larger areas until the destination node is found. This is done by, for every RREQ retransmission until a route is found, incrementing the time to live (TTL) value carried in every RREQ packet, thus expanding the ``search ring in which the source is centered.