Distance Vector

Distance vector routing is a class of routing algorithms in which each node maintains a table of estimated distances to all destinations and periodically shares this table with its immediate neighbors. The protocol is simple, elegant, and catastrophically fragile: a single link failure can trigger a cascade of incorrect updates that propagate through the network like a rumor, producing the infamous count-to-infinity loop that distance-vector protocols can only escape by imposing an arbitrary maximum hop count. The algorithm's simplicity is its virtue and its vice; it is a demonstration that local optimality does not guarantee global optimality, and that the price of distributed coordination is the risk of distributed misunderstanding.