1. An apparatus for implementing adaptive routing in packet switched networks using routing tables, a traffic model structure and Ant packets of AntNet, comprising: a link selector for selecting a next node to which an Ant will be moved with reference only to a preference value in a current routing table; a reinforcement value calculator for calculating a reinforcement value in consideration only of the routing time of the Ant; an updating unit for updating values stored in the routing tables based on the reinforcement value and the collected routing information; and a controller for controlling logic for connecting the blocks to external devices and analyzing Ant packets upon arrival, wherein the Ant packet has a fixed length including a field Type representing whether an Ant packet is a forward Ant or a backward Ant, a field sNode representing IP address of a node that initially generates a current Ant, a field dNode representing the IP address of a final destination node of a current Ant, a field pNodeOdr representing the order of nodes the current Ant passes through while moving from a source node to the destination node, a field tNodeNum representing the number of the nodes the current Ant passes through while moving from the source node to the destination node, a field intNode representing the IP addresses of the nodes the current Ant passes through while moving from the source node to the destination node, and a field visTime representing the time at which the current Ant visits each node.