2. Proactive protocols

In this class of protocols, a system of periodic exchange of control packets is set up so that each node can build the network topology in a distributed way.

There can be several types of control packets. As a general rule, a distinction is made between packets that are sent locally to a hop and packets that are broadcast throughout the network. The former are used to acquire knowledge of the surrounding area. The latter enable a given node to broadcast the state of its neighborhood throughout the network, which usually consists of its neighbors or a subset of them. In a proactive protocol, a node periodically updates its routing tables when it receives control packets. Sending and processing information packets on a regular basis is the counterpart to obtaining topological information immediately (figure