Answer

Flooding is a routing technique in which a router forwards an incoming packet on all outgoing links except the link on which it arrived, subject to rules that prevent indefinite circulation.

Key idea

Instead of calculating one best route, the packet is propagated throughout the network. A packet can reach the destination through multiple paths.

Advantages

• Very simple routing method.
• Does not require complete routing information.
• Can be highly robust because multiple copies may reach the destination.

Disadvantages

• Creates many duplicate packets and wastes bandwidth.
• Can cause congestion unless controlled.

Common controls include a hop count/TTL and packet sequence numbers to discard duplicates.

Exam-ready definition: Flooding forwards packets over all possible outgoing paths, with mechanisms such as hop limits used to control duplicates and loops.