This can occur, for example, in overlay networks where information about the destination's location in the underlying network is not available.
Peer counting and sampling in overlay networks: random walk methods.
PlanetSim is an object oriented simulation framework for overlay networks and services.
An overlay network then connects the nodes, allowing them to find the owner of any given key in the keyspace.
This is a popular concept in peer-to-peer overlay networks like Chord.
Find a node already in the overlay network.
Nodes in the overlay network are connected by virtual or logical links.
The topology of the overlay network may (and often does) differ from that of the underlying one.
The most striking example of an overlay network is the Internet itself.
In this model, the overlay network is used for service or node discovery and rendezvous.