Hosts on different networks communicate using a layer-3 address (layer 3 in the OSI reference model). In the networks used today, that would normally be an IP address.
Data Link Layer
layer 4 - transport layer
A network layer is not needed if both the hosts are in the same network. A data link layer can be used in such cases.
There are in total seven layers in OSI model . OSI model layer that is responsible for the termination of connections between hosts is session layer . Session layer is responsible for the dialog control .
Hub and Swithc
distribution
Application layer
host adderss
destination host address
switch,hub.
A Hub or a Switch