Editing Network layer (section)

==Functions==
The network layer provides the means of transferring variable-length [[network packet]]s from a source to a destination [[Host (network)|host]] via one or more networks. Within the service layering semantics of the OSI (Open Systems Interconnection) network architecture, the network layer responds to service requests from the [[transport layer]] and issues service requests to the [[data link layer]].

Functions of the network layer include:
; [[Connectionless communication]]
: For example, [[Internet Protocol]] is connectionless, in that a data packet can travel from a sender to a recipient without the recipient having to send an acknowledgement. Connection-oriented protocols exist at other, higher layers of the OSI model.
; Host addressing
:Every host in the network must have a unique address that determines where it is. This address is normally assigned from a hierarchical system.  For example, you can be:
:
:"Fred Murphy"                                                    to people in your house, 
:"Fred Murphy, 1 Main Street"                             to Dubliners,
:"Fred Murphy, 1 Main Street, Dublin"                 to people in Ireland, 
:"Fred Murphy, 1 Main Street, Dublin, Ireland"    to people anywhere in the world. 
:
:On the Internet, addresses are known as [[IP address]]es (Internet Protocol).
:
; Message forwarding
:Since many networks are partitioned into subnetworks and connect to other networks for wide-area communications, networks use specialized hosts, called gateways or [[Router (computing)|routers]], to forward packets between networks.