The ISO/OSI Reference Model, continued

3. The Network Layer

is responsible for providing the connection between "end systems" across a network. These connections might include multiple, intermediate links and are intended to be independent of the (sub)networks used to transmit the data.

Network layer functions include:

• routing: deciding how to transmit frames between source and destination using addresses.
• relaying: enables data transfer (transparently) across intermediate (sub)networks.
• flow control: matches traffic flow with the physical capacity of a transmission path.
• sequencing: control ordering of frames across a network.