netværksskiktet

The network layer, or netværksskiktet in Danish, is the third layer of the OSI model and the Internet protocol suite. Its primary responsibility is to handle logical addressing and routing of data packets across different networks. This layer defines the logical addresses, such as IP addresses, that uniquely identify devices on a network.

The network layer is responsible for determining the best path for data to travel from the source to the destination. This process is known as routing. Routers, which operate at this layer, examine the destination IP address of a packet and consult their routing tables to forward the packet to the next hop on its journey.

Key protocols operating at the network layer include the Internet Protocol (IP) for IPv4 and IPv6, which provides the addressing scheme and packet delivery services. Other important protocols include the Internet Control Message Protocol (ICMP) for error reporting and diagnostics, and the Address Resolution Protocol (ARP) which maps IP addresses to physical MAC addresses within a local network.

In essence, the network layer ensures that data can traverse the internetwork, moving packets from a source device on one network to a destination device on potentially a completely different network, by providing logical addressing and efficient routing mechanisms. It sits above the data link layer and below the transport layer.