liittymäkerroksen

Liittymäkerros, also known as the network interface layer or link layer, is the lowest layer in the standard TCP/IP networking model. It is responsible for the transmission of data packets over a physical network medium. This layer deals with the physical addressing of devices on a local network, using MAC addresses to uniquely identify network interfaces.

Key functions of the liittymäkerros include framing, where data from the higher layers is encapsulated into frames suitable for transmission. It also handles error detection, often using checksums, to ensure data integrity during transmission. Access to the physical medium is another crucial role, managing how devices share the network to avoid collisions, particularly in technologies like Ethernet.

The liittymäkerros operates on a local network segment. It does not concern itself with routing packets across different networks. Instead, it focuses on delivering data reliably between two directly connected nodes. Examples of protocols operating at this layer include Ethernet, Wi-Fi (IEEE 802.11), and PPP. The hardware components like network interface cards (NICs) are directly involved in the operations of the liittymäkerros.