linklaag

Linklaag, in Dutch networking terminology, refers to the data link layer of the OSI model (Layer 2). It sits between the physical layer (Layer 1) and the network layer (Layer 3) and is responsible for the transmission of frames between adjacent network devices over a single link. The layer provides services such as framing, physical addressing via MAC addresses, error detection, and the management of access to shared media. It also handles flow control and, in many implementations, multiplexing of higher-level protocols.

The data link layer is commonly divided into two sublayers: the Logical Link Control (LLC), which interfaces with the network layer and handles protocol multiplexing, and the Media Access Control (MAC), which implements addressing and access control on the physical medium. Technologies and standards at this layer include Ethernet (IEEE 802.3), Wi‑Fi (IEEE 802.11), and Bluetooth (IEEE 802.15.x). VLAN tagging (IEEE 802.1Q) and link-layer bridging/switching operate at this layer. Some link-layer protocols provide reliable delivery (e.g., PPP, HDLC), while most Ethernet in switched networks relies on higher-layer protocols for end-to-end reliability.

In practice, devices such as switches, bridges, and network interface cards operate primarily at the link layer, learning MAC addresses to forward frames and isolating collision domains in legacy networks. Security considerations at the link layer include MAC spoofing risks and port-based access control mechanisms like 802.1X.