The Data Link layer performs a number of separate activities, including:
Different data link layer specifications define different network and protocol characteristics, including physical addressing, network topology, error notification, sequencing of frames, and flow control.
Physical addressing, is not to be confused with network or IP addresing. The physical address defines how devices are labeled in the data link layer. This physical address is most commonly called the Media Access Control (MAC) address. The MAC address is a unique number assigned by the manufacturer. This numbering system is actually administered by one of the networking governing bodies.
Tags: data link layer, link layer, data link layer data packet segmentation, datalink layer, link-layer, linklayer, data segment packet frame bits, packet layers, physical/data link layers, osi frame packet segment