DATALINK LAYER
Definition:
The data link layer provides error-free transfer of data frames from one node to another over the physical layer, allowing layers above it to assume virtually error-free transmission over the link. To do this, the data link layer provides
Link establishment and termination:
It establishes and terminates the logical link between two nodes.
Frame traffic control:
It tells the transmitting node to "back-off" when no frame buffers are available.
Frame sequencing:
It transmits/receives frames sequentially.
Frame acknowledgment:
It provides/expects frame acknowledgments. Detects and recovers from errors that occur in the physical layer by retransmitting non-acknowledged frames and handling duplicate frame receipt.
Frame delimiting:
It creates and recognizes frame boundaries.
Frame error checking:
It checks received frames for integrity.
Media access management:
It determines when the node "has the right" to use the physical medium.