Link layer is the network layer to provide data transmission services, such services have to rely on the function of this layer to achieve. Link layer should have the following functions:
① link connection establishment, removal, separation.
② frame delimitation and frame synchronization. Link-layer data transmission unit is the frame, the agreement is different from the length of the frame and interface is also a difference, but in any case must be delimited frames.
③ sequence control, refers to the order of sending and receiving frame control.
① link connection establishment, removal, separation.
② frame delimitation and frame synchronization. Link-layer data transmission unit is the frame, the agreement is different from the length of the frame and interface is also a difference, but in any case must be delimited frames.
③ sequence control, refers to the order of sending and receiving frame control.
