Link Layer Services(more) o Flow Control o Pacing between adjacent sending and receiving nodes o Error detection o Errors caused by signal attenuation, noise o Receiver detects presence of errors Signals sender for retransmission or drops frame o Error correction: o Receiver identifies and corrects bit error(s] without resorting to retransmission o Half-duplex and full-duplex e With half duplex, nodes at both ends of link can transmit but not at same time 5: DatLink Layer Services (more)  Flow Control:  Pacing between adjacent sending and receiving nodes  Error Detection:  Errors caused by signal attenuation, noise.  Receiver detects presence of errors:  Signals sender for retransmission or drops frame  Error Correction:  Receiver identifies and corrects bit error(s) without resorting to retransmission  Half-duplex and full-duplex  With half duplex, nodes at both ends of link can transmit, but not at same time 5: DataLink Layer 5-5