Link 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 Link Layer and LANs 6-7▪ 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 Link layer services (more) Link Layer and LANs 6-7