rdt2.0: FSM specification rat rcv(rcvpkt)&& corrupt(rcvpkt) rat send(data) udt send(NACK compute checksum make pkt(sndpkt, data, checksum) udt send(sndpkt wait for W ait for rat rcv(rcvpkt & is NACK(rcvpkt) cd‖from ca‖from ACK or below above AK uat send(sndpkt) rat rcv(rcvpkt rat rcv(rcvpkt)&& & isACKircvokt notcorrupt(rcvpkt) extract(rcvpkt, data deliver data(data uat send(ACK) sender FSM receiver FSM 3: Transport Layer 3a-153: Transport Layer 3a-15 rdt2.0: FSM specification sender FSM receiver FSM