The pair of signal wires (CAN_H and CAN_L) constitutes a transmission line. If the transmission line is not terminated, each signal change on the line causes reflections that may cause communication failures.
Every device on the Low-Speed CAN network requires a termination resistor for each CAN data line: RRTH for CAN_H and RRTL for CAN_L. The following figure shows termination resistor placement in a Low-Speed CAN network.
To determine the correct termination resistor values for the Low-Speed CAN transceiver, refer to the Determining the Necessary Termination Resistance for Your Low-Speed CAN Device topic.