The present disclosure discloses network devices and systems for sending and receiving service packet. The network device is configured to: receive an insensitive service packet; obtain a current slicing length according to a modulation mode of a communication link; perform slicing processing once on the insensitive service packet according to the current slicing length to obtain one slice, and send the slice through the communication link, If the current slicing length is smaller than a length of the insensitive service packet, for the remaining part of the insensitive service packet which has undergone the slicing processing once, the network device repeats the obtaining of the current slicing length, the slicing processing, and the sending the slice, until the insensitive service packet is completely sent.