Embodiments of the present invention provide a method, network device, and system for sending and receiving a packet. The method includes fragmenting, by a first network device, a first Hello packet. Each Hello fragment packet has a fragment ID and a content identifier. The first network device sends fragment brief information of the first Hello packet to a second network device. The fragment brief information of the first Hello packet includes fragment information of each Hello fragment packet. The first network device sends the Hello fragment packet corresponding to the first Hello packet if the first network device receives a request packet sent by the second network device.