A method for sending a Hello packet on a transparent interconnection of lots of links TRILL network, comprising: fragmenting, by a first network device, a first Hello packet into m Hello fragment packets in a preset packet fragmentation manner, wherein each Hello fragment packet has a fragment ID and a content identifier, wherein when content of an n th Hello fragment packet corresponding to the first Hello packet is different from content of an n th Hello fragment packet corresponding to a second Hello packet, a content identifier of the n th Hello fragment packet corresponding to the first Hello packet is set to be different from a content identifier of the n th Hello fragment packet corresponding to the second Hello packet, wherein n is a fragment ID of the n th Hello fragment packet, n can be all positive integers ranging from 1 to m, and m is a positive integer; the second Hello packet is a Hello packet sent by the first network device at the last time before sending the first Hello packet, and the first network device has already fragmented the second Hello packet into p Hello fragment packets in the preset packet fragmentation manner, wherein p is a positive integer; sending, by the first network device, fragment brief information of the first Hello packet to a second network device, wherein the fragment brief information of the first Hello packet comprises fragment information of each Hello fragment packet of the m Hello fragment packets, and the fragment information comprises the fragment ID and the content identifier; and sending a Hello fragment packet corresponding to the first Hello packet to the second network device if the first network device receives a request packet sent by the second network device, wherein the request packet is sent after the second network device receives the fragment brief information of the first Hello packet and determines that the fragment brief information of the first Hello packet is different from fragment brief information of the second Hello packet saved on the second network device, and the fragment brief information of the second Hello packet comprises fragment information of each Hello fragment packet of the p Hello fragment packets. fragmenting, by a first network device, a first Hello packet into m Hello fragment packets in a preset packet fragmentation manner, wherein each Hello fragment packet has a fragment ID and a content identifier, wherein when content of an n th Hello fragment packet corresponding to the first Hello packet is different from content of an n th Hello fragment packet corresponding to a second Hello packet, a content identifier of the n th Hello fragment packet corresponding to the first Hello packet is set to be different from a content identifier of the n th Hello fragment packet corresponding to the second Hello packet, wherein n is a fragment ID of the n th Hello fragment packet, n can be all positive integers ranging from 1 to m, and m is a positive integer; the second Hello packet is a Hello packet sent by the first network device at the last time before sending the first Hello packet, and the first network device has already fragmented the second Hello packet into p Hello fragment packets in the preset packet fragmentation manner, wherein p is a positive integer; sending, by the first network device, fragment brief information of the first Hello packet to a second network device, wherein the fragment brief information of the first Hello packet comprises fragment information of each Hello fragment packet of the m Hello fragment packets, and the fragment information comprises the fragment ID and the content identifier; and sending a Hello fragment packet corresponding to the first Hello packet to the second network device if the first network device receives a request packet sent by the second network device, wherein the request packet is sent after the second network device receives the fragment brief information of the first Hello packet and determines that the fragment brief information of the first Hello packet is different from fragment brief information of the second Hello packet saved on the second network device, and the fragment brief information of the second Hello packet comprises fragment information of each Hello fragment packet of the p Hello fragment packets.