A multi-link convergence method, comprising: receiving, by a server, a first binding request sent by a client by using a first link, wherein at least two links are established between the client and the server, and the first link is one link in the at least two links; sending, by the server, a first link session identity, LSID, to the client by using the first link; receiving, by the server, a first authentication request sent by the client by using the first link, wherein the first authentication request comprises the first LSID and first authentication information; performing, by the server, authentication on the first link according to the first authentication request; characterized in that the method further comprises: if the first link is authenticated successfully, sending, by the server, a binding identity, BID, to the client by using the first link; receiving, by the server, a second binding request sent by the client by using a second link, wherein the second binding request carries the BID, and the second link is a link other than the first link in the at least two links; sending, by the server, a second LSID to the client by using the second link; receiving, by the server, a second authentication request sent by the client by using the second link, wherein the second authentication request comprises the second LSID and second authentication information; performing, by the server, authentication on the second link according to the second authentication request; and if the second link is authenticated successfully, sending, by the server, a binding acknowledgement message to the client by using the second link, so that the client can use both the first link and the second link to send to-be-sent data packets, wherein extension headers of the to-be-sent data packets carry the BID. receiving, by a server, a first binding request sent by a client by using a first link, wherein at least two links are established between the client and the server, and the first link is one link in the at least two links; sending, by the server, a first link session identity, LSID, to the client by using the first link; receiving, by the server, a first authentication request sent by the client by using the first link, wherein the first authentication request comprises the first LSID and first authentication information; performing, by the server, authentication on the first link according to the first authentication request; characterized in that the method further comprises: if the first link is authenticated successfully, sending, by the server, a binding identity, BID, to the client by using the first link; receiving, by the server, a second binding request sent by the client by using a second link, wherein the second binding request carries the BID, and the second link is a link other than the first link in the at least two links; sending, by the server, a second LSID to the client by using the second link; receiving, by the server, a second authentication request sent by the client by using the second link, wherein the second authentication request comprises the second LSID and second authentication information; performing, by the server, authentication on the second link according to the second authentication request; and if the second link is authenticated successfully, sending, by the server, a binding acknowledgement message to the client by using the second link, so that the client can use both the first link and the second link to send to-be-sent data packets, wherein extension headers of the to-be-sent data packets carry the BID. if the first link is authenticated successfully, sending, by the server, a binding identity, BID, to the client by using the first link; receiving, by the server, a second binding request sent by the client by using a second link, wherein the second binding request carries the BID, and the second link is a link other than the first link in the at least two links; sending, by the server, a second LSID to the client by using the second link; receiving, by the server, a second authentication request sent by the client by using the second link, wherein the second authentication request comprises the second LSID and second authentication information; performing, by the server, authentication on the second link according to the second authentication request; and if the second link is authenticated successfully, sending, by the server, a binding acknowledgement message to the client by using the second link, so that the client can use both the first link and the second link to send to-be-sent data packets, wherein extension headers of the to-be-sent data packets carry the BID.