A data transmission method, comprising: receiving, by a first access network device, a data packet sent by user equipment, wherein the data packet comprises a first cookie and raw data; verifying, by the first access network device, the first cookie, to obtain a verification result; and processing, by the first access network device, the raw data based on the verification result, wherein the first cookie comprises an expire time T, and the first access network verifies the first cookie at a time T0; and the verifying, by the first access network device, the first cookie, to obtain a verification result comprises: if TO < T - TX, the verification result is that the first cookie is valid; if T - TX < TO < T + TX, the verification result is that the first cookie is to expire; or if TO > T + TX, the verification result is that the first cookie is invalid, wherein TX is a preset time value, wherein the processing, by the first access network device, the raw data based on the verification result comprises: if the verification result is that the first cookie is valid, decrypting, by the first access network device, the raw data, and sending the decrypted raw data to a core network device; or if the verification result is that the first cookie is to expire, performing, by the first access network device, fast re-authentication with the user equipment, to update the first cookie in the user equipment, and sending, by the first access network device, the decrypted raw data to a core network device. receiving, by a first access network device, a data packet sent by user equipment, wherein the data packet comprises a first cookie and raw data; verifying, by the first access network device, the first cookie, to obtain a verification result; and processing, by the first access network device, the raw data based on the verification result, wherein the first cookie comprises an expire time T, and the first access network verifies the first cookie at a time T0; and the verifying, by the first access network device, the first cookie, to obtain a verification result comprises: if TO < T - TX, the verification result is that the first cookie is valid; if T - TX < TO < T + TX, the verification result is that the first cookie is to expire; or if TO > T + TX, the verification result is that the first cookie is invalid, wherein TX is a preset time value, wherein the processing, by the first access network device, the raw data based on the verification result comprises: if the verification result is that the first cookie is valid, decrypting, by the first access network device, the raw data, and sending the decrypted raw data to a core network device; or if the verification result is that the first cookie is to expire, performing, by the first access network device, fast re-authentication with the user equipment, to update the first cookie in the user equipment, and sending, by the first access network device, the decrypted raw data to a core network device. if TO < T - TX, the verification result is that the first cookie is valid; if T - TX < TO < T + TX, the verification result is that the first cookie is to expire; or if TO > T + TX, the verification result is that the first cookie is invalid, wherein TX is a preset time value, wherein the processing, by the first access network device, the raw data based on the verification result comprises: if the verification result is that the first cookie is valid, decrypting, by the first access network device, the raw data, and sending the decrypted raw data to a core network device; or if the verification result is that the first cookie is to expire, performing, by the first access network device, fast re-authentication with the user equipment, to update the first cookie in the user equipment, and sending, by the first access network device, the decrypted raw data to a core network device. if the verification result is that the first cookie is valid, decrypting, by the first access network device, the raw data, and sending the decrypted raw data to a core network device; or if the verification result is that the first cookie is to expire, performing, by the first access network device, fast re-authentication with the user equipment, to update the first cookie in the user equipment, and sending, by the first access network device, the decrypted raw data to a core network device.