Handover method and communication apparatus
A handover method and a communication apparatus are provided. The method includes: A target access network device obtains a first message and information used for transmitting multicast data, where the first message is used for requesting to establish a resource for handing over a terminal device to the target access network device. The target access network device sends a second message, where the second message indicates the established resource on the target access network device; receives a first packet from a user plane network element, where the first packet corresponds to the information used for transmitting the multicast data; and sends the first packet to the terminal device. In this way, the terminal device is handed over from a source access network device to the target access network device when the terminal device receives the multicast data.
1 . A handover method, comprising:
receiving, by a target access network device, a first message requesting establishment of a resource for handing over a terminal device to the target access network device;
obtaining, by the target access network device from the first message, information for transmitting multicast data;
sending, by the target access network device, a second message indicating the established resource on the target access network device, wherein the second message carries related information for the terminal device to access the target access network device and container information sent to the terminal device;
receiving, by the target access network device, a first packet from a user plane network element, wherein the first packet corresponds to the information for transmitting the multicast data and includes a first sequence number corresponding to the first packet;
receiving, by the target access network device, a second packet from a source access network device through a forwarding tunnel, wherein the second packet corresponds to the information for transmitting the multicast data and includes a second sequence number corresponding to the second packet, and wherein the second packet is received by the source access network device from the user plane network element; and
sending, by the target access network device, the first packet to the terminal device when the first sequence number is less than or equal to the second sequence number, and sending, by the target access network device, the second packet to the terminal device when the first sequence number is greater than the second sequence number.
2 . The method according to claim 1 , further comprising:
buffering, by the target access network device, the first packet; and
sending, by the target access network device, the buffered first packet to the terminal device.
3 . A communication apparatus, comprising:
a non-transitory memory storage comprising instructions; and
one or more processors in communication with the memory storage, wherein execution of the instructions by the one or more processors causes the communication apparatus to:
receive a first message requesting establishment of a resource for handing over a terminal device to a target access network device;
obtain, from the first message, information for transmitting multicast data;
send a second message indicating the established resource on the target access network device, wherein the second message carries related information for the terminal device to access the target access network device and container information sent to the terminal device;
receive a first packet from a user plane network element, wherein the first packet corresponds to the information for transmitting the multicast data and includes a first sequence number corresponding to the first packet;
receive a second packet from a source access network device through a forwarding tunnel, wherein the second packet corresponds to the information for transmitting the multicast data and comprises a second sequence number corresponding to the second packet, and wherein the second packet is received by the source access network device from the user plane network element; and
send to the terminal device the first packet when the first sequence number is less than or equal to the second sequence number and send to the terminal device the second packet when the first sequence number is greater than the second sequence number.
4 . The apparatus according to claim 3 , wherein execution of the instructions by the one or more processors further causes the communication apparatus to:
buffer the first packet; and
send the buffered first packet to the terminal device.
5 . A handover system, comprising:
a source access network device; and
a target access network device, wherein:
the source access network device is configured to send a first message requesting establishment of a resource for handing over a terminal device to the target access network device, wherein the first message comprises information for transmitting multicast data;
the target access network device is configured to receive the first message and to send a second message indicating an established resource on the target access network device, wherein the second message carries related information for the terminal device to access the target access network device and container information sent to the terminal device;
the source access network device is further configured to receive the second message; and
the target access network device is configured to receive a first packet from a user plane network element and to send the first packet to the terminal device, wherein the first packet corresponds to the information for transmitting the multicast data and includes a first sequence number corresponding to the first packet;
the source access network device is configured to send to the target access network device through a forwarding tunnel a second packet corresponding to the information for transmitting the multicast data, the second packet including a second sequence number corresponding to the second packet, and wherein the second packet is received by the source access network device from the user plane network element;
wherein the target access network device is further configured to:
send the first packet to the terminal device when the first sequence number is less than or equal to the second sequence number; and
send the second packet to the terminal device when the first sequence number is greater than the second sequence number.
6 . The system according to claim 5 , wherein the target access network device is configured to:
buffer the first packet; and
send the buffered first packet to the terminal device.
7 . A non-transitory computer readable storage medium comprising instructions which, when executed by one or more processors, cause the one or more processors to perform operations comprising:
receiving a first message, wherein the first message includes a request to establish a resource for handing over a terminal device to a target access network device;
obtaining, from the first message, information for transmitting multicast data;
sending a second message indicating the established resource on the target access network device, wherein the second message carries related information for the terminal device to access the target access network device and container information sent to the terminal device;
receiving a first packet from a user plane network element, the first packet corresponding to the information for transmitting the multicast data and comprising a first sequence number corresponding to the first packet;
receiving a second packet from a source access network device through a forwarding tunnel, wherein the second packet corresponds to the information for transmitting the multicast data and comprises a second sequence number corresponding to the second packet, and wherein the second packet is received by the source access network device from the user plane network element; and
sending to the terminal device the first packet when the first sequence number is less than or equal to the second sequence number and send to the terminal device the second packet when the first sequence number is greater than the second sequence number.