Communication method and apparatus

1. A communication method comprising:

sending a session establishment request message to a session management function network element, wherein the session establishment request message is for requesting to establish or modify a session;

receiving at least one of a session identifier or an address of a terminal from the session management function network element, wherein both the session identifier and the address of the terminal correspond to the session;

obtaining virtual interface information corresponding to the at least one of the session identifier or the address of the terminal, wherein the virtual interface information is an identifier of a virtual interface between the terminal and an access gateway function network element; and

sending the virtual interface information and the at least one of the session identifier or the address of the terminal to the terminal;

wherein the obtaining of the virtual interface information corresponding to the at least one of the session identifier or the address of the terminal comprises:

receiving an access stratum message from the terminal, wherein the access stratum message comprises the virtual interface information; and

determining that the virtual interface information corresponds to the session identifier.

2. The method according to claim 1 , further comprising:

receiving a packet from a user plane function network element, wherein the packet comprises a user plane tunnel identifier of the user plane function network element; and

determining, based on a session identifier corresponding to the user plane tunnel identifier, the virtual interface information corresponding to the session identifier, and sending the packet to the terminal through a virtual interface corresponding to the virtual interface information, wherein the virtual interface is the virtual interface between the terminal and the access gateway function network element.

3. The method according to claim 1 , wherein identifier of the virtual interface is configured to distinguish between virtual channel information of a fixed network service.

4. The method according to claim 1 , wherein the virtual interface information is virtual path identifier (VPI) or virtual channel identifier (VCI) information in a digital subscriber line (DSL).

5. The method according to claim 1 , wherein the virtual interface information is a virtual local area network (VLAN) identifier accessible by an ethernet.

6. A communication method comprising:

sending a session establishment request message to a session management function network element, wherein the session establishment request message is for requesting to establish or modify a session;

receiving at least one of a session identifier or an address of a terminal from the session management function network element, wherein both the session identifier and the address of the terminal correspond to the session;

obtaining virtual interface information corresponding to the at least one of the session identifier or the address of the terminal, wherein the virtual interface information is an identifier of a virtual interface between the terminal and an access gateway function network element;

sending the virtual interface information and the at least one of the session identifier or the address of the terminal to the terminal;

receiving a packet from the terminal, wherein the packet comprises the virtual interface information; and

sending the packet to a user plane function network element based on the session identifier corresponding to the virtual interface information via a user plane tunnel corresponding to the session identifier, wherein the user plane tunnel is a transmission channel between the access gateway function network element and the user plane function network element.

7. A communication apparatus comprising: a transceiver; at least one processor; and one or more memories coupled to the at least one processor and storing programming instructions which when executed by the at least one processor cause the communication apparatus to at least perform:

sending a session establishment request message to a session management function network element, wherein the session establishment request message is for requesting to establish or modify a session;

receiving at least one of a session identifier or an address of a terminal from the session management function network element, wherein both the session identifier and the address of the terminal correspond to the session;

obtaining virtual interface information corresponding to the at least one of the session identifier or the address of the terminal, wherein the virtual interface information is an identifier of a virtual interface between the terminal and an access gateway function network element;

sending the virtual interface information and the at least one of the session identifier or the address of the terminal to the terminal;

receiving an access stratum message from the terminal, wherein the access stratum message comprises the virtual interface information; and

determining that the virtual interface information corresponds to the session identifier.

8. The communication apparatus according to claim 7 , wherein the programming instructions, when executed by the at least one processor, cause the communication apparatus to further perform:

receiving a packet from a user plane function network element, wherein the packet comprises a user plane tunnel identifier of the user plane function network element; and

determining, based on a session identifier corresponding to the user plane tunnel identifier, the virtual interface information corresponding to the session identifier, and sending the packet to the terminal through a virtual interface corresponding to the virtual interface information, wherein the virtual interface is the virtual interface between the terminal and the access gateway function network element.

9. The communication apparatus according to claim 7 , wherein identifier of the virtual interface is configured to distinguish between virtual channel information of a fixed network service.

10. The communication apparatus according to claim 7 , wherein the virtual interface information is virtual path identifier (VPI) or virtual channel identifier (VCI) information in a digital subscriber line (DSL).

11. The communication apparatus according to claim 7 , wherein the virtual interface information is a virtual local area network (VLAN) identifier accessible by an ethernet.

12. A communication apparatus comprising: a transceiver; at least one processor; and one or more memories coupled to the at least one processor and storing programming instructions which when executed by the at least one processor cause the communication apparatus to at least perform:

sending a session establishment request message to a session management function network element, wherein the session establishment request message is for requesting to establish or modify a session;

receiving at least one of a session identifier or an address of a terminal from the session management function network element, wherein both the session identifier and the address of the terminal correspond to the session;

obtaining virtual interface information corresponding to the at least one of the session identifier or the address of the terminal, wherein the virtual interface information is an identifier of a virtual interface between the terminal and an access gateway function network element;

sending the virtual interface information and the at least one of the session identifier or the address of the terminal to the terminal;

receiving a packet from the terminal, wherein the packet comprises the virtual interface information; and

sending the packet to a user plane function network element based on the session identifier corresponding to the virtual interface information via a user plane tunnel corresponding to the session identifier, wherein the user plane tunnel is a transmission channel between the access gateway function network element and the user plane function network element.