Domain name server allocation method and apparatus

1. A method of domain name system (DNS) server allocation, comprising:

receiving, by a session management function (SMF), a session establishment request message from user equipment (UE), wherein the request message comprises a name of a data network to be accessed by the UE;

determining, by the SMF, a first user plane function (UPF) based on the data network to be accessed by the UE and a location of the UE, and determining a first data network access identifier (DNAI) based on the first UPF and the data network;

querying, by the SMF, a list of mapping relationships between IP addresses of DNS servers and DNAIs based on the first DNAI, to obtain an IP address of a first DNS server; and

sending, by the SMF, a session establishment response message to the UE, wherein the response message comprises the IP address of the first DNS server.

2. The method according to claim 1 , wherein the step of querying comprises obtaining the list of mapping relationships between IP addresses of DNS servers and DNAIs from a policy control function (PCF).

3. The method according to claim 1 , wherein the step of determining the first UPF comprises selecting the first UPF from a plurality of UPFs based on a relatively light load of the first UPF.

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

receiving, by the first UPF, a DNS request message from the UE, wherein the request message comprises a domain name of an application service that the UE requests to access, and a destination address of the request message is the IP address of the first DNS server;

routing, by the first UPF, the request message to the first DNS server based on the destination address;

receiving, by the first UPF, a response message from the first DNS server, wherein the response message comprises an IP address of the domain name of the requested application service; and

sending, by the first UPF, the response message to the UE.

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

detecting, by the SMF, that the UE moves to a new geographical location;

obtaining, by the SMF, an IP address of a second DNS server based on a name of a data network currently accessed by the UE and the new geographical location of the UE; and

initiating, by the SMF, a PDU session modification request to the UE, wherein the modification request comprises the IP address of the second DNS server.

6. The method according to claim 5 , wherein the step of obtaining the IP address of the second DNS server comprises:

determining, by the SMF, a second UPF, and determining a second DNAI based on the second UPF and the data network currently accessed by the UE; and

querying, by the SMF, the list of mapping relationships between IP addresses of DNS servers and DNAIs based on the second DNAI, to obtain the IP address of the second DNS server.

7. The method according to claim 6 , further comprising:

receiving, by the second UPF, a DNS request message from the UE, wherein the request message comprises a domain name of an application service that the UE requests to access, and a destination address of the request message is the IP address of the second DNS server;

routing, by the second UPF, the request message to the second DNS server;

receiving, by the second UPF, a response message from the second DNS server, wherein the response message comprises an IP address of the domain name of the requested application service; and

sending, by the second UPF, the response message to the UE.

8. The method according to claim 6 , wherein the step of determining the second UPF comprises:

determining, by the SMF, the second UPF based on the data network to be accessed by the UE and the geographical location of the UE after the UE moves.

9. A domain name system (DNS) server allocation system, comprising:

a session management function (SMF); and

a user plane function (UPF),

wherein the SMF comprises:

a memory storing executable instructions; and

a processor configured to execute the executable instructions in the memory of the SMF to perform operations of:

receiving a session establishment request message from user equipment (UE), wherein the session establishment request message comprises a name of a data network to be accessed by the UE;

determining a first user plane function (UPF) based on the data network to be accessed by the UE and a location of the UE, and determine a first data network access identifier (DNAI) based on the first UPF and the data network;

querying a list of mapping relationships between IP addresses of DNS servers and DNAIs based on the first DNAI, to obtain an IP address of a first DNS server; and

sending a session establishment response message to the UE, wherein the session establishment response message comprises the IP address of the DNS server;

wherein the UPF comprises:

a memory storing executable instructions; and

a processor configured to execute the executable instructions in the memory of the UPF to perform operations of:

receiving a DNS request message from the UE, wherein the DNS request message comprises a domain name of an application service that the UE requests to access, and a destination address of the DNS request message is the IP address of the DNS server;

routing the DNS request message to the DNS server based on the destination address;

receiving a DNS response message from the DNS server, wherein the DNS response message received from the DNS server comprises an IP address of the domain name of the requested application service; and

sending the DNS response message received from the DNS server to the UE.

10. The system according to claim 9 , further comprising an application function, wherein the application function comprises:

a memory storing executable instructions;

a processor configured to execute the executable instructions in the memory of the application function to perform operations:

creating the list of mapping relationships between IP addresses of DNS servers and DNAIs; and

sending said list of mapping relationships to a policy control function (PCF), wherein the operation of the SMF querying comprises obtaining said list of mapping relationships from the PCF, and wherein the application function is an MEC platform, an MEC platform manager, or an MEC orchestrator in a multi-access edge computing MEC system.

11. An apparatus for domain name system (DNS) server allocation, comprising:

a memory storing executable instructions;

a processor configured to execute the executable instructions to:

receive a session establishment request message from a UE, wherein the request message comprises a name of a data network to be accessed by the UE;

determine a first user plane function (UPF) based on the data network to be accessed by the UE and a location of the UE, and determining a first data network access identifier (DNAI) based on the first UPF and the data network;

query a list of mapping relationships between IP addresses of DNS servers and DNAIs based on the first DNAI, to obtain an IP address of a first DNS server; and send a session establishment response message to the UE, wherein the response message comprises the IP address of the DNS server.

12. The apparatus according to claim 11 , wherein the processor is configured to receive the list of mapping relationships between IP addresses of DNS servers and DNAIs from a policy control function (PCF).