WO2021253301A1

WO2021253301A1 - Method and apparatus for providing server discovery information

Info

Publication number: WO2021253301A1
Application number: PCT/CN2020/096667
Authority: WO
Inventors: Tingfang Tang; Dimitrios Karampatsis
Original assignee: Lenovo (Beijing) Limited
Priority date: 2020-06-17
Filing date: 2020-06-17
Publication date: 2021-12-23

Abstract

Embodiments of the present disclosure relate to methods and apparatuses for providing server discovery information. According to an embodiment of the present disclosure, a method performed at a first network function includes: receiving server discovery information from a second network function; and sending a domain name service (DNS) query to a target DNS server in a data network based at least in part on the server discovery information.

Description

METHOD AND APPARATUS FOR PROVIDING SERVER DISCOVERY INFORMATION

TECHNICAL FIELD

Embodiments of the present disclosure are related to wireless communication technology, and more particularly, related to methods and apparatuses for providing server discovery information.

BACKGROUND

Wireless communication technologies have been developed to support edge computing in a 5G core network (5GC) . In edge computing deployment, one application service might be served by multiple edge application servers (EAS) typically deployed in different sites. These multiple EAS instances that host the same content or service may use a single Intemet protocol (IP) address (anycast address) or different IP addresses. A user equipment (UE) accesses an application server via a user plane function (UPF) , which is used as a protocol data unit (PDU) session anchor (PSA) , by a PDU session. The PDU session is established between the UE and the PSA UPF. One PDU session may support one or more applications. Before an application or user equipment (UE) starts to connect to the service, it is very important for the application or UE to discover an IP address of a suitable EAS (e.g., the one closest to the UE) , so that the traffic can be locally routed to the EAS via uplink classifier or branching point (UL CL/BP) mechanisms or a PDU session established directly with the local data network (DN) where the EAS is deployed, and service latency, traffic routing path and user service experience can be optimized. Also, once a discovered EAS becomes non-optimized (e.g., after the UE moves far away) , a new EAS may be discovered and used to replace the old one to serve the application or UE.

Thus, how to support efficient discovery of a suitable EAS is an important issue to be resolved for edge computing.

SUMMARY

According to an embodiment of the present disclosure, a method performed at a first network function may include: receiving server discovery information from a second network function; and sending a domain name service (DNS) query to a target DNS server in a data network based at least in part on the server discovery information.

According to another embodiment of the present disclosure, a method performed at a first network function may include: obtaining information on server discovery; and sending the information on server discovery to a core network.

According to another embodiment of the present disclosure, amethod performed at a first network function may include: receiving information on server discovery from a second network function; and sending server discovery information based on the information on server discovery to a third network function.

According to another embodiment of the present disclosure, a method performed at a first network function may include: obtaining information on server discovery; and sending server discovery information based on the information on server discovery to a second network function.

According to yet another embodiment of the present disclosure, an apparatus may include: at least one non-transitory computer-readable medium having stored thereon computer executable instructions; at least one receiving circuitry; at least one transmitting circuitry; and at least one processor coupled to the at least one non-transitory computer-readable medium, the at least one receiving circuitry and the at least one transmitting circuitry. The computer executable instructions may cause the at least processor to implement a method according to any embodiment of the present disclosure.

The details of one or more examples are set forth in the accompanying drawings and the description below. Other features, objects, and advantages will be apparent from the description and drawings, and from the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to describe the manner in which advantages and features of the present disclosure can be obtained, a description of the present disclosure is rendered by reference to specific embodiments thereof which are illustrated in the appended drawings. These drawings depict only exemplary embodiments of the present disclosure and are not therefore intended to limit the scope of the present disclosure.

FIG. 1 illustrates an exemplary network architecture supporting edge computing, in accordance with some embodiments of the present disclosure;

FIG. 2 illustrates a flow chart of an exemplary procedure for providing server discovery information using a traffic routing information provisioning procedure, in accordance with some embodiments of the present disclosure;

FIG. 3 illustrates a flow chart of an exemplary procedure for providing server discovery information using a service provided by a unified data repository (UDR) , in accordance with some embodiments of the present disclosure;

FIG. 4 illustrates a flow chart of an exemplary procedure for providing server discovery information using a service provided by a policy control function (PCF) , in accordance with some embodiments of the present disclosure;

FIG. 5 illustrates a flow chart of an exemplary parameter provisioning procedure used for providing server discovery information, in accordance with some embodiments of the present disclosure;

FIG. 6 illustrates an exemplary block diagram of an apparatus, in accordance with some embodiments of the present disclosure;

FIG. 7 illustrates an exemplary block diagram of another apparatus, in accordance with some embodiments of the present disclosure;

FIG. 8 illustrates an exemplary block diagram of another apparatus, in accordance with some embodiments of the present disclosure; and

FIG. 9 illustrates an exemplary block diagram of another apparatus, in accordance with some embodiments of the present disclosure.

DETAILED DESCRIPTION

The detailed description of the appended drawings is intended as a description of the currently preferred embodiments of the present disclosure and is not intended to represent the only form in which the present disclosure may be practiced. It is to be understood that the same or equivalent functions may be accomplished by different embodiments that are intended to be encompassed within the spirit and scope of the present disclosure.

In the following description, numerous specific details are provided, such as examples of programming, software modules, network transactions, database structures, hardware modules, hardware circuits, etc., to provide a thorough understanding of embodiments. One skilled in the relevant art will recognize, however, that embodiments may be practiced without one or more of the specific details, or with other methods, components, materials, and so forth. In other instances, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring aspects of an embodiment.

Reference will now be made in detail to some embodiments of the present disclosure, examples of which are illustrated in the accompanying drawings. To facilitate understanding, embodiments are provided under specific network architecture and new service scenarios, such as 3rd Generation Partnership Project (3GPP) 5G, 3GPP Long Term Evolution (LTE) and so on. Persons skilled in the art know very well that, with the development of network architecture and new service scenarios, the embodiments in the present disclosure are also applicable to similar technical problems; and moreover, the terminologies recited in the present disclosure may change, which should not affect the principle of the present disclosure.

FIG. 1 illustrates an exemplary network architecture 100 supporting edge computing. The network architecture 100 includes several network functions (NFs) , in which the techniques, processes and methods described herein can be implemented, in accordance with various embodiments. An NF may be implemented either as a network element on a dedicated hardware, as a software instance running on a dedicated hardware, or as a virtualized function instantiated on an appropriate platform, e.g., a cloud infrastructure. A single NF may be implemented by a single entity or multiple entities in conjunction.

Seen from the core network side, the network architecture 100 shown in FIG. 1 includes a network exposure function (NEF) 102, a policy control function (PCF) 104, an application function (AF) 106, an access and mobility management function (AMF) 108, and a session management function (SMF) 110. Nnefis a service-based interface exhibited by the NEF 102. Npcf is a service-based interface exhibited by the PCF 104. Nar is a service-based interface exhibited by the AF 106. Namf is a service-based interface exhibited by the AMF 108. Nsmf is a service-based interface exhibited by the SMF 110.

Seen from the access side, the network architecture 100 shown in FIG. 1 includes a UE 112 connected to an access network (AN) 112 as well as to the AMF 108. Typically, the AN 112 includes one or more base stations, e.g., enhanced or evolved Node Bs (eNBs) , 5G base stations (gNBs) or the like. The AN 112 may connect to a data network (DN) 122 via a user plane function (UPF) 116 and a UPF 118, and to a DN 124 via the UPF 116 and a UPF 120. A UPF to steer a traffic can be a UL CL or BP UPF (e.g., UPF 116) when there are multiple PSA UPFs (e.g., UPFs 118 and 120) for a PDU session. The UL CL or BP UPF can be a standalone UPF or be co-located with a PSA UPF. The UPF to steer a traffic can also be a PSA UPF or a UPF of N3 terminating point when there is only one PSA UPF for a PDU session (which means that there is no UL CL or BP UPF) . The SMF 110 may make routing decisions for traffic of PDU sessions. For example, the SMF 110 may decide to select which of UPFs 118 and 120 as a PSA for a traffic. The UE 112 communicates with the AMF 108 via an interface N1. The AN 114 communicates with the AMF 108 via an interface N2, and communicates with the UPF 116 via an interface N3. The UPFs 116, 118, and 120 communicate with the SMF 110 via an interface N4, respectively. The UPF 116 communicates with the UPFs 118 and 120 via an interface N9, respectively. The UPFs 118 and 120 communicate with the

DNs

122 and 124 via an interface N6, respectively. Although only one UE and two DNs are depicted in FIG. 1, it is contemplated that any number of UEs and DNs may be included in the network architecture 100. Further, the network architecture 100 may also include other components, for example, other NFs not shown in FIG. 1.

As shown in FIG. 1, one or more EAS 126 may be deployed in the DN 124. Other DNs (e.g., DN 122) may also include one or more EAS. In edge computing deployment, one application service might be served by multiple EAS typically deployed in different sites. These multiple EAS instances that host the same content or service may use a single IP address (anycast address) or different IP addresses. Before an application or UE starts to connect to the service, it is very important for the application or UE to discover the IP address of a suitable EAS (e.g., the one closest to the UE) , so that the traffic can be locally routed to the EAS, and service latency, traffic routing path and user service experience can be optimized.

In 3GPP TS 23.501 and TS 23.502, "Application Function influence on traffic routing" is defined. An AF may send requests to influence SMF routing decisions for traffic of PDU sessions. Traffic routing information including a data network access identifier (DNAI) list per application or per traffic can be included in the AF requests. The AF requests may influence UPF (re) selection and allow routing user traffic to a local access to a DN (identified by a DNAI) . As defined in 3GPP TS 23.502 clause 5.6.7, the AF requests may contain the information as described in the following Table 1:

Table 1: Information element contained in an AF request

In 3GPP TS 23.502, "Traffic influence procedures" are specified in clause 4.3.6. The traffic routing procedure between the AF and the core network includes the following situations: (1) AF requests to influence traffic routing for Sessions identified by an UE address, (2) AF requests to influence traffic routing for Sessions not identified by an UE address, affecting future PDU sessions, and (3) AF requests to influence traffic routing for Sessions not identified by an UE address, affecting ongoing PDU sessions. If an AF request targets an individual UE address, such request will be routed to an individual PCF directly or via an NEF, and target an on-going PDU session managed by an SMF. The PCF will update the SMF with corresponding new policy and charging control (PCC) rules based on the AF request, e.g., via a PCF initiated session management (SM) policy association modification procedure. If an AF request targets PDU sessions that are not identified by an UE address, for such request, the AF will contact an NEF and the NEF will store information on the AF request in a unified data repository (UDR) . The stored information on the AF request can affect future PDU sessions or ongoing PDU sessions. For example, if a PCF subscribes to modifications olAF requests, the UDR will send a notification of data change to the PCF. Then the PCF will determine any PDU session that is potentially impacted by the AF request and update an SMF managing the PDU session with corresponding new PCC rules based on the AF request. Alternatively or additionally, the PCF can retrieve traffic routing information stored in the UDR and send it to the SMF, e.g., during a PDU session establishment. Through the above procedures, the SMF can get traffic routing information for an application or traffic after application detection.

3GPP TR 23.748 clause 6.6 provides a solution for discovery of EAS by reusing the domain name service (DNS) mechanism without additional impacts on a UE. In this solution, the DNS servers can be centrally deployed or locally deployed within an edge hosting environment. The core network provides information on a UE′s location (e.g., as specified by RFC 7871) to a centralized DNS (C-DNS) server or selects an appropriate localized DNS (L-DNS) server to resolve a DNS query from a UE to discover an IP address of a suitable EAS. The solution uses an SMF in the core network as a DNS forwarder. That is, the SMF receives a DNS query from a UE, and sends a DNS query for resolving the DNS query received from the UE to a C-DNS server or a selected L-DNS server with the address of the C-DNS server or a selected L-DNS server as a destination address. The L-DNS server is selected based on a UE location, the received DNS query, and DNAI (s) supporting the FQDN contained in the received DNS query. Thus, the SMF is required to be configured with traffic routing information for all the supported FQDN (s) in the above solution for discovery of EAS. However, if the traffic routing information is configured from an AF, according to the current AF influenced traffic routing procedure as described above, the SMF cannot obtain traffic routing information for all the supported FQDN (s) before application detection.

Various embodiments of the present disclosure provide solutions for providing server discovery information for edge computing to improve discovery of EAS.

In the present disclosure, the term "server discovery information" refers to information from which a target DNS server for DNS resolution for a target application can be determined. According to some embodiments of the present disclosure, the server discovery information includes at least one set of parameters, each set of parameters comprising one or more off (1) a list of one or more FQDNs, wherein each FQDN is associated with an application; (2) a DNAI supporting the FQDNs in the list; and (3) information of a DNS server. According to other embodiments of the present disclosure, the server discovery information includes an IP address of a target DNS server.

In the present disclosure, the term "information on server discovery" refers to information from which server discovery information can be obtained. The information on server discovery may be the server discovery information per se, include the server discovery information, or be different from the server discovery information. According to some embodiments of the present disclosure, the information on server discovery includes at least one set of parameters, each set of parameters comprising one or more of: (1) a list of one or more FQDNs, wherein each FQDN is associated with an application; (2) a DNAI supporting the FQDNs in the list; and (3) information of a DNS server. According to other embodiments of the present disclosure, the information on server discovery includes at least one FQDN associated with an application, and information of a DNS server in a data network for each FQDN.

It should be understood that other terms can be used to refer to the same information as the above two terms, without departing from the spirit and scope of the disclosure.

FIG. 2 illustrates a flow chart of an exemplary procedure for providing server discovery information using a traffic routing information provisioning procedure. In the embodiment shown in FIG. 2, a service provider may deploy services or applications into edge data networks (EDNs, also referred to as local DNs) . An AF can obtain information on server discovery for the services or applications deployed in the EDNs or local DNs. For example, this can be done via local configuration on the AF. The AF may send an AF request with traffic routing information identified or not identified by an UE address, which is used to influence traffic routing, to a core network (e.g., to an NEF in the core network) . The AF request may include information on server discovery. For simplicity, the embodiment shown in FIG. 2 merely relates to AF requests not identified by an UE address, i.e., the information on server discovery impact future PDU sessions. It is contemplated that the similar method can also be used to impact existing PDU sessions, for example, when the information on server discovery is sent to the core network after the PDU session establishment, or when the information on server discovery is updated due to a change of application deployment within the EDNs or local DNs.

As shown in FIG. 2, an AF transmits an AF request to influence traffic routing per application without an UE address to an NEF (step 202) . The AF request may include an FQDN associated with an application, which can be indicated in an application ID or a separate parameter. In some embodiments, an application may have different FQDNs for different DNAIs, and the AF request may include more than one FQDN for the application. The AF request may also include information of a DNS server for each FQDN. The DNS server can be an L-DNS server that can resolve the FQDN corresponding to the application.

The NEF stores the traffic routing information into an UDR (step 204) as the received AF request has no UE address (IP address or medium access control (MAC) address) . As such, the information on server discovery included in the AF request can be stored in the UDR. Then the NEF transmits a response message to the AF request (step 206) .

In step 208, a UE initiates a PDU session establishment procedure with a SMF. It can be understood that steps 202-206 are independent from the PDU session establishment procedure. That is, step 208 can be performed before or after any of steps 202-206. In step 210, the SMF initiates an SM policy association establishment procedure to retrieve SM policies from a PCF during the PDU session establishment procedure. In step 212, the PCF invokes a service provided by the UDR (e.g., Nudr_DataRepository_Query service) to retrieve stored AF influenced traffic routing information from the UDR during the SM policy association establishment procedure.

The PCF can retrieve all traffic routing information (including information on server discovery) for all the supported application. For example, the information in the following Table 2 can be retrieved by the PCF per data network name (DNN) and single network slice selection assistance information (S-NSSAI) :

Table 2

It can be understood that different applications may correspond to the same or different L-DNS servers. For example, L-DNS server 1 and L-DNS server 2 in Table 2 may be the same or different. One or more DNAIs in the list of DNAIs for APPLICATION 1 may also be included in the list of DNAIs for APPLICATION 2. APPLICATION 1 and APPLICATION 2 are not necessarily supported by the same number of DNAIs.

According to some embodiments of the present disclosure, when the traffic routing information is sent to the core network from the AF after the PDU session establishment, the information on server discovery can also be notified to the PCF by the UDR. When the information is updated from the AF due to, e.g., a change of application deployment within the EDNs or local DNs, the updated information on server discovery can also be notified to the PCF by the UDR. The information can also be notified to the SMF using an SM policy association modification procedure when the PCF receives any related notification.

To provide server discovery information to the SMF, the PCF generates the related information for all the supported FQDN (s) based on the information received in step 210, which may include a subscription permanent identifier (SUPI) of the UE, and based on the information retrieved from the UDR, and includes the related information into the message sent to the SMF as PDU session policy information (step 214) . For example, the information in the following Table 3 can be sent to the SMF. The DNAIs can share the same L-DNS server to use the same L-DNS server.

Table 3

DNN 1+S-NSSAI 1/SUPI
DNAI 1, L-DNS server 1, FQDN list (FQDN 1, FQDN 2, …, FQDN r)
DNAI 2, L-DNS server 2, FQDN list (FQDN 1′, FQDN 2′, …, FQDN s′)
…
DNAI n, L-DNS server n, FQDN list (FQDN 1″, FQDN 2″, …, FQDN t″)

The example shown in Table 3 includes server discover information. The server discovery information includes at least one set of parameters, wherein each set of parameters comprises a list of one or more FQDNs each associated with an application, a DNAI supporting the FQDNs in the list, and information of an L-DNS server. It is contemplated that the set of parameters in the server discovery information may include more or fewer parameters. For example, the information of the related DNS server (s) may not be included in the server discovery information. For example, the information of the related DNS server (s) can be configured to the core network via other ways, e.g., a local configuration or configuration via a network operator′s Operation Administration and Maintenance (OAM) system.

In step 216, the SMF sends a message to the UE indicating that the PDU session establishment is accepted.

In step 218, the UE sends a DNS query for DNS resolution for a target application to the SMF. Although not shown in FIG. 2, the DNS query can be forwarded by a UPF to the SMF. The DNS query should include a target FQDN for the target application.

In step 220, the SMF determines a DNS server for DNS resolution for the target application. According to some embodiments of the present disclosure, when L-DNS are used, the SMF may select one or more DNAIs based on a location of the UE, the received DNS query and the server discovery information which indicates DNAIs supporting the target FQDN in the DNS query. The SMF may further determine an address of an L-DNS server at the selected DNAI (s) . According to other embodiments of the present disclosure, when a C-DNS server is used, the SMF may determine an IP address of the UE corresponding to the selected DNAI.

In step 222, the SMF sends a DNS query to a DNS server for DNS resolution for the target application and the DNS server sends a DNS response with a resolved IP address for the target FQDN to the SMF. In some embodiments of the present disclosure, the DNS server is the L-DNS server determined in step 220. In other embodiments of the present disclosure, the DNS server is a C-DNS server, and the SMF sends a DNS query including the ENDS Client Subnet (ECS) parameter based on the IP address determined in step 220 to the C-DNS server. In either case, the DNS query can also be forwarded by the UPF under the control of the SMF based on the related information and handling. Alternatively, the DNS query can also be sent by a local DNS resolver (LDNSR) if it is the NF handling the DNS query. The DNS query sent by the SMF or LDNSR is for resolving the DNS query received from the UE, but with the address of the L-DNS server as the destination address.

According to some embodiments of the present disclosure, when the DNS query is handled by another network function, for example, an LDNSR as a standalone NF for the DNS handling, the LDNSR needs to get the L-DNS server information using the similar method. For example, the PCF may provide a new service (e.g., a server discovery information related procedure which can be consumed by the LDNSR to provide the service discovery information) for providing the service discovery information. Alternatively, the service may also be consumed by the SMF instead of reusing the SM policy management procedure. As another example, if it is the LDNSR handles the DNS query, the LDNSR may receive the L-DNS server information from the SMF based on the DNS query sent from the UE, wherein the target FQDN should be sent to the SMF and the SMF gets the L-DNS server information using the method as described in the present disclosure.

In step 224, after receiving the DNS response from the L-DNS server or the C-DNS server, the SMF sends the DNS response to the UE with the resolved IP address for the target FQDN. Alternatively, the DNS response can also be sent by the LDNSR if it is the NF handling the DNS query.

FIG. 3 illustrates a flow chart of an exemplary procedure for providing server discovery information using a service provided by a UDR. In the embodiment shown in FIG. 3, a service provider may deploy services or applications into EDNs or local DNs. An AF can obtain information on server discovery for the services or applications deployed in the EDNs or local DNs. For example, this can be done via local configuration on the AF. The AF may send an AF request with traffic routing information identified or not identified by an UE address, which is used to influence traffic routing, to a core network (e.g., to an NEF in the core network) . The AF request may include information on server discovery. For simplicity, the embodiment shown in FIG. 3 merely relates to AF requests not identified by an UE address, i.e., the information on server discovery impact future PDU sessions. It is contemplated that the similar method can also be used to impact existing PDU sessions, for example, when the information on server discovery is sent to the core network after the PDU session establishment, or when the information on server discovery is updated due to a change of application deployment within the EDNs or local DNs.

In step 302, an AF transmits an AF request to influence traffic routing per application without an UE address to an NEF. This step can be similar to step 202. The AF request may include an FQDN associated with an application, which can be indicated in an application ID or a separate parameter. In some embodiments, an application may have different FQDNs for different DNAIs, and the AF request may include more than one FQDN for the application. The AF request may also include information of a DNS server for each FQDN. The DNS server can be an L-DNS server that can resolve the FQDN corresponding to the application. Different from the AF request involved in the procedure illustrated in FIG. 2, the AF request in this embodiment may include information on server discovery as a separate parameter. For example, a new parameter named dnsRoutes can be used, which can be formulated as dnsRoutes (RoutetoServicel (DNAI-1, L-DNS1) , ... ) . It is contemplated that various parameters can be used to indicate the information on server discovery.

In step 304, the NEF stores the traffic routing information into an UDR. In step 306, the NEF transmits a response message to the AF request. These steps are the same as step 204 and step 206, respectively.

In step 308, a UE initiates a PDU session establishment procedure with a SMF. It can be understood that steps 302-306 are independent from the PDU session establishment procedure. That is, step 308 can be performed before or after any of steps 302-306. In step 310, the SMF initiates an SM policy association establishment procedure to retrieve SM policies from a PCF during the PDU session establishment procedure. In step 312, the PCF invokes a service provided by the UDR (e.g., Nudr_DataRepository_Query service) to retrieve stored AF influenced traffic routing information from the UDR during the SM policy association establishment procedure. Different from the embodiment illustrated in FIG. 2, the PCF does not retrieve the information on server discovery from the UDR in this embodiment. Thus, in step 314, the PCF sends PDU session policy information to the SMF without the information on server discovery.

In step 316, the SMF sends a message to the UE indicating that the PDU session establishment is accepted.

In step 318, the UE sends a DNS query for DNS resolution for a target application to the SMF. Although not shown in FIG. 3, the DNS query can be forwarded by a UPF to the SMF. The DNS query should include a target FQDN for the target application.

In the embodiment shown in FIG. 3,

steps

320, 321, and 322 are performed when L-DNS servers are used. In step 320, the SMF invokes a service provided by the UDR to retrieve an L-DNS server for the DNS query. The input parameters for the service may include the target FQDN and a location of the UE. In some embodiments of the present disclosure, the location of the UE may include DNAI (s) selected based on the location of the UE. In step 321, the UDR sends an IP address of an L-DNS server which is appropriate for the DNS query to the SMF. In this embodiment, the IP address of the appropriate L-DNS server is an example of the server discovery information. The UDR provides the service for the SMF to retrieve the DNS server information when the DNS query needs to be resolved by other DNS server than the one configured to the UE, wherein the other DNS server is determined based on the received DNS query, the UE location or the selected DNAI (s) based on the UE location, and the information on server discovery stored in the UDR. In other embodiments, when the DNS query is handled by another network function, for example, the LDNSR as a standalone NF for the DNS handling, the service provided by the UDR can also be used by the LDNSR to get the local DNS server information. In step 322, the SMF sends a DNS query to the selected L-DNS server for DNS resolution for the target application and the L-DNS server sends a DNS response with a resolved IP address for the target FQDN to the SMF. Alternatively, the DNS query can also be forwarded by the UPF under the control of the SMF based on the related information and handling. Alternatively, the DNS query can also be sent by the LDNSR if it is the NF handling the DNS query. The DNS query sent by the SMF or LDNSR is for resolving the DNS query received from the UE, but with the address of the L-DNS server as the destination address.

For the cases where a C-DNS server is used, a method similar to that described with respect to FIG. 2 can be used for DNS resolution.

In step 324, after receiving the DNS response from the L-DNS server or the C-DNS server, the SMF sends the DNS response to the UE with the resolved IP address for the target FQDN. Alternatively, the DNS response can also be sent by the LDNSR if it is the NF handling the DNS query.

It should be understood that, in other embodiments of the present disclosure, the PCF may retrieves the information on server discovery from the UDR and send it to the SMF, which is similar to the embodiment of FIG. 2. In these cases, the subsequent steps may be the same as those illustrated in FIG. 2. Also, in other embodiments of the present disclosure, the PCF in FIG. 2 may not retrieves the information on server discovery from the UDR, and the subsequent steps may be the same as those illustrated in FIG. 3.

FIG. 4 illustrates a flow chart of an exemplary procedure for providing server discovery information using a service provided by a PCF. In the embodiment shown in FIG. 4,

steps

408, 410, 416, 418, 422, and 424 may be the same as

steps

308, 310, 316, 318, 322, and 324, respectively. Thus, descriptions with respect to these steps will not be repeated herein. The other steps are described in detail below.

In step 402, the AF sends an AF request to influence server discovery to an NEF, instead of the AF request to influence traffic routing as described with respect to FIGS. 1 and 2. The AF request to influence server discovery may include information on server discovery.

In some embodiments of the present disclosure, the information on server discovery includes at least one set of parameters, wherein each set of parameters comprises one or more off (1) a list of one or more FQDNs, wherein each FQDN is associated with an application; (2) a DNAI supporting the FQDNs in the list; and (3) information of a DNS server. It is contemplated that the set of parameters in the information on server discovery may include more or fewer parameters. For example, when DNAIs for a local DN share the same L-DNS server, or DNAIs for several local DNs share the same L-DNS server, or no DNAI is applied, the information on server discovery may include the supported FQDN (s) and information of the related L-DNS server (s) without DNAI information. Alternatively or additionally, the information of the related DNS server (s) may not be included in the information on server discovery. For example, the information of the related DNS server (s) can be configured to the core network via other ways, e.g., a local configuration or configuration via a network operator′s OAM system.

The information on server discovery, as well as other information contained in the AF request, can be stored by the NEF into the UDR in step 404. In step 406, the NEF transmits a response message to the AF request.

In step 412, the PCF invokes a service provided by the UDR (e.g., Nudr_DataRepository_Query service) to retrieve stored AF influenced traffic routing information from the UDR during the SM policy association establishment procedure. The PCF also retrieves stored information on server discovery from the UDR. However, in step 414, the PCF sends PDU session policy information to the SMF without the information on server discovery. In this way, the information on server discovery is maintained in the PCF.

Since the SMF does not have the information on server discovery, it invokes a service provided by the PCF to retrieve an L-DNS server for the DNS query (step 420) . The input parameters for the service may include a target FQDN in the DNS query received from the UE and a location of the UE. In some embodiments of the present disclosure, the location of the UE may include DNAI (s) selected based on the location of the UE. In step 421, the PCF sends an IP address of an L-DNS server which is appropriate for the DNS query to the SMF. In this embodiment, the IP address of the appropriate L-DNS server is an example of the server discovery information. The PCF provides the service for the SMF to retrieve the DNS server information when the DNS query needs to be resolved by other DNS server than the one configured to the UE, wherein the other DNS server is determined based on the received DNS query, the UE location or the selected DNAI (s) based on the UE location, and the information on server discovery stored in the PCF. In other embodiments, when the DNS query is handled by another network function, for example, the LDNSR as a standalone NF for the DNS handling, the service provided by the PCF can also be used by the LDNSR to get the local DNS server information.

It is contemplated that the embodiment of FIG. 4 can be combined with one or more steps described above with respect to FIGS. 2 and 3. For example, the PCF may retrieve the information on server discovery from the UDR and send it to the SMF during a session management policy association procedure (e.g., a session management policy association establishment procedure or a session management policy association modification procedure) . Alternatively, the PCF may not retrieve the information on server discovery from the UDR. In these cases, the procedure for handling the DNS query may be modified in accordance with the embodiment illustrated in FIG. 2 or FIG. 3. Likewise, the service provided by the PCF as described with respect to FIG. 4 may also be used by the SMF in the embodiment illustrated in FIG. 2 or FIG. 3, when the PCF therein retrieves the information on server discovery from the UDR but does not send it to the SMF.

According to other embodiments of the present disclosure, server discovery information can be provided using a parameter provisioning procedure, which is illustrated in FIG. 5.

In step 502, an AF transmits an AF request for external parameter provisioning without an UE address to an NEF. The AF request for external parameter provisioning may include information on server discovery.

In some embodiments of the present disclosure, the information on server discovery may include the supported FQDN (s) per DNAI for a local DN, which can be identified by an AF-service-ID in the AF request, and information of the related L-DNS server (s) . In other embodiments of the present disclosure, the supported FQDN (s) and/or information of the related L-DNS server (s) can be included in the information on server discovery information independent on the specific DNAI information. For example, when DNAIs for a local DN share the same L-DNS server, or DNAIs for several local DNs share the same L-DNS server, or no DNAI is applied, the information on server discovery may include the supported FQDN (s) and information of the related L-DNS server (s) without DNAI information. Alternatively or additionally, the information of the related DNS server (s) may not be included in the information on server discovery. For example, the information of the related DNS server (s) can be configured to the core network via other ways, e.g., a local configuration or configuration via a network operator′s OAM system.

In some embodiments of the present disclosure, the information on server discovery includes at least one set of parameters, wherein each set of parameters comprises one or more of: (1) a list of one or more FQDNs, wherein each FQDN is associated with an application; (2) a DNAI supporting the FQDNs in the list; and (3) information of a DNS server. It is contemplated that the set of parameters in the information on server discovery may include more or fewer parameters. For example, when DNAIs for a local DN share the same L-DNS server, or DNAIs for several local DNs share the same L-DNS server, or no DNAI is applied, the information on server discovery may include the supported FQDN (s) and information of the related L-DNS server (s) without DNAI information. Alternatively or additionally, the information of the related DNS server (s) may not be included in the information on server discovery. For example, the information of the related DNS server (s) can be configured to the core network via other ways, e.g., a local configuration or configuration via a network operator′s OAM system.

In step 504, the NEF stores information contained in the AF request, such as the information on server discovery, into an UDR as the received AF request has no UE address (IP address or MAC address) . Then the NEF transmits a response message to the AF request (step 506) .

In some embodiments of the present disclosure, a PCF has subscribed to server discovery information or information on server discovery with the UDR. In these cases, the UDR may send a notification including the subscribed information to the PCF (step 508) . In other embodiments of the present disclosure, a SMF has subscribed to the server discovery information or information on server discovery with the UDR. In these cases, the UDR may send a notification including the subscribed information to the SMF (step 510) . When any other NF (e.g., an LDNSR) has subscribed to the server discovery information or information on server discovery with the UDR, the UDR may send a notification including the subscribed information to the NF.

In the cases where the PCF is provided with the server discovery information or information on server discovery, the PCF may send the server discovery information to the SMF during a session management policy association procedure (e.g., a session management policy association establishment procedure or a session management policy association modification procedure) . Then the SMF may handle a DNS query received from a UE in accordance with the embodiment illustrated in FIG. 2. Alternatively, the PCF may not send the server discovery information or the information on server discovery to the SMF, and the SMF may use the service provided by the PCF to handle the DNS query received from the UE in accordance with the embodiment illustrated in FIG. 4.

In the cases where the SMF is provided with the server discovery information or information on server discovery, the SMF may handle the DNS query received from the UE in accordance with the embodiment illustrated in FIG. 2.

In the cases where neither the PCF nor the SMF is provided with the server discovery information or information on server discovery, the SMF may use the service provided by the UDR to handle the DNS query received from the UE in accordance with the embodiment illustrated in FIG. 3.

When the DNS query is handled by another network function, for example, a local DNS resolver (LDNSR) as a standalone NF for the DNS handling, the LDNSR may subscribe to the server discovery information with the UDR, use a service provided by the UDR, or use a service provided by the PCF to obtain the server discovery information in a similar manner.

FIG. 6 illustrates an exemplary block diagram of an apparatus 600 according to some embodiments of the present disclosure. In some embodiments of the present disclosure, the apparatus 600 may be an SMF (e.g., any SMF described herein) or other network functions (such as an LDNSR) having similar functionalities, which can at least perform any of the methods illustrated in FIGS. 2-5.

As shown in FIG. 6, the apparatus 600 may include at least one receiving circuitry 602, at least one transmitting circuitry 604, at least one non-transitory computer-readable medium 606, and at least one processor 608 coupled to the at least one receiving circuitry 602, the at least one transmitting circuitry 604, the at least one non-transitory computer-readable medium 606. While shown to be coupled to each other via the at least one processor 608 in the example of FIG. 6, the at least one receiving circuitry 602, the at least one transmitting circuitry 604, the at least one non-transitory computer-readable medium 606, and the at least one processor 608 may be coupled to one another in various arrangements. For example, the at least one receiving circuitry 602, the at least one transmitting circuitry 604, the at least one non-transitory computer-readable medium 606, and the at least one processor 608 may be coupled to each other via one or more local buses (not shown for simplicity) .

Although in FIG. 6, elements such as receiving circuitry 602, transmitting circuitry 604, non-transitory computer-readable medium 606, and processor 608 are described in the singular, the plural is contemplated unless limitation to the singular is explicitly stated. In some embodiments of the present disclosure, the at least one receiving circuitry 602 and the at least one transmitting circuitry 604 are combined into a single device, such as a transceiver. In certain embodiments of the present disclosure, the apparatus 600 may further include a memory, and/or other components.

In some embodiments of the present disclosure, the at least one non-transitory computer-readable medium 606 may have stored thereon computer-executable instructions which are programmed to cause the at least one processor 608 to implement the steps of the methods, for example as described in view of FIGS. 2-5, with the at least one receiving circuitry 602 and the at least one transmitting circuitry 604. For example, when executed, the instructions may cause the at least one processor 608 to receive server discovery information from a second network function with the at least one receiving circuitry 602. The instructions may further cause the at least one processor 608 to send a DNS query to a target DNS server in a data network based at least in part on the server discovery information with the at least one transmitting circuitry 604.

FIG. 7 illustrates an exemplary block diagram of an apparatus 700 according to some embodiments of the present disclosure. In some embodiments of the present disclosure, the apparatus 700 may be an AF (e.g., any AF described herein) or other network functions having similar functionalities, which can at least perform any of the methods illustrated in FIGS. 2-5.

As shown in FIG. 7, the apparatus 700 may include at least one receiving circuitry 702, at least one transmitting circuitry 704, at least one non-transitory computer-readable medium 706, and at least one processor 708 coupled to the at least one receiving circuitry 702, the at least one transmitting circuitry 704, the at least one non-transitory computer-readable medium 706. While shown to be coupled to each other via the at least one processor 708 in the example of FIG. 7, the at least one receiving circuitry 702, the at least one transmitting circuitry 704, the at least one non-transitory computer-readable medium 706, and the at least one processor 708 may be coupled to one another in various arrangements. For example, the at least one receiving circuitry 702, the at least one transmitting circuitry 704, the at least one non-transitory computer-readable medium 706, and the at least one processor 708 may be coupled to each other via one or more local buses (not shown for simplicity) .

Although in FIG. 7, elements such as receiving circuitry 702, transmitting circuitry 704, non-transitory computer-readable medium 706, and processor 708 are described in the singular, the plural is contemplated unless limitation to the singular is explicitly stated. In some embodiments of the present disclosure, the at least one receiving circuitry 702 and the at least one transmitting circuitry 704 are combined into a single device, such as a transceiver. In certain embodiments of the present disclosure, the apparatus 700 may further include a memory and/or other components.

In some embodiments of the present disclosure, the at least one non-transitory computer-readable medium 706 may have stored thereon computer-executable instructions which are programmed to cause the at least one processor 708 to implement the steps of the methods described herein with the at least one receiving circuitry 702 and the at least one transmitting circuitry 704. For example, when executed, the instructions may cause the at least one processor 708 to obtain information on server discovery. The instructions may further cause the at least one processor 708 to send the information on server discovery to a core network.

FIG. 8 illustrates an exemplary block diagram of an apparatus 800 according to some embodiments of the present disclosure. In some embodiments of the present disclosure, the apparatus 800 may be a PCF (e.g., any PCF described herein) or other network functions having similar functionalities, which can at least perform any of the methods illustrated in FIGS. 2-5.

As shown in FIG. 8, the apparatus 800 may include at least one receiving circuitry 802, at least one transmitting circuitry 804, at least one non-transitory computer-readable medium 806, and at least one processor 808 coupled to the at least one receiving circuitry 802, the at least one transmitting circuitry 804, the at least one non-transitory computer-readable medium 806. While shown to be coupled to each other via the at least one processor 808 in the example of FIG. 8, the at least one receiving circuitry 802, the at least one transmitting circuitry 804, the at least one non-transitory computer-readable medium 806, and the at least one processor 808 may be coupled to one another in various arrangements. For example, the at least one receiving circuitry 802, the at least one transmitting circuitry 804, the at least one non-transitory computer-readable medium 806, and the at least one processor 808 may be coupled to each other via one or more local buses (not shown for simplicity) .

Although in FIG. 8, elements such as receiving circuitry 802, transmitting circuitry 804, non-transitory computer-readable medium 806, and processor 808 are described in the singular, the plural is contemplated unless limitation to the singular is explicitly stated. In some embodiments of the present disclosure, the at least one receiving circuitry 802 and the at least one transmitting circuitry 804 are combined into a single device, such as a transceiver. In certain embodiments of the present disclosure, the apparatus 800 may further include a memory and/or other components.

In some embodiments of the present disclosure, the at least one non-transitory computer-readable medium 806 may have stored thereon computer-executable instructions which are programmed to cause the at least one processor 808 to implement the steps of the methods described herein with the at least one receiving circuitry 802 and the at least one transmitting circuitry 804. For example, when executed, the instructions may cause the at least one processor 808 to receive information on server discovery from a second network function with the at least one receiving circuitry 802. The instructions may further cause the at least one processor 808 to send server discovery information based on the information on server discovery to a third network function with the at least one transmitting circuitry 804.

FIG. 9 illustrates an exemplary block diagram of an apparatus 900 according to some embodiments of the present disclosure. In some embodiments of the present disclosure, the apparatus 900 may be a UDR (e.g., any UDR described herein) or other network functions having similar functionalities, which can at least perform any of the methods illustrated in FIGS. 2-5.

As shown in FIG. 9, the apparatus 900 may include at least one receiving circuitry 902, at least one transmitting circuitry 904, at least one non-transitory computer-readable medium 906, and at least one processor 908 coupled to the at least one receiving circuitry 902, the at least one transmitting circuitry 904, the at least one non-transitory computer-readable medium 906. While shown to be coupled to each other via the at least one processor 908 in the example of FIG. 9, the at least one receiving circuitry 902, the at least one transmitting circuitry 904, the at least one non-transitory computer-readable medium 906, and the at least one processor 908 may be coupled to one another in various arrangements. For example, the at least one receiving circuitry 902, the at least one transmitting circuitry 904, the at least one non-transitory computer-readable medium 906, and the at least one processor 908 may be coupled to each other via one or more local buses (not shown for simplicity) .

Although in FIG. 9, elements such as receiving circuitry 902, transmitting circuitry 904, non-transitory computer-readable medium 906, and processor 908 are described in the singular, the plural is contemplated unless limitation to the singular is explicitly stated. In some embodiments of the present disclosure, the at least one receiving circuitry 902 and the at least one transmitting circuitry 904 are combined into a single device, such as a transceiver. In certain embodiments of the present disclosure, the apparatus 900 may further include a memory and/or other components.

In some embodiments of the present disclosure, the at least one non-transitory computer-readable medium 906 may have stored thereon computer-executable instructions which are programmed to cause the at least one processor 908 to implement the steps of the methods described herein with the at least one receiving circuitry 902 and the at least one transmitting circuitry 904. For example, when executed, the instructions may cause the at least one processor 908 to obtain information on server discovery. The instructions may further cause the at least one processor 908 to send server discovery information based on the information on server discovery to a second network function with the at least one transmitting circuitry 904.

As will be appreciated by one skilled in the art, aspects of the embodiments may be embodied as a system, apparatus, method, or a program product. Accordingly, embodiments may take the form of an all-hardware embodiment, an all-software embodiment (including firmware, resident software, micro-code, etc. ) or an embodiment combining software and hardware aspects.

For example, the disclosed embodiments may be implemented as a hardware circuit comprising custom very-large-scale integration (VLSI) circuits or gate arrays, off-the-shelf semiconductors such as logic chips, transistors, or other discrete components. The disclosed embodiments may also be implemented in programmable hardware such as field programmable gate arrays, programmable array logic, programmable logic devices, or the like. As another example, the disclosed embodiments may include one or more physical or logical blocks of executable code which may, for instance, be organized as an object, procedure, or function.

Furthermore, embodiments may take the form of a program product embodied in one or more computer readable storage devices storing machine readable code, computer readable code, or program code. The storage devices may be tangible, non-transitory, or non-transmission. The storage devices may not embody signals. In a certain embodiment, the storage devices only employ signals for accessing code.

Any combination of one or more computer readable medium may be utilized. The computer readable medium may be a computer readable storage medium. The computer readable storage medium may be a storage device storing the code. The storage device may be, for example, but is not limited to being, an electronic, magnetic, optical, electromagnetic, infrared, holographic, micromechanical, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing.

A non-exhaustive list of more specific examples of the storage device may include the following: an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random-access memory (RAM) , a read-only memory (ROM) , an erasable programmable read-only memory (EPROM or Flash memory) , a portable compact disc read-only memory (CD-ROM) , an optical storage device, a magnetic storage device, or any suitable combination of the foregoing. In the context of this document, a computer readable storage medium may be any tangible medium that can contain or store a program for use by or in connection with an instruction execution system, apparatus, or device.

Furthermore, the described features, structures, or characteristics of the embodiments may be combined in any suitable manner. While this disclosure has been described with specific embodiments thereof, it is evident that many alternatives, modifications, and variations may be apparent to those skilled in the art. For example, various components of the embodiments may be interchanged, added, or substituted in the other embodiments. Also, all of the elements of each figure are not necessary for operation of the disclosed embodiments. For example, those having ordinary skills in the art would be enabled to make and use the teachings of the disclosure by simply employing the elements of the independent claims. Accordingly, embodiments of the disclosure as set forth herein are intended to be illustrative, not limiting. Various changes may be made without departing from the spirit and scope of the disclosure.

Reference throughout this specification to "one embodiment, " "an embodiment, " or similar language means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, appearances of the phrases "in one embodiment, " "in an embodiment, " and similar language throughout this specification may, but do not necessarily, all refer to the same embodiment, but mean "one or more but not all embodiments" unless expressly specified otherwise. In this document, the terms "includes, " "including, " or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element proceeded by "a, " "an, " or the like does not, without more constraints, preclude the existence of additional identical elements in the process, method, article, or apparatus that includes the element. Also, the term "another" is defined as at least a second or more. The term "having" and the like, as used herein, are defined as "including. "

Claims

A method performed at a first network function, comprising:

receiving server discovery information from a second network function; and

sending a domain name service (DNS) query to a target DNS server in a data network based at least in part on the server discovery information.
The method of Claim 1, wherein the server discovery information comprises at least one set of parameters, each set of parameters comprising one or more of:

(1) a list of one or more fully qualified domain names (FQDNs) , wherein each FQDN is associated with an application;

(2) a data network access identifier (DNAI) supporting the FQDNs in the list; and

(3) information of a DNS server.
The method of Claim 2, further comprising:

determining the target DNS server based at least in part on a location of a user equipment (UE) , a target FQDN received from the UE for server discovery, and the server discovery information.
The method of Claim 3, wherein the server discovery information is received from the second network function via a Session Management Policy Association procedure.
The method of Claim 3, wherein the server discovery information is received from the second network function via a server discovery information related procedure.
The method of Claim 3, wherein the server discovery information is received in a notification that is subscribed from the second network function.
The method of Claim 1, wherein the server discovery information comprises an address of the target DNS server.
The method of Claim 7, wherein the server discovery information, for at least in part a location of a user equipment (UE) and a target fully qualified domain name (FQDN) received from the UE for server discovery, is received from the second network function via a service provided by the second network function.
The method of Claim 8, wherein the second network function is a unified data repository (UDR) or a policy control function (PCF) .
A method performed at a first network function, comprising:

obtaining information on server discovery; and

sending the information on server discovery to a core network.
The method of Claim 10, the information on server discovery is sent to the core network via an application function (AF) request to influence traffic routing.
The method of Claim 11, wherein the AF request comprises at least one fully qualified domain name (FQDN) associated with an application, and information of a domain name service (DNS) server in a data network for each FQDN.
The method of Claim 10, wherein the information on server discovery is sent to the core network via an application function (AF) request to influence server discovery.
The method of Claim 10, wherein the information on server discovery is sent to the core network via an application function (AF) request for external parameter provisioning.
The method of Claim 13 or 14, wherein the information on server discovery comprises at least one set of parameters, each set of parameters comprising one or more of:

(1) a list of one or more fully qualified domain names (FQDNs) , wherein each FQDN is associated with an application;

(2) a data network access identifier (DNAI) supporting the FQDNs in the list; and

(3) information of a domain name service (DNS) server.
A method performed at a first network function, comprising:

receiving information on server discovery from a second network function; and

sending server discovery information based on the information on server discovery to a third network function.
The method of Claim 16, wherein the information on server discovery is based on one of the following information:

(1) information on an application function (AF) request to influence traffic routing;

(2) information on an AF request to influence server discovery; or

(3) information on an AF request for external parameter provisioning.
The method of Claim 16, wherein the information on server discovery is received in a notification that is subscribed from the second network function.
The method of Claim 17, wherein the information on server discovery comprises at least one set of parameters, each set of parameters comprising one or more of:

(1) a list of one or more fully qualified domain names (FQDNs) , wherein each FQDN is associated with an application;

(2) a data network access identifier (DNAI) supporting the FQDNs in the list; and

(3) information of a domain name service (DNS) server.
The method of Claim 17, wherein the information on server discovery comprises at least one fully qualified domain name (FQDN) associated with an application, and information of a domain name service (DNS) server in a data network for each FQDN.
The method of Claim 19 or 20, wherein the server discovery information sent to the third network function comprises at least one set of parameters, each set of parameters comprising one or more of:

(1) a list of one or more FQDNs, wherein each FQDN is associated with an application;

(2) a data network access identifier (DNAI) supporting the FQDNs in the list; and

(3) information of a DNS server.
The method of Claim 21, further comprising:

generating the server discovery information sent to the third network function based on the received information on server discovery.
The method of Claim 19 or 20, wherein the server discovery information comprises an address of a target DNS server.
The method of Claim 23, wherein the server discovery information, for at least in part a location of a user equipment (UE) and a target fully qualified domain name (FQDN) received from the UE for server discovery, is sent from the first network function via a service provided by the first network function.
A method performed at a first network function, comprising:

obtaining information on server discovery; and

sending server discovery information based on the information on server discovery to a second network function.
The method of Claim 25, wherein the information on server discovery is obtained from one of the following information:

(1) information on an application function (AF) request to influence traffic routing;

(2) information on an AF request to influence server discovery; or

(3) information on an AF request for external parameter provisioning.
The method of Claim 25, wherein the server discovery information is sent in a notification that is subscribed by the second network function.
The method of Claim 26, wherein the information on server discovery comprises at least one set of parameters, each set of parameters comprising one or more of:

(1) a list of one or more fully qualified domain names (FQDNs) , wherein each FQDN is associated with an application;

(2) a data network access identifier (DNAI) supporting the FQDNs in the list; and

(3) information of a domain name service (DNS) server.
The method of Claim 26, wherein the information on server discovery comprises at least one fully qualified domain name (FQDN) associated with an application, and information of a domain name service (DNS) server in a data network for each FQDN.
The method of Claim 28 and 29, wherein the server discovery information sent to the second network function comprises at least one set of parameters, each set of parameters comprising one or more of:

(1) a list of one or more FQDNs, wherein each FQDN is associated with an application;

(2) a data network access identifier (DNAI) supporting the FQDNs in the list; and

(3) information of a DNS server.
The method of Claim 30, wherein the second network function is a policy control function (PCF) or a session management function (SMF) or a local DNS resolver (LDNSR) .
The method of Claim 29, wherein the second network function is a policy control function (PCF) .
The method of Claim 28 or 29, wherein the server discovery information comprises an address of a target DNS server.
The method of Claim 33, wherein the server discovery information, for at least in part a location of a user equipment (UE) , and a target fully qualified domain name (FQDN) received from the UE for server discovery, is sent from the first network function via a service provided by the first network function.
An apparatus, comprising:

at least one non-transitory computer-readable medium having stored thereon computer-executable instructions;

at least one receiving circuitry;

at least one transmitting circuitry; and

at least one processor coupled to the at least one non-transitory computer-readable medium, the at least one receiving circuitry and the at least one transmitting circuitry,

wherein the computer-executable instructions cause the at least one processor to implement the method according to any of Claims 1-9.
An apparatus, comprising:

at least one non-transitory computer-readable medium having stored thereon computer-executable instructions;

at least one receiving circuitry;

at least one transmitting circuitry; and

at least one processor coupled to the at least one non-transitory computer-readable medium, the at least one receiving circuitry and the at least one transmitting circuitry,

wherein the computer-executable instructions cause the at least one processor to implement the method according to any of Claims 10-15.
An apparatus, comprising:

at least one non-transitory computer-readable medium having stored thereon computer-executable instructions;

at least one receiving circuitry;

at least one transmitting circuitry; and

at least one processor coupled to the at least one non-transitory computer-readable medium, the at least one receiving circuitry and the at least one transmitting circuitry,

wherein the computer-executable instructions cause the at least one processor to implement the method according to any of Claims 16-24.
An apparatus, comprising:

at least one non-transitory computer-readable medium having stored thereon computer-executable instructions;

at least one receiving circuitry;

at least one transmitting circuitry; and

at least one processor coupled to the at least one non-transitory computer-readable medium, the at least one receiving circuitry and the at least one transmitting circuitry,

wherein the computer-executable instructions cause the at least one processor to implement the method according to any of Claims 25-34.