OPTIMIZED SERVING GATEWAY NODE SELECTION FOR INTERWORKING NETWORKS

In one example, a first connectivity request for a first network connection between a user equipment and a first network is obtained. A control plane serving gateway node for the first network connection is selected. The control plane serving gateway node is co-located with a control plane packet data network gateway node configured to support a second network connection between the user equipment and a second network that is different from the first network. A second connectivity request for the second network connection is obtained. The second network connection is established with the control plane serving gateway node and the control plane packet data network gateway node.

TECHNICAL FIELD

The present disclosure relates to telecommunications technology.

BACKGROUND

Interworking networks are networks that are connected directly or indirectly within a system. Interworking networks can include fourth generation (4G) only networks, fifth generation (5G) only networks, and 4G and 5G networks. Thus, interworking networks can include both 4G network components and 5G network components integrated into a single system.

DESCRIPTION OF EXAMPLE EMBODIMENTS

Overview

In one example embodiment, a first connectivity request for a first network connection between a user equipment and a first network is obtained. A control plane serving gateway node for the first network connection is selected. The control plane serving gateway node is co-located with a control plane packet data network gateway node configured to support a second network connection between the user equipment and a second network that is different from the first network. A second connectivity request for the second network connection is obtained. The second network connection is established with the control plane serving gateway node and the control plane packet data network gateway node.

Example Embodiments

FIG. 1illustrates an example system100configured to optimize serving gateway node selection for fourth generation (4G) and/or fifth generation (5G) interworking networks. System100includes User Equipment (UE)102, 4G Radio Access Network (RAN)104, Domain Name System (DNS) server106and standalone Control plane and User plane Serving Gateway (SGW-C/U)108. System100further includes 4G/5G network slice110, 4G/5G network slice112, 4G network gateway core114, Packet Data Network (PDN)116, Internet Protocol (IP) Multimedia Subsystem (IMS) core118, and PDN/IMS core120.

UE102is configured to communicate with cellular AP122over a Uu interface. Cellular AP122is configured to communicate with MME124over a Control plane S1 (S1-C) interface. Cellular AP122is configured to communicate with co-located SGW-U, PGW-U, and UPF128over multiple User plane S1 (S1-U) interfaces in the 4G Evolved Universal Mobile Telecommunications Service (UMTS) Terrestrial RAN (EUTRAN) access. For example, there may be one S1-U interface to facilitate a network connection with PDN116and another S1-U interface to facilitate a network connection with IMS core118. Cellular AP122may also be configured to communicate with co-located SGW-U, PGW-U, and UPF128over multiple N3 interfaces in the 5G New Radio (NR) access. Cellular AP122is further configured to communicate with standalone SGW-C/U108over an S1-U interface, and with co-located SGW-U and PGW-U136over an S1-U interface to facilitate a network connection with PDN/IMS core120.

MME124is configured to communicate with co-located SGW-C, PGW-C, and SMF126over multiple S11 interfaces (e.g., one S11 interface to facilitate a network connection with PDN116and another S11 interface to facilitate a network connection with IMS core118). MME124is also configured to communicate with standalone SGW-C/U108over an S11 interface, and with co-located SGW-C and PGW-C134over an S11 interface to facilitate a network connection with PDN/IMS core120. Standalone SGW-C/U108is configured to communicate with co-located SGW-C, PGW-C, and SMF126, co-located SMF and PGW-C132, and co-located SGW-C and PGW-C134over respective Control plane S5/S8 (S5/S8-C) interfaces. Co-located SGW-C, PGW-C, and SMF126is configured to communicate with co-located SGW-U, PGW-U, and UPF128over a concatenated Sxa/N4 interface. Co-located SGW-U, PGW-U, and UPF128is configured to communicate with co-located UPF and PGW-U130over a User plane S5/S8 (S5/S8-U) interface to facilitate a network connection with IMS core118.

UE102may be associated with any suitable device configured to initiate a flow in system100, and may be 4G-capable, 5G-capable, or both 4G- and 5G-capable. For example, UE102may include a computer, a vehicle and/or any other transportation-related device having electronic devices configured thereon, an automation device, an enterprise device, an appliance, an Internet of Things (IoT) device, a Personal Digital Assistant (PDA), a laptop or electronic notebook, a cellular telephone, a smartphone, a tablet, an Internet Protocol (IP) phone, and/or any other device and/or combination of devices, components, elements, and/or objects capable of initiating voice, audio, video, media, or data exchanges within system100. UE102may also include any suitable interface to a human user such as a microphone, a display, a keyboard, or other terminal equipment. UE102may also be any device that seeks to initiate a communication on behalf of another entity or element such as a program, a database, or any other component, device, element, or object capable of initiating an exchange within system100. UE102may be configured with appropriate hardware (e.g., processor(s), memory element(s), antennas and/or antenna arrays, baseband processors (modems), and/or the like), software, logic, and/or the like to facilitate respective over-the-air (air) interfaces for accessing/connecting to cellular AP122. It will be appreciated that any number of UEs may be present in system100.

Cellular AP122may terminate a cellular (e.g., 4G Long-Term Evolution (LTE)) air interface and may be configured with appropriate hardware (e.g., processor(s), memory element(s), antennas and/or antenna arrays, baseband processors (modems), and/or the like), software, logic, and/or the like to provide over-the-air coverage for cellular access. Cellular AP122may be implemented as an evolved Node B (eNB) to facilitate 4G LTE air access.

MME124is a 4G component configured to perform various Mobility Management (MM) operations including SGW selection for UE102during attach procedures. DNS server106may provide lookup services for system resources (e.g., hosts, services, functions, etc.) to provide resource records for various DNS queries. The resource records may include Naming Authority Pointer (NAPTR) resource records, and may define IP version 4 (IPv4) or IP version 6 (IPv6) host addresses. DNS server106may include resource records for any number of resources (e.g., SGWs and PGWs).

An SGW is a 4G component configured to route/forward network data packets to facilitate a network connection. A PGW is a 4G component configured to provide connectivity between a UE and an external network by serving as a point of exit to, or entry from, the external network. Control and User Plane Separation (CUPS) is a technology that enables separation of one or more SGWs and PGWs into the control and user planes to provide independent location and scaling of the control and user planes. Thus, for example, CUPS may effectuate separation of an SGW into an SGW-U and an SGW-C, and a PGW into a PGW-U and a PGW-C. System100implements SGW-U, SGW-C, PGW-U, and PGW-C functionality, for example, in standalone SGW-C/U108, co-located SGW-C, PGW-C, and SMF126, co-located SGW-U, PGW-U, and UPF128, co-located UPF and PGW-U130, co-located SMF and PGW-C132, co-located SGW-C and PGW-C134, and co-located SGW-U and PGW-U136.

An SMF is a 5G component and may provide functionality that is analogous to functionality provided by an SGW-C and a PGW-C. Typically, Data Network Name (DNN) based SMF selection and slicing is used to establish Protocol Data Unit (PDUs) on different Network Functions (NFs). System100implements SMF functionality, for example, in co-located SGW-C, PGW-C, and SMF126and co-located SMF and PGW-C132. A UPF is a 5G component and may provide functionality that is analogous to functionality provided by an SGW-U and a PGW-U. Typically, a UPF may serve as a PDU Session Anchor (PSA) connected directly to a RAN, while an SGW-U is located between the PGW-U and the RAN. System100implements UPF functionality, for example, in co-located SGW-U, PGW-U, and UPF128and co-located UPF and PGW-U130.

Although embodiments described herein focus on 4G and 5G technology, it will be appreciated that any suitable telecommunications technology (e.g., 3G, 4G, 5G, etc.) may be utilized. For example, any suitable SGW-C node configured to perform similar operations as an SGW-C may be used; any suitable PGW-C node configured to perform similar operations as a PGW-C may be used; any suitable SMF node configured to perform similar operations as an SMF may be used; any suitable SGW-U node configured to perform similar operations as an SGW-U may be used; any suitable PGW-C node configured to perform similar operations as a PGW-C may be used; and any suitable UPF node configured to perform similar operations as a UPF may be used.

In various embodiments, PDN116may be any combination of the Internet, a Fixed Wireless Access (FWA) network, an Ethernet network, an Ethernet switching system(s), and/or the like. PDN116may be configured to facilitate user plane (e.g., user data/data transfer) connectivity for UE102. For example, UE102may be configured to access various services, applications, etc. from PDN116. IMS core118may be configured to provide IP multimedia services for UE102. PDN/IMS core120may be any combination of the Internet, an IMS core, an Ethernet network, an Ethernet switching system(s), and/or the like.

Oftentimes, a UE sends an initial connectivity request for a network connection between the UE and an IMS core. In this situation, an MME typically selects an SGW and PGW based on the PGW of the IMS core (many operators maintain separate PGWs for different services, such as IMS core, Internet, etc.). For example, the MME can select the SGW and PGW that is topologically closest to the IMS core (e.g., on a network slice configured to serve the IMS core). The MME does not take into consideration possible subsequent network connections (e.g., over different network slices).

This becomes an issue when the UE sends a subsequent connectivity request for a network connection between the UE and a PDN. The MME selects a new PGW for the PDN, but the SGW used for the network connection between the UE and an IMS core is still used. This is because an SGW is selected on a per-UE basis, whereas a PGW is selected on a per-connection basis. That is, once an SGW is selected, that same SGW is used with all PGWs that are selected for subsequent network connections. Using the SGW that is topologically close to the IMS core for the network connection between the UE and the PDN can lead to inefficiencies due to poor selection of user plane nodes, such as establishment of a split session between an SGW-U hosted on one node in the IMS core network slice and a PGW-U and/or UPF hosted on other nodes in the PDN network slice. This can also create issue with charging/billing because use cases (e.g., involving inbound roaming subscribers) often involve the SGW being located in the network slice for the PDN.

Accordingly, SGW selection logic138is provided on MME124in order to cause MME124to intelligently select co-located SGW-C, PGW-C, and SMF126and co-located SGW-U, PGW-U, and UPF128for the network connection between UE102and IMS core118. When a subsequent network connection is established between UE102and PDN116, co-located SGW-C, PGW-C, and SMF126and co-located SGW-U, PGW-U, and UPF128continue to be used. Co-located SGW-C, PGW-C, and SMF126includes the optimal SGW-C for the subsequent network connection between UE102and PDN116. Similarly, co-located SGW-U, PGW-U, and UPF128includes the optimal SGW-U for the network connection between UE102and PDN116. Those SGW-C and SGW-U functionalities are topologically closest to PDN116.

Moreover, the UPF of co-located SGW-U, PGW-U, and UPF128is located at the edge proximate to PDN116, and selecting a co-located UPF and SGW-U in co-located SGW-U, PGW-U, and UPF128reduces infrastructure cost. Initial selection of the SGW-C in co-located SGW-C, PGW-C, and SMF126ensures optimal user experience for the network connection between UE102and PDN116, even though UE102sends a network connectivity request for the network connection between UE102and IMS core118before the network connectivity request for the network connection between UE102and PDN116.

As shown at140, MME124obtains a connectivity request for a network connection between UE102and IMS core118. The connectivity request may include a UE capability indication (e.g., via a Dual Connectivity with NR (DCNR) bit) that UE102is both 4G- and 5G-capable. UE102may send the connectivity request to MME124via cellular AP122. Cellular AP122may be identified based on a Tracking Area List (TAL) that includes a number of Tracking Area Codes (TACs), with at least one TAC corresponding to cellular AP122.

At142, MME124uses DNS server106to resolve the appropriate SGW for the network connection between UE102and IMS core118. MME124may provide, to DNS server106, a query for a plurality of identifiers of candidate SGWs (e.g., SGW-Cs and SGW-Us). MME124may obtain the plurality of identifiers from DNS server106in a DNS response. The plurality of identifiers may include SGW-Cs (and SGW-Us) of 4G/5G network slice110, standalone SGW-C/U108, and SGW-Cs 4G network gateway core114. The plurality of identifiers may include an indication that the SGW-C of 4G/5G network slice110is co-located with the PGW-C of 4G/5G network slice110(i.e., as part of co-located SGW-C, PGW-C, and SMF126). The plurality of identifiers may further include an indication that the SGW-U of 4G/5G network slice110is co-located with the PGW-U of 4G/5G network slice110(i.e., as part of co-located SGW-U, PGW-U, and UPF128).

In this example, DNS server106may return the SGW-Cs and SGW-Us of 4G/5G network slice110, standalone SGW-C/U108, and 4G network gateway core114. MME124may select the SGW-C and the SGW-U of 4G/5G network slice110even though another SGW-C and SGW-U (e.g., standalone SGW-C/U108) may be more optimal for the network connection between UE102and IMS core118. MME124selects the SGW-C and SGW-U of 4G/5G network slice110in anticipation of a subsequent network connection between UE102and PDN116. More specifically, MME124is aware that the SGW-C of 4G/5G network slice110is co-located with the PGW-C of 4G/5G network slice110(i.e., as part of co-located SGW-C, PGW-C, and SMF126), and that the SGW-U of 4G/5G network slice110is co-located with the PGW-U of 4G/5G network slice110(i.e., as part of co-located SGW-U, PGW-U, and UPF128). The placement of that SGW-C, SGW-U, PGW-C, and PGW-U in 4G/5G network slice110will provide a more efficient experience for the subsequent network connection between UE102and PDN116.

MME124may also use DNS server106to resolve the appropriate PGW for the network connection between UE102and IMS core118. MME124may provide, to DNS server106, a query for a plurality of identifiers of candidate PGWs (e.g., PGW-Cs and PGW-Us). MME124may obtain the plurality of identifiers from DNS server106in a DNS response. The plurality of identifiers may include PGW-Cs of 4G/5G network slice110, 4G/5G network slice112, and 4G network gateway core114. The plurality of identifiers may include an indication that the PGW-C of 4G/5G network slice110is co-located with the SGW-C of 4G/5G network slice110(i.e., as part of co-located SGW-C, PGW-C, and SMF126). The plurality of identifiers may further include an indication that the PGW-U of 4G/5G network slice110is co-located with the SGW-U of 4G/5G network slice110(i.e., as part of co-located SGW-U, PGW-U, and UPF128).

In one example, if a topon Fully Qualified Domain Name (FQDN) matching feature is enabled, DNN (e.g., Access Point Name (APN)) and Tracking Area Identity (TAI) resolution operations may return SGW and PGW identities that have the same locality (such as the SGW-Cs, SGW-Us, PGW-Cs, and PGW-Us of 4G/5G network slice110and 4G/5G network slice112). Topon selection may indicate that co-located/topologically close node selection is preferred, and may aim to find optimal SGW and PGW locations through a DNS look up of the APN(s) and TAI(s). One or more APNs may be used to identify candidate PGWs, and one or more TAIs may be used to identify candidate SGWs.

At144, MME124may select the PGW-C (and the PGW-U) of 4G/5G network slice112from the PGW-Cs and PGW-Us of 4G/5G network slice110, 4G/5G network slice112, and 4G network gateway core114. MME124may select the PGW-C and PGW-U of 4G/5G network slice112so as to enable the network connection between UE102and IMS core118. Thus, when the network connection between UE102and IMS core118is established, the control plane may include the SGW-C in 4G/5G network slice110and the PGW-C in 4G/5G network slice112. The user plane may include the SGW-U in 4G/5G network slice110and the PGW-U in 4G/5G network slice112. The SGW-U in 4G/5G network slice110may communicate with the PGW-U in 4G/5G network slice112over the S5/S8-U interface.

At146, MME124obtains a connectivity request for a network connection between UE102and PDN116. In response to the connectivity request, MME124establishes the network connection with the SGW (e.g., SGW-C and SGW-U) in 4G/5G network slice110and the PGW (e.g., PGW-C and PGW-U) in 4G/5G network slice110. The SGW therefore remains the same across both network connections, while the PGW has changed from the PGW in 4G/5G network slice112(in the network connection between UE102and IMS core118) to the PGW in 4G/5G network slice110(in the network connection between UE102and PDN116). This is because an SGW is used on a per-UE basis and may not change across network connections, whereas the PGW is used on a per-session/connection basis and may change across network connections. The control plane for the network connection between UE102and PDN116may include the SGW-C and the PGW-C in 4G/5G network slice110(i.e., in co-located SGW-C, PGW-C, and SMF126). The user plane may include the SGW-U and the PGW-U in 4G/5G network slice110(i.e., in co-located SGW-U, PGW-U, and UPF128).

To help facilitate optimized user plane selection and session establishment, the chosen SGW-C and PGW-C are co-located with an SMF (i.e., in co-located SGW-C, PGW-C, and SMF126). Furthermore, co-located SGW-C, PGW-C, and SMF126is configured to communicate with co-located SGW-U, PGW-U, and UPF128via a concatenated Sxa/N4 interface. The concatenated Sxa/N4 interface may be a single interface that combines functionalities of both an Sxa interface and an N4 interface. Combining the SGW-C and SMF in co-located SGW-C, PGW-C, and SMF126allows for efficient and coordinated programming of the SGW-U and the UPF in co-located SGW-U, PGW-U, and UPF128over the concatenated Sxa/N4 interface.

With continued reference toFIG. 1,FIG. 2illustrates an example system200configured to establish an initial network connection between UE102and IMS core118with an optimal SGW. System200includes cellular AP122, MME124, DNS server106, co-located SGW-C, PGW-C, and SMF126, co-located UPF and PGW-U130, and co-located SMF and PGW-C132. Co-located SGW-C, PGW-C, and SMF126is represented by an S11 interface and an SMF. Here, the S11 interface represents the SGW-C of co-located SGW-C, PGW-C, and SMF126, and the SMF represents the co-located PGW-C and SMF of co-located SGW-C, PGW-C, and SMF126. Co-located UPF and PGW-U130is represented by a UPF. Co-located SMF and PGW-C132is represented by a Control plane S5 (S5-C) interface and an SMF, where the S5-C interface represents the PGW-C of co-located SMF and PGW-C132.

System200also includes cellular AP202, Access and Mobility Management Function (AMF)204, SGW-U206, and UPF208. Cellular AP202may terminate a cellular (e.g., 5G NR) air interface and may be configured with appropriate hardware (e.g., processor(s), memory element(s), antennas and/or antenna arrays, baseband processors (modems), and/or the like), software, logic, and/or the like to provide over-the-air coverage for cellular access. Cellular AP202may be implemented as a next-generation Node B (gNB) to facilitate 5G NR air access. AMF204is a 5G component and may be configured to handle mobility management and connection tasks based on information relating to network connections and sessions obtained from UE102over an N1 interface. SGW-U206may be the SGW-U in co-located SGW-U, PGW-U, and UPF128, and UPF208may be the UPF in co-located SGW-U, PGW-U, and UPF128. In one example, UPF208may be an Intermediate UPF (I-UPF). Cellular AP202may communicate with one or more UPFs (e.g., UPF208, the UPF in co-located UPF and PGW-U130, etc.) over one or more N3 interfaces.

At210, MME124obtains, from UE102, an initial 4G PDN connectivity attach request for IMS core118. The attach request may identify one or more APNs (e.g., for both PDN116and IMS core118). At212, MME124may resolve each APN. DNS server106may search for an SGW-C co-location attribute referred to as a network capability indication, which may indicate that the SGW-C is co-located with one or more other network components (e.g., PGW-C and/or SMF), and return the SGW-C record of the SGW-C in co-located SGW-C, PGW-C, and SMF126. At214, MME124may select that SGW-C for the network connection with IMS core118so that a subsequent attach request for PDN116may continue to use the same SGW-C. If there are multiple responses for SGW-Cs with an SGW-C co-location attribute, the most optimal SGW-C (e.g., the topologically closest SGW-C to PDN116) may be selected. MME124may use an Nnrf interface to select the SGW-C in co-located SGW-C, PGW-C, and SMF126. At216, MME124selects the PGW-C of co-located SMF and PGW-C132for the network connection with IMS core118.

With continued reference toFIG. 1,FIG. 3illustrates an example call flow diagram300for establishing an initial network connection between UE102and IMS core118with an optimal SGW. Call flow diagram300illustrates operations between UE102, cellular AP122, MME124, co-located SGW-U, PGW-U, and UPF128, co-located UPF and PGW-U130, co-located SGW-C, PGW-C, and SMF126, co-located SMF and PGW-C132, Home Subscriber Server (HSS)302, and DNS server106. An HSS is a 4G component, and may include a repository of subscriber information.

At304, MME124obtains, from UE102, an IMS PDN connectivity request as part of an initial attach request. At306, MME124sends an Update Location Request (ULR) to HSS302and further obtains an Update Location Answer (ULA) from HSS302. The ULA may include all APNs associated with the subscription of UE102. The APNs may be intended for network connections to PDN116in addition to IMS core118. Obtaining PGW addresses of all the relevant APNs, rather than just one, may permit MME124to choose the optimal SGW-C for the initial attach request. Querying all potential APNs/PDNs for UE102(from HSS302) may enable MME124to make a location (e.g., TAI) and service (e.g., APNs/PDNs) based selection of an SGW (and co-located PGW/UPF) with full visibility.

The ULA may also include an indication or a hint to MME124to select an optimal SGW for UE102. The hint may help MME124and/or DNS server106assist with optimal SGW selection, since MME124may not know a priori whether a given PDN request is to be established based on co-located SGW-C, PGW-C, and SMF126. One example of a hint is a UE usage type. A UE usage type may indicate the usage characteristics of a UE that enables the selection of a specific core network, and may allow for a specific SGW, PGW, and even MME to be set for a given UE. This may assist MME124in selecting an appropriate co-located control plane node based on the UE usage type indicating an appropriate core network for the network connection.

In other examples, an indication or hint may be provided to an MME based on a local operator policy configuration, DCNR capability, an (e.g., appended) N1 Non-Access Stratum (NAS) capability, an International Mobile Subscriber Identity (IMSI) range, an attribute in the UE subscription in an Sha message, an S10 (N26) UE context, etc. Local operator policy configuration may be used, for example, if all the relevant APN names are managed locally on the MME. Alternatively, instead of using a hint, an IMS network slice may be constructed without an SGW-C so as to prompt selection of an SGW-C in a PDN network slice, provided that steps are taken to prevent selection of any other SGW-Cs (e.g., an SGW-C in a 4G-only network slice or in a standalone SGW-C/U).

Operations308,310, and312relate to PGW selection by MME124. At308, after obtaining all APNs associated with the subscription of UE102, MME124may provide multiple APN NAPTR queries for every APN (e.g., including both the APN for PDN116and the APN for IMS core118). At310, DNS server106resolves the PGW(s) for all the subscribed/authorized APNs. At312, MME124obtains an answer to the DNS NAPTR queries from DNS server106. The answer may include a list of IP addresses for the PGWs resolved for the individual APNs (e.g., “x-3gpp-pgw:x-s5-gtp+nc-smf:x-s8-gtp+nc-smf”). The list may also include a network capability indication. For example, the list may include a network capability service parameter extension indicating that the PGW-Cs are co-located with respective SGW-Cs and/or SMFs (e.g., “x-3gpp-pgw:x-s5-gtp+nc-smf.combo:x-s8-gtp+nc-smf.combo”).

Provided below are example APN FQDN DNS NAPTR resource records for PGW address resolution that may be included in the answer to the DNS query.

Operations314,316, and318relate to SGW selection by MME124. At314, MME124may provide a TAI NAPTR query for UE102. The TAI NAPTR query may include a network capability indication of UE102(e.g., specifying that there is a preference for the SGW to be co-located with an SMF). At316, DNS server106resolves the SGW(s) that serve the TAI based on the network capability indication. At318, MME124obtains an answer to the TAI NAPTR query from DNS server106. The answer may include a list of IP addresses for the SGWs resolved for the relevant TAI (e.g., “x-3gpp-sgw:x-s5-gtp:x-s8-gtp”). The list may also include a network capability service parameter extension indicating that the SGW-Cs are co-located with respective PGW-Cs and/or SMFs (e.g., “x-3gpp-sgw:x-s5-gtp+nc-smf.combo:x-s8-gtp+nc-smf.combo”). This may assist MME124in selecting an appropriate co-located control plane node. In particular, if MME124is aware that multiple PDNs are going to be established for multiple APNs, then MME124may search the authorized APN list in anticipation that there may be subsequent PDN connection requests.

Thus, the UE usage type and network capability indication may serve to provide an explicit indication that an SGW-C should be selected that is co-located with a PGW-C configured to support a network connection with PDN116. The SGW-C may be specified for UE102through DNS NAPTR resolution of a TAI FQDN. For example, the UE usage type for UE102may be set to “5G Combo” and the network capability for UE102may be set to “smf” to ensure that DNS server106returns an SGW-C that is co-located with an SMF that serves PDN116.

Provided below are example TAI FQDN DNS NAPTR resource records for SGW address resolution that may be included in the answer to the DNS query.

At320, MME124identifies co-located SGW-C, PGW-C, and SMF126based on a reference to a local policy configuration, combination attribute(s), and/or network capability service parameter extension(s). For example, MME124may search the list of IP addresses for the appropriate SGW-C based on the network capability service parameter extension indicating that the SGW-C is co-located with the SGW-C and SMF (and/or based on the UE usage type specifying a particular core network). MME124may select the SGW-C in the co-located SGW-C, PGW-C, and SMF126in response (at least in part) to obtaining the UE usage type at306. At322, MME124may provide a Create Session (CS) request to co-located SGW-C, PGW-C, and SMF126, and at324, co-located SGW-C, PGW-C, and SMF126may provide the CS request to co-located SMF and PGW-C132.

Operations326,328, and330relate to IMS data plane path setup for 4G access. At326, an Sxa session is established between co-located SGW-U, PGW-U, and UPF128and co-located SGW-C, PGW-C, and SMF126. At328, an Sxb session is established between co-located UPF and PGW-U130and co-located SMF and PGW-C132. At330, an S5/S8-U tunnel is set up between co-located SGW-U, PGW-U, and UPF128and co-located UPF and PGW-U130. At332, co-located SMF and PGW-C132may provide a CS response to co-located SGW-C, PGW-C, and SMF126, and at334, co-located SGW-C, PGW-C, and SMF126may provide the CS response to MME124.

At336, an N4 session is established between co-located UPF and PGW-U130and co-located SMF and PGW-C132. This permits IMS data plane path setup for 5G access. At338, PDN network traffic is transmitted between UE102and co-located SGW-U, PGW-U, and UPF128, and at340, the PDN network traffic is transmitted between co-located SGW-U, PGW-U, and UPF128and co-located UPF and PGW-U130(e.g., to/from IMS core118). Thus, an IMS PDN connection is established to IMS core118.

With continued reference toFIGS. 1-3,FIG. 4illustrates an example system400configured to establish a subsequent APN based 4G PDN session with an optimal SGW. The operations associated with system400may occur after the operations associated with system200. Thus, MME124has already established a network connection between UE102and IMS core118. This example involves a follow-up connection initiated by UE102shortly after the previous network session was successfully established. At402, MME124obtains, from UE102, a request for a network connection to a PDN. At404, MME124obtains candidate PGW-Cs from DNS server106. At406, MME124selects the PGW-C of co-located SGW-C, PGW-C, and SMF126and establishes the connection with that PGW-C.

With continued reference toFIGS. 1 and 3,FIG. 5illustrates an example call flow diagram500for establishing a subsequent PDN session with an optimal SGW. At502, UE102establishes a PDN APN. At504, MME124obtains an attach request (e.g., a PDN connectivity request) from UE102. Operations506,508, and510relate to PGW selection. At506, MME124provides an APN NAPTR query to DNS server106. At508, DNS server106resolves the PGW(s) of the APN(s) for the PDN(s). At510, MME124obtains an answer to the DNS NAPTR queries from DNS server106. The answer may include one or more IP addresses for the PGW(s) resolved for the APN(s). The answer may also include a network capability service parameter extension indicating that the PGW-C(s) are co-located with SGW-C(s) and SMF(s) (e.g., “x-3 gpp-pgw:x-s5-gtp+nc-smf.combo:x-s8-gtp+nc-smf.combo”).

Operations506,508, and510may not be necessary if a Time-To-Live (TTL) associated with the previous DNS answer (FIG. 3, operation312) has not expired. In that case, MME124may select the PGW-C based on the previous DNS answer. If the TTL has expired, the previous DNS answer was flushed out from the local DNS client cache of MME124, and operations506,508, and510may be performed. In any event, at512, MME124selects the PGW-C of co-located SGW-C, PGW-C, and SMF126. MME124may select the PGW-C closest to the SGW-C of co-located SGW-C, PGW-C, and SMF126. Here, the PGW-C of co-located SGW-C, PGW-C, and SMF126is selected for the PDN session, and the SGW-C of co-located SGW-C, PGW-C, and SMF126continues to be used for the PDN session.

With continued reference toFIG. 1,FIG. 6illustrates a hardware block diagram of an example device600(e.g., a computing device that hosts MME124). It should be appreciated thatFIG. 6provides only an illustration of one embodiment and does not imply any limitations with regard to the environments in which different embodiments may be implemented. Many modifications to the depicted environment may be made.

As depicted, the device600includes a bus612, which provides communications between computer processor(s)614, memory616, persistent storage618, communications unit620, and Input/Output (I/O) interface(s)622. Bus612can be implemented with any architecture designed for passing data and/or control information between processors (such as microprocessors, communications and network processors, etc.), system memory, peripheral devices, and any other hardware components within a system. For example, bus612can be implemented with one or more buses.

Memory616and persistent storage618are computer readable storage media. In the depicted embodiment, memory616includes Random Access Memory (RAM)624and cache memory626. In general, memory616can include any suitable volatile or non-volatile computer readable storage media. Instructions for SGW selection logic138may be stored in memory616or persistent storage618for execution by computer processor(s)614.

One or more programs may be stored in persistent storage618for execution by one or more of the respective computer processors614via one or more memories of memory616. The persistent storage618may be a magnetic hard disk drive, a solid state hard drive, a semiconductor storage device, Read-Only Memory (ROM), Erasable Programmable ROM (EPROM), Flash memory, or any other computer readable storage media that is capable of storing program instructions or digital information.

Communications unit620, in these examples, provides for communications with other data processing systems or devices. In these examples, communications unit620includes one or more network interface cards. Communications unit620may provide communications through the use of either or both physical and wireless communications links.

I/O interface(s)622allows for input and output of data with other devices that may be connected to device600. For example, I/O interface(s)622may provide a connection to external devices628such as a keyboard, keypad, a touch screen, and/or some other suitable input device. External devices628can also include portable computer readable storage media such as database systems, thumb drives, portable optical or magnetic disks, and memory cards.

Software and data used to practice embodiments can be stored on such portable computer readable storage media and can be loaded onto persistent storage618via I/O interface(s)622. I/O interface(s)622may also connect to a display630. Display630provides a mechanism to display data to a user and may be, for example, a computer monitor.

With continued reference toFIG. 1,FIG. 7is a flowchart of an example method700for optimizing SGW selection for interworking networks. In this example, MME124performs method700. At710, MME124obtains a first connectivity request for a first network connection between a UE and a first network. At720, MME124selects an SGW-C node for the first network connection. The SGW-C node is co-located with a PGW-C node configured to support a second network connection between the UE and a second network that is different from the first network. At730, MME124obtains a second connectivity request for the second network connection. At740, MME124establishes the second network connection with the SGW-C node and the PGW-C node.

Techniques described herein may support Regional Data Center (RDC), Mobile Edge Computing (MEC), and/or I-UPF selection use cases in interworking networks deployments. Selecting a co-located SGW-C, PGW-C, and SMF node as discussed herein may be useful for matching expectations for 4G/5G capable subscribers in an RDC/MEC use case. In this use case, Internet/data APN based user plane instances (e.g., SGW-U, PGW-U, and UPF) may be combined together and hosted in an RDC. In particular, a combined, efficient, and optimized user plane node may be selected for a 4G/5G capable subscribers. Simplified and optimized user plane node selection for an Internet/data APN based PDN session may be achieved to efficiently support RDC/MEC and I-UPF use cases. The control plane may consistently select the combined user plane node for Internet APN calls for improved efficiency. The techniques described herein may avoid split sessions for SGW, PGW and SMF, thereby ensuring user/data plane efficiency in 4G/5G interworking mobility networks.

Data relating to operations described herein may be stored within any conventional or other data structures (e.g., files, arrays, lists, stacks, queues, records, etc.) and may be stored in any desired storage unit (e.g., database, data or other repositories, queue, etc.). The data transmitted between entities may include any desired format and arrangement, and may include any quantity of any types of fields of any size to store the data. The definition and data model for any datasets may indicate the overall structure in any desired fashion (e.g., computer-related languages, graphical representation, listing, etc.).

The software of the present embodiments may be available on a non-transitory computer useable medium (e.g., magnetic or optical mediums, magneto-optic mediums, floppy diskettes, Compact Disc ROM (CD-ROM), Digital Versatile Disk (DVD), memory devices, etc.) of a stationary or portable program product apparatus or device for use with stand-alone systems or systems connected by a network or other communications medium.

Each of the elements described herein may couple to and/or interact with one another through interfaces and/or through any other suitable connection (wired or wireless) that provides a viable pathway for communications. Interconnections, interfaces, and variations thereof discussed herein may be utilized to provide connections among elements in a system and/or may be utilized to provide communications, interactions, operations, etc. among elements that may be directly or indirectly connected in the system. Any combination of interfaces can be provided for elements described herein in order to facilitate operations as discussed for various embodiments described herein.

Computer readable program instructions described herein can be downloaded to respective computing/processing devices from a computer readable storage medium or to an external computer or external storage device via a network, for example, the Internet, a LAN, a WAN, and/or a wireless network. The network may comprise copper transmission cables, optical transmission fibers, wireless transmission, routers, firewalls, switches, gateway computers and/or edge servers. A network adapter card or network interface in each computing/processing device receives computer readable program instructions from the network and forwards the computer readable program instructions for storage in a computer readable storage medium within the respective computing/processing device.

In one form, a method is provided. The method comprises: obtaining a first connectivity request for a first network connection between a user equipment and a first network; selecting a control plane serving gateway node for the first network connection, wherein the control plane serving gateway node is co-located with a control plane packet data network gateway node configured to support a second network connection between the user equipment and a second network that is different from the first network; obtaining a second connectivity request for the second network connection; and establishing the second network connection with the control plane serving gateway node and the control plane packet data network gateway node.

In one example, the control plane serving gateway node and the control plane packet data network gateway node are co-located with a session management function node.

In one example, one or more of the control plane serving gateway node, the control plane packet data network gateway node, or the session management function node are configured to communicate with a co-located user plane serving gateway node, user plane packet data network gateway node, and user plane function node via a concatenated Sxa and N4 interface.

In one example, the method further comprises: providing a query for a plurality of identifiers of candidate control plane serving gateway nodes; and obtaining the plurality of identifiers including an identifier of the control plane serving gateway node and an indication that the control plane serving gateway node is co-located with the control plane packet data network gateway node, and wherein selecting the control plane serving gateway node includes selecting the control plane serving gateway node from the candidate control plane serving gateway nodes based on the indication.

In one example, the method further comprises: selecting one of a plurality of candidate control plane packet data network gateway nodes for the first network connection; in response to obtaining the second connectivity request, determining that a time to live associated with the plurality of candidate control plane packet data network gateway nodes has not expired; and in response to determining that the time to live has not expired, selecting the control plane packet data network gateway node from the plurality of candidate control plane packet data network gateway nodes.

In one example, the method further comprises: obtaining a user equipment usage type information element indicating that a particular control plane serving gateway node should be selected that is co-located with a particular control plane packet data network gateway node configured to support the second network connection, wherein selecting the control plane serving gateway node includes selecting the control plane serving gateway node in response to obtaining the user equipment usage type information element.

In one example, the first network is an internet protocol multimedia subsystem core network, and the second network is a packet data network.

In another form, an apparatus is provided. The apparatus comprises: a network interface configured to obtain or provide network communications; and one or more processors coupled to the network interface, wherein the one or more processors are configured to: obtain a first connectivity request for a first network connection between a user equipment and a first network; select a control plane serving gateway node for the first network connection, wherein the control plane serving gateway node is co-located with a control plane packet data network gateway node configured to support a second network connection between the user equipment and a second network that is different from the first network; obtain a second connectivity request for the second network connection; and establish the second network connection with the control plane serving gateway node and the control plane packet data network gateway node.

In another form, one or more non-transitory computer readable storage media are provided. The non-transitory computer readable storage media are encoded with instructions that, when executed by a processor, cause the processor to: obtain a first connectivity request for a first network connection between a user equipment and a first network; select a control plane serving gateway node for the first network connection, wherein the control plane serving gateway node is co-located with a control plane packet data network gateway node configured to support a second network connection between the user equipment and a second network that is different from the first network; obtain a second connectivity request for the second network connection; and establish the second network connection with the control plane serving gateway node and the control plane packet data network gateway node.