KR20220036614A - Network device, control method for session load performed by the device - Google Patents

Abstract

The present invention provides a network device and a session load control method performed in the device which can realize a technology capable of segmenting session load control in a manner of controlling the existing control per node with segmented classification criteria (ex: LCI information per interface) in the session load control between a control plane and a user plane.

Description

Network device and session load control method performed on the device

The present invention relates to a session load control technique between a control plane (CP) and a user plane (UP). It is about a technique for subdividing session load control in a way that controls the previous control for each interface of the node.

5G communication system, while accommodating the maximum number of terminals based on limited radio resources, eMBB (enhanced mobile broadband) / mMTC (massive machine type communications) / URLLC (ultra-reliable and It supports scenarios of low latency communications, high reliability and low latency communications).

In particular, in 5G, a network structure to support a terminal, a base station (access), a core, and a server from end to end is defined, and a single node (eg, S-GW, P-GW, etc.) in existing LTE (4G) By separating the functions of control signaling and data transmission/reception that were complexly performed, a network structure is defined in which the control signaling function area (Control Plane) and the data transmission/reception function area (User Plane) are divided.

At this time, in 5G, the control node of the Control Plane (CP) controls AMF (Access and Mobility Management Function) that controls access to the wireless section of the terminal, and PCF that manages/controls policies such as terminal information, subscription service information for each terminal, and billing. (Policy Control Function), SMF (Session Management Function) to control/manage sessions for data service use by terminal, NEF (Network Exposure Function) to share information with external networks, user’s subscriber DB It can be defined as UDM/AUSF (Unified Data Management / AUthentication Function) to manage/control authentication and NRF (NF Repository Function) to manage/control NF storage functions, and CHF (CHarging Function) to handle subscriber billing. there is.

In 5G, the data node of the User Plane (UP) transmits and receives data between the terminal and the server on an external service network (eg, Internet) through a session with the terminal based on the control (interlocking) of the SMF (User Plane Function) ) can be defined as

Among the control nodes of the CP, the SMF allocates an IP so that the UE can use the User Plane service, creates/controls/manages a session, and considers the node state of each UPF when creating a session to determine the UPF to participate in the session. Session load control is performed by the allocation method.

Meanwhile, in the case of session load control between SMF and UPF, in order to effectively operate a large/small capacity UPF system, there is an increasing need to be performed with a more subdivided classification criterion than for a node unit.

However, until now, session load control performed by SMF in the standard is limited to the method performed by each UPF unit, that is, each node.

Therefore, in the present invention, in the session load control between CP and UP, a technique that can subdivide session load control in a way that controls the control performed for each node with more granular classification criteria (eg, load information for each interface) would like to propose

The present invention was created in consideration of the above circumstances, and the object to be reached in the present invention is to reduce the control performed for each node in the session load control between the CP and the UP into more granular classification criteria (eg, load by interface). Information) to provide a network device capable of subdividing session load control in a method of controlling the session load and a session load control method performed in the device.

A network device according to a first aspect of the present invention for achieving the above object includes: a load information acquisition unit configured to acquire load information for each interface of the network node for each network node of a user plane; and a load control unit that performs load control based on load information for each interface of each network node when load control for a subscriber's session is performed.

Specifically, the load information acquisition unit receives load information for each interface of the network node through an Association response message received during an association procedure for connecting with a network node or a Report message received from a network node in a connected state. can be obtained by

Specifically, the interface identifier for classifying the load information in the load information for each interface is a communication interface through which the network node communicates with other NF (Network Function), DNN (Data Network Name), APN (Access Point Name), Virtual Port It may be defined as at least one of / Physical Port, IP Address / Prefix, NW Slice ID, regional information (ECGI / NCGI), and subscriber ID.

Specifically, the load information for each interface may include a bandwidth usage rate of the interface for each interface of the network node.

Specifically, the load control unit, based on the load information for each interface of each network node, when the load on the specific interface of the specific network node exceeds a specific threshold, releases the session connection related to the specific interface of the specific network node, and A disconnected session can be reestablished.

Specifically, the load control unit may allocate a network node to be involved in session establishment based on load information for each interface of each network node when re-establishing a session or establishing a new session after disconnecting the session.

In order to achieve the above object, the session load control method performed in the network device of the control plane according to the second aspect of the present invention for achieving the above object is the load for each network node of the user plane and the load for each interface of the network node. (Load) a load information acquisition step of acquiring information; and a load control step of performing load control based on load information for each interface of each network node when controlling a load for a subscriber session (Session).

Specifically, in the load control step, based on the load information for each interface of each network node, when the load on a specific interface of a specific network node exceeds a specific threshold, the session connection related to the specific interface of the specific network node is released Allocating a network node to be involved in session establishment based on the load information for each interface of each network node when reestablishing a session or establishing a new session after disconnecting the session may include

According to the network device of the present invention and the session load control method performed in the device, in the session load control between the CP and the UP, the control previously performed for each node is controlled by more granular classification criteria (eg, load information for each interface). In this way, we are realizing a new technology that can subdivide session load control.

Accordingly, according to the present invention, by more subdividing the session load control between the control plane and the user plane, more detailed UP resource management is possible, and an overload condition can be prevented in advance through detailed UP resource management. It is possible to derive the effect of improving the UP operation efficiency.

1 is an exemplary diagram showing the structure of a 5G system.
2 is a block diagram showing the configuration of a network device according to an embodiment of the present invention.
3 and 4 show an embodiment of an IE structure defined to transmit load information for each interface in the present invention.
5 and 6 are exemplary views showing embodiments in which load information for each interface is transmitted/obtained in the present invention.
7 and 8 are exemplary views showing embodiments of session load control performed based on load information for each interface in the present invention.
9 is an operation flowchart illustrating a session load control method performed in a network device according to an embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

The present invention relates to a session load control technique between a control plane (CP) and a user plane (UP).

More specifically, it relates to a technique for subdividing session load control in such a way that, in the session load control between the CP and the UP, the control previously performed for each node is controlled for each interface of the node.

First, FIG. 1 is an exemplary diagram showing the structure of a 5G system.

As can be seen from FIG. 1, the 5G communication system accommodates the maximum number of terminals based on limited radio resources, while eMBB (enhanced mobile broadband)/mMTC (massive machine type communications) /URLLC (ultra-reliable and low latency communications) scenarios are supported.

In particular, in 5G, a network structure to support a terminal, a base station (access), a core, and a server from end to end is defined, and a single node (eg, S-GW, P-GW, etc.) in existing LTE (4G) By separating the functions of control signaling and data transmission/reception that were complexly performed, a network structure is defined in which the control signaling function area (Control Plane) and the data transmission/reception function area (User Plane) are divided.

At this time, in 5G, the control node of the control plane manages/controls policies such as AMF (Access and Mobility Management Function) that controls access to the wireless section of the terminal, terminal information, subscription service information for each terminal, and charging policy (Policy Control) Function), SMF (Session Management Function) that manages/controls sessions for data service use by terminal, NEF (Network Exposure Function) that is responsible for information sharing with external networks, and manages the user’s subscriber DB and authentication It can be defined as UDM/AUSF (Unified Data Management / AUthentication Function) that manages/controls, NRF (NF Repository Function) manages/controls NF storage function, and CHF (CHarging Function) that handles subscriber billing.

In 5G, the data node of the user plane is defined as a UPF (User Plane Function) that transmits and receives data between the terminal and the server on an external service network (eg, Internet) through a session with the terminal based on the control (interlocking) of the SMF. can do.

Among the control nodes of the CP, the SMF allocates an IP so that the UE can use the User Plane service, creates/controls/manages a session, and considers the node state of each UPF when creating a session to determine the UPF to participate in the session. Session load control is performed by the allocation method.

Meanwhile, in the case of session load control between SMF and UPF, in order to effectively operate a large/small capacity UPF system, there is an increasing need to be performed with a more subdivided classification criterion than for a node unit.

However, until now, session load control performed by SMF in the standard is limited to the method performed by each UPF unit, that is, each node.

Therefore, in the present invention, in the session load control between CP and UP, the session load control can be further subdivided by controlling the control performed for each node with a more subdivided classification criterion (eg, load information for each interface). We would like to propose a technology (hereinafter referred to as an interface-based session load control function).

More specifically, the present invention intends to propose a network device that realizes an interface-based session load control function.

2 shows the configuration of a network device according to an embodiment, which realizes the interface-based session load control function proposed in the present invention.

First, a network device for realizing the proposed technology of the present invention, that is, an interface-based session load control function, may be a NF (Network Function) of the control plane (CP), that is, a control node (network node).

Hereinafter, as a network device for realizing the proposed technology of the present invention, the SMF of the control plane (CP) will be referred to and described.

Meanwhile, the base station (gNB) may be divided into a Central Unit Control Plane (CU-CP) and a Central Unit User Plane (CU-UP), the CU-CP may be integrated with the SMF, and the CU-UP may be integrated with the UPF. can be integrated.

In this case, the CU-CP corresponds to a network device that realizes the proposed technology of the present invention, for example, SMF as the NF of the control plane (CP), and the CU-UP corresponds to the UPF as the NF of the user plane (UP). For reference, the CU-CP may process a terminal session through CU-UP and E1 signaling I/F.

Meanwhile, since the present invention considers SMF and UPF that can also accommodate NSA/LTE EPC functions, SMF is a function of S/PGW-C (Serving Gateway/Packet Data Network Gateway Control), and UPF is S/PGW- Functions of U (Serving Gateway/Packet Data Network Gateway User) can be accommodated together.

In this case, S/PGW-C corresponds to a network device that realizes the proposed technology of the present invention, for example, SMF as the NF of the control plane (CP), and S/PGW-U corresponds to the UPF as the NF of the user plane (UP). do. For reference, the CU-CP may process a terminal session through CU-UP and Sx signaling I/F.

As such, as shown in FIG. 2, in the present invention, between CU-CP + SMF + S/PGW-C (100, control plane) and CU-UP + UPF + S/PGW-U (10, user plane) In session load control, a technique that can further subdivide session load control, that is, interface-based session load control function, by controlling the control performed by each node with more granular classification criteria (e.g., load information for each interface). will suggest

However, in the description with reference to FIG. 2 , the SMF will be referred to as the network device 100 for realizing the proposed technology of the present invention.

2 , the network device 100 , SMF according to an embodiment of the present invention may include a load information acquisition unit 110 and a load control unit 120 .

First, the SMF of 5G is briefly described. The SMF allocates and creates/controls/manages an IP to use the User Plane service to the UE. The SMF performs session load control by allocating UPFs to be involved in the session in consideration of the node state of each UPF when the UE creates/modifies a session.

On the other hand, the network device 100 (SMF) according to an embodiment of the present invention controls session load control in a way that controls the control performed for each node with more granular classification criteria (eg, load information for each interface). There is a key to performing segmentation.

The network device (100, SMF) of the present invention is a configuration of an interface-based session load control function that realizes the proposed technique of the present invention, that is, more granular session load control, and includes a load information acquisition unit 110 and a load control unit 120 ) is included.

The load information acquisition unit 110 may play a role of acquiring load information for each interface of the network node for each network node of the user plane.

That is, the load information acquisition unit 110 may acquire load information for each interface of the UPF 10 for each UPF 10 of the user plane UP through the N4 signaling I/F.

Of course, the load information acquisition unit 110, when the network device 100 is a CU-CP, load information for each interface of the CU-UP 10 for each CU-UP 10 of the user plane UP. can be obtained through E1 signaling I/F, and when the network device 100 is S/PGW-C, S/PGW-U(10) for each S/PGW-U(10) of the user plane (UP) Load information for each interface of can be acquired through Sx signaling I/F.

The load control unit 120, when controlling the load for the subscriber's session (Session), each interface of each network node, that is, each network node (10, CU-UP + UPF + S/PGW-U) of the user plane (UP) Based on the load information, it is responsible for performing load control.

Hereinafter, as an embodiment in which the network device 100 is an SMF, a method of acquiring load information for each interface of the UPF 10 will be described in detail.

The load information acquisition unit 110 receives an Association response message received during an association procedure for performing a connection with the network node of the user plane UP, that is, the UPF 10, or a Report message received from the UPF 10 in a connected state. Through this, load information for each interface of the UPF 10 may be received and obtained.

Before giving a session control command to the UPF of the user plane (UP), the SMF of the control plane (CP) performs the PFCP Association Setup procedure to establish a PFCP association with the corresponding UPF to perform interconnection, and in this procedure You can check the features supported by each other.

According to one embodiment, in the present invention, in the (N4) PFCP Association Setup Response message transmitted by the UPF to the SMF in the PFCP Association Setup procedure performed between the SMF and the UPF, the UPF includes load information for each interface and delivers it. can be defined

In this case, the load information acquisition unit 110 loads each interface of the UPF 10 from the (N4) PFCP Association Setup Response message received during the PFCP Association Setup procedure performed with the UPF 10 of the user plane UP. Information can be received/acquired.

On the other hand, the SMF of the control plane CP provides a policy such as a Usage Reporting Rule (URR) for each session to the UPF of the user plane UP. The URR includes the information the SMF wants to collect, the measurement method of the information, and the time when it wants to receive the information.

The UPF of the user plane (UP) collects related information according to the URR provided by the SMF, and if a specific period or event condition is met according to the measurement method, (N4) PFCP Session Report Request to report information for each session It delivers/reports the information to the SMF through a message.

Accordingly, according to another embodiment, in the present invention, it is defined that the UPF includes load information for each interface in a Report message in which the UPF reports the UPF session information to the SMF, for example, (N4) PFCP Session Report Request message. can do.

In this case, the load information acquisition unit 110 may receive/obtain load information for each interface of the UPF 10 from the (N4) PFCP Session Report Request message received from the UPF 10 of the user plane UP. there is.

Meanwhile, in the present invention, in order to deliver load information for each interface through a PFCP Association Setup Response message or a PFCP Session Report Request message, a new interface identifier IE may be defined.

Specifically, for example, as shown in FIG. 3 , an interface identifier IE (hereinafter, a Source Interface (or Destination Interface) IE) is added to an Information Element (IE) indicating the existing Load Control Information (LCI). It can be further defined.

That is, in the present invention, a Source Interface (or Destination Interface) IE is additionally defined in the Load Control Sequence Number IE and Load Metric IE as the existing LCI IEs, so that the network device 100 (SMF) causes the PFCP Association Setup Response message. Alternatively, it is possible to obtain load information for each interface from the Source Interface (or Destination Interface) IE, which is checked in the LCI IE in the PFCP Session Report Request message.

At this time, in the present invention, the load information for each interface is a network node, that is, the bandwidth usage rate of the interface for each interface of CU-UP + UPF + S/PGW-U 10 that delivers load information for each interface. may include

In the LCI IE, the load metric expressed as a percentage (0~100%) contains the load information of the sender (eg UPF). The calculation criteria for such a load metric can be freely defined by the sender (eg UPF).

However, in the present invention, as an NF in which a network node of the user plane UP, for example, CU-UP + UPF + S/PGW-U 10 controls the packet, the most important load calculation criterion to be considered is Since it is judged to be the bandwidth, the load metric calculation criterion can be defined as the bandwidth usage rate.

Meanwhile, the above-mentioned bandwidth usage rate may also be expressed in units of PPS (Packet per second), Throughput (Mbps, Gbps, Tbps, etc), latency, and jitter.

In addition, the above-described bandwidth usage rate may be expressed as a CPU processing load, a memory load, and an I/O transaction per second (TPS) allocated to the network node, that is, CU-UP + UPF + S/PGW-U 10 .

Accordingly, in the present invention, a Source Interface (or Destination Interface) IE is additionally defined to the existing LCI IE, but the Load Metric IE is defined to indicate the bandwidth usage rate of the corresponding Source Interface (or Destination Interface) IE, so that the network device ( 100, SMF) to obtain the bandwidth usage rate as load information for each interface from the Source Interface (or Destination Interface) IE / Load Metric IE checked in the LCI IE in the PFCP Association Setup Response message or PFCP Session Report Request message. let there be

Furthermore, the interface identifier that separates the load information from the load information for each interface is the network node of the user plane (UP), that is, the UPF that delivers the load information for each interface this time is different from the other NFs (20). It can be defined as at least one of communication interface, DNN (Data Network Name), APN (Access Point Name), Virtual Port / Physical Port, IP Address / Prefix, NW Slice ID, regional information (ECGI / NCGI), and subscriber ID there is.

That is, the interface identifier that distinguishes the load information from the load information for each interface delivered through the Source Interface IE, which is additionally defined in the LCI IE as described above, is defined through each or combination of various criteria as follows. can be done

- Communication interface (eg Uplink, Downlink, SGi-LAN/N6-LAN, CP-Function, etc.)

- DNN (eg 5g.sktelecom.com)

- APN (eg 5g.sktelecom.com)

- Virtual Port / Physical Port (eg v_eth0, eth1, etc.)

- IP Address / Prefix (Example: 172.2.2.2, 172.2.0.0/16, etc.)

- NW Slice ID

- Local information (ECGI / NCGI)

- Subscriber ID (eg phone number)

An example of an Interface Value value in Load information for each interface will be described in detail as shown in FIG. 4 .

The Source Interface IE may have the same communication interface as a delimiter, that is, an Interface Value value as shown in FIG. 4 , where “Access” may mean Uplink and “Core” may mean Downlink.

As described above, communication interfaces such as Uplink, Downlink, SGi-LAN/N6-LAN, and CP-Function can be expressed according to each Interface Value in the Source Interface IE.

That is, in the present invention, the network node of the user plane (UP), for example, CU-UP + UPF + S/PGW-U 10, has an N3 Interface for communicating with the RAN, an N9 Interface for communicating between UPFs, and an N6 going out to the Internet. By classifying the interface by the Interface Value value shown in FIG. 4 above, load information for each interface can be delivered.

Of course, in the present invention, the network node of the user plane (UP), for example, CU-UP + UPF + S/PGW-U (10), to distinguish each or combination of subscriber ID / NW Slice ID / regional information (ECGI / NCGI) The interface can be divided by the expressed Interface Value, and load information for each interface can be delivered.

5 and 6 show embodiments in which load information for each interface is transmitted/obtained in the present invention as described above.

First, FIG. 5 shows an embodiment in which the network device 100 (SMF) acquires load information for each interface for each UPF by utilizing the PFCP Association Setup Response message.

5, in the present invention, in the PFCP Association Setup Response message transmitted by UPF #1 to the SMF in the PFCP Association Setup procedure performed between the SMF and UPF #1, load information for each interface of UPF #1, such as LCI 1 and LCI 2 can be included and delivered (5-1).

Accordingly, the SMF may acquire (acquire) and manage the load information (LCI information for each interface) of the UPF #1 for each interface (5-2).

Similarly, in the present invention, in the PFCP Association Setup Response message transmitted by UPF #2 to the SMF in the PFCP Association Setup procedure performed between the SMF and UPF #2, load information for each interface of UPF #2, such as LCI 1, LCI 2 It can be delivered by including (5-3).

Accordingly, the SMF may acquire (acquire) and manage the load information (LCI information for each interface) of UPF #2 for each interface (5-4).

As described above, in the present invention, the SMF acquires (acquires) load information for each interface (LCI information for each interface) for each of the plurality of UPFs while performing the PFCP Association Setup procedure for each of the plurality of UPFs including UPF #1 and #2. can manage

Next, FIG. 6 shows an embodiment in which the network device 100 (SMF) acquires load information for each interface for each UPF by utilizing the PFCP Session Report Request message.

As shown in FIG. 6 , in the present invention, when the SMF receives a PDU Session creation request from the AMF, it allocates UPF #1 to create the subscriber's PDU Session (6-1), and then UPF #1 periodically sends the SMF In the N4 Session Report Request message transmitted to UPF #1, load information for each interface of UPF #1, for example, LCI 1, LCI 2 can be included and delivered.

As a result, the SMF may acquire (acquire) load information (LCI information for each interface) of UPF #1 for each interface and manage it (6-2).

Similarly, in the present invention, when the SMF receives a PDU Session creation request from the AMF, it allocates UPF #2 to create the subscriber's PDU Session (6-3), and then UPF #2 periodically transmits the N4 to the SMF. In the Session Report Request message, load information for each interface of UPF #2, for example, LCI 1, LCI 2 can be included and delivered.

As a result, the SMF may acquire (acquire) and manage the load information for each interface (LCI information for each interface) of UPF #2 (6-4).

As described above, in the present invention, the SMF acquires (acquires) load information for each interface (LCI information for each interface) for each of the plurality of UPFs while receiving the N4 Session Report Request message for each of the plurality of UPFs including UPF #1 and #2. can be managed by

The load control unit 120, each network node (10, CU-UP + UPF + S/PGW) of the user plane (UP) that acquires (acquires) and manages as described above when controlling the load for the subscriber's session (Session). Based on the load information for each interface of -U), it is responsible for performing load control.

Hereinafter, as an embodiment in which the network device 100 is an SMF, an embodiment of load control performed based on load information for each interface of the UPF 10 will be described in detail.

The load control unit 120 connects the session related to the specific interface of the specific network node when the load on the specific interface of the specific network node exceeds a specific threshold based on the load information for each interface of each network node, that is, each UPF 10 . UPF re-allocation can be performed, which releases and resets the disconnected session.

More specifically, in the network device 100 (SMF) of the present invention, load thresholds for each interface (hereinafter, LCI Limit Info.) may be initially set, and the load control operation suitable for each LCI Limit may be determined. For example, LCI Limit and load control operation can be set in 3 steps as follows.

MINOR_LIMIT : Issue an alarm

MAJOR_LIMIT : Control the incoming of additional sessions after the alarm is issued

CRITICAL_LIMIT : Session is released after an alarm is issued

Accordingly, the load control unit 120, based on the interface-specific load information (bandwidth usage rate) of each UPF 10 acquired (acquired) and managed as described above, exceeds a specific threshold of the LCI Limit Info. You can monitor the presence of a specific UPF / specific interface.

When there is a specific UPF/specific interface exceeding a specific threshold, the load control unit 120 may perform a load control operation that meets the corresponding specific threshold for a session related to the specific UPF/specific interface.

For example, when there is a specific UPF / specific interface exceeding CRITICAL_LIMIT, the load control unit 120 releases the session connection for the related session of the specific UPF / specific interface, but in the session connection release procedure, to the terminal (UE) Re-establishment of the disconnected PDU Session can be induced by setting “reactivation requested” as the Cause value of the outgoing PDU Session Release message.

Accordingly, the load control unit 120 induces re-establishment of the disconnected PDU Session, and thus, when re-establishing the PDU Session of the corresponding UE (UE), obtains (acquires) and manages as described above for each interface of each UPF 10 . Based on the load information (bandwidth usage rate), it is possible to allocate a UPF to participate in the session.

Of course, the load control unit 120, when establishing a new session, that is, a PDU Session of the UE, based on the interface load information (bandwidth usage rate) of each UPF 10 acquired (acquired) and managed as described above, UPF Selection can be performed, allocating UPF to participate in the session.

In this case, the function of allocating the UPF to be involved in the session in the PDU Session reconfiguration process when performing the above-described UPF re-allocation may be the same as the above-mentioned UPF selection execution.

7 and 8 are exemplary views showing embodiments of session load control performed based on load information for each interface in the present invention.

First, FIG. 7 is an embodiment of segmented session load control in the interface-based session load control function of the present invention, and describes performing UPF re-allocation using load information (bandwidth usage rate) for each interface.

As described above, in the SMF of the present invention, the load threshold for each interface, that is, the LCI Limit Info. can be initially set (7-1).

And, in the SMF, load information (bandwidth usage rate) for each interface of each UPF (hereinafter, LCI information for each interface) may be acquired in the manner shown in FIG. 5 or FIG. 6 described above. However, in FIG. 7 , as shown in FIG. 6 , the LCI information for each interface of the UPF is acquired through the N4 Session Report request message.

Accordingly, in the SMF, LCI information for each interface of UPF #1 may be obtained, and it may be monitored whether or not a specific threshold value of a preset LCI Limit Info. is exceeded.

In SMF, for example, when the specific interface LCI of UPF #1 exceeds CRITICAL_LIMIT (95%), the session connection may be released for the session related to the specific interface of UPF #1 (7-22).

Here, the session to be disconnected may be an N4 Report-related session used to transmit LCI information for each interface in UPF #1, or a session selected arbitrarily or according to a set rule among sessions related to a specific interface of UPF #1. it may be

In addition, in the SMF, re-establishment of the disconnected PDU Session can be induced by setting “reactivation requested” as the Cause value of the PDU Session Release message sent to the UE in the session disconnection procedure (7-3).

Accordingly, in the SMF, when re-establishing the PDU Session of the corresponding terminal (UE) by inducing re-establishment of the disconnected PDU Session, based on the LCI information for each interface of each UPF that is acquired (acquired) and managed as described above, the session A UPF to be involved in, for example, UPF #2 may be allocated (7-4).

Next, FIG. 8 is an embodiment of the subdivided session load control in the interface-based session load control function of the present invention, and describes performing UPF selection using load information (bandwidth usage rate) for each interface.

As described above, in the SMF of the present invention, LCI information for each interface of each UPF is acquired (acquired) and managed.

Accordingly, in the SMF, upon receiving a PDU Session creation request from the AMF and establishing a new session, that is, a PDU Session of the UE, as described above, based on the LCI information for each interface of the UPFs acquired (acquired) and managed as described above, the PDU Session Allocate UPF to be involved (8-1).

For example, when SMF wants to allocate one of UPF #1 and #2, based on the LCI information for each interface of UPF #1 and #2, the Core Interface load is greater than that of UPF #1, where the Core Interface load is 90%. UPF #2 as low as 20% can be allocated as a UPF to be involved in PDU Session.

As mentioned above, when performing the above-described UPF re-allocation, the function 7-4 for allocating the UPF to be involved in the session in the PDU Session re-establishment process may be the same as the above-mentioned UPF selection execution ( FIG. 8 ).

In the present invention, a network node of the user plane (UP), for example, CU-UP + UPF + S/PGW-U 10 may control the session load control operation by referring to LCI information for each interface itself.

For example, CU-UP + UPF + S/PGW-U(10) has the same Interface name (eg, same N6 name, N6_a, N6_b, N6_c, ...) can distribute the load, and through this, the load in CU-UP + UPF + S/PGW-U 10 can be controlled according to various load distribution criteria (eg, priority weight schedule).

As described above, according to the present invention, in the session load control between the control plane and the user plane, the control performed for each existing node is divided into more subdivided classification criteria (eg, LCI information for each interface). We are realizing a new technology that can subdivide session load control in a way that controls it.

Accordingly, according to the present invention, by further subdividing the session load control between the control plane (CP) and the user plane (UP), more detailed UP resource management is possible, and an overload state can be prevented in advance through detailed UP resource management. etc., to derive the effect of improving the UP operation efficiency.

Hereinafter, with reference to FIG. 9 , the proposed method of the present invention, that is, a method for realizing an interface-based session load control function that can further subdivide session load control (hereinafter, a session load control method) will be described in detail.

In FIG. 9, as the network device NF of the control plane CP according to the present invention, the SMF among CU-CP, SMF, and S/PGW-C will be described as an embodiment.

According to the session load control method of the present invention, the SMF 100 utilizes the Association Setup Response message or the Session Report Request message transmitted by the UPF, and the Source Interface (or Destination Interface) IE / Load Metric identified in the LCI IE in the message. Load information (eg, bandwidth usage rate) for each interface of the UPF may be acquired from the IE (S10).

Accordingly, according to the session load control method of the present invention, the SMF 100 may acquire (acquire) and manage load information for each interface (hereinafter, LCI information for each interface) for each of a plurality of UPFs (S20).

On the other hand, according to the session load control method of the present invention, the SMF 100 may initially set a load threshold for each interface (hereinafter, LCI Limit Info.) and determine the load control operation suitable for each LCI Limit ( S30).

According to the session load control method of the present invention, the SMF 100 may perform session load control based on the load information for each interface of the UPF, that is, the LCI information for each interface (S40).

To describe an example, the SMF 100 releases the session connection for the session related to the Core Interface of UPF #1, for example, when the load of the Core Interface of UPF #1, that is, LCI exceeds CRITICAL_LIMIT (95%). can

In addition, the SMF 100 induces re-establishment of the disconnected PDU Session by setting “reactivation requested” as the Cause value of the PDU Session Release message sent to the UE in the session disconnection procedure, and the UE Upon re-establishing the PDU Session of , based on the LCI information for each interface of each UPF that is acquired (acquired) and managed as described above, a UPF, for example, UPF #2, to be involved in the session may be allocated (S40).

To describe another example, when the SMF 100 receives a PDU Session creation request from the AMF and establishes a new session, that is, a PDU Session of the UE, as described above, the SMF 100 acquires (acquires) and manages each interface of the UPFs as described above. A UPF to participate in the PDU Session is allocated based on the LCI information (S40).

For example, when the SMF 100 intends to allocate one of UPF #1 and #2 when establishing a new session of the UE, that is, a PDU Session, based on LCI information for each interface of UPF #1 and #2 Therefore, UPF #2, which has a core interface load of 20% lower than UPF #1 with a core interface load of 90%, can be allocated as the UPF to be involved in the PDU Session.

According to the session load control method of the present invention, the SMF 100 repeats steps S10 and subsequent steps as long as the interface-based session load control function of the present invention is not turned off (S50 No).

As described above, according to the present invention, in the session load control between the control plane and the user plane, the control performed for each existing node is divided into more subdivided classification criteria (eg, LCI information for each interface). We are realizing a new technology that can subdivide session load control in a way that controls it.

Accordingly, according to the present invention, by further subdividing the session load control between the control plane (CP) and the user plane (UP), more detailed UP resource management is possible, and an overload state can be prevented in advance through detailed UP resource management. etc., to derive the effect of improving the UP operation efficiency.

The session load control method according to an embodiment of the present invention may be implemented in the form of a program command that can be executed through various computer means and recorded in a computer-readable medium. The computer-readable medium may include program instructions, data files, data structures, etc. alone or in combination. The program instructions recorded on the medium may be specially designed and configured for the present invention, or may be known and available to those skilled in the art of computer software. Examples of the computer-readable recording medium include magnetic media such as hard disks, floppy disks and magnetic tapes, optical media such as CD-ROMs and DVDs, and magnetic media such as floppy disks. - includes magneto-optical media, and hardware devices specially configured to store and execute program instructions, such as ROM, RAM, flash memory, and the like. Examples of program instructions include not only machine language codes such as those generated by a compiler, but also high-level language codes that can be executed by a computer using an interpreter or the like. The hardware devices described above may be configured to operate as one or more software modules to perform the operations of the present invention, and vice versa.

Although the present invention has been described in detail with reference to preferred embodiments so far, the present invention is not limited to the above-described embodiments, and the technical field to which the present invention belongs without departing from the gist of the present invention as claimed in the claims below It will be said that the technical spirit of the present invention extends to a range where various modifications or modifications can be made by anyone with ordinary knowledge in the present invention.

According to the network device and the session load control method performed in the device according to the present invention, in the session load control between the control plane and the user plane, more granular classification criteria (eg, LCI for each interface) information) in terms of realizing a new technology that can subdivide the session load control It is an invention with industrial applicability because it is a degree that can be clearly implemented.

100: network device
110: load information acquisition unit 120: load control unit

Claims (8)

a load information acquisition unit configured to acquire load information for each network node of the user plane and for each interface of the network node; and
and a load control unit configured to perform load control based on load information for each interface of each network node when load control for a subscriber's session is performed. The method of claim 1,
The load information acquisition unit,
A network device, characterized in that it receives and obtains load information for each interface of the network node through an association response message received during an association procedure for performing a connection with a network node or a report message received from a network node in a connected state . The method of claim 1,
The interface identifier for classifying the load information from the load information for each interface is,
Communication interface through which the network node communicates with other NF (Network Function), DNN (Data Network Name), APN (Access Point Name), Virtual Port / Physical Port, IP Address / Prefix, NW Slice ID, regional information (ECGI / NCGI), a network device characterized in that it is defined as at least one of a subscriber ID. The method of claim 1,
The load information for each interface is
Network device, characterized in that for each interface of the network node, including the bandwidth usage rate of the interface. The method of claim 1,
The load control unit,
Based on the load information for each interface of each network node, when the load on a specific interface of a specific network node exceeds a specific threshold, the session connection related to the specific interface of the specific network node is released and the disconnected session is reset. Network device, characterized in that. The method of claim 1,
The load control unit,
A network device, characterized in that when reestablishing a session after disconnecting a session or when establishing a new session, a network node to be involved in session establishment is allocated based on load information for each interface of each network node. In the session load control method performed in the network device of the control plane (Control Plane),
Load information acquisition step of acquiring load information for each interface of the network node for each network node of the user plane; and
and a load control step of performing load control based on load information for each interface of each network node when load control for a subscriber session (Session) is performed. 8. The method of claim 7,
The load control step is
Based on the load information for each interface of each network node, when the load on a specific interface of a specific network node exceeds a specific threshold, the session connection related to the specific interface of the specific network node is released and the disconnected session is reset. step and
Session load control method comprising the step of allocating a network node to be involved in session establishment based on load information for each interface of each network node when re-establishing a session or establishing a new session after disconnecting the session.

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