KR20180047172A - Method and Apparatus for Controlling Congestion in Communication Systems with Services - Google Patents

Abstract

A method and an apparatus for controlling network congestion for each service are disclosed. Embodiments of the present invention provide a method and an apparatus for protecting a network from congestion while improving user realistic service quality by considering different properties of each function when the congestion occurs in network functions in a slice in a network slicing-based mobile communication system.

Description

Technical Field [0001] The present invention relates to a method and an apparatus for controlling network congestion per service,

The present embodiment relates to a method and apparatus for controlling network congestion in a mobile communication system in which one physical network is separated according to the type of a user subscription service and is composed of separate logical networks.

The contents described in this section merely provide background information on the present embodiment and do not constitute the prior art.

Conventional mobile communication systems have been optimized for specific services rather than providing various services. For example, in the related art, a network has been configured with a structure optimized only for mobile phone terminals. However, in the next generation mobile communication system, there is a demand for a network structure capable of providing services not only to a mobile phone terminal but also to various terminals having different attributes.

For example, Enhanced Mobile Broadband (eg UHD, VR video), Massive Machine Type Communications (eg smart city, smart home, etc.), Ultra- Reliable and Low Latency Communications (eg autonomous vehicles, factory automation, etc.) differ in service attributes and network requirements in terms of mobility, billing, security, latency, and reliability.

Accordingly, network slicing has been discussed as a technique for appropriately configuring a network for each type of service. Network slicing is a technique of logically separating one physical network according to a service type and providing a plurality of dedicated networks specific to each service. Here, each logically separated network is referred to as a network slice.

In the next generation mobile communication system applying network slicing, various functions in the network can be virtualized and implemented in one device. Therefore, unlike congestion occurring in a conventional single network, congestion may occur in each network function . Accordingly, in the next generation mobile communication system, a congestion control method considering characteristics of each network function is needed.

Embodiments of the present invention provide a method for protecting a network from congestion while improving user perceptual service quality in consideration of different characteristics of each function when congestion occurs in network functions in a slice in a mobile communication system based on a network slicing method ≪ RTI ID = 0.0 > and / or < / RTI >

The problems to be solved by the embodiments of the present invention are not limited to those mentioned above, and another problem to be solved not mentioned can be clearly understood by those skilled in the art from the description below .

According to an embodiment of the present invention, there is provided a method for a network device to control network congestion in a mobile communication system in which a physical network is divided according to a service type into a plurality of slices that are logical networks, Selecting a specific slice according to a registration request message for a specific type of slice received from the terminal device, and selecting a congestion state of the mobility management node in the selected specific slice based on the congestion information And a step of performing a registration procedure with a specific slice selected according to the occurrence of congestion of a mobility management node in the selected specific slice or transmitting a registration rejection message including a back off timer to a terminal device Providing a method for controlling network congestion All.

According to an embodiment of the present invention, there is provided a method for controlling network congestion in a mobile communication system in which one physical network is divided into service types and is composed of a plurality of slices which are logical networks, Receiving a registration reject message including a backoff timer due to congestion of a mobility management node in a slice of a type selected from a network device, and receiving a registration reject message including a backoff timer, Waiting for a registration request until the back-off timer expires according to a message, or transmitting a registration request message for a predetermined slice type to a network device.

According to an embodiment of the present invention, there is provided a method for a network device to control network congestion in a mobile communication system in which one physical network is divided into service types and composed of a plurality of slices which are logical networks, Receiving a session establishment request message for a particular type of session in a particular type of slice from the terminal device; receiving a session establishment request message from the terminal device in the session establishment request message, Selecting a node, and checking the congestion state of the selected specific session management node based on the congestion information. And a step of performing a session establishment procedure to a specific session management node according to the occurrence of congestion of the selected specific session management node or transmitting a session rejection message including a back off timer to the terminal device Control method.

A method for controlling network congestion in a mobile communication system in which a physical network is divided into a plurality of slices, each logical network being divided according to a service type, the method comprising the steps of: establishing a session for a specific type of session Receiving a session rejection message including a backoff timer due to congestion of a particular session management node in a particular type of slice selected according to a session establishment request message from a network device, Waiting for a registration request with a specific type of slice until the backoff timer expires according to a message or transmitting a registration request message for a predetermined slice type to a network device .

According to an embodiment of the present invention, there is provided a method for controlling network congestion in a mobile communication system in which one physical network is divided into service types and composed of a plurality of slices that are logical networks, Receiving congestion information from one or more user plane nodes interlocked with session management nodes, receiving a session establishment request message for a specific type of session in a particular type of slice from a terminal device, Determining congestion status of one or more user plane nodes associated with a particular session management node based on congestion information, selecting a user plane node that has not been congested, and transmitting information about the selected user plane node to the base station device And selects information about the base station device Transmitted to the user plane node to provide the network congestion control method comprising the step of performing the session establishment procedure.

As described above, according to embodiments of the present invention, when congestion occurs in the network functions in the slice in the network slicing-based mobile communication system, the user experience service quality can be improved by considering the different characteristics of each function, Can be protected from congestion.

According to the embodiment of the present invention, congestion is controlled according to the characteristics of the network function in which congestion occurs, in the mobile communication system to which the network slicing is applied, thereby improving the utilization efficiency of the entire network resources.

According to the embodiment of the present invention, it is possible to utilize the optimal network slice and QoS in consideration of the service use state of the terminal apparatus and the type of the subscribed service in the network congestion state.

1 is a schematic block diagram of a network slicing-based mobile communication system according to an embodiment of the present invention.
2 is a flowchart illustrating a congestion control method for a network device and a terminal device when congestion occurs in a mobility management node in a network slice according to an embodiment of the present invention.
3 is a flowchart illustrating a congestion control method for a network device and a terminal device when congestion occurs in a session management node in a network slice according to an embodiment of the present invention.
4 is a flowchart illustrating a congestion control method for a network device and a terminal device when congestion occurs in a user plane node in a network slice according to an embodiment of the present invention.
5 is a flowchart illustrating a congestion control method for a network device and a terminal device when congestion occurs in a user plane node in a network slice according to another embodiment of the present invention.

Hereinafter, some embodiments of the present invention will be described in detail with reference to the accompanying drawings. In explaining the present invention, '... Quot ;, " module ", and " module " refer to a unit that processes at least one function or operation, and may be implemented by hardware or software or a combination of hardware and software.

The embodiment of the present invention is a method for protecting a network from congestion while improving user perceived service quality in consideration of different characteristics of each function when congestion occurs in network functions in a slice in a mobile communication system based on a network slicing And apparatus.

1 is a schematic block diagram of a network slicing-based mobile communication system according to an embodiment of the present invention.

1, a network slicing-based mobile communication system 100 includes a plurality of network slices 110, a UE 150, a Radio Access Network (RAN) 140, and a PDN (Public Data Network) . Although only one network slice is shown in FIG. 1 for convenience of description, the mobile communication system 100 includes a plurality of network slices specific to each service type. A network slice (hereinafter, referred to as 'slice') will be described in detail as follows.

Each slice is an independent logical network dedicated to a specific service. When the terminal device 150 connects to the network, an appropriate slice among a plurality of slices is selected according to the subscription of the user.

One slice structure is divided into a control plane 120 and a user plane 130. The control plane 120 is divided into a mobility management node 122 and a session management node And a user plane node (UPGW: User Plane Gateway) 132 may be included in the user plane 130.

The mobility management node 122, the session management node 124, and the user plane node 132 may be implemented in a form in which software for each network function is loaded on one virtualized network device. That is, it means a node that provides each function as a virtualized node (not a physical node).

A plurality of slices may be implemented in a network device according to an embodiment of the present invention and each of the slices includes a mobility management node 122, one or more session management nodes 124, and one or more user plane nodes 132 . Here, the network device may include one or more processors for performing respective network functions, and may include a transmission / reception module for communication with the terminal device and the base station device.

One mobility management node 122 may be interworked with one or more session management nodes 124 and one or more user plane nodes 132 may be associated with each session management node 124. [ That is, one slice is hierarchical in which a plurality of session management nodes 124 are connected to one mobility management node 122, and a plurality of user plane nodes 132 are connected to one session management node 124 again. Structure. Here, the session management node 124 may be defined according to traffic characteristics or service characteristics.

The mobility management node 122 manages the overall state of the terminal device 150 such as authentication, connection management, and mobility management. The session management node 124 performs session-based traffic transmission such as session management and QoS management. And the user plane node 132 performs a function of transmitting a User Data packet from one node to another node.

In the network slicing-based mobile communication system 100, congestion may occur in each of the slice network functions (i.e., MM, SM, UPGW, etc.), which is a logical network. Since each network function is embedded in one network device, resources such as physically defined computing, memory, and network are used. Accordingly, congestion occurs when the amount of resources to be processed is larger than the resource allocated to each network function.

Here, the throughput of each function is the number of connected terminal devices in the case of the mobility management node 122, the number of managed sessions in the case of the session management node 124, the number of sessions in the case of the user plane node 132, In addition, it can be represented by the number of packets actually processed.

If the congestion occurs in each function in the slice, if the congestion control is not properly performed, the network may malfunction due to the congestion, and if the congestion control is performed excessively, the quality of service for the user may be deteriorated. Therefore, there is a need for a method of controlling congestion so as to increase the quality of user experience service and to operate the network appropriately in consideration of different characteristics of each function in the slice.

Hereinafter, a method of controlling congestion according to each case when congestion occurs in each network function in a slice will be described in detail with reference to FIG. 2 to FIG.

2 is a flowchart illustrating a congestion control method for a network device and a terminal device when congestion occurs in a mobility management node 122 in a network slice according to an embodiment of the present invention.

In the network device (not shown) of the present embodiment, the functions of the mobility management nodes included in the slice selection node and each slice (slice 1, slice 2, ..., slice n) are implemented. However, the slice select node may be implemented in a base station apparatus (not shown). The slice selection node selects an appropriate slice according to the subscriber information of the terminal device 150 when the terminal device 150 accesses the network.

In the above-described network structure, the mobility management node 122 functions to process a slice connection of the terminal device 150, and a session establishment request to all the session management nodes 124 is transmitted / received only through the mobility management node 122 do. The mobility management node 122 performs the function of processing the slice connection, so that when congestion occurs, the additional connection to the slice should not be permitted. In addition, it is necessary to control the terminal device 150 to suspend and wait for a connection request or to connect with another slice until the mobility management node 122 is cleared of congestion.

To this end, the network device according to the embodiment of the present invention acquires congestion information from mobility management nodes in a plurality of slices (S210). Although FIG. 2 shows a case where only the mobility management node in the slice 1 transmits congestion information, the mobility management nodes in the remaining slices also transmit the congestion information to the slice selection node.

The in-slice mobility management node 122 may detect congestion and transmit the congestion information to the slice selection node. Here, the congestion information may indicate at least one of congestion level and congestion occurrence, as information indicating congestion status based on the maximum number of terminal devices connectable to the mobility management node 122 and the number of terminal devices in the connection status.

For example, the congestion level may be expressed as a ratio of the number of terminal devices in the current connection state to the maximum number of connectable terminal devices, and congestion occurrence may be simply expressed as bits indicating congestion / non-congestion.

When connecting to the network, the terminal device 150 selects a slice type to be connected according to the service type (S212), and transmits a registration request message to the slice selection node (S214). The registration request message includes information about the selected slice type.

The slice selection node selects a specific slice of the requested type among a plurality of slices according to the registration request message received from the terminal device 150 and confirms the congestion state of the mobility management node in the selected specific slice based on the congestion information S216). In the example of FIG. 2, a mobility management node of slice 1 is selected and a congestion state is confirmed.

In step S216, the slice selection node can check the congestion state by checking the bit or the congestion level indicating the congestion included in the congestion information. For example, a bit indicating congestion may be defined as 1 in case of congestion and 0 in case of congestion. If the bit indicating congestion is 1, it can be determined that congestion has occurred in the mobility management node in the corresponding slice have. The opposite is also possible. As another example, it may be determined that congestion has occurred when the congestion level (i.e., the numerical value indicating the degree of congestion) is equal to or greater than a preset threshold value.

The slice selection node may perform the registration procedure with the selected slice according to the occurrence of congestion of the mobility management node determined in step S216 or transmit the registration reject message including the back off timer to the terminal device 150 have. If it is determined that congestion has occurred in the mobility management node, the slice selection node transmits a registration rejection message to reject the registration request of the terminal device 150 (S218). At this time, the registration rejection message may include a backoff timer and a cause indicating that the request is rejected due to congestion.

The time value of the backoff timer may be set by the slice selection node based on the congestion information received from the mobility management node. For example, if it is determined that congestion has occurred due to the congestion information, a backoff timer may be set at a predetermined time or a backoff timer may be variably set according to the congestion level. The backoff timer may be set at the slice selection node as described above, but the present invention is not limited thereto. The mobility management node may directly detect the congestion state, set the backoff timer according to the congestion level, and transmit the congestion information together with the congestion information .

When the terminal device 150 receives the registration rejection message from the slice selection node, the back-off timer included in the registration reject message starts, and the slice is transmitted for a predetermined time until the back-off timer expires (S220), or selects a slice type different from the registered slice.

When the registration rejected slice and another slice type are selected, the terminal device 150 has information for selecting another slice. In this case, the other slice type selected by the terminal device 150 is a preset slice type, for example, a default slice type, or a slice of the next priority according to the priority list for the slice type May be set to be selected. The default slice type may be a slice type to provide a minimum required service, such as an emergency call.

The terminal device 150 transmits a registration request message for another selected slice type (i.e., a predetermined slice type) to the slice selection node (S222). The slice selection node selects the slice again according to the second registration request of the terminal device 150 to check the congestion state of the mobility management node in the slice (S224). If the congestion is not congested, the mobility management node : Slice n mobility management node) (S226). Thereafter, the network device of this embodiment performs the remaining registration procedure with the terminal device (S228).

3 is a flowchart illustrating a congestion control method for a network device and a terminal device when congestion occurs in a session management node in a network slice according to an embodiment of the present invention. In the network device (not shown) of the present embodiment, the functions of a plurality of in-slice mobility management nodes and one or more session management nodes associated therewith are implemented. In Fig. 3, only the mobility management node in a specific slice among a plurality of slices is shown for clarity of explanation.

In the conventional mobile communication system, when a terminal device is attached to a network, a session (i.e., a PDN connection) is unconditionally provided to provide a service. However, in the mobile communication system 100 according to the embodiment of the present invention, It is possible to provide a service by creating a session only when necessary for a specific service.

The congestion control method according to the embodiment of the present invention is a method of controlling the session management node 124 in which congestion has occurred according to each service by distinguishing a mandatory service from a service to be optional, .

For example, if a terminal device makes a connection request to a specific slice for a service that requires session establishment, if congestion occurs in the session management node managing the session, it is no longer meaningful to connect to the slice, It is necessary to select a slice or wait until congestion is resolved.

Conversely, during the process of registering a slice by a terminal device, there is a service that does not require session establishment (i.e., a service that generates a session only when data transmission / reception is necessary). In this case, even if congestion occurs in the session management node required during the connection to the slice, connection to the slice is possible.

The terminal device 150 according to the present embodiment may include information on whether or not registration is required to the session management node 124 when a slice is selected and a connection is requested. Here, the information as to whether or not registration is necessary to the session management node 124 may include information on the necessity of session establishment (or assignment of the session management node) and information on which session management node should be registered .

Hereinafter, this embodiment will be described in detail with reference to Fig.

The network device of this embodiment obtains congestion information from one or more session management nodes in each slice (S310). The session management nodes can detect congestion and send congestion information to the mobility management node. Here, the congestion information is information indicating a congestion state based on the maximum number of sessions that can be managed by the session management node and the number of sessions being managed, and may indicate at least one of congestion level and congestion occurrence.

For example, the congestion level can be expressed as a ratio of the number of currently managed sessions to the maximum number of manageable sessions, and the occurrence of congestion can be simply expressed as a bit indicating congestion / non-congestion.

The terminal device selects a slice type to be connected according to the service type according to the service type (S312), and transmits a session establishment request message for the specific type of session in the selected slice to the corresponding mobility management node (S314) . Here, the session establishment request message may be included in the registration request message for the slice of a specific type, and may be transmitted to the mobility management node. In addition, the session establishment request message may include a flag indicating whether session establishment is essential.

The mobility management node selects a specific session management node in the slice of a specific type according to the session establishment request message received from the terminal device, and confirms the congestion state of the selected session management node based on the congestion information (S316).

In step S316, the mobility management node can confirm the congestion state by checking the bit or the congestion level indicating the congestion included in the congestion information. For example, the bit indicating the congestion can be defined as 1 in case of congestion and 0 in case of congestion, and when the bit indicating congestion is 1, it can be determined that congestion has occurred in the corresponding session management node. The opposite is also possible. As another example, it may be determined that congestion has occurred when the congestion level (i.e., the numerical value indicating the degree of congestion) is equal to or greater than a preset threshold value.

The mobility management node may perform a session establishment procedure with a specific session management node or send a session rejection message including a back off timer to the terminal device depending on whether congestion has occurred in the session management node determined in step S316 . If it is determined that congestion has occurred in the session management node, the mobility management node transmits a session rejection message to reject the session establishment request of the terminal device (S318). At this time, the session rejection message may include a backoff timer and a cause indicating that the request is rejected due to congestion.

The time value of the backoff timer may be set by the mobility management node based on the congestion information received from the session management node. For example, if it is determined that congestion has occurred due to the congestion information, a backoff timer may be set at a predetermined time or a backoff timer may be variably set according to the congestion level. The backoff timer may be set in the mobility management node as described above, but the present invention is not limited thereto. The session management node may directly detect the congestion state, set the backoff timer according to the congestion level, and transmit the congestion information together with the congestion information .

When a terminal receives a session rejection message from a mobility management node, a backoff timer included in a session rejection message starts and a registration request for a slice for a predetermined time until the backoff timer expires Or selects a slice type different from the registered slice type (S320 and S322).

Specifically, if the session rejection message includes a backoff timer in the case of a service in which session establishment is essential (that is, in a case where registration to a session management node is indispensable), the terminal device may notify the corresponding slice The registration request can not be made. Accordingly, the terminal waits until the backoff timer expires, and then transmits a registration request message for the slice again.

If session establishment is essential, the terminal device may select a slice of a different type from the slice not registered in accordance with the embodiment. In this case, the terminal device has information for selecting another slice. The other slice type selected by the terminal device may be set as a preset slice type, for example, a default slice type, or may be set to select a slice of the next priority according to the priority list for the slice type . The default slice type may be a slice type to provide a minimum required service, such as an emergency call.

The terminal device transmits a registration request message (including information on the type of session and the necessity of session establishment) to the network device for another selected slice type (i.e., the predetermined slice type). The mobility management node of the corresponding slice in the network device checks the congestion state of the corresponding session management node again according to the second registration request of the terminal device and performs the registration procedure to the corresponding session management node when the congestion is not conclusive.

On the other hand, if session establishment is an optional service (that is, registration to a session management node is an optional service), it is not necessary to establish a session in the slice connection process. Therefore, even if a session reject message is received, So there is no need to attempt a registration request. Accordingly, the terminal device waits for the registration request until the backoff timer included in the session reject message expires.

The terminal device according to the embodiment of the present invention may have a backoff timer for each of the mobility management node and one or more session management nodes. That is, one or more backoff timers may be provided for each slice and service.

4 is a flowchart illustrating a congestion control method for a network device and a terminal device when congestion occurs in a user plane node in a network slice according to an embodiment of the present invention. 5 is a flowchart illustrating a congestion control method for a network device and a terminal device when congestion occurs in a user plane node in a network slice according to another embodiment of the present invention.

The network device (not shown) of this embodiment includes a plurality of intra-slice mobility management nodes, one or more session management nodes interlocked with each mobility management node, and one or more user plane nodes (user plane node 1, ..., user plane node n) is implemented. 4 and 5, only a specific session management node that is associated with a mobility management node in a specific slice among a plurality of slices is shown for clarity of explanation.

The user plane node (UPGW) performs a function of processing a user packet. If congestion occurs, the packet can not be processed. Therefore, the packet discard is discarded, thereby degrading the quality of service experienced by the user. To prevent this, when congestion occurs in the user plane node, the session management node selects a user plane node that has not caused congestion and allocates the user plane node to the terminal apparatus.

In particular, since a plurality of user plane nodes are interworked in one session management node, it is possible to prevent congestion from being intensified by allocating other user plane nodes, which have not been congested, to the terminal apparatus even if congestion occurs in one user plane node .

Referring to FIG. 4, the network device according to the present embodiment acquires congestion information from one or more user plane nodes associated with one or more session management nodes in a specific slice (S410). In FIG. 4, only the user plane node 1 transmits the congestion information, but the remaining user plane nodes also transmit the congestion information to the session management node.

User plane nodes may detect congestion and send congestion information to the session management node. Here, the congestion information may be based on the maximum number of packets that can be processed by the user plane node and the number of packets being processed, or may indicate a congestion state based on the number of packets discarded. The congestion information may include at least one of congestion level and congestion occurrence.

For example, the congestion level may be expressed as a ratio of the number of packets currently being processed to the maximum number of packets that can be processed or the number of discarded packets with respect to the total number of packets reaching the user plane node, It can be simply expressed as a bit indicating congestion / non-congestion.

The terminal device selects a slice of a specific type according to the service type for network connection (S412), and transmits a session establishment request message for the specific type of session in the slice of the selected type to the network device when the session creation is required S414). The session establishment request message is transmitted to the session management node, and may include a flag indicating whether information on the requesting session type and session establishment (i.e., assignment of the session management node) is essential.

The session management node confirms the congestion state of one or more user plane nodes interlocked with the specific session management node in the specific type of slice based on the congestion information according to the session establishment request message received from the terminal device, The plane node is selected (S416). 4 illustrates a case where user plane node n is selected as a user plane node without congestion occurring.

In step S416, the session management node can check the congestion state by checking the bit or the congestion level indicating the congestion included in the congestion information. For example, the bit indicating congestion can be defined as 1 in case of congestion and 0 in case of congestion. If the bit indicating congestion is 1, it can be determined that congestion has occurred in the corresponding user plane node. The opposite is also possible. As another example, it may be determined that congestion has occurred when the congestion level (i.e., the numerical value indicating the degree of congestion) is equal to or greater than a preset threshold value.

According to an embodiment, when there are a plurality of user plane nodes that are determined not to cause congestion, the user plane node having the best congestion degree may be selected in a manner of comparing the congestion levels with each other.

The session management node transmits information on the user plane node that has not been congested in step S416 to the base station apparatus in step S418, and transmits the information on the base station apparatus to the corresponding user plane node in step S420. do. Each of the information delivery to the base station apparatus and the user plane node of the session management node is not necessarily limited to the time series order as shown in FIG.

Through the session establishment procedure, a user plane tunnel (i.e., a session) is created between the terminal device and the user plane node that has not caused congestion, so that the traffic can be transmitted (S422).

On the other hand, congestion may occur in a user plane node when a session with a specific user plane node has already been established. In this case, the session management node may move the already established session to another congested user plane node without performing the new session establishment procedure. Hereinafter, this will be described in detail with reference to Fig.

5 illustrates a state in which a session has already been established between the user plane node 1 and the terminal device (S510). If congestion is detected in the user plane node 1 in this state, the user plane node 1 may transmit congestion information indicating at least one of congestion occurrence and congestion level to the session management node to the session management node in operation S512.

The session management node may determine another congestion-free user plane node (e.g., user plane node n) to move at least a portion of the session of the congested user plane node 1 based on the acquired congestion information (step S514 ). For example, if a congestion-free user plane node is selected by checking a flag indicating whether congestion has occurred, or if there are a plurality of user plane nodes having no congestion, the congestion level is compared with each other, And select other user plane nodes.

In order to move an existing session, the session management node transmits information on the user plane node determined in step S514 and existing session information to the base station device (S516), and transmits information on the base station device and existing session information to the determined user plane node (S518) to perform the session movement procedure. Likewise, steps S516 and S518 are not necessarily limited to the time-series sequence shown in Fig.

According to the session movement procedure, the terminal device forms a user plane tunnel with a new user plane node in which congestion has not occurred and can transmit the traffic (S520).

2 to 5 illustrate that the processes are sequentially executed, but the present invention is not limited thereto. 2 to 5 may be modified or omitted, or one or more processes may be executed in parallel, so that the embodiments of FIGS. 2 to 5 are not limited to the time-series order.

The congestion control method of the network device and the terminal device according to the present embodiment described in FIGS. 2 to 5 may be implemented by a program and recorded in a computer-readable recording medium. A program for implementing the congestion control method according to the present embodiment is recorded, and a computer-readable recording medium includes all kinds of recording devices for storing data that can be read by a computing system.

The foregoing description is merely illustrative of the technical idea of the present embodiment, and various modifications and changes may be made to those skilled in the art without departing from the essential characteristics of the embodiments. Therefore, the present embodiments are to be construed as illustrative rather than restrictive, and the scope of the technical idea of the present embodiment is not limited by these embodiments. The scope of protection of the present embodiment should be construed according to the following claims, and all technical ideas within the scope of equivalents thereof should be construed as being included in the scope of the present invention.

100: mobile communication system
110: network slice
122: Mobility Management Node
124: Session Management Node
132: User plane node

Claims (16)

CLAIMS 1. A method for controlling network congestion in a mobile communication system in which a physical network is composed of a plurality of slices separated by service types and being a logical network,
Obtaining congestion information from mobility management nodes in the plurality of slices;
Selecting a specific slice according to a registration request message for a slice of a specific type received from a terminal device and confirming a congestion state of the mobility management node in the selected specific slice based on the congestion information; And
Performing a registration procedure with the selected specific slice according to the occurrence of congestion of the mobility management node in the selected specific slice or transmitting a registration rejection message including a back off timer to the terminal device
Gt; a < / RTI > network congestion control method. The method according to claim 1,
Wherein the congestion information indicates a congestion state based on the maximum number of terminal devices connectable to the mobility management node and the number of terminal devices connected to the mobility management node. The method according to claim 1,
Wherein the step of verifying the congestion state based on the congestion information comprises:
And determining whether congestion occurs if the bit indicates a congestion state or the congestion level is equal to or greater than a predetermined threshold by checking a bit or a congestion level indicating a congestion state included in the congestion information. A method for controlling network congestion in a mobile communication system in which a physical network is divided into a plurality of slices,
Selecting a slice type to be connected, and transmitting a registration request message for a slice of the selected type to a network device;
Receiving a registration reject message including a backoff timer due to congestion of a mobility management node in a slice of the selected type from the network device; And
Waiting for a registration request until the backoff timer expires according to the registration rejection message or transmitting a registration request message for a predetermined slice type to the network device
Gt; a < / RTI > network congestion control method. 5. The method of claim 4,
Wherein the predetermined slice type is determined based on a priority of slice types to be registered by the terminal device. CLAIMS 1. A method for controlling network congestion in a mobile communication system in which a physical network is composed of a plurality of slices separated by service types and being a logical network,
Obtaining congestion information from one or more session management nodes in each slice;
Receiving a session establishment request message for a specific type of session in a particular type of slice from a terminal device;
Selecting a specific session management node in the slice of the specific type according to the session establishment request message and checking the congestion state of the selected specific session management node based on the congestion information; And
Performing a session establishment procedure with the specific session management node according to whether the selected specific session management node has congestion or transmitting a session rejection message including a back off timer to the terminal device
Gt; a < / RTI > network congestion control method. The method according to claim 6,
Wherein the congestion information indicates a congestion state based on the maximum number of sessions that can be managed by the session management node and the number of sessions being managed. The method according to claim 6,
Wherein the step of verifying the congestion state based on the congestion information comprises:
And determining whether congestion occurs if the bit indicates a congestion state or the congestion level is equal to or greater than a predetermined threshold by checking a bit or a congestion level indicating a congestion state included in the congestion information. The method according to claim 6,
Wherein the session establishment request message includes a flag indicating whether session establishment is essential. A method for controlling network congestion in a mobile communication system in which a physical network is divided into a plurality of slices,
Sending a session establishment request message for a particular type of session within a particular type of slice to a network device;
Receiving a session rejection message including a backoff timer due to congestion of a specific session management node in a particular type of slice selected according to the session establishment request message from the network device; And
Waiting for a registration request to the slice of the specific type until the back-off timer expires according to the session rejection message, or transmitting a registration request message for a predetermined slice type to the network device
Gt; a < / RTI > network congestion control method. 11. The method of claim 10,
Wherein the predetermined slice type is determined based on a priority of slice types to be registered by the terminal device. CLAIMS 1. A method for controlling network congestion in a mobile communication system in which a physical network is composed of a plurality of slices separated by service types and being a logical network,
Obtaining congestion information from one or more user plane nodes associated with one or more session management nodes in a particular slice;
Receiving a session establishment request message for a specific type of session in a particular type of slice from a terminal device;
Checking a congestion state of one or more user plane nodes interlocked with a specific session management node based on the congestion information according to the session establishment request message, and selecting a user plane node without congestion; And
Transmitting the information on the selected user plane node to the base station apparatus and transmitting the information on the base station apparatus to the selected user plane node to perform a session establishment procedure
Gt; a < / RTI > network congestion control method. 13. The method of claim 12,
Wherein the congestion information indicates a congestion state based on a maximum number of packets that the user plane node is capable of processing and a number of packets being processed or based on the total number of packets arriving at the user plane node and the number of packets discarded. Congestion control method. 13. The method of claim 12,
Wherein the step of verifying the congestion state based on the congestion information comprises:
And determining whether congestion occurs if the bit indicates a congestion state or the congestion level is equal to or greater than a predetermined threshold by checking a bit or a congestion level indicating a congestion state included in the congestion information. 13. The method of claim 12,
Wherein the session establishment request message includes a flag indicating whether session establishment is essential. 13. The method of claim 12,
Obtaining congestion information indicating at least one of a congestion occurrence level and a congestion level from a user plane node in which a session is established with the terminal apparatus;
Determining another user plane node that has not been congested to move at least a portion of the session of the user plane node where congestion has occurred based on the congestion information; And
Transmitting the information on the determined user plane node and existing session information to the base station apparatus and transmitting information on the base station apparatus and the existing session information to the determined user plane node to perform a session moving procedure
Further comprising the step of:

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