KR20210007231A - Operating method of server load balancing apparatus, local domain name server and content delivery service system - Google Patents

Abstract

The present invention provides an operating method of a server load balancing apparatus, an operating method of a local domain name server, and a content delivery service system which can contribute to 5G commercialization. The operating method of a server load balancing apparatus comprises: a step of receiving a domain name query of a terminal from a local domain name server; a step of identifying a user plane function (UPF) to which the local domain name server is connected; a step of selecting a content delivery service node corresponding to the domain name query among a plurality of content delivery service nodes connected to the identified user plane function; and a step of transmitting a domain name query response including information on the selected content delivery service node to the local domain name server. The selected content delivery service node provides a content delivery service for the terminal.

Description

Server load balancer operation method, local domain name server operation method, and content delivery service system {OPERATING METHOD OF SERVER LOAD BALANCING APPARATUS, LOCAL DOMAIN NAME SERVER AND CONTENT DELIVERY SERVICE SYSTEM}

The present invention relates to a method of operating a server load balancer, a method of operating a local domain name server, and a content delivery service system.

BACKGROUND ART In recent years, as smart devices such as smart phones become more common and mobile communication technologies are developed, the demand for video streaming services is rapidly increasing.

The market size of video streaming through the network is expected to increase continuously, and video traffic is expected to increase rapidly as UHD (Ultra High Definition Television) content is recently provided.

In particular, as content transmission technology develops and users' demand for high-quality services increases, online video services such as VOD (Video On Demand) and live streaming (Live Streaming), music streaming, file upload and file download, etc. Transmission became frequent.

However, while the number of servers provided by a content provider (CP) is limited, the number of users who want to access the server is rapidly increasing. For this reason, service quality problems due to data loss, bottlenecks, transmission delays, instability such as data disconnection, and lowering the transmission speed of content are becoming an issue. What appeared to solve this problem is a content delivery (Contents Delivery Network or Content Distribution Network Service, hereinafter referred to as'CDN') service.

CDN is a new concept of content delivery technology that has emerged to overcome the problem of the middle mile (Internet network) that causes congestion of network traffic and the limitations of caching strategies.

The purpose of the CDN is to distribute multiple servers to the edge of the network to improve the quality of Internet service, and to replicate the content to the distributed server so that the replication server near the client responds to the content request, providing fast service to clients. Is to provide.

Currently, the CDN service has a CDN node in a specific area unit. However, the conventional CDN service cannot control CDN access at the access end of the terminal.

In particular, in the conventional 4G Long-Term Evolution (LTE), a packet data network gateway (PGW) includes both signaling and traffic control and is disposed in the center. Therefore, it was almost impossible to provide CDN service per zone in the PGW area.

The problem to be solved by the present invention is in a 5G communication network separated into a control plane function (hereinafter referred to as'CPF') and a user plane function (hereinafter referred to as'UPF'), To provide a method and a system for providing a CDN service in units of UPF.

According to one feature of the present invention, a method of operating a server load balancer, comprising: receiving a domain name query of a terminal from a local domain name server, a user plane function (UPF) to which the local domain name server is connected Identifying a content delivery service node corresponding to the domain name query from among a plurality of content delivery service nodes connected to the identified user plane device, and a domain name query response including information of the selected content delivery service node And transmitting to the local domain name server, wherein the selected content delivery service node provides a content delivery service to the terminal.

The user plane device is connected to one centralized unit, the one centralized unit is connected to a plurality of remote units, the centralized unit is installed at the office, and the plurality of remote units may be installed at a cell site outside the office. have.

The content delivery service node may be divided into service units.

In the selecting step, a service type may be determined based on the domain name query, and a content delivery service node providing the determined service may be selected.

The identifying may include transmitting information on a local domain name server that has transmitted the domain name query to a content delivery service node management device, and receiving information on a user plane device connected to the transmitted local domain name server. The content delivery service node management apparatus may map and manage information of a local domain name server and a plurality of content delivery service nodes connected for each user plane device.

According to another feature of the present invention, as a method of operating a local domain name server, receiving a domain name query of a terminal from a user plane function (UPF), if the queryed domain name is previously registered, the server Transmitting the domain name query to a load balancer, and receiving information on a content delivery service node corresponding to the domain name query from the server load balancer and transmitting the information to the user plane device, the content The delivery service node is selected from among a plurality of content delivery service nodes connected to the user plane device, and is connected to the terminal to provide a content delivery service to the terminal.

After the receiving step, if the queried domain name is not registered, determining whether or not a predefined unique identifier is included in the queried domain name, and if the unique identifier is not included, to a plurality of name servers Requesting a recursive query, and if the unique identifier is included, transmitting the domain name query to a server load balancer.

Prior to the receiving step, a step of updating the domain name by receiving at least one of a domain name registration request, a change request, and a deletion request from the content delivery service node management apparatus may be further included.

According to another feature of the present invention, the content delivery service system includes a server load balancing device disposed in the center, and a plurality of edge cloud devices disposed at the edge, wherein the plurality of edge cloud devices are provided between the terminal and the data network. A user plane function (UPF) in charge of transmitting user traffic by connecting a user plane, a group content delivery service node including a plurality of content delivery service nodes connected to the user plane device, and the user plane device Each includes a local domain name server connected to, wherein the server load balancer identifies a user plane device connected to the local domain name server that has transmitted a domain name query, and a plurality of content delivery services connected to the identified user plane device Among nodes, a content delivery service node to be connected to the terminal is selected.

The server load balancer may determine a service type based on the domain name query, and select a content delivery service node that provides the determined service.

The local domain name server may transmit the domain name query to the server load balancer when the queried domain name is previously registered.

The local domain name server may transmit the domain name query to the server load balancer when not all of the queried domain names are registered, but a pre-defined unique identifier is included in the queried domain name.

The content delivery service system further includes a media conversion device for converting content received from the content server into chunks, and the group content delivery service node receives content received in chunks from the media conversion device. Thus, it may include a first content delivery service node that transmits to the terminal through the user plane device.

The content delivery service system further comprises a content delivery service node management device disposed centrally and connected to a plurality of local domain name servers, the server load balancer, the media conversion device, and the plurality of content delivery service nodes, The content delivery service node management device registers, changes, and deletes domain names to the plurality of local domain name servers and the server load balancer according to a request of at least one of the content server, the media conversion device, and a content provider You can update the domain name by requesting at least one of them.

According to an embodiment, an ultra-low-latency media transmission service may be provided to a 5G subscriber terminal through a 5G edge CDN service that provides a CDN service in units of UPF.

In addition, since the 5G edge CDN service can be provided under the control of the network without changing the domain name of the CDN application installed in the terminal, it is easy to spread the 5G edge CDN service because it does not require changes to the existing terminal. As such, it can contribute to the commercialization of 5G by emphasizing 5G characteristics through ultra-low-latency media transmission services.

1 is a block diagram of a 5G edge CDN service system according to an embodiment of the present invention.
FIG. 2 shows another configuration example of the edge cloud of FIG. 1.
3 shows a network environment in which a CDN system and a legacy CDN system coexist according to an embodiment of the present invention.
4 is a diagram illustrating a CDN service operation according to an embodiment of the present invention.
5 is a diagram illustrating a conventional CDN service operation for comparison with an embodiment of the present invention.
6 is a flow chart showing a CDN service method according to an embodiment of the present invention.
7 is a flow chart showing a CDN service method according to another embodiment of the present invention.
8 is a network configuration diagram showing a domain name update operation according to an embodiment of the present invention.
9 is a flowchart showing a method of updating a domain name according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those of ordinary skill in the art may easily implement the present invention. However, the present invention may be implemented in various different forms, and is not limited to the embodiments described herein. In the drawings, parts irrelevant to the description are omitted in order to clearly describe the present invention, and similar reference numerals are assigned to similar parts throughout the specification.

Throughout the specification, when a part "includes" a certain component, it means that other components may be further included rather than excluding other components unless specifically stated to the contrary.

In addition, terms such as "... unit", "... group", and "... module" described in the specification mean a unit that processes at least one function or operation, which can be implemented by hardware or software or a combination of hardware and software. I can.

The devices described in the present invention are composed of hardware including at least one processor, a memory device, a communication device, etc., and a program that is executed in combination with the hardware is stored in a designated place. do. The hardware has a configuration and capability to implement the method of the present invention. The program includes instructions for implementing the operation method of the present invention described with reference to the drawings, and executes the present invention by combining it with hardware such as a processor and a memory device.

In this specification, "transmitting or providing" may include not only direct transmission or provision, but also transmission or provision indirectly through other devices or using a bypass path.

Expressions described in the singular in this specification may be interpreted as the singular or plural unless an explicit expression such as "one" or "single" is used.

In the present specification, the same reference numbers refer to the same elements regardless of the drawings, and "and/or" includes each and all combinations of one or more of the mentioned elements.

In the present specification, a terminal is a generic concept that refers to a user terminal in communication, and includes User Equipment (UE), Mobile Station (MS), Mobile Terminal (MT), Subscriber Station (SS), Portable Subscriber Station (PSS), and AT ( Access Terminal), mobile station, mobile terminal, subscriber station, mobile subscriber station, user device, access terminal, wireless device, etc., and may be called UE, MS, MT, SS, PSS, AT, mobile station, mobile terminal, subscription It may include all or part of the functions of the local station, mobile subscriber station, user equipment, access terminal, wireless device, etc.

The terminal is a base station (BS), an access point (AP), a radio access station (RAS), a node B (Node B), an advanced node B (evolved NodeB, eNodeB), a transmission/reception base station ( It can be connected to a remote server by accessing network devices such as Base Transceiver Station, BTS), and Mobile Multihop Relay (MMR)-BS.

The base station (BS) is an access point (AP), a radio access station (RAS), a node B, a base transceiver station (BTS), and a mobile multihop relay (MMR). )-It may refer to a BS or the like, and may include all or part of functions such as an access point, a radio access station, a node B, a transceiver base station, and an MMR-BS.

Embodiments of the present invention may be supported by a standard document related to a 3rd Generation Partnership Project (3GPP) 5G system such as Study on Architecture for Next Generation System (FS_NextGen). That is, among the embodiments of the present invention, steps or parts not described in order to clearly reveal the technical idea of the present invention may be supported by the document. In addition, all terms disclosed in this document can be described by the standard document.

Now, referring to the drawings, a method of operating a server load balancing device (Global Server Load Balancing, hereinafter collectively referred to as'GSLB device') according to an embodiment of the present invention, a local domain name server (hereinafter, referred to as' (Collectively referred to as'local DNS') operation method and CDN service system will be described.

1 is a configuration diagram of a 5G edge CDN service system according to an embodiment of the present invention, and FIG. 2 is a diagram illustrating another configuration of the edge cloud of FIG. 1.

Referring to FIG. 1, a 5G edge CDN service system is a distributed cloud infrastructure structure and includes a plurality of edge clouds 100 and a central cloud 200.

The plurality of edge clouds 100 and the central cloud 200 are implemented in the form of a system including a plurality of network devices.

The plurality of edge clouds 100 and the central cloud 200 provide a cloud service (or cloud computing) that realizes a data service based on virtualized information technology (IT) resources. The plurality of edge clouds 100 and the central cloud 200 may use Mobile Edge Computing (MEC) technology.

The plurality of edge clouds 100 includes a plurality of network devices disposed at the edge, and the central cloud 200 includes a plurality of network devices disposed at the center.

According to an embodiment, the plurality of edge clouds 100 may be implemented in units of geographic areas. For example, it can be implemented on a per-region basis. In this case, the central cloud 200 may be implemented in some areas of the metropolitan area.

The plurality of edge clouds 100 includes a user plane device (User Plane Function, hereinafter referred to as'UPF') 101, a local DNS 103, and a plurality of CDN nodes 105 and 107, respectively.

The central cloud 200 is connected to a plurality of edge clouds 100 and includes a GSLB device 201, a media conversion device 203, and a CDN management device 205.

The UPF 101 is connected to the local DNS 103 and a plurality of CDN nodes 105 and 107. The UPF 101 is connected to the terminal 400 through at least one base station 300.

According to an embodiment, at least one base station 300 may be a 5G gNB that supports interworking between a standalone (SA) 5G core and a new 5G radio technology.

According to another embodiment, at least one base station 300 may be formed in the form of a distributed base station as shown in FIG. 2.

2, the base station 300 includes one central unit (Central Unit, hereinafter referred to as'CU') 301 and a plurality of distributed units (Distributed Unit, hereinafter referred to as'DU') ( 303).

According to the 5G standard, a base station module constituting a separate base station is defined as a CU 301 and a wireless module is defined as a DU 303.

The CU 301 is included in the edge cloud 100 and is connected to the UPF 101. The DU 303 is installed in a service area, that is, a cell site, and is connected to the terminal 400.

Referring again to FIG. 1, the UPF 101 provides Internet Protocol (IP) routing and forwarding functions, and packet filtering.

The UPF 101 may be connected to the content server 600 through the Internet network 500 and may receive content from the content server 600 and transmit the content to the terminal 400. Here, the content server 600 collectively refers to a server of a service provider that provides content through the Internet network 500. That is, although one is shown in the drawings, there may be several, and it is not limited to a specific service.

In addition, service providers and telecommunications providers have an origin server that manages the original data to prevent the data rate from decreasing as many terminals access the media content server at the same time. . The content server 600 may be such an origin server.

The terminal 400 is a device capable of accessing the UPF 101 through the base station 300. The terminal 400 is a terminal capable of wireless communication, and may be a mobile terminal such as a smart phone or a tablet PC. The terminal 400 may be a modular terminal that is connected to a wired terminal or a wireless terminal and connects the connected terminals to the UPF 101 through the base station 300. For example, it may be an egg, a mobile router, or the like.

When the domain name of the content requested by the terminal 400 is registered in the local DNS 103, the UPF 101 receives the content through one of the plurality of CDN nodes 105 and 107 and transmits it to the terminal 400. I can. That is, the terminal 400 connected to the UPF 101 can use the CDN service of the present invention for content registered with a domain name in the local DNS 103.

The local DNS 103 receives a domain name query from the terminal 400. The local DNS 103 stores domain names for CDN service in edge cloud #1 (100). Since the GSLB device 201 is mapped to these domain names, the local DNS 103 transmits the domain name query received from the terminal 400 to the GSLB device 201. In addition, the local DNS 103 receives the IP addresses of the CDN nodes 105 and 107 determined by the GSLB device 201 and transmits them to the terminal 400.

The plurality of CDN nodes 105 and 107 are network entities for providing the content of the content server 600 to the terminal 400. For example, the plurality of CDN nodes 105 and 107 may be a media streaming server, a web server, a cache device, or the like. In the embodiment of the present invention, a media streaming server is described as an example, but for those of ordinary skill in this field, a plurality of CDN nodes 105 and 107 store content, such as a web server, and provide content upon request. It will be appreciated that it can be applied to any entity that has a function to transmit and receive.

According to an embodiment, the plurality of CDN nodes 105 and 107 may be divided into service units. For example, the CDN node type A 105 may provide a general media service, and the CDN node type B 107 may provide an adaptive streaming transmission service. The adaptive streaming transfer service plays media content in data chunk units based on HTTP (HyperText Transfer Protocol). In the adaptive streaming transmission service, a corresponding player must be installed in the terminal 400.

The CDN node type A 105 providing general media services is directly connected to the content server 600. The CDN node type A 105 receives the content from the content server 600 and transmits the content to the terminal 400 through the UPF 101.

The CDN node type B 107 that provides the adaptive streaming transmission service is connected to the media conversion device 203. The media conversion device 203 divides the content received from the content server 600 into data chunks and transmits the content to the CDN node type B 107. The data chunk refers to a segment obtained by cutting a content into several pieces in advance, and refers to a minimum unit necessary for the terminal 400 to play the content. When content is transmitted in units of data chunks, delay time can be minimized. Accordingly, the GSLB device 201 allocates the CDN node type B 107 to a specific domain name, thereby enabling an ultra-low delay CDN streaming service.

The GSLB device 201 is connected to the local DNSs 103 respectively belonging to the plurality of edge clouds 100. The GSLB device 201 is connected to the CDN management device 205.

The CDN management device 205 is connected to the plurality of CDN nodes 105 and 107 of each edge cloud 100 and periodically checks the state to manage normal operation, failure, and load. The CDN management device 205 monitors the status of the plurality of CDN nodes 105 and 107, and manages the CDN node 105, 107 in which a failure or the like has occurred so that the GSLB device 201 does not allocate the terminal 400. . Here, the status of the CDN nodes 105 and 107 is managed by the CDN management device 205, and the CDN management device 205 provides the GSLB device 201 with status information of the CDN nodes 105 and 107. I can. Alternatively, the GSLB device 201 may directly manage the state of the CDN nodes 105 and 107.

In addition, the CDN management device 205 manages information of each edge cloud 100. That is, mapping information between the UPF 101, the local DNS 103, and a plurality of CDN nodes 105 belonging to each edge cloud 100 is stored, and this mapping information is provided according to the request of the GSLB device 201. .

The GSLB device 201 stores the IP addresses of the CDN nodes 105 and 107 corresponding to each domain name. When a DNS query is received from the local DNS 103, the GSLB device 201 is the most suitable CDN node among the CDN nodes 105 and 107 in normal operation checked through the CDN management device 205 according to criteria such as location and load. The IP address of (105, 107) is transmitted to the local DNS 103. The GSLB device 201 identifies the UPF 101 to which the local DNS 103 is connected, based on the mapping information received from the CDN management device 205. In addition, CDN nodes 105 and 107 to be connected to the terminal 400 are selected from among the plurality of CDN nodes 105 and 107 connected to the identified UPF 101.

In addition, each local DNS 103 is connected to a plurality of name servers 701, 703, and 705. If a DNS query for a domain name not registered in the local DNS 103 is received, the local DNS 103 requests a recursive query to a plurality of name servers 701, 703, and 705. Since the plurality of name servers 701, 703, and 705 are already known configurations, detailed descriptions are omitted. Each name server 701, 703, 705 provides an IP address for a corresponding domain name to the local DNS 103 as registered. Then, the local DNS 103 provides this IP address to the terminal 400, and the terminal 400 is accessed through the UPF 101 rather than the CDN nodes 105 and 107 in the edge cloud #1 (100). Content is received through the Internet network 500.

3 shows a network environment in which a CDN system and a legacy CDN system coexist according to an embodiment of the present invention.

Here, legacy is used to refer to an existing configuration that has already been built. Also, for convenience of description, only one edge cloud 100 is illustrated among the plurality of edge clouds 100 of FIG. 1.

Referring to FIG. 3, terminal 1 401 is a 5G terminal mentioned in FIG. 1. Terminal 2 (403) is a terminal that does not access edge cloud #1 (100) of the present invention, and is distinguished from terminal 1 (401) and is referred to as a Non-5G terminal. In addition, the access network to which the terminal 2 403 is connected is collectively referred to as the Non-5G network 800. The Non-5G network 800 is an existing network that is distinct from the 5G base station (300 in FIG. 1), and may include all wired and wireless networks that have already been established.

The Non-5G network 800 is connected to a legacy local DNS 900 and a plurality of legacy CDN nodes 1000. The legacy local DNS 900 is connected to a plurality of name servers 701, 703, 705 and the legacy GSLB device 707. The legacy GSLB device 707 stores the IP addresses of the legacy CDN node 1000 corresponding to the domain name, and provides the IP addresses to the legacy local DNS 900.

In addition, the legacy CDN node 1000 is connected to the content server 600 and transmits the content received from the content server 600 to the terminal 2 403. Of course, the terminal 2 403 directly receives the content having a domain name to which the CDN service is not applied from the content server 600 through the Internet network 500 -> Non-5G network 800.

In this way, in the network environment, the CDN system of the present invention and the legacy CDN system coexist. For example, if the domain name "dn.xxcdn.co.kr" of a specific content is registered in the local DNS 103 and also registered in the legacy local DNS 900, the terminal 1 401 is the edge cloud #1 ( 100) can be provided with the CDN service, and terminal 2 403 can be provided with the legacy CDN service. Even if the domain name is not modified from the perspective of the content provider, that is, even if the domain name matches the existing legacy CDN service, there is no need to change the domain name to suit the CDN service of the present invention.

When the CDN node type B 107 is matched to the GSLB device 201 corresponding to "dn.xxcdn.co.kr", the terminal 1 401 can receive an adaptive streaming service. In addition, even when you want to process free billing for "dn.xxcdn.co.kr" and 5G subscribers, free billing is processed in response to "dn.xxcdn.co.kr" to GSLB device 201 without domain change. The CDN nodes 105 and 107 are matched. Even in this case, since the existing legacy CDN service only needs to provide the service as it is, it does not conflict with the CDN service of the present invention even if the same domain name is used.

Therefore, the 5G edge CDN service or general CDN service can be classified and provided according to the access network 101, 800 accessed by the terminal (401, 403) or the app mounted on the terminal (401, 403) using the same domain name. I can.

Even if there is no change in the terminals 401 and 403 or the app mounted on the terminals 401 and 403, that is, even if the terminal 1 401 connects to the app domain operating in the existing CDN service installed in the existing terminal 403 If the local DNS 103 knows this app domain, it can be connected to CDN nodes 105 and 107 operating only in the corresponding region. Therefore, there is no need to develop apps separately for CDN and 5G. In addition, even if an app is made for an existing CDN service, 5G network operators can accommodate such apps.

The operation of the 5G edge CDN service and the legacy CDN service according to the present invention are compared as follows.

4 is a diagram illustrating an operation of a 5G edge CDN service according to an embodiment of the present invention.

Referring to FIG. 4, the central cloud 200 is located in area A, and the edge cloud #1 100 is located in area B. Area A and Area B correspond to geographically different areas. The content server 600 may have a different region from the central cloud 200, but it is assumed that the content server 600 is in the A region.

Terminal 1 (401) located in area B is connected to UPF #1 (101) and transmits a DNS query to local DNS #1 (103). If the DNS query domain name is registered, the local DNS #1 103 forwards the DNS query to the GSLB device 201. The GSLB device 201 transfers the IP address of the CDN node mapped to the queried domain name to the local DNS #1 103. Local DNS #1 (103) transfers the IP address of the received CDN node to terminal 1 (401).

Then, the terminal 1 401 can receive the content through two paths. If the CDN node mapped to the domain name is the CDN node type B 107, terminal 1 401 is the content server 600 → media conversion device 203 → CDN node type B 107 → UPF #1 ( The content is received through the path (①) of 101).

In addition, if the CDN node mapped to the domain name is CDN node type A (105), terminal 1 (401) is the content server (600) → CDN node type A (105) → path of UPF #1 (101) (②) Receives the content.

As described above, the terminal 1 401 is connected to the CDN nodes 105 and 107 located in a geographically close location, that is, the area B where the UPF 101 to which the terminal 1 401 is connected, is installed to receive the CDN service.

On the other hand, FIG. 5 is a diagram illustrating an operation of a legacy CDN service for comparison with an embodiment of the present invention. In this case, the core network is an Evolved Packet Core (EPC) of Long Term Evolution (LTE) as an example.

Referring to FIG. 5, it is assumed that the EPC 1100 is located in the C area and the terminal 403 is in the D area. Area C and Area D are geographically different areas.

The terminal 403 is connected to the EPC 1100 through the base station 801 in area D. The base station 801 is a non-5G base station and is connected to the legacy local DNS 900. When the terminal 403 transmits a DNS query for the domain name of the content provided by the content server 600, it is transmitted to the legacy local DNS 900. The legacy local DNS 900 checks the IP address of the CDN node (ie, CDN node #5) mapped to the domain name, and transfers the IP address to the terminal 403. Then, the terminal 403 is connected to the CDN node #5 (1000) to receive the content from the content server 600. At this time, the terminal 403 is the content server 600 → CDN node #5 (1000) → PGW (Packet GateWay) (1101) → SGW (Serving GateWay) (1103) → Non-5G base station 801 Receive.

Here, the legacy CDN nodes 1000 may be classified by region, but may be located overseas rather than in Korea, and in particular, although considering the geographical location closest to the terminal 403, it is not possible to guarantee that they are in the same region. none. In addition, since the content transmitted by the CDN node #5 (1000) is first received by the terminal 403 through the base station 801 through the EPC nodes 1101 and 1103 in the C region, the terminal 403 It goes through.

Therefore, comparing FIG. 4 and FIG. 5, in the 5G edge CDN service of the present invention, since the UPF 101 to which the terminal 1 401 is connected is directly connected to the CDN nodes 105 and 107, the delay of the content is reduced. By lowering it, it can provide the ultra-low latency service that 5G ultimately pursues. However, it is difficult to provide the ultra-low delay service of the present invention with the existing legacy CDN structure as shown in FIG. 5.

In particular, in the 4G LTE as shown in FIG. 5, since the PGW 1101 includes both signaling and traffic control and is disposed in the center, it was almost impossible to provide a CDN service per zone in the PGW 1101 area itself. However, in 5G, by separating the control plane and the user plane and distributing them locally, it is possible to provide a CDN service in units of the UPF 101.

6 is a flowchart illustrating a 5G edge CDN service method according to an embodiment of the present invention.

Referring to FIG. 6, the CDN management device 205 stores edge cloud information (S101). The edge cloud information may store mapping information between the UPF 101, the local DNS 103, and a plurality of CDN nodes 105 and 107 included in each edge cloud 100 for each edge cloud 100. Alternatively, the edge cloud information may include information for identifying a region, such as an IP address of the local DNS 103 and a network address translation (NAT) IP band of a terminal for each UPF 101.

The GSLB device 201 stores the IP addresses of the CDN nodes 105 and 107 corresponding thereto for each domain name (S103).

The local DNS 103 stores a domain name that is a 5G edge CDN service target of the present invention (S105). Thereafter, the terminal 400 connects the UPF 101 and the data session (S107). The UPF 101 connects the user plane between the terminal 400 and the data network 500 to deliver user traffic.

The terminal 400 transmits a DNS query to access the content server 600 (S109). The DNS query is transmitted to the local DNS 103 through the UPF 101 (S111).

The local DNS 103 determines whether the queried domain name is a domain name registered in step S105 (S113).

If it is not the registered domain name, the existing DNS query operation is performed (S115, S117). That is, DNS queries are sequentially transmitted to the plurality of name servers 701, 703, 705, and 707 (S115), and an IP address corresponding to a domain name or an IP address of a legacy CDN node is obtained (S117).

The local DNS 103 transmits a DNS query response including the IP address obtained in step S117 to the terminal 400 through the UPF 101 (S119 and S121).

On the other hand, if the DNS queryed domain name is a registered domain name, the local DNS 103 transmits a DNS query to the GSLB device 201 (S123).

The GSLB device 201 interworks with the CDN management device 205 to obtain edge cloud information (S125). Since the edge cloud information may be set-up in advance in the form of provisioning in the GSLB device 201, step S125 may be omitted. At this time, the GSLB device 201 may receive and store the edge cloud information registered in step S101 from the CDN management device 205 in advance. Alternatively, the GSLB device 201 may register and manage edge cloud information separately from the CDN management device 205.

The GSLB device 201 identifies the UPF 101 connected to the local DNS 103 based on the edge cloud information (S127). The GSLB device 201 may identify the UPF 101 based on the IP address of the local DNS 103. Alternatively, the GSLB device 201 may identify the UPF 101 based on the NAT IP band of the terminals 400 and 401 that transmitted the DNS query to the UPF 101. However, a method of identifying the UPF 101 is not limited to this content, and various methods may be used.

The GSLB device 201 selects the CDN nodes 105 and 107 corresponding to the queried domain address among the plurality of CDN nodes 105 and 107 connected to the identified UPF 101 (S129).

The GSLB device 201 transmits a DNS query response including the IP address of the selected CDN node 105 and 107 to the terminal 400 (S131, S133, S135).

The terminal 400 accesses the IP address obtained from the DNS query response in step S121 or S135 to receive the content. The terminal 400 accesses and connects to the IP address of the CDN nodes 105 and 107 received from the DNS query response in step S135, and receives the contents of the content server 600 through the CDN service.

However, in a structure in which the same domain name is divided into a 5G edge CDN service and a general CDN service as described above, an error may occur due to a domain name not registered in the GSLB device 201. For example, a content service provider adds a name in front of a domain name registered in the local DNS 103 in order not to provide a specific content as a 5G edge CDN service.

For example, the domain name of "dn.xxcdn.co.kr" in the local DNS 103 is registered to be forwarded to the GSLB device 201. However, in order for the content provider to provide specific content to the terminal 403 only, "xx4g" is added in front of "dn.xxcdn.co.kr", and this domain name, that is, "xx4g.dn.xxcdn.co.kr" May be registered only in the name servers 701, 703, 705, and 707 and not registered in the GSLB device 201.

In this case, when the DNS query for "xx4g.dn.xxcdn.co.kr" is received from the terminal 1 401, the local DNS 103 forwards the DNS query to the GSLB device 201. This is because "dn.xxcdn.co.kr" is set to be forwarded to the GSLB device 201 among "xx4g.dn.xxcdn.co.kr". However, since "xx4g.dn.xxcdn.co.kr" is not registered in the GSLB device 201, the IP addresses of the CDN nodes 105 and 107 corresponding to "xx4g.dn.xxcdn.co.kr" are assigned. Because it cannot respond, an error occurs.

As another example, when a domain URL (Uniform Resource Locator) of "sn1.kt.com" is registered in the local DNS 103, but a DNS query for a domain URL of "cn1.sn1.kt.com" is received. , If "cn1.sn1.kt.com" is not registered in the GSLB device 201, an error occurs in the DNS query.

That is, if the domain name is not registered in the GSLB device 201, even though it must be transmitted to the name servers 701, 703, 705, if it is a domain name partially registered in the local DNS 103, the GSLB device 201 It is passed to and an error occurs.

By the way, basically DNS should not cause errors. DNS is supposed to somehow provide an IP address corresponding to that domain name.

In the legacy CDN architecture, the local DNS (900) is called "." A circular query is performed on the name servers 701, 703, 705, 707 in units. For example, querying a name server corresponding to ".com" and querying a name server corresponding to "kt.com" sequentially queries a plurality of name servers (701, 703, 705, 707), No error message occurs.

As described above, in the legacy DNS structure, even though the domain URL does not generate an error, it is not registered in the GSLB device 201 of the present invention, and thus an error message may occur. In this case, the local DNS 103 cannot provide the terminal 400 with the IP address itself corresponding to the domain name.

The use of the local DNS 103 is essential in order to provide a service by distinguishing at a network level without distinguishing a domain name according to the access network type of the terminal 400.

In order to eliminate errors that may occur during the operation described above, an identifier representing the 5G edge CDN service may be included in the domain name.

For example, this is how to add "~.5g.dn.xxcdn.co.kr" in the name band of "~.dn.xxcdn.co.kr". The local DNS 103 forwards to the GSLB device 201 if "5g" is included in the DNS queried domain name. In addition, for a domain name that does not include "5g", it is possible to perform a circular query to the existing DNS, that is, a plurality of domain name servers 701, 703, 705, and 707. This operation will be described as follows.

7 is a flow chart showing a CDN service method according to another embodiment of the present invention.

Referring to FIG. 7, when a DNS query is received (S201), the local DNS 103 determines whether the queried domain name is a registered domain name (S203).

The local DNS 103 determines whether an identifier specified in the DNS queried domain name, for example "5G", is included (S205).

At this time, if the specified identifier is not included, the existing DNS query procedure, that is, a plurality of name servers 701, 703, 705, 707 is sequentially queried (S207).

On the other hand, if it is determined from the domain name registered in step S203 or the identifier specified in the domain name in step S205 is included, a DNS query is transmitted to the GSLB device 201 (S209).

Here, in step S205, as in the example described above, when the DNS queryed domain name is "~.5g.dn.xxcdn.co.kr", the local DNS 103 is "~.dn.xxcdn.co.kr" Even if only registered, it is a procedure to determine whether the specified identifier "5g" is included in the DNS queried domain name.

Meanwhile, the domain name registered in the local DNS 103 can be updated for various reasons. In order to automate the domain name management of the local DNS 103 when the 5G edge CDN service is frequently created, deleted, or changed, the CDN management device 205 may automatically update the domain name. This will be described in FIG. 8.

8 is a network configuration diagram showing a domain name update operation according to an embodiment of the present invention.

Referring to FIG. 8, when the domain name is updated, the CDN management device 205 transmits and registers the updated domain name to the GSLB device 201 and a plurality of local DNS 103. Then, the GSLB device 201 and a plurality of local DNS 103 update the domain name.

The CDN management device 205 may provide a user interface for domain name registration of content on the Internet. The CDN management device 205 updates the changed domain name when content providers change the host domain name of the content through the user interface.

Also, the content server 600 may register new content to the media conversion device 203 or the plurality of CDN nodes 105 and 107. Then, the media conversion device 203 or the plurality of CDN nodes 105 and 107 may register the host domain name of the newly registered content to the CDN management device 205.

Also, the content server 600 may request the CDN management device 205 to register the host domain name of the content.

In this case, the CDN management device 205 may be connected to a plurality of local DNS 103 through the NEF 207. Here, the NEF 207 is a 5G standard network device that shares information related to an external management area and a network network with each other. Accordingly, the CDN management device 205 transmits the updated domain name to the NEF 207. Then, the NEF 207 transmits the updated domain name to a plurality of local DNS 103 to be registered. When the updated domain name is applied to all edge clouds 100, it is transmitted to all local DNS 103. When the updated domain name is applied to a specific edge cloud 100, it is transmitted to the local DNS 103 belonging to the corresponding edge cloud 100.

9 is a flowchart illustrating a method of updating a domain name according to an embodiment of the present invention. Here, the update includes registering a new domain name, changing a previously registered domain name, and deleting a previously registered domain name.

Referring to FIG. 9, the CDN management device 205 collects a domain name to be registered (S301).

The CDN management apparatus 205 registers (S303, S305) the collected domain name in the corresponding local DNS 103 (S303, S305). Then, it is registered with the GSLB device 201 (S307). Then, the GSLB device 201 stores the mapping information between the domain name and the CDN nodes 105 and 107 corresponding thereto (S309).

In addition, the CDN management device 205 collects the changed domain name (S311). Then, the domain name collected in step S311 is registered in the corresponding local DNS 103 (S313 and S315). Then, it is registered with the GSLB device 201 (S317). Then, the GSLB device 201 changes and stores the mapping information between the registered domain name and the CDN node 107 corresponding thereto (S319).

Further, the CDN management device 205 collects a domain name to be deleted (S321). Then, the collected domain name is requested to be deleted to the corresponding local DNS 103 (S323 and S325). Then, a deletion request is made to the GSLB device 201 (S327). Then, the GSLB device 201 deletes the mapping information between the domain name requested to be deleted and the CDN node 107 corresponding thereto (S329).

Here, the collection paths of domain names registered, changed, and deleted in steps S301, S311, and S321 are as described in FIG. 8.

The embodiments of the present invention described above are not implemented only through an apparatus and a method, but may be implemented through a program that realizes a function corresponding to the configuration of the embodiment of the present invention or a recording medium on which the program is recorded.

Although the embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements by those skilled in the art using the basic concept of the present invention defined in the following claims are also provided. It belongs to the scope of rights.

Claims (14)

As a method of operating a server load balancer,
Receiving a domain name query of the terminal from the local domain name server,
Identifying a user plane device (UPF) to which the local domain name server is connected,
Selecting a content delivery service node corresponding to the domain name query from among a plurality of content delivery service nodes connected to the identified user plane device, and
Transmitting a domain name query response including information of the selected content delivery service node to the local domain name server,
The selected content delivery service node,
Providing a content transmission service to the terminal, operation method. In claim 1,
The user plane device is connected to one centralized unit,
The one centralized unit is connected to a plurality of remote units,
The centralized unit is installed in the office and the plurality of remote units are installed in a cell site outside the office. In claim 1,
The content delivery service node,
Operation method, divided by service unit. In paragraph 3,
The selecting step,
Determining a service type based on the domain name query, and selecting a content delivery service node that provides the determined service. In claim 1,
The identifying step,
Transmitting information on a local domain name server that has transmitted the domain name query to a content delivery service node management device, and
Including the step of receiving information on the user plane device connected to the transmitted local domain name server,
The content delivery service node management device,
An operation method of mapping and managing information of a local domain name server and a plurality of content delivery service nodes connected to each user plane device. As a method of operating a local domain name server,
Receiving a domain name query of the terminal from the user plane device (User Plane Function, UPF),
If the queried domain name is already registered, transmitting the domain name query to a server load balancer, and
Receiving information on a content delivery service node corresponding to the domain name query from the server load balancer and transmitting it to the user plane device,
The content delivery service node,
A method of operation, which is selected from a plurality of content delivery service nodes connected to the user plane device, and is connected to the terminal to provide a content delivery service to the terminal. In paragraph 6,
After the receiving step,
If the queried domain name is not registered, determining whether or not a predefined unique identifier is included in the queried domain name,
If the unique identifier is not included, requesting a recursive query from a plurality of name servers, and
When the unique identifier is included, transmitting the domain name query to a server load balancer
Further comprising, the operation method. In paragraph 6,
Before the receiving step,
Updating the domain name by receiving at least one of a domain name registration request, a change request, and a deletion request from the content delivery service node management device.
Further comprising, the operation method. Centrally located server load balancer, and
Including a plurality of edge cloud devices disposed at the edge,
The plurality of edge cloud devices,
User Plane Function (UPF) in charge of transmitting user traffic by connecting the user plane between the terminal and the data network,
A group content delivery service node including a plurality of content delivery service nodes connected to the user plane device, and
Each includes a local domain name server connected to the user plane device,
The server load balancer,
A content delivery service system for identifying a user plane device connected to a local domain name server that has transmitted a domain name query, and selecting a content delivery service node to be connected to the terminal from among a plurality of content delivery service nodes connected to the identified user plane device. In claim 9,
The server load balancer,
A content delivery service system for determining a service type based on the domain name query, and selecting a content delivery service node that provides the determined service. In claim 9,
The local domain name server,
When the queried domain name is previously registered, the domain name query is transmitted to the server load balancer. In clause 11,
The local domain name server,
When not all of the queried domain names are registered, but when the queried domain name includes a pre-defined unique identifier, the domain name query is transmitted to the server load balancer. In claim 9,
Further comprising a media conversion device for converting the content received from the content server in chunks,
The group content delivery service node,
And a first content delivery service node for receiving content received in chunks from the media conversion device and transmitting the content to a terminal through the user plane device. In claim 13,
A content delivery service node management device disposed in the center and connected to a plurality of local domain name servers, the server load balancer, the media conversion device, and the plurality of content delivery service nodes,
The content delivery service node management device registers, changes, and deletes domain names to the plurality of local domain name servers and the server load balancer according to a request of at least one of the content server, the media conversion device, and a content provider. A content delivery service system for updating a domain name by requesting at least one of.

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