Patent Description:
To meet the demand for wireless data traffic having increased since deployment of <NUM>th generation (<NUM>) communication systems, efforts have been made to develop an improved <NUM>th generation (<NUM>) or pre-<NUM> communication system.

In the <NUM> system, Hybrid FSK and QAM Modulation (FQAM) and sliding window superposition coding (SWSC) as an advanced coding modulation (ACM), and filter bank multi carrier (FBMC), non-orthogonal multiple access (NOMA), and sparse code multiple access (SCMA) as an advanced access technology have been developed.

In line with evolution of network technologies, next-generation networks, which are represented by <NUM>th generation (<NUM>) and clouds, require a higher level of quality of experience (QoE) by users. From the viewpoint of QoE, existing wireless communication schemes require only increased bandwidths, but major requirements of next-generation networks include low delay and low jitter, which need real-time responsiveness and mutual reactivity. In addition, a large number of devices, represented by Internet of Things (IoT), need to be controlled in the next-generation networks, and this may increase the network complexity exponentially. Furthermore, since multiple service providers constitute a single network, satisfying a service level agreement (SLA) among the multiple network operators may be an important factor that may have a direct influence not only on network quality management, but also on actual network operating costs.

A publication of <CIT> concerns a system for measuring user quality of experience in a network, the system comprising: a system controller for configuring measurement criteria for user quality of experience between network elements and controlling so that the network elements measure the user quality of experience according to the set criteria; a network element for transmitting a packet to a counterpart network element in order to measure, according to the control of the system controller, the user quality of experience for at least one counterpart network element; and a counterpart network element for receiving the packet from the network element and transmitting a response packet.

A document <CIT> discloses selecting and monitoring a plurality of services key performance indicators using TWAMP.

A disclosure of <CIT> recites data path performance measurement using network traffic in a software defined network.

Lastly, <CIT> describes a method comprising the steps of: setting a quality measurement request message by using a quality measurement condition received from a user; transmitting the quality measurement request message to a quality measurement device; and receiving information on the quality which is measured by using the quality measurement condition, wherein the quality measurement request message and the information on the quality are transmitted while being included in an open flow message.

Various embodiments of the disclosure may provide a method and an apparatus capable of providing a network service assurance in an incorporated manner by using a software-defined network (SDN) and a network function virtualization (NFV) technology.

Various embodiments of the disclosure may provide a method and an apparatus for securing the visibility of the entire interval for testing network quality by using the SDN technology in a communication system, and managing the network quality by using an SDN orchestration device.

Various embodiments of the disclosure may provide a method and an apparatus for testing and managing the entire quality test interval with regard to each lower-level interval by using an SDN test scheme in a communication system.

Various embodiments of the disclosure may provide a method and an apparatus for dynamically controlling the test performance and capacity by using a software-based network function virtualization (NFV) technology in a communication system, and testing the network quality regardless of the performance and capacity of hardware equipment.

Various embodiments of the disclosure may provide a method and an apparatus for testing network quality regarding various physical/logical network elements (NEs) within a data center in a communication system.

Various embodiments of the disclosure may provide a method and an apparatus for removing a failure occurring to a data center in a communication system.

Various embodiments of the disclosure may provide a method and an apparatus regarding a user interface for managing, in an incorporated manner, network quality regarding an NE of a data center in a communication system, and providing a service guarantee.

Various embodiments of the disclosure provide a method and an apparatus for managing service quality with regard to a path along which traffic moves in real time with regard to NEs of a data center in a communication system, and with regard to each interval constituting the path.

Various embodiments of the disclosure may provide a method and an apparatus for not only testing network quality in real time with regard to NEs of a data center in a communication system, but also statistically managing the results of measured network quality, thereby statistically analyzing the cause of quality degradation.

According to various aspects of the disclosure, a method for operating a management device for testing network quality in a communication system is provided as per the appended claims.

According to various aspects of the disclosure, a method for operating a controller device for testing network quality in a communication system is provided as per the appended claims.

According to various aspects of the disclosure, a method for operating a server device for testing network quality in a communication system is provided as per the appended claims.

According to various aspects of the disclosure, a management device for testing network quality in a communication system is provided as per the appended claims.

According to various aspects of the disclosure, a controller device for testing network quality in a communication system is provided as per the appended claims.

According to various aspects of the disclosure, a server device for testing network quality in a communication system is provided as per the appended claims.

A method and an apparatus according to various embodiments of the disclosure configure a network by using a software-defined network (SDN) and a network function virtualization (NFV) technology, and test network quality regarding network elements (NEs) constituting the network, thereby enabling more efficient network quality management.

Effects which can be acquired by the disclosure are not limited to the above described effects, and other effects that have not been mentioned may be clearly understood by those skilled in the art from the following description.

The terms used in the disclosure are only used to describe specific embodiments, and are not intended to limit the disclosure. A singular expression may include a plural expression unless they are definitely different in a context. Unless defined otherwise, all terms used herein, including technical and scientific terms, have the same meaning as those commonly understood by a person skilled in the art to which the disclosure pertains. Such terms as those defined in a generally used dictionary may be interpreted to have the meanings equal to the contextual meanings in the relevant field of art, and are not to be interpreted to have ideal or excessively formal meanings unless clearly defined in the disclosure. In some cases, even the term defined in the disclosure should not be interpreted to exclude embodiments of the disclosure.

Hereinafter, various embodiments of the disclosure will be described based on an approach of hardware. However, various embodiments of the disclosure include a technology that uses both hardware and software and thus, the various embodiments of the disclosure may not exclude the perspective of software.

Hereinafter, the disclosure relates to an apparatus and a method for managing network quality in a wireless communication system. Specifically, the disclosure describes a technology for conducting quality management and service assurance in a software-defined network (SDN) by using network function virtualization (NFV) in a wireless communication system. The index of service quality to be managed in the disclosure may include, for example, quality of experience (QoE). As will be used in the following description, terms denoting parameters related to display of data (for example, target entity, data time interval, resource level, and data type level), terms denoting network entities, terms denoting a device's constituent elements (modified appropriately according to the disclosure), and the like are examples given for convenience of description. Therefore, the disclosure is not limited to the following terms, and other terms having equivalent technical meanings may be used instead.

Hereinafter, terms used in this disclosure will be defined as follows:
"Soft-defined networking (SDN)" refers to a technology for dividing a control area in an individual network element (NE) constituting a network into accessible devices, and logically controlling and managing the network by using an application in the accessible devices. In the SDN, respective individual NEs may be programmed through an open application programming interface (API) such that the same can be controlled or managed. In other words, the network and/or the NEs may be managed in a centralized type according to the SDN.

"Network function virtualization (NFV)" refers to a technology for virtualizing hardware equipment constituting a network such that an upper-level entity (for example, server) implements the same as software. When the NFV technology is applied, virtualization of hardware equipment may make any separate hardware equipment unnecessary.

"A network path" refers to a route along which a packet or data is transmitted between two NEs. For example, in the case of communication between first and second terminals in a single base station cell, the network path between the two terminals may be "first terminal -> base station -> second terminal". It can also be stated in this case that "the network path between the first and second terminals includes the first terminal, the base station, and the second terminal". When the network path between two specific NEs solely includes the two NEs, as a special case of the network path, the two NEs are directly connected, and the network path between the two NEs may be referred to as "a direction path". A network path may simply be referred to as "a path".

<FIG> illustrates a communication system <NUM> according to various embodiments of the disclosure. Referring to <FIG>, the system <NUM> for network quality management (or simply referred to as a system <NUM>) may include NEs such as a first base station <NUM> to a fourth base station <NUM>, a terminal <NUM>, a first tester <NUM>, a second tester <NUM>, a switch/router <NUM>, a gateway <NUM>, a test manager <NUM>, and an operational support system/business support system (OSS/BSS) <NUM>.

In order to test network quality in the system <NUM>, the test manager <NUM> may transmit a test request to the first tester <NUM>. In response to the test request, the first tester <NUM> may perform an operation for testing the network quality with the second tester <NUM>. According to various embodiments of the disclosure, the first tester <NUM> may perform an operation for testing the network quality with the second tester <NUM> by using an active monitoring technology. Specifically, the first tester <NUM> may generate a test (probe or measure) packet for testing the network quality, and may transmit the generated test packet to the second tester <NUM>. The second tester <NUM> may process, as needed, the received test packet, such as storing a parameter related to network test in the received test packet, and may transmit the processed packet or test result packet back to the first tester <NUM>. That is, the first tester <NUM> may operate as a sender, and the second tester <NUM> may operate as a reflector. The first tester <NUM> may transmit the test result packet received from the second tester <NUM> to the test manager <NUM>, thereby transmitting a test report corresponding to the test request of the test manager <NUM>. After receiving the test result report, the test manager <NUM> may conduct comprehensive analysis and control of the test result through an interface with the OSS/BSS <NUM>. According to the above-mentioned operations, network quality may be measured and managed with regard to the network path between the first tester <NUM> and the second tester <NUM> by using the active monitoring technology.

According to various embodiments of the disclosure, the second tester <NUM> may embedded in at least one of the first base station <NUM> to the fourth base station <NUM>, the switch/router <NUM>, and the gateway <NUM>. In this case, the system <NUM> may include no separate second tester <NUM>. When the second tester <NUM> is embedded in at least one of the first base station <NUM> to the fourth base station <NUM>, the switch/router <NUM>, and the gateway <NUM>, quality may be measured and managed with regard to the network path between the first tester <NUM> and each of the first base station <NUM> to the fourth base station <NUM>, the switch/router <NUM>, and the gateway <NUM>. As illustrated in <FIG>, testing the quality with regard to the network path between the first tester <NUM> and each of the first base station <NUM> to the fourth base station <NUM>, the switch/router <NUM>, and the gateway <NUM> is an example, and network quality may also be measured in a similar manner with regard to a network path between any two NEs included in the system <NUM>. As described above, by managing network quality regarding each NE in the system <NUM>, the terminal <NUM> communicating with at least one of the first base station <NUM> to the fourth base station <NUM> may accomplish a high-level user quality-of-service (QoS), and may receive assurance of the service to be provided.

A test of network quality in the system <NUM> may require separate test equipment such as the first tester <NUM> and/or the second tester <NUM>, or may require that test equipment be embedded in NEs (for example, the first base station <NUM> to the fourth base station <NUM>, the switch/router <NUM>, and the gateway <NUM>). Such a hardware-based network quality management scheme may require a huge capital expenditure (CAPEX) for separately installing test equipment or for embedding the same in each NE. Moreover, in the case of the hardware-based network quality management scheme, it may be difficult to manage, in an incorporated manner, information regarding the result of network quality test acquired from multiple pieces of test equipment or from the NEs having test equipment embedded therein. Particularly, it may be difficult to apply the hardware-based network quality management scheme to an NE with a complicated structure, such as a data center (DC).

Therefore, in order to overcome the problems of the hardware-based network quality management scheme, various embodiments of the disclosure provide a method and an apparatus capable of managing network quality by using NFV and SDN technologies and providing service assurance. In other words, various embodiments of the disclosure provide a method and an apparatus for virtualizing hardware devices necessary to configure a network by using NFV technology, programming respective physical/virtual NEs through an open API by using SDN technology, and controlling and managing the same in a centralized manner.

<FIG> illustrates a structure for SDN-based network quality management in a communication system according to various embodiments of the disclosure. The system <NUM> may include, as exemplary end-to-end management devices, an SDN management device <NUM> and a management and an orchestration (MANO)/NFV management device <NUM>. Although the SDN management device <NUM> and the MANO/NFV management device <NUM> are illustrated in <FIG> as separate entities, the SDN management device <NUM> and the MANO/NFV management device <NUM> may be a single incorporated management device for managing physical/virtual NEs. A management device may be referred to as an orchestrator. In addition, the system <NUM> may include an edge cloud DC SDN controller <NUM>, a transport network controller <NUM>, a core cloud DC controller <NUM>, an edge cloud DC <NUM>, a transport network <NUM>, and a core cloud DC <NUM>.

The SDN management device <NUM> and/or the MANO/NFV management device <NUM> may provide the user with an interface for testing, controlling, and managing the network quality. The SDN management device <NUM> and/or the MANO/NFV management device <NUM> may receive an input for controlling the network from the user through the interface, and may send a request corresponding to the input to at least one edge cloud DC SDN controller <NUM>, transport network controller <NUM>, and core cloud DC controller <NUM>. In addition, the SDN management device <NUM> and/or the MANO/NFV management device <NUM> may receive a result corresponding to the request (for example, information regarding measured network quality) from at least one edge cloud DC SDN controller <NUM>, transport network controller <NUM>, and core cloud DC controller <NUM> and may display the same.

The edge cloud DC SDN controller <NUM> may test, control, and manage network quality regarding NEs included in the edge cloud DC <NUM>. The edge cloud DC SDN controller <NUM> may have a service assurance application, and may receive a command for testing network quality from the SDN management device <NUM> and/or the MANO/NFV management device <NUM> through an open API. For example, the edge cloud DC SDN controller <NUM> may configure a path between NEs for testing network quality in the edge cloud DC <NUM>, and may control such that network quality is measured with regard to a path having at least one NE configured in connection with the configured path. The edge cloud DC SDN controller <NUM> may receive information regarding the network quality test result from at least one NE, and may provide the same to the SDN management device <NUM> and/or the MANO/NFV management device <NUM>. The transport network SDN controller <NUM> and the core cloud DC SDN controller <NUM> may also perform a function identical or similar to that of the edge cloud DC SDN controller <NUM>, and may test, control, and manage network quality regarding NEs included in the transport network <NUM> and the core cloud DC <NUM>, respectively.

The edge cloud DC <NUM> and the core cloud DC <NUM> may store data to be consumed by the terminal <NUM>. In this regard, the edge cloud DC <NUM> may be a DC relatively close to the terminal <NUM> from the viewpoint of the network path, and the core cloud DC <NUM> may be a DC relatively far from the terminal <NUM> from the viewpoint of the network path. The transport network <NUM> may be an NE existing on a path connecting the edge cloud DC <NUM> and the core cloud DC <NUM>, and may mediate packet exchange between the edge cloud DC <NUM> and the core cloud DC <NUM>.

As illustrated in <FIG>,each of the edge cloud DC <NUM> and the core cloud DC <NUM> may include multiple switches (for example, spine switches, leaf switches, and open virtual switches (OVS)), multiple virtual machines (VMs) (for example, virtual deep packet inspection (vDPI), virtualized radio access network (vRAN), virtual service assurance (vSA), virtual evolved packet core (vEPC), and virtual firewall (vFW)). The terminal <NUM> may transmit or receive data through a path extending through multiple switches and/or virtual machines included in each of the edge cloud DC <NUM> and the core cloud DC <NUM>, as illustrated in <FIG>. The detailed structure and function of the DC will now be descried in detail with reference to <FIG>.

<FIG> illustrates the structure of a DC <NUM> in a communication system according to various embodiments of the disclosure.

The DC <NUM> may include multiple spine switches <NUM>, <NUM>, and <NUM>, multiple leaf switches <NUM>, <NUM>, <NUM>, <NUM>, and <NUM>, a data center interconnect (DCI) <NUM>, multiple virtual switches <NUM>, <NUM>, <NUM>, and <NUM>, and multiple VMs <NUM>-<NUM>. As illustrated in <FIG>, the DC <NUM> may include multiple switches and VMs in a hierarchy structure. Hereinafter, spine switches and leaf switches may be simply referred to as "spines" and "leaves", respectively.

The spine <NUM> may be directly connected to at least one of the leaves <NUM>, <NUM>, <NUM>, <NUM>, and <NUM>. In other words, a direct path may be configured between the spine <NUM> and at least one leaf <NUM>, <NUM>, <NUM>, <NUM>, and <NUM>, and data or a packet may be exchanged between the spine <NUM> and at least one leaf <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> through the direct path. Although not illustrated, the spine <NUM> may exchange data or a packet with another NE through a direct path with the other NE. The spine <NUM> may control such that a packet or data received by the spine <NUM> is transmitted through an appropriate path. For example, when the spine <NUM> has received a packet from the leaf <NUM>, the spine <NUM> may determine, based on information included in the transmitted packet, that the received packet needs to be transmitted to the leaf <NUM>, and may transmit the received packet to the leaf <NUM>. Other spines <NUM> and <NUM> may also perform the same function as that of the spine <NUM>.

The leaf <NUM> may be directly connected to at least one of the spines <NUM>, <NUM>, and <NUM>. In addition, the leaf <NUM> may be directly connected to at least one of the virtual switches <NUM>, <NUM>, <NUM>, and <NUM> and the DCI <NUM>. Similarly to the spine <NUM>, the leaf <NUM> may control such that a packet or data received by the leaf <NUM> is transmitted through an appropriate path. Other leaves <NUM>, <NUM>, <NUM>, and <NUM> may also perform the same function as that of the leaf <NUM>.

The DCI <NUM> refers to a set of multiple DCs which have a structure as illustrated in <FIG>, and which are connected to each other. In other words, the DCI <NUM> may include multiple DCs, and each of the multiple DCs may include multiple spines, multiple leaves, multiple virtual switches, and multiple VMs. According to various embodiments of the disclosure, a DC constituting the DCI <NUM> may include only some of the constituent elements of the DC illustrated in <FIG>. For example, the DC constituting the DCI <NUM> may solely include at least one virtual switch and at least one VM. Each DC constituting the DCI <NUM> may be directly connected to the leaf <NUM>, and may exchange a packet or data with another DC through the leaf <NUM>.

The virtual switch <NUM> may be directly connected to the VMs <NUM>, <NUM>, and <NUM>. In addition, the virtual switch <NUM> may be directly connected to the leaf <NUM>. The virtual switch <NUM> may be a virtual logical switch implemented as software, unlike the spines <NUM>, <NUM>, and <NUM> and the leaves <NUM>, <NUM>, <NUM>, <NUM>, and <NUM>, which are physical switches. The virtual switch <NUM> may control such that a packet or data received by the virtual switch <NUM> is transmitted through an appropriate path, similarly to the leaf <NUM> and/or the spine <NUM>. Other virtual switches <NUM> and <NUM> may also perform the same function as that of the virtual switch <NUM>.

The VM <NUM> refers to a virtual logical processor or computer implemented as software. In addition, the VM <NUM> may further include a virtual central processing unit (CPU) and a virtual input/output (I/O) device, and may function as an independent device. From the viewpoint of network quality management, the VM <NUM> may receive a message requesting a network quality test, and may perform an operation for testing network quality with the other VMs <NUM>-<NUM> in response to the message. To this end, the VM <NUM> may transmit or receive a packet through the virtual switch <NUM> directly connected to the VM <NUM>. Other VMs <NUM>-<NUM> may also perform the same function as that of the VM <NUM>.

According to various embodiments of the disclosure, the spines <NUM>, <NUM>, and <NUM> and the leaves <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> may be physical switches, but may also be implemented as virtual switches by using NFV technology. In addition, all constituent elements of the DC <NUM> illustrated in <FIG> may be controlled in an incorporated manner by a single device (for example, SDN controller) through an open API. Such a DC <NUM> by which all constituent elements of the DC <NUM> are controlled in an incorporated manner may be referred to as a software-defined data center (SDDC). The term "DC" used herein may refer to such an SDDC.

<FIG> illustrates a structure for SDN-based network quality management interlinked with NFV in a communication system according to various embodiments of the disclosure. The system <NUM> includes a management device <NUM>, a controller device <NUM>, an MANO <NUM>, a network function virtualization infrastructure (NFVI) <NUM>, a first server <NUM>, and a second server <NUM>.

The management device <NUM> may provide the use with an interface for testing, controlling, and managing network quality. For example, the management device <NUM> may provide the user with an interface through a QoE diagnosis/topology application. The management device <NUM> may receive an input for controlling the network from the user through the interface, and may send a request corresponding to the input to the controller device <NUM>. In addition, the management device <NUM> may receive a result corresponding to the request (for example, information regarding measured network quality) from the controller device <NUM>, and may display the same.

The controller device <NUM> may test, control, and manage network quality regarding NEs included in the DC. The controller device <NUM> may have service assurance applications such as a DC virtual tenant network (VTN) application, a DC fabric application, and a QoE diagnosis application. Such service assurance applications may communicate with an application of another NE through an open API. For example, the QoE diagnosis application of the controller device <NUM> may receive a command for testing network quality from the management device <NUM>, and the DC fabric application of the controller device <NUM> may communicate with at least one NE (for example, spine switch, leaf switch, virtual switch, or virtual machine) included in the DC so as to control and manage the at least one NE. The DC VTN application of the controller device <NUM> may receive a command from the MANO <NUM> and may perform an operation corresponding to the command.

The MANO <NUM> and the NFVI <NUM> may virtualize a physical hardware device of the system <NUM>, or may generate a virtual device. As a result thereof, the MANO <NUM> and the NFVI <NUM> may generate a virtual network. In addition, the MANO <NUM> and the NFVI <NUM> may control and manage NEs constituting the virtualized network. For example, the MANO <NUM> may include functional modules such as network function virtualization - orchestration (NFV-O), virtual network function - management (VNF-M), and virtualized infrastructure manager (VIM), and may support the controller device <NUM> such that the same can generate and manage a virtual network through the DC VTN application. The NFVI <NUM> may include devices including virtual NEs such as the first server <NUM> and the second server <NUM> (for example, open virtual switch, VM, and virtual service assurance (vSA) device (a type of VM)). The VMs included in the first server <NUM> and the second server <NUM> may generate a packet and may transmit the generated packet to another device. The packet transmitted from the VMs may be received by a VM of another server, or may be transmitted to the Internet through a leaf switch, a spine switch, and a DC gateway (GW) router.

<FIG> illustrates a function performed by an NE for network quality management in a communication system according to various embodiments of the disclosure.

The management device <NUM> may provide the user with an interface for testing, controlling, and managing network quality. The management device <NUM> may receive a condition for a network quality test (test condition) and information regarding the target for the network quality test (test target) from the user through the interface. Hereinafter, the term "test" will be used interchangeably with "diagnose" or "measure". <FIG> illustrates an example of configuring a test condition such that the management device <NUM> uses a TWAMP protocol when testing network quality according to the user's input, and an example of configuring test targets with regard to respective test cases. For example, in the first test case <NUM>, the first VNF and the sixth VNF are configured as test targets, and in the second test case <NUM>, the third VNF and the second VNF are configured as test targets. The first VNF, the second VNF, the third VNF, and the sixth VNF are a type of VMs, and may generate, transmit, or receive a packet for testing network quality. In this regard, the VNF with "S" mark refers to a target that generates a packet for testing network quality, and the VNF with "D" mark refers to a target that performs a process corresponding to the test condition with regard to the generated packet. Hereinafter, the target that generates a packet for testing network quality may be referred to as "a source target (or source)", and the target that performs a process corresponding to the test condition with regard to the generated packet may be referred to as "a destination target (or destination)". Referring to <FIG>, in the first test case <NUM>, the source target is the first VNF, and the destination target is the sixth VNF, and in the second test case <NUM>, the source target is the second VNF, and the destination target is the third VNF. The management device <NUM> may transmit a test request message including information regarding the configured test targets and the test condition to the controller device <NUM>.

The controller device <NUM> may control, in response to the test request message received from the management device <NUM>, such that network quality between the test targets of the DC <NUM> is measured. The controller device <NUM> may configure a path between the test targets, and may transmit a request message to the source target, among the test targets, such that network quality is measured based on the configured path (active monitoring started). In addition, the controller device <NUM> may receive information regarding the result of measured network quality (active monitoring result collected), and may receive statistical information regarding switches (for example, the first spine, the second spine, the first leaf, the second leaf, the third leaf, the first OVS, the second OVS, and the third OVS) included in the path between the source target and the destination target while the network quality is measured (switch statistics collected). The statistic information regarding switches may include, for example, information indicating whether or not the packet has been delivered via an appropriate path through the switches, information regarding whether or not elements that degrade network quality exist in the switches, information regarding the degree of network quality degradation, and information regarding whether or not a problem has occurred to the path between the switches. The controller device <NUM> may transmit the received information regarding the result of network quality and the statistical information regarding the switches to the management device <NUM>.

The management device <NUM> may receive the information regarding the result of network quality test and the statistical information regarding the switches from the controller device <NUM>, and may display the same through a user interface. <FIG> illustrates the management device <NUM> displaying the result of network quality test regarding the first test case <NUM> and the result of network quality test regarding the second test case <NUM>. The first test case <NUM> indicates that the path between test targets configured for a network quality test is first VNF (source target) -> first OVS -> first leaf -> second spine -> third leaf -> third OVS -> sixth VNF (destination target). Such a path between test targets in the first test case <NUM> may also be inferred from the internal structure of the DC <NUM>. According to the first test case <NUM>, a packet was appropriately transmitted from the source target to the destination target through the path: first VNF - > first OVS -> first leaf -> second spine -> third leaf -> third OVS -> sixth VNF, and corresponding loss (L), delay (D), jitter (J), and mean opinion score (M) values were derived accordingly. The second test case <NUM> indicates that the path between test targets configured for a network quality test is third VNF (source target) -> second OVS -> second leaf -> first spine -> first leaf -> first OVS -> second VNF (destination target). Such a path between test targets in the second test case <NUM> may also be inferred from the internal structure of the DC <NUM>. According to the second test case <NUM>, the packet was appropriately transmitted from the third VNF to the second leaf through the path: third VNF -> second OVS -> second leaf, but failed to be transmitted from the second leaf to the first spine, and L, D, J, and M values failed to be derived. According to the network quality test result in as the second test case <NUM>, the management device <NUM> may visually display the fact that the second leaf and/or the first spine has a failure such that the user can troubleshoot the second leaf and/or the first spine.

As illustrated in <FIG>, network quality may be measured with regard to a path between VMs, but according to various embodiments of the disclosure, network quality may also be measured with regard to a path between any two NEs of the DC. Various paths and targets, for which network quality may be measured, will now be described with reference to <FIG>.

<FIG> illustrates the type of targets for which network quality may be measured in a communication system according to various embodiments of the disclosure. According to various embodiments of the disclosure, paths and targets for which network quality may be measured in a DC may be classified into one of the following types:.

In order to test network quality with regard to a path between two targets, the source target may be required to generate a test packet and to transmit the generated test packet to the destination target, and the destination target may be required to perform a process corresponding to the test condition with regard to the received test packet and to transmit the processed test packet back to the source target. However, NEs of the DC other than the VMs (for example, a virtual switch, a leaf switch, a spine switch, and a DCI) may fail to generate a test packet for testing network quality or to perform a process with regard to the test packet. According to various embodiments of the disclosure, in order to test network quality with regard to a path between two targets, including at least one NE that is not a VM, a path is configured between the VMs including such a path, and network quality may be indirectly measured by VMs that generate and transmit/receive a test packet with regard to the path between the two targets including at least one NE that is not a VM.

<FIG> illustrates NEs in a system <NUM> for managing network quality in a communication system according to various embodiments of the disclosure. As illustrated in <FIG>, the system <NUM> includes a management device <NUM> (for example, management device <NUM>), a controller device <NUM> (for example, controller device <NUM>), a switch <NUM>, multiple servers including a server <NUM> (for example, first server <NUM> or second server <NUM>), and an external test device <NUM>.

The management device <NUM> provides an interface and a function capable of monitoring parameters related to performance of other devices in the network (for example, diagnosis and performance evaluation). The controller device <NUM> provides functions for controlling configuration/functions related to the SDN of other devices in the network. The switch <NUM> is equipment for connection between the controller device <NUM> and other devices (for example, server <NUM> and external test device <NUM>). The server <NUM> is a versatile server capable of playing various roles (for example, mobility management entity (MME), gateway, and the like) according to the installed program/application. The external test device <NUM> is equipment configured to transmit or receive a packet for performance inspection. The external test device <NUM> is a versatile server, and may be a server including a virtual machine playing the role of a sender or a reflector for performance inspection. Each of the management device <NUM>, the controller device <NUM>, the switch <NUM>, the server <NUM>, and the external test device <NUM> may include at least one application having an open API, and may communicate with another device through the at least one application. The operation performed by each of the management device <NUM>, the controller device <NUM>, the switch <NUM>, the server <NUM>, and the external test device <NUM> will now be described in more detailed. In the description, "management device" may be referred to as "SDN management device", and "controller device" may be referred to as "SDN controller device".

<FIG> is a block diagram of a management device <NUM> in a communication system according to various embodiments of the disclosure. As used herein, the term ". unit" or "-er" refers to a unit entity configured to process at least one function or operation, and may be implemented as hardware, software, or a combination of hardware and software.

Referring to <FIG>, the management device <NUM> may include a display <NUM>, a processor <NUM>, a communication unit <NUM>, a storage unit <NUM>, and an input/output (I/O) interface <NUM>.

The display <NUM> is configured to display a screen including an image, a graphic, a text, and the like. For example, the display <NUM> may be made of a liquid crystal, a light-emitting diode display, or a different material. The display <NUM> may display a screen corresponding to data received through the processor <NUM>. In addition, the display <NUM> may include a touch screen for sensing the user's input.

The processor <NUM> may control overall operations of the management device <NUM>. For example, the processor <NUM> may transmit or receive a signal through the communication unit <NUM>. The processor <NUM> may record data in the storage unit <NUM>, and may read data stored in the storage unit <NUM>. To this end, the processor <NUM> may include at least one processor or at least one microprocessor. The processor <NUM> may be configured to implement operating procedures and/or methods of the management device <NUM> proposed in the disclosure. The processor <NUM> may control the management device <NUM> so as to perform operations related to network quality management according to various embodiments described later.

The communication unit <NUM> may perform functions for transmitting or receiving a signal through a wireless channel. The communication unit <NUM> may perform a function for conversion between a baseband signal and a bit string according to the physical layer specification of the system. For example, when transmitting data, the communication unit <NUM> may generate complex symbols by encoding and modulating a transmission bit string. As another example, when receiving data, the communication unit <NUM> may restore a reception bit string by demodulating and decoding a baseband signal.

The communication unit <NUM> is configured to provide an interface for performing communication with other nodes in the network. That is, the communication unit <NUM> converts a bit string transmitted from the management device <NUM> to another node (for example, base station, core network, or authentication server) into a physical signal, and converts a physical signal received from the other node into a bit string. That is, the communication unit <NUM> may transmit and receive signals. Accordingly, the communication unit <NUM> may be referred to as a transmitting unit, a receiving unit, or a transmitting/receiving unit.

The communication unit <NUM> is configured to enable the management device <NUM> to communicate with other devices or the system via backhaul connection or via the network. The communication unit <NUM> may support communication via appropriate wired or wireless connection. For example, when the management device <NUM> is implemented as a part of a mobile communication system (such as one supporting <NUM>, LTE, or LTE-A), the communication unit <NUM> may enable the management device <NUM> to communicate with other devices via wired or wireless backhaul connection. When the management device <NUM> is implemented as an access point, the communication unit <NUM> may enable the management device <NUM> to communicate via a wired or wireless near-field network, or to communicate with a network having a larger scale (such as the Internet) via wired or wireless connection. The communication unit <NUM> may include a structure for supporting communication via wired or wireless connection, such as Ethernet or RF transceiver.

The storage unit <NUM> may store a control instruction code for controlling the management device <NUM>, control data, or user data. For example, the storage unit <NUM> may include an application, an operating system (OS), middleware, and a device driver. The storage unit <NUM> may include at least one of a volatile memory or a nonvolatile memory. The volatile memory may include a dynamic RAM (DRAM), a static RAM (SRAM), a synchronous DRAM (SDRAM), a phase-change RAM (PRAM), a magnetic RAM (MRAM), a resistive RAM (RRAM), a ferroelectric RAM (FeRAM), and the like. The nonvolatile memory may include a read only memory (ROM), a programmable ROM (PROM), an electrically programmable ROM (EPROM), an electrically erasable ROM (EEPROM), a flash memory, and the like. The storage unit <NUM> may include a nonvolatile medium such as a hard disk drive (HDD), a solid state disk (SSD), an embedded multimedia card (eMMC), or a universal flash storage (UFS). The storage unit <NUM> may be operatively coupled to the processor <NUM>.

The input unit <NUM> may receive an input from the user. To this end, the input unit <NUM> may include an input interface. The input received through the input unit <NUM> may be processed by the processor <NUM> and then transmitted to the display <NUM>, the storage unit <NUM>, and the communication unit <NUM>. As a result thereof, information corresponding to the input received through the input unit <NUM> may be displayed on the display <NUM>, transmitted to another device through the communication unit <NUM>, or stored in the storage unit <NUM>.

<FIG> is a block diagram of a controller device <NUM> in a communication system according to various embodiments of the disclosure. As used herein, the term ". unit" or "-er" refers to a unit entity configured to process at least one function or operation, and may be implemented as hardware, software, or a combination of hardware and software.

Referring to <FIG>, the controller device may include a processor <NUM>, a communication unit <NUM>, and a storage unit <NUM>.

The processor <NUM> may control overall operations of the management device <NUM>. For example, the processor <NUM> may transmit or receive a signal through the communication unit <NUM>. The processor <NUM> may record data in the storage unit <NUM>, and may read data stored in the storage unit <NUM>. To this end, the processor <NUM> may include at least one processor or at least one microprocessor. The processor <NUM> may be configured to implement operating procedures and/or methods of the controller device <NUM> proposed in the disclosure. The processor <NUM> may control the controller device <NUM> so as to perform operations related to network quality management according to various embodiments described later.

The communication unit <NUM> is configured to enable the controller device <NUM> to communicate with other devices or the system via backhaul connection or via the network. The communication unit <NUM> may support communication via appropriate wired or wireless connection. For example, when the controller device <NUM> is implemented as a part of a mobile communication system (such as one supporting <NUM>, LTE, or LTE-A), the communication unit <NUM> may enable the management device <NUM> to communicate with other devices via wired or wireless backhaul connection. When the controller device <NUM> is implemented as an access point, the communication unit <NUM> may enable the controller device <NUM> to communicate via a wired or wireless near-field network, or to communicate with a network having a larger scale (such as the Internet) via wired or wireless connection. The communication unit <NUM> may include a structure for supporting communication via wired or wireless connection, such as Ethernet or RF transceiver.

The storage unit <NUM> may store a control instruction code for controlling the controller device <NUM>, control data, or user data. For example, the storage unit <NUM> may include an application, an operating system (OS), middleware, and a device driver. The storage unit <NUM> may include at least one of a volatile memory or a nonvolatile memory. The volatile memory may include a dynamic RAM (DRAM), a static RAM (SRAM), a synchronous DRAM (SDRAM), a phase-change RAM (PRAM), a magnetic RAM (MRAM), a resistive RAM (RRAM), a ferroelectric RAM (FeRAM), and the like. The nonvolatile memory may include a read only memory (ROM), a programmable ROM (PROM), an electrically programmable ROM (EPROM), an electrically erasable ROM (EEPROM), a flash memory, and the like. The storage unit <NUM> may include a nonvolatile medium such as a hard disk drive (HDD), a solid state disk (SSD), an embedded multimedia card (eMMC), or a universal flash storage (UFS). The storage unit <NUM> may be operatively coupled to the processor <NUM>.

<FIG> is a block diagram of a server device <NUM> in a communication system according to various embodiments of the disclosure. As used herein, the term ". unit" or "-er" refers to a unit entity configured to process at least one function or operation, and may be implemented as hardware, software, or a combination of hardware and software.

Referring to <FIG>, the server device <NUM> may include a processor <NUM>, a communication unit <NUM>, and a storage unit <NUM>.

The processor <NUM> may control overall operations of the server device <NUM>. For example, the processor <NUM> may transmit or receive a signal through the communication unit <NUM>. The processor <NUM> may record data in the storage unit <NUM>, and may read data stored in the storage unit <NUM>. To this end, the processor <NUM> may include at least one processor or at least one microprocessor. The processor <NUM> may be configured to implement operating procedures and/or methods of the server device <NUM> proposed in the disclosure. The processor <NUM> may control the server device <NUM> so as to perform operations related to network quality management according to various embodiments described later.

The communication unit <NUM> is configured to provide an interface for performing communication with other nodes in the network. That is, the communication unit <NUM> converts a bit string transmitted from the server device <NUM> to another node (for example, base station, core network, or authentication server) into a physical signal, and converts a physical signal received from the other node into a bit string. That is, the communication unit <NUM> may transmit and receive signals. Accordingly, the communication unit <NUM> may be referred to as a transmitting unit, a receiving unit, or a transmitting/receiving unit.

The communication unit <NUM> is configured to enable the server device <NUM> to communicate with other devices or the system via backhaul connection or via the network. The communication unit <NUM> may support communication via appropriate wired or wireless connection. For example, when the server device <NUM> is implemented as a part of a mobile communication system (such as one supporting <NUM>, LTE, or LTE-A), the communication unit <NUM> may enable the server device <NUM> to communicate with other devices via wired or wireless backhaul connection. When the server device <NUM> is implemented as an access point, the communication unit <NUM> may enable the server device <NUM> to communicate via a wired or wireless near-field network, or to communicate with a network having a larger scale (such as the Internet) via wired or wireless connection. The communication unit <NUM> may include a structure for supporting communication via wired or wireless connection, such as Ethernet or RF transceiver.

The storage unit <NUM> may store a control instruction code for controlling the server device <NUM>, control data, or user data. For example, the storage unit <NUM> may include an application, an operating system (OS), middleware, and a device driver. The storage unit <NUM> may include at least one of a volatile memory or a nonvolatile memory. The volatile memory may include a dynamic RAM (DRAM), a static RAM (SRAM), a synchronous DRAM (SDRAM), a phase-change RAM (PRAM), a magnetic RAM (MRAM), a resistive RAM (RRAM), a ferroelectric RAM (FeRAM), and the like. The nonvolatile memory may include a read only memory (ROM), a programmable ROM (PROM), an electrically programmable ROM (EPROM), an electrically erasable ROM (EEPROM), a flash memory, and the like. The storage unit <NUM> may include a nonvolatile medium such as a hard disk drive (HDD), a solid state disk (SSD), an embedded multimedia card (eMMC), or a universal flash storage (UFS). The storage unit <NUM> may be operatively coupled to the processor <NUM>.

<FIG> is an operation flowchart of a management device <NUM> in a communication system according to various embodiments. <FIG> illustrates an exemplary operating method of a management device <NUM>.

Referring to <FIG>, in step <NUM>, the management device <NUM> configures at least one target for measuring network quality and a test condition. The at least one target includes a source target and a destination target. In addition, the at least one target may be a virtual device (for example, VM or virtual switch), or may be a physical device (for example, spine switch or leaf switch).

In step <NUM>, the management device <NUM> transmits a measurement request message including information regarding the at least one target and the test condition. For example, the management device <NUM> may transmit a measurement request message including information regarding the at least one target and the test condition to a controller device that controls a path related to the at least one target.

In step <NUM>, the management device <NUM> receives information regarding network quality measured with regard to the path, based on the test condition. The information regarding network quality may be measured with regard to a path between the source target and the destination target. In addition, the information regarding network quality may include at least one of the address of each of at least one target, information regarding a path between two targets included in the at least one target, information regarding a change in network quality over time, and statistical information regarding the network quality. Furthermore, the information regarding network quality may include an index for indicating network quality regarding the path between the source target and the destination target, and index values. For example, the index for indicating network quality may include at least one of the bandwidth regarding the packet transmitted/received between the two targets, delay, jitter, loss, loss ratio, MOS, PPS, the amount of packets, and information regarding the packet size.

In step <NUM>, the management device <NUM> displays information regarding network quality. The display <NUM> of the management device <NUM> may display the information regarding network quality. For example, the information regarding network quality may be displayed through a UI as illustrated in <FIG>.

<FIG> is an operation flowchart of a controller device <NUM> in a communication system according to various embodiments of the disclosure.

Referring to <FIG>, in step <NUM>, the controller device <NUM> receives a message including information regarding targets for measuring network quality.

In step <NUM>, the controller device <NUM> configures a path between the targets. In this regard, the controller device <NUM> may configure a path by using SDN technology. To this end, although not illustrated, the controller device <NUM> may generate a first flow path regarding the configured path. The first flow path may be configured such that, when a corresponding NE has received a test packet transmitted along the path, another NE on the path, to which the test packet is to be transmitted, can be indicated.

In step <NUM>, the controller device <NUM> transmits information regarding the path to at least one different NE. The controller device <NUM> may transmit information regarding the path to at least one different NE. The at least one different NE is an NE constituting the path, and may include at least one of a virtual switch, a physical switch, and a DCI. The information regarding the path may include the first flow rule.

In step <NUM>, the controller device <NUM> transmits a measurement request message to at least one of the targets such that network quality is measured based on the information. The communication unit <NUM> of the controller device <NUM> may transmit a measurement request message to at least one of the targets such that network quality is measured based on the information through the communication unit <NUM>. For example, among the targets that have received the measurement request message, the source target may generate a test packet and may transmit the generated test packet to the destination target along the information indicated by the first flow rule included in the information. In addition, the measurement request message may include a test condition for testing network quality. In order to test network quality, the destination target that has received the test packet may perform a process corresponding to the test condition with regard to the test packet, and may transmit the processed packet back to the source target. In other words, network quality regarding the source target and the destination target may be measured based on the test condition.

<FIG> is a flowchart illustrating operations related to a first flow rule performed by a controller device <NUM> according to various embodiments of the disclosure.

Referring to <FIG>, in step <NUM>, the controller device <NUM> generates a first flow rule regarding a path. The processor <NUM> of the controller device <NUM> may generate a first flow rule regarding a path. The first flow rule may be configured such that, when an NE has received a test packet transmitted along the path, another NE on the path, to which the test packet is to be transmitted, is indicated to the NE.

In step <NUM>, the controller device <NUM> transmits the first flow rule to at least one different NE. The communication unit <NUM> of the controller device <NUM> transmits the first flow rule to at least one different NE through the communication unit <NUM>. The at least one different NE may be an NE constituting the path. Therefore, the test packet generated by the source target may be transmitted to the destination target through at least one NE on the path indicated by the first flow rule, and the packet transmitted by the destination target may be received by the source target through at least one NE on the path indicated by the first flow rule.

<FIG> is a flowchart illustrating operations related to a second flow rule performed by a controller device <NUM> according to various embodiments of the disclosure.

Referring to <FIG>, in step <NUM>, the controller device <NUM> generates a second flow rule for receiving information regarding measured network quality. The processor <NUM> of the controller device <NUM> may generate a second flow rule for receiving information regarding measured network quality. The second flow rule may be configured such that, when an NE has received information regarding network quality transmitted along a reception path, another NE on the reception path, to which the information regarding network quality is to be transmitted, is indicated to the NE. The reception path may be a path along which the information regarding network quality is received by the management device <NUM>.

In step <NUM>, the controller device <NUM> transmits the second flow rule to at least one NE related to the second flow rule. The communication unit <NUM> of the controller device <NUM> may transmit the second flow rule to at least one NE related to the second flow rule through the communication unit <NUM>. The at least one NE may be an NE constituting the reception path.

In step <NUM>, the controller device <NUM> receives information regarding measured network quality, based on the second flow rule. The communication unit <NUM> of the controller device <NUM> may receive information regarding measured network quality, based on the second flow rule, through the communication unit <NUM>. The controller device <NUM> receives information regarding network quality from the source target, and the information regarding network quality is received along the reception path indicated by the second flow rule.

In step <NUM>, the controller device <NUM> transmits information regarding network quality to the management device <NUM>. The communication unit <NUM> of the controller device <NUM> may transmit information regarding network quality to the management device <NUM> through the communication unit <NUM>. The management device <NUM> may display the information regarding network quality in response thereto.

<FIG> is an operation flowchart of a server device <NUM> according to various embodiments of the disclosure.

Referring to <FIG>, in step <NUM>, the server device <NUM> receives a measurement request message including a test condition and information regarding a path between targets for measuring network quality. The communication unit <NUM> of the server device <NUM> may receive a measurement request message including a test condition and information regarding a path between targets for measuring network quality through a backhaul <NUM>. The management device <NUM> may determine the targets and the test condition, may provide the targets and the test condition to the controller device <NUM>, and the server device <NUM> may receive, from the controller device <NUM>, the test condition and information regarding the path determined by the controller device <NUM>. The information regarding the path may include a first flow rule regarding the path. The first flow rule may be configured such that, when an NE has received a transmission packet transmitted along the path, another NE on the path, to which the test packet is to be transmitted, is indicated to the NE.

Although not illustrated, the server device <NUM> may install the first flow rule. For example, the server device <NUM> may store the first flow rule in the storage unit <NUM>. In addition, the server device <NUM> may generate a second flow rule for transmitting information regarding measured network quality. The second flow rule may be configured such that, when an NE has received information regarding network quality transmitted along the reception path, another NE on the path, to which the information regarding network quality is to be transmitted, is indicated to the NE. The reception path may be a path along which information regarding network quality is received by the management device <NUM>. The server device <NUM> may install the second flow rule. For example, the server device <NUM> may store the second flow rule in the storage unit <NUM>.

In step <NUM>, the server device <NUM> generates a test packet, based on the test condition. The processor <NUM> of the server device <NUM> may generate a test packet, based on the test condition. The test packet may be used to test network quality regarding the path between the source target and the destination target.

In step <NUM>, the server device <NUM> measures network quality with regard to the targets, based on the path-related information and the test packet. The processor <NUM> of the server device <NUM> may test network quality with regard to the targets, based on the path-related information and the test packet. In order to measure network quality, the source target of the server device <NUM> may transmit a test packet to the destination target among the targets, based on the path-related information, in order to measure network quality, and the destination target may perform a process corresponding to the test condition with regard to the test packet received from the source target. The source target may receive the processed test packet from the destination target, based on the path-related information, may analyze the processed test packet, and may generate information regarding network quality. The server device <NUM> may transmit information regarding network quality to the controller device <NUM>, based on the second flow rule. The server device <NUM> may transmit information regarding network quality to the management device <NUM> along the path indicated by the second flow rule.

<FIG> illustrates functional modules of a management device <NUM> according to various embodiments of the disclosure. The functional modules illustrated in block shapes in <FIG> may be physical devices, or may refer to logical entities implemented by software. In addition, the functional modules of the management device <NUM> may be controlled by the processor <NUM> of the management device <NUM>.

The 3D topology display module <NUM> may display a UI for inputting information regarding a test condition and measure targets as illustrated in <FIG>. In addition, the 3D topology display module <NUM> may display a UI indicating information regarding the result of quality test.

The QoE diagnosis test condition display module <NUM> may provide a UI for enabling the user to configure a test condition. The QoE diagnosis result brief display module <NUM> may provide a UI for displaying information regarding the result of measured network quality. The QoE diagnosis test list display module <NUM> may display multiple results of network quality measurements performed by the management device <NUM> according to the index.

The QoE diagnosis result detailed display module (table) <NUM> may display multiple results of network quality measurements in a table type. The QoE diagnosis result detailed display module (topology/path) <NUM> may display information regarding a test condition (for example, protocol) used to measure network quality, and information for visually indicating the path between measurement targets. The QoE diagnosis result detailed display module (chart) <NUM> may display multiple results of network quality meaurements in a chart type. The QoE diagnosis result detailed display module (text) <NUM> may display the result of analyzing network quality measured with regard to specific targets in detail as a text. The QoE statistic result display module <NUM> may display an aspect of the change in network quality measured with regard to specific targets over time.

The topology manager <NUM> may control and manage topologies related to the network quality meausrements. The QoE diagnosis manager <NUM> may generate a message including information regarding a network quality measurement target and a test condition, and may transmit the message to another device. In addition, the QoE diagnosis manager <NUM> may cause the display <NUM> of the management device <NUM> to display information regarding the result of measured network quality. The QoE statistics manager <NUM> may process statistic information regarding multiple results of network quality measurements, and may cause the display <NUM> of the management device <NUM> to display the same.

The QoE statistics manager <NUM> may analyze and manage statistic materials acquired from multiple results of network quality measurements. The QoE diagnosis storage unit <NUM> may store the results of network quality meausrements. The QoE statistics storage unit <NUM> may store statistic materials regarding network quality measured with regard to specific targets over time.

<FIG> illustrates functional modules of an SDN controller device <NUM> according to various embodiments of the disclosure. The functional modules illustrated in block shapes in <FIG> may be physical devices, or may refer to logical entities implemented by software. Alternatively, the functional modules of the controller device <NUM> may be controlled by the processor <NUM> of the controller device <NUM>.

The QoE request message processing unit <NUM> may receive a diagnosis request message including a measurement target and a test condition through an API. In addition, the QoE request message processing unit <NUM> may parse the received diagnosis request message, thereby identifying the measurement target and the test condition included in the diagnosis request message, and may deliver information regarding the identified measurement target and test condition to the QoE diagnosis manager <NUM>.

The QoE result message processing unit <NUM> may receive a message including information regarding the result of measured network quality through the API. In addition, the QoE result message processing unit <NUM> may parse the message and may transmit information regarding the identified result of network quality to the management device <NUM>.

The QoE diagnosis manager <NUM> may control such that a message for requesting a network quality measurement or the result of measured network quality is encoded, the encoded message is transmitted to another device. In addition, the QoE diagnosis manager <NUM> may generate a flow rule regarding the path between measurement targets. The QoE statistics manager <NUM> may control such that statistic information regarding multiple pieces of network quality information is encoded, and the encoded message is transmitted to another device.

The flow statistics manager <NUM> may control such that statistic materials regarding the path for which network quality is measured are generated, and the generated materials are transmitted to another device. The flow rule manger <NUM> may receive a flow rule from the QoE diagnosis manager <NUM>. In addition, the flow rule manager <NUM> may encode the received flow rule in a message format.

The packet manager <NUM> may encode a packet related to the network quality measurement, and may transmit the encoded packet to another device. The path manager <NUM> may configure a path for test packet transmission between measurement targets (source target and destination target) under the control of the QoE diagnosis manager <NUM>. The host manager <NUM> may determine the network addresses of the measurement targets and the positions of the measurement targets corresponding to the addresses on the network, under the control of the QoE diagnosis manager <NUM>.

The device manager <NUM> may control and manage physical constituent elements and/or logical modules of the controller device <NUM>. The link manager <NUM> may transmit a message to another device or may measure and manage the quality of a link for receiving a message from another device.

The open flow SB protocol <NUM> may transmit a message or a packet to another device. Besides, the controller device <NUM> may include protocols such as an NETCONF SB protocol, an SNMP SB protocol, an OVSDB SB protocol, and an REST SB protocol.

<FIG> illustrates functional modules of a server device <NUM> according to various embodiments of the disclosure. The functional modules illustrated in block shapes in <FIG> may be physical devices, or may refer to logical entities implemented by software. In addition, the functional modules of the server device <NUM> may be controlled by the processor <NUM> of the server device <NUM>.

The virtual switch <NUM> may control such that a packet or data received by the virtual switch <NUM> is transmitted through an appropriate path. The VM <NUM> may perform operations of receiving a message requesting a network quality measurement, and measuring the network quality with other VMs <NUM>-<NUM> in response to the message. The VM <NUM> may include a test agent <NUM> and a test protocol <NUM>. The detailed configuration of the VM <NUM> will be described later in more detail with reference to <FIG>.

<FIG> illustrates functional modules of the VM <NUM> according to various embodiments of the disclosure. The functional modules illustrated in block shapes in <FIG> may be physical devices, or may refer to logical entities implemented by software.

The quality assurance manager (QAM) layer <NUM> of the test agent <NUM> may include a QoE request processing unit <NUM> and a QoE result processing unit <NUM>. The QoE request processing unit <NUM> may receive a packet including a test condition and information regarding a destination target from the virtual switch <NUM>, and may parse the packet received from the virtual switch <NUM>, thereby identifying the destination target and the test condition. As a result thereof, the VM <NUM> may test network quality with regard to the destination target based on the test condition. The QoE result processing unit <NUM> may receive a packet processed by the destination target from the virtual switch <NUM>, and may generate information regarding the result of network quality.

The QoE layer <NUM> of the test agent <NUM> may include a user traffic emulation, a QoE metric, a service level agreement (SLA), and a log. The test protocol <NUM> is a protocol used to test network quality, and may include TWAMP, TWAMP light, Y. 1731PM, iPerf, PING.

<FIG> is a flowchart of operations for requesting a network quality test according to various embodiments of the disclosure.

Referring to <FIG>, in step <NUM>, the management device <NUM> selects a test target for testing network quality, and configures a test condition. The I/O <NUM> of the management device <NUM> may receive an input for selecting the test target and an input for configuring the test condition. The user may select the test target through the 3D topology display module <NUM> of the management device <NUM>, and may configure the test condition through the QoE diagnosis test condition display module <NUM>.

In step <NUM>, the management device <NUM> encodes the selected test target and the test condition in a message format, and generates a diagnosis request message. The processor <NUM> of the management device <NUM> may encode the selected test target and the test condition in a message format. The selected test target and the test condition may be delivered to the QoE diagnosis manager <NUM> of the management device <NUM>, and may be encoded in a message format such that the same is delivered to the SDN QoE application <NUM> of the controller device <NUM>. According to various embodiments of the disclosure, the diagnosis request message may include content as given in Table <NUM> below:.

In step <NUM>, the management device <NUM> transmits the encoded diagnosis request message. The communication unit <NUM> of the management device <NUM> may transmit the encoded diagnosis request message through a backhaul <NUM>. The QoE request message processing unit <NUM> of the SDN QoE application <NUM> of the controller device <NUM> may receive the encoded diagnosis request message through the API.

In step <NUM>, the controller device <NUM> parses and processes the received diagnosis request message. The processor <NUM> of the controller device <NUM> may parse and process the received diagnosis request message. The QoE request message processing unit <NUM> of the controller device <NUM> may parse the received diagnosis request message, thereby identifying the test target and the test condition included in the diagnosis request message, and may deliver information regarding the identified test target and the test condition to the QoE diagnosis manager <NUM>.

In step <NUM>, the controller device <NUM> determines the address and position of the test target from the diagnosis request message. The processor <NUM> of the controller device <NUM> may determine the address and position of the test target from the diagnosis request message. The QoE diagnosis manager <NUM> of the controller device <NUM> may determine the network address of the test target and the position of the test target corresponding to the address on the network, with reference to the delivered information regarding the test target, by using the host manager <NUM>.

In step <NUM>, the controller device <NUM> configures a path between test targets. The processor <NUM> of the controller device <NUM> may configure a path between test targets. The QoE diagnosis manager <NUM> of the controller device <NUM> may configure a path for test packet transmission between test targets (source target and destination target) by using the path manager <NUM>.

In step <NUM>, the controller device <NUM> generates a flow rule regarding the configured path. The processor <NUM> of the controller device <NUM> may generate a flow rule regarding the configured path. The flow rule may be configured such that, when an NE has received a packet, another NE, to which the NE needs to deliver the received packet, is indicated. According to various embodiments of the disclosure, the NE may store at least one flow rule, and the packet may include information regarding a preconfigured flow rule. A step of flow rules stored in the NE may be referred to as "a flow table". Accordingly, after receiving a packet including information regarding a flow rule, an NE may identify the flow rule corresponding to the packet in the flow table, based on the information regarding the flow rule, and may transmit the packet to another NE indicated by the flow rule.

According to various embodiments of the disclosure, the controller device <NUM> may generate not only a flow rule regarding a configured path, but also a flow rule for receiving the result of measured network quality from the source target. The processor <NUM> of the controller device <NUM> may generate a flow rule for receiving the result of measured network quality from the source target. The flow rule for receiving the result of measured network quality from the source target may refer to a flow rule regarding the path between the source target and the management device <NUM>. The QoE diagnosis manager <NUM> of the controller device <NUM> may generate a flow rule regarding a path, may generate a flow rule for receiving the result of measured network quality from the source target, and may transmit the generated flow rules to the flow rule manager <NUM>.

In step <NUM>, the controller device <NUM> encodes the generated flow rule in a message format. The processor <NUM> of the controller device <NUM> may encode the generated flow rule in a message format. The flow rule manager <NUM> may encode the flow rule received from the QoE diagnosis manager <NUM> in an open flow message format through the open flow SB protocol <NUM>.

In step <NUM>, the controller device <NUM> transmits a message regarding the encoded flow rule to at least one NE related to the flow rule. The processor <NUM> of the controller device <NUM> may transmit a message regarding the flow rule to at least one NE related to the flow rule. The open flow SB protocol <NUM> of the controller device <NUM> may transmit a message regarding the encoded flow rule to at least one NE related to the flow rule, and the at least one NE that has received the message regarding the flow rule may store the corresponding flow rule. For example, when a flow rule has been generated with regard to a path between the source target and the destination target "first VNF (source target) -> first OVS -> first leaf -> second spine -> third leaf -> third OVS -> sixth VNF (destination target)" as in the first test case <NUM> of <FIG>, the controller device <NUM> may transmit the flow rule to each of the first OVS, the first leaf, the second spine, the third leaf, and the third OVS related to the flow rule. Accordingly, when the first leaf has received a test packet from the first OVS, the first leaf may deliver the received test packet to the second spine according to the flow rule, and, on the other hand, when the first leaf has received a packet that has undergone a process corresponding to the test condition from the second spine, the first leaf may deliver the processed packet to the first OVS according to the flow rule. In addition, the controller device <NUM> may transmit information regarding the flow rule related to the path between the management device <NUM> and the source target to at least one NE related to the flow rule such that the management device <NUM> receives information regarding the result of measured network quality from the source target.

In step <NUM>, the controller device <NUM> generates a packet related to the diagnosis request message. The processor <NUM> of the controller device <NUM> may generate a packet related to the diagnosis request message. As given in Table <NUM> above, the packet related to the diagnosis request message may include information regarding test targets (source and destination) and information regarding the test condition, and may further include information regarding the flow rule generated in step <NUM>. The QoE diagnosis manager <NUM> may convert the diagnosis request message in a packet format, in order to transmit the diagnosis request message to at least one source target and destination target. The QoE diagnosis manager <NUM> may transmit the diagnosis request message in the packet format to at least one source target and destination target through the packet manager <NUM>.

In step <NUM>, the controller device <NUM> encodes the generated packet. The processor <NUM> of the controller device <NUM> may encode the generated packet. The packet manager <NUM> may encode the packet in order to transmit the generated packet to a virtual switch directly connected to the source target and to a virtual switch directly connected to the destination target.

In step <NUM>, the controller device <NUM> transmits the encoded packet to a virtual switch related to the test target. The processor <NUM> of the controller device <NUM> may transmit the encoded packet to a virtual switch related to the test target. In other words, the controller device <NUM> may transmit the encoded packet to at least one of a virtual switch directly connected to the source target and a virtual switch directly connected to the destination target. The encoded packet may include an indicator configured such that the packet is appropriately received by the source target or the destination garget from the virtual switch. The open flow SB protocol <NUM> of the controller device <NUM> may receive the encoded packet from the packet manager <NUM>, and may transmit the encoded packet to at least one of the virtual switch directly connected to the source target and the virtual switch directly connected to the destination target.

In step <NUM>, the server device <NUM> receives a packet through a virtual switch. The communication unit <NUM> of the server device <NUM> may receive a packet from the controller device <NUM> through a backhaul <NUM>. The virtual switch <NUM> of the server device <NUM> may identify a source target or a destination target, to which the packet is to be transmitted, from the identifier included in the packet, and may transmit the packet to the identified source target or destination target. The test agent <NUM> of the source target or the destination target may receive the packet from the virtual switch <NUM>.

In step <NUM>, the server device <NUM> may perform an operation for testing network quality, based on the diagnosis condition acquired from the packet. The processor <NUM> of the server device <NUM> may perform an operation for testing network quality, based on the diagnosis condition acquired from the packet. The test agent <NUM> may parse the packet received from the virtual switch <NUM>, thereby identifying the diagnosis condition and the destination target, and may measure the network quality with regard to the destination target based on the diagnosis condition.

<FIG> is a flowchart of operations for transmitting/receiving a test packet for testing network quality according to various embodiments of the disclosure. The flowchart of <FIG> is related to a situation in which the test packet is transmitted/received through the path illustrated in <FIG>: "VM (source) <NUM> -> first virtual switch <NUM> -> first leaf switch <NUM> -> first spine switch <NUM> -> third leaf switch <NUM> -> second virtual switch <NUM> -> VM (destination) <NUM>". However, this is only for convenience of description, and the test packet may be transmitted/received through a path different from the path illustrated in <FIG>, depending on how the destination target is configured. In addition, the switch <NUM> in <FIG> includes a first spine switch <NUM>, a second spine switch <NUM>, a first leaf switch <NUM>, a second leaf switch <NUM>, and a third leaf switch <NUM>, but this is only for convenience of description, and the switch <NUM> may include various numbers of spine switches and various numbers of leaf switches. In <FIG>, the external server <NUM> may be identified with an external text device <NUM>. Alternatively, the external server <NUM> and the second virtual switch <NUM> may be identified with the server <NUM> and the first virtual switch <NUM>, respectively. In this case, the test packet may be transmitted/received through the path "VM (source) <NUM> -> first virtual switch <NUM> (or second virtual switch <NUM>) -> VM (destination) <NUM>", and the switch <NUM> may not be used.

Referring to <FIG>, in step <NUM>, the VM (source) <NUM> generates a test packet based on a test condition, and transmits the generated test packet to the VM (destination) <NUM>. The server <NUM> may control the VM (source) <NUM> so as to generate a test packet based on a test condition and to transmit the generated test packet to the VM (destination) <NUM>.

In step <NUM>, the first virtual switch <NUM> receives the test packet, and transmits the test packet based on a flow rule. The processor <NUM> of the server <NUM> may control the first virtual switch <NUM> to receive the test packet and to transmit the test packet based on a flow rule. The first virtual switch <NUM> may identify the flow rule corresponding to the received test packet, based on information regarding the flow rule included in the received test packet, with reference to the flow table stored in the first virtual switch <NUM>. The first virtual switch <NUM> may transmit the test packet to the NE indicated by the identified flow rule (that is, first leaf switch <NUM>).

In step <NUM>, the first leaf switch <NUM> receives the test packet and transmits the test packet based on the flow rule. The first leaf switch <NUM> may identify the flow rule corresponding to the received test packet, based on information regarding the flow rule included in the received test packet, with reference to the flow table stored in the first leaf switch <NUM>. The first leaf switch <NUM> may transmit the test packet to the NE indicated by the identified flow rule (that is, first spine switch <NUM>).

In step <NUM>, the first spine switch <NUM> receives the test packet and transmits the test packet based on the flow rule. The first spine switch <NUM> may identify the flow rule corresponding to the received test packet, based on information regarding the flow rule included in the received test packet, with reference to the flow table stored in the first spine switch <NUM>. The first spine switch <NUM> may transmit the test packet to the NE indicated by the identified flow rule (that is, third leaf switch <NUM>).

In step <NUM>, the third leaf switch <NUM> receives the test packet and transmits the test packet based on the flow rule. The third leaf switch <NUM> may identify the flow rule corresponding to the received test packet, based on information regarding the flow rule included in the received test packet, with reference to the flow table stored in the third leaf switch <NUM>. The third leaf switch <NUM> may transmit the test packet to the NE indicated by the identified flow rule (that is, second virtual switch <NUM>).

In step <NUM>, the second virtual switch <NUM> receives the test packet and transmits the test packet based on the flow rule. The second virtual switch <NUM> may identify the flow rule corresponding to the received test packet, based on information regarding the flow rule included in the received test packet, with reference to the flow table stored in the second virtual switch <NUM>. The second virtual switch <NUM> may transmit the test packet to the NE indicated by the identified flow rule (that is, VM (destination) <NUM>).

In step <NUM>, the VM (destination) <NUM> receives the test packet, processes the test packet based on the test condition, and transmits the processed test packet to the VM (source) <NUM>. For example, the VM (destination) <NUM> may perform a process corresponding to the test protocol of the test condition with regard to the test packet, and may transmit the processed test packet to the VM (source) <NUM>.

In step <NUM>, the second virtual switch <NUM> receives the processed test packet and transmits the processed test packet based on the flow rule. The second virtual switch <NUM> may identify the flow rule corresponding to the received test packet, based on information regarding the flow rule included in the received test packet, with reference to the flow table stored in the second virtual switch <NUM>. The second virtual switch <NUM> may transmit the processed test packet to the NE indicated by the identified flow rule (that is, third leaf switch <NUM>).

In step <NUM>, the third leaf switch <NUM> receives the processed test packet and transmits the processed test packet based on the flow rule. The third leaf switch <NUM> may identify the flow rule corresponding to the received test packet, based on information regarding the flow rule included in the received test packet, with reference to the flow table stored in the third leaf switch <NUM>. The third leaf switch <NUM> may transmit the processed test packet to the NE indicated by the identified flow rule (that is, first spine switch <NUM>).

In step <NUM>, the first spine switch <NUM> receives the processed test packet and transmits the processed test packet based on the flow rule. The first spine switch <NUM> may identify the flow rule corresponding to the received test packet, based on information regarding the flow rule included in the received test packet, with reference to the flow table stored in the first spine switch <NUM>. The first spine switch <NUM> may transmit the processed test packet to the NE indicated by the identified flow rule (that is, first leaf switch <NUM>).

In step <NUM>, the first leaf switch <NUM> receives the processed test packet and transmits the processed test packet based on the flow rule. The first leaf switch <NUM> may identify the flow rule corresponding to the received test packet, based on information regarding the flow rule included in the received test packet, with reference to the flow table stored in the first leaf switch <NUM>. The first leaf switch <NUM> may transmit the processed test packet to the NE indicated by the identified flow rule (that is, first virtual switch <NUM>).

In step <NUM>, the first virtual switch <NUM> receives the processed test packet and transmits the processed test packet based on the flow rule. The processor <NUM> of the server <NUM> may control the first virtual switch <NUM> so as to receive the processed packet and to transmit the processed packet to the VM (source) <NUM> based on the flow rule. The first virtual switch <NUM> may identify the flow rule corresponding to the received test packet, based on information regarding the flow rule included in the received test packet, with reference to the flow table stored in the first virtual switch <NUM>. The first virtual switch <NUM> may transmit the processed test packet to the NE indicated by the identified flow rule (that is, VM (source <NUM>).

<FIG> is a flowchart of operations for processing the result of a network quality test according to various embodiments of the disclosure.

Referring to <FIG>, in step <NUM>, the test agent <NUM> of the VM <NUM> receives a packet processed according to a test condition from the first virtual switch <NUM>. The processor <NUM> of the server <NUM> may control the test agent <NUM> of the VM <NUM> to receive a packet processed according to a test condition from the first virtual switch <NUM>.

In step <NUM>, the test agent <NUM> of the VM <NUM> generates a packet for reporting the test result based on the received packet. The processor <NUM> of the server <NUM> may control the test agent <NUM> of the VM <NUM> to generate a packet for reporting the test result based on the received packet. The packet for reporting the test result may include information regarding the result of testing network quality with regard to the path between the source target and the destination target. According to various embodiments of the disclosure, the packet for reporting the test result may include content as given in Table <NUM> below:.

In addition, the packet for reporting the test result may include information regarding a flow rule related to the path between the management device <NUM> and the VM <NUM>. Accordingly, the management device <NUM> may receive the packet for reporting the test result from the VM <NUM>. For example, the VM <NUM> may receive information regarding the flow rule related to the path between the management device <NUM> and the VM <NUM> from the packet related to the diagnosis request message, received in step <NUM>, and may cause the information regarding the flow rule included in the test packet. The test agent <NUM> of the VM <NUM> may transmit the packet for reporting the test result to the controller device <NUM>.

In step <NUM>, the server <NUM> transmits a packet generated based on the flow rule to the controller device <NUM> in a message format. The communication unit <NUM> of the server <NUM> may transmit a packet generated based on the flow rule to the controller device <NUM> through a backhaul <NUM> in a message format. The virtual switch <NUM> of the server <NUM> may receive the packet for reporting the test result, transmitted by the test agent <NUM> of the VM <NUM>, and may identify the flow rule corresponding to the received packet, based on information regarding the flow rule included in the received packet, with reference to the flow table stored in the virtual switch <NUM>. The virtual switch <NUM> may transmit the packet for reporting the test result to the NE indicated by the identified flow rule. For example, the virtual switch <NUM> may transmit the packet for reporting the test result to the controller device <NUM> through the switch <NUM> according to the indication of the flow rule, or may transmit the same directly to the controller device <NUM>, not through the switch <NUM>. The packet transmitted to the controller device <NUM> may be encoded in a message format and then transmitted.

In step <NUM>, the controller device <NUM> receives a message from the switch <NUM> or the server <NUM> and parses the received message. The communication unit <NUM> of the controller device <NUM> may receive a message from the switch <NUM> or the server <NUM> through the communication unit <NUM>, and the processor <NUM> may parse the received message. When the message is received, the open flow SB protocol <NUM> of the controller <NUM> may parse the message, and may transmit information regarding the result of testing network quality to the packet manager <NUM>. The packet manager <NUM> may generate a packet including information regarding the result of testing network quality. According to various embodiments of the disclosure, the generated packet may include content as given in Table <NUM> below:.

In step <NUM>, the controller device <NUM> processes the packet. The processor <NUM> of the controller device <NUM> may process the packet. The packet manager <NUM> of the controller device <NUM> may deliver a packet including the generated information regarding the result of testing network quality to the QoE diagnosis manager <NUM>.

In step <NUM>, the controller device <NUM> processes the test result message in the packet and information regarding a test traffic path. The processor <NUM> of the controller device <NUM> may process the test result message in the packet and information regarding a test traffic path. The test result message may include information regarding the result of testing network quality, and the test traffic path may include information regarding the path between the source target and the destination target. The QoE diagnosis manager <NUM> may deliver the test result message in the packet and information regarding a test traffic path to the QoE result message processing unit <NUM>.

In step <NUM>, the controller device <NUM> may encode the test result message and the information regarding a traffic path in a message format, and may transmit the encoded message to the management device <NUM>. The processor <NUM> of the controller device <NUM> may encode the test result message and the information regarding a traffic path in a message format, and the communication unit <NUM> may transmit the encoded message to the management device <NUM> through the communication unit <NUM>. The QoE result message processing unit <NUM> may encode the test result message and the information regarding a traffic path in a message format, and may transmit the encoded message to the management device <NUM>.

In step <NUM>, the management device <NUM> parses the received message so as to acquire information regarding the test result, and stores the test result. The communication unit <NUM> of the management device <NUM> may receive the encoded message from the controller device <NUM> through a backhaul <NUM>, and the processor <NUM> may parse the received message so as to acquire information regarding the test result. In addition, the processor <NUM> may store the test result in the storage unit <NUM>. The QoE diagnosis manager <NUM> of the management device <NUM> may parse the received message so as to acquire information regarding the test result, and store the test result in the QoE diagnosis storage unit <NUM>.

In step <NUM>, the management device <NUM> displays the test result. The display <NUM> of the management device <NUM> may display the test result. To this end, the QoE diagnosis manager <NUM> may provide information regarding the test result to respective display modules <NUM>-<NUM> of the management device <NUM> such that respective display modules update information regarding the test result related thereto. The display <NUM> of the management device <NUM> may display the test result, the content of which is illustrated in <FIG>, through a UI.

<FIG> illustrate examples of a UI for displaying the result of a network quality test according to various embodiments of the disclosure.

Referring to <FIG>, in the first display area <NUM> of the UI <NUM>, information regarding targets (source target and destination target), for which network quality is measured, is display. For example, the first display area <NUM> indicates that the source target is vm6, and the destination target is vm9. In the second display area <NUM> of the UI <NUM>, information regarding the test condition used to test network quality is displayed. For example, the second display area <NUM> may indicate various parameter values used to test network quality, and a test protocol (for example, TWAMP). Moreover, the UI <NUM> may visually display the structure of a DC related to the source target and the destination target. For example, the UI <NUM> may visually display the logical deployment structure and logical position of the NEs included in the DC.

Referring to <FIG>, the UI <NUM> may display a path <NUM> between a source target and a destination target, for which network quality is measured. <FIG> illustrates an exemplary path <NUM> "VM6 (source target) -> second virtual switch -> second leaf switch -> second spine switch -> third leaf switch -> third virtual switch -> VM9 (destination target)". In addition, the third display area <NUM> of the UI <NUM> may display indices indicating the result of network quality (for example, bandwidth, delay, jitter, loss, MOS), and information regarding to which value each index corresponds with regard to the entire path <NUM> and respective direct paths constituting the path <NUM>.

Referring to <FIG>, the fourth display area <NUM> of the UI <NUM> may display values of respective indices regarding the path <NUM> on a time basis. As a result thereof, the user may understand how values of respective indices regarding the path <NUM> values change over time.

Referring to <FIG>, the fifth display area <NUM> of the UI <NUM> may display a graph having the time as an independent variable and having an index value as a dependent variable, with regard to respective indices. A specific time value may be selected from the time axis of the graph with regard to respective indices, and the index value at the specific time value in this case may be displayed.

Referring to <FIG>, the sixth display area <NUM> of the UI <NUM> may display a time-dependent index value with regard to a specific index (for example, bandwidth), and the degree of quality indicted by the index value. For example, the degree of quality may be classified into good quality, normal quality, and bad quality. The sixth display area <NUM> of the UI <NUM> may display an index value regarding a specific index at a specific time, and may display, through an arrow-shaped indictor, the category (among good, normal, and bad) to which the index value belongs.

Referring to <FIG>, the seventh display area <NUM> of the UI <NUM> may display statistic information regarding multiple results of network quality tests. Each of the multiple results of network quality tests may have an index assigned thereto so as to indicate the specific result of network quality test, and the seventh display area <NUM> may display the source target, the destination target, and index values regarding the test result, corresponding to each index.

Methods according to embodiments stated in claims and/or specifications of the disclosure may be implemented in hardware, software, or a combination of hardware and software.

The programs (software modules or software) may be stored in non-volatile memories including a random access memory and a flash memory, a Read Only Memory (ROM), an Electrically Erasable Programmable Read Only Memory (EEPROM), a magnetic disc storage device, a Compact Disc-ROM (CD-ROM), Digital Versatile Discs (DVDs), or other type optical storage devices, or a magnetic cassette. Alternatively, any combination of some or all of the may form a memory in which the program is stored.

In the above-described detailed embodiments of the disclosure, a component included in the disclosure is expressed in the singular or the plural according to a presented detailed embodiment. However, the singular form or plural form is selected for convenience of description suitable for the presented situation, and various embodiments of the disclosure are not limited to a single element or multiple elements thereof. Further, either multiple elements expressed in the description may be configured into a single element or a single element in the description may be configured into multiple elements.

Claim 1:
A method performed by a software-defined network, SDN, management device (<NUM>) in a communication system (<NUM>), the method comprising:
identifying a test object and a test condition based on a user input, wherein the test object indicates a source target and a destination target associated with a path in a data center, DC, based on topology information regarding at least one spine switch and at least one leaf switch in the DC;
transmitting, to a SDN controller device (<NUM>), a measurement request message including first information on the source target, second information on the destination target, and third information on the test condition;
receiving, from the SDN controller device (<NUM>), result information including:
information on a network quality for the path, and
information on the path for which the network quality is measured; and
displaying the result information regarding the network quality and the path,
wherein the third information on the test condition includes interval of the test packets and information on a test termination condition, wherein the test termination condition includes a number of test packets,
wherein, in case that the source target and the destination target are implemented in a server operating as a virtual machine, VM:
the test packets are generated by the source target,
the test packets are transmitted, by the source target, to the destination target,
a network quality measuring process is performed with the test condition, by the destination target, for the test packets, and
the processed test packets are transmitted, by the destination target, to the source target,
wherein, in case that at least one of the source target or the destination target is implemented in a server operating as a virtual switch, a leaf switch, or a spine switch:
a path is configured between a first VM and a second VM, the configured path including the path,
the test packets are generated by the first VM,
the test packets are transmitted, by the first VM, to the second VM of the configured path,
a network quality measuring process is performed with the test condition, by the second VM, for the test packets, and
the processed test packets are transmitted, by the second VM, to the first VM,
wherein network elements, NEs, of the path include a virtual switch connected to the VM,
wherein a leaf switch is connected to the virtual switch, and
wherein a spine switch is connected to the leaf switch.