JP6632556B2 - Link quality measurement device and its flow entry determination server device and switch - Google Patents

Description

  The present invention relates to a link quality measurement device, a flow entry determination server device thereof, and a switch. In particular, the present invention relates to a link quality measurement device capable of transferring a test packet to a measurement device without rewriting a packet header in a target switch in which the test packet returns. The present invention relates to the flow entry determination server device and the switch.

  In recent years, the penetration of IoT has made it necessary to control communication traffic for a huge number of hosts. In order to provide high-quality communication services on the OpenFlow network, which is a typical technology of the SDN (Software Defined Network) architecture that centrally and flexibly controls communication traffic by software, network administrators must It is important to constantly monitor the communication quality of each link in the network and, when quality deterioration is detected, identify the cause and then perform appropriate operation such as path control.

  In Patent Document 1, in an OpenFlow network, a test packet is transmitted from one measurement terminal after setting a route so as to comprehensively pass through all links on the network, and each switch returns and returns. A technique for monitoring the communication quality (loss rate, average delay, etc.) of each link by observing the behavior of a test packet has been proposed.

  However, in the active measurement technology for the OpenFlow network disclosed in Patent Literature 1, (substantially) the same number of flow entries as the number of test packet flows passing through the switch are registered in each switch. Therefore, as the size of the network to be monitored increases, the number of flow entries registered in each switch also increases.

  In response to such a technical problem, the inventors of the present invention use a single measurement terminal in an OpenFlow network to comprehensively pass through all links on the network and to register each switch in each switch. By setting a route that reduces the number of transfer rules (flow entries) for test packets, sending test packets from the measuring terminal, and observing the behavior of test packets returning from each switch, A technology for monitoring the communication quality of a link (loss rate, average delay, etc.) was invented, and patent applications (Patent Documents 2 and 3) were filed.

Japanese Patent Application No. 2013-064413 Japanese Patent Application No. 2013-202316 Japanese Patent Application No. 2013-217302

  In the conventional active measurement technology for OpenFlow networks according to Patent Documents 2 and 3, in each switch, a plurality of measurement flow entries to be registered are aggregated into one flow entry by using a header field of a new test packet. This reduces the number of flow entries.

  However, in this method, when the test packet (outgoing path) transmitted from the measurement terminal reaches the target switch, the test packet is returned by rewriting the destination IP address in the header field. Each relay switch on the path returning to the measurement terminal (return path) identifies the packet transmission direction by referring to the destination IP address. Therefore, there has been a technical problem that processing of one action is required by rewriting the header in the target switch.

  SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned technical problem, and to provide a link quality measurement device capable of transferring a test packet to a measurement device without rewriting a packet header in a target switch in which a test packet returns, a flow entry determination server device and a switch Is to provide.

  In order to achieve the above object, the present invention provides a link quality measurement device that relays a test packet transmitted by a measurement terminal according to a flow entry registered in each switch on a network, a flow entry determination server device thereof, and a switch. Is characterized by having the following configuration.

  (1) In the link quality measuring device of the present invention, the flow entry registered in each switch is classified into one of a return flow entry, a forward flow entry, and a return flow entry. The higher priority is set to each flow entry for this order in this order, and each switch processes each input test packet with a flow entry having a higher priority with a matching match condition.

  (2) The flow entry determination server device of the link quality measurement device according to the present invention is configured such that the measurement route calculation unit that calculates the communication route of the test packet and the switch that is registered in each switch according to the route calculation result pass Flow entry aggregating section for aggregating flow entries of test packets to be executed, a flow entry classifying section for classifying each flow entry into one of a return flow entry, a forward flow entry, and a return flow entry for each switch; Priority setting unit that sets higher priorities for each flow entry for forward, forward, and return trips in that order, and communication for registering each flow entry along with its classification result and priority in each corresponding switch. A path setting unit.

  (3) The switch of the link quality measuring apparatus according to the present invention, wherein the registered flow entry is classified into one of a return flow entry, a forward flow entry, and a return flow entry, and the return, forward, and return flows are entered. The higher priority is set in each flow entry for this order in this order, and each input test packet is processed by a flow entry having a higher priority with a matching match condition.

  According to the present invention, the following effects are achieved.

  (1) The number of flow entries registered in each switch is minimized, and the target switch does not rewrite the header. The flow entry processing load on the packet is also reduced, and the processing time is shortened.

  (2) The flow entry registered in each switch is classified into one of a return flow entry, a forward flow entry, and a return flow entry, and the return, forward, and return flow entries are arranged in that order. Higher priority is set, and for each input test packet, processing is performed in order from the flow entry with the highest priority according to the transfer rule, so correct packet transfer can be performed without rewriting the destination IP address of the test packet become.

FIG. 1 is a block diagram showing a configuration of a main part of a link quality measuring device system to which the present invention is applied. FIG. 7 is a diagram (before aggregation) for explaining a method of integrating flow entries. FIG. 11 is a diagram (after aggregation) for explaining a method of integrating flow entries. FIG. 3 is a diagram for explaining the inclusion relation of communication paths. It is a figure for explaining a method of additional aggregation. It is a figure for explaining formula (3) and (4). FIG. 4 is a diagram for explaining a flow entry classification function. FIG. 11 is a diagram illustrating an example of a result of aggregation and classification of flow entries. 11 is a flowchart illustrating a procedure for transferring a test packet based on the aggregation and classification results of flow entries.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The present invention uses a single measuring terminal to register a large number of test flow entries to be registered in each switch on the network by using a new header field of a test packet. Aggregation is performed so that the number of flows is minimized, and a flow entry is registered in each switch so that each test packet can be transferred from the destination switch to the measurement terminal without rewriting the header.

  FIG. 1 is a block diagram showing a configuration of a main part of a link quality measuring device to which the present invention is applied, and is configured by a link quality measuring unit 10 and an SDN network 20. Here, the case where the SDN is OpenFlow will be described as an example, and a configuration unnecessary for the description of the present invention is omitted.

  The link quality measurement unit 10 includes a flow entry determination server device 1 and a measurement terminal 2. The server device 1 includes a measurement route calculation unit 101, a flow entry aggregation unit 102, a flow entry classification unit 103, a priority setting unit 104, and a communication. A route setting unit 105 is provided.

  The network 20 includes an OpenFlow controller 201, a plurality of OpenFlow switches (corresponding to a router), and a plurality of hosts. The controller 201 and each switch communicate using the OpenFlow protocol. Each switch is connected by SDN, and data (packet) transfer is performed between each switch SW and the host.

  The flow entry determination server device 1 and the measurement terminal 2 may be configured by mounting an application (program) for realizing each function on a general-purpose computer or server, or a part of the application may be implemented by hardware or ROM. It may be configured as a specialized dedicated machine or a single-purpose machine.

  In the server device 1, the measurement path calculation unit 101 calculates a communication path of a test packet by a method disclosed in Patent Document 1, for example, and acquires a group of communication paths of the test packet. The flow entry aggregating unit 102 aggregates flow entries of test packets that are registered in each switch SW and that pass through the switch SW in accordance with the calculation result of the communication path, and reduce the number of flow entries. Reduce.

  As will be described later in detail, the flow entry classifying unit 103 collects all the flow entries for each switch SW, and forward flow entries for aggregating the forward packet flow entries according to destinations and return packet flow entries for each incoming link. The return flow entry to be managed and the flow entry of the return packet are classified into one of return flow entries that are aggregated into one.

  A match condition and an action are registered in the forward flow entry and the return flow entry, respectively. At least one of the match condition and the action is registered in the return flow entry.

  The priority setting unit 104 sets a higher priority in the above order for the return, forward, and return flow entries. That is, the highest priority is set in the return flow entry, the next priority is set in the forward flow entry, and the lowest priority is set in the return flow entry. The communication path setting unit 105 registers the flow entry registered for each switch SW together with the classification result from the controller 201 to the corresponding switch SW.

  In the measurement terminal 2, the measurement execution unit 106 transmits and receives a test packet, and performs measurement processing such as estimating the communication quality of each link from observation data. In the present embodiment, it is assumed that topology information indicating a connection relationship between physical network devices and management information (for example, a MAC address) of each switch SW are known, and these information are stored in the server device 1 in advance. .

  First, the measurement path calculation unit 101 sets the interface of each switch SW to the vertex, sets the link between the interfaces to the side, and sets the measurement terminal 2 to the shortest tree so that all the links are covered. Is calculated. Next, each test packet is transferred to each switch SW along the calculated shortest path, and further, a packet transfer rule (flow entry) is provided to each switch so that the test packet returns to the measurement terminal 2 by returning to a predetermined interface. Set.

  FIG. 2 is a diagram schematically showing an example of a flow entry set by the measurement route calculation unit 101. Here, description will be given focusing on the forward flow entry registered in the switch SW8.

  A test port number (DstPort) is assigned as identification information to each test flow transmitted from the measuring terminal 2 to each switch (interface) SW via each switch SW and link li. In the example of FIG. 2, five transfer rules for transferring the test flows of DstPort = 1, 2, 3, 4, and 7 to the link 17 are registered in the flow entry of the switch SW8. Of the eight test flows sent out of the switch SW8 and input to the switch SW8, five test flows DstPort = 1, 2, 3, 4, and 7 are transferred to the link l7.

  In the illustrated example, the test flows of DstPort = 5 and 6 are transferred to the link l5, and the test flow of DstPort = 8 is returned to the measurement terminal 2. Therefore, entries relating to these test flows are also registered in the flow entries. However, illustration is omitted here. The flow entry aggregation unit 102 aggregates the flow entries for the forward path (until the specified switch is reached) and the return path (until the measurement terminal 2 is reached) in each switch SW.

  Among them, for the return flow entry, a plurality of test packets transferred from the upstream link to the downstream link are grouped, and the same identifier is set in a new header field (for example, a source port number). Since a common transfer rule is applied to the aggregated flow entry set, the flow entry must originally be the flow entry to which the same transfer rule is applied. That is, a set of a plurality of test flows output from the same interface (link) of the same switch is to be aggregated.

  FIG. 3 is a diagram schematically illustrating a state of each flow entry after aggregation by the flow entry aggregation unit 102.

  Since the test flows of DstPort = 1, 2, 3, 4, and 7 are all transferred to the same link 17, there is no need to uniquely identify each flow in the switch SW8. Therefore, the flow entry aggregating unit 102 aggregates the five flow entries uniquely identified by the destination port number (DstPort) so far into one, and sets the source port number as a unique identifier common to each entry. By separately assigning (SrcPort = 100) and associating it with the link l7, a transfer rule (action) of transferring all test packets in which SrcPort = 100 is described to the link l7 is additionally introduced.

  Then, in the test packet transmitted in the aggregated flow, for example, in the header field, the SrcPort = 100 is described, so that each switch SW has the SrcPort number, the flow entry, and the SrcPort number described in the test packet. Are compared and collated, and if the switch is SW8, all test packets in which SrcPort = 100 is transferred to the link 17 based on the corresponding action.

  The number of flow entries registered in each switch SW is influenced by the packet transfer processing performance of the switch and the maximum number of flow entries that can be registered other than the test packet flow. Therefore, in this embodiment, an optimal combination of flow entries to be aggregated (which switch aggregates each flow) is formulated below so that the number of flow entries registered in one switch is minimized. It is calculated by solving the integer programming problem.

  It is assumed that topology information indicating a connection relationship between physical network devices (hereinafter, switches) and management information (MAC address, IF port number) of each switch are known. In addition, the present invention aims to reduce the number of flow entries by aggregating the flow entries registered in each switch SW, but hereinafter, for convenience, a plurality of test flows in which the flow entries are aggregated are referred to as "test flows are aggregated." Is sometimes used.

  It is assumed that the information of the flow entry set in each switch SW is given as an initial state by the measurement path calculation unit 101. Consider a monitored network composed of switches SWi (i = 1,…, N) and links lj (j = 1 to L). If the number of flow entries of switches SWi is Fi, the objective function is Is represented by This means that the maximum value of the number of flow entries registered in each switch SW is minimized.

  Next, a topology for each interface (link) will be considered. Assuming that the number of flows of the test packet passing through the link lj (only the forward path) is fj, the number Fi of flow entries of the switch SWi is expressed by the following equation (2). Here, lj∈SWi expresses that the link lj is connected as an upstream link (incoming link) of the switch SWi, and can be determined by topology information indicating a physical connection relationship between switches.

  Note that the shortest tree calculated by the above equation (1) is configured for each interface, and is expressed as different vertices even if they belong to the same switch. Therefore, it is necessary to use physical topology information that is not the shortest tree for the calculation of the following equation (2). For example, since two links 14 and 15 are input to SW5 in FIGS. 2 and 3, it is calculated by the sum of the test flows passing through both links.

  The number of flows fj (j = 1, 2,... L) of the test packet passing through each link satisfies the relational expression expressed by the following expression (3) based on the topology information for each interface. The symbol R in equation (3) is a route matrix expressing connection information between links (topology information for each interface), and is “1” if there is a connection relationship between the links li and lj, and “1” if there is no connection relationship. The element (i, j) has a value of “0”.

  For example, in FIG. 6, the number of test flows f1 passing through the incoming link l1 on the upstream side of the switch SW2 is obtained by the sum of the numbers of test flows f2 and f3 of the two outgoing links l2 and l3 on the downstream side. Only the elements (1, 2) and elements (1, 3) corresponding to l2 and l3 are calculated using the path matrix R of "1" as in the following equation (4).

  Note that the addition of “1” to each element in the second term on the right side of Expressions (3) and (4) indicates that one test flow turned back at the interface is added. Equation (3) also means that the number of outbound test flows at the upstream interface is calculated based on the sum of the number of test flows at the downstream switch, so that the aggregation rule at the downstream switch is Also applies.

  Further, if a binary function bj indicating whether or not to aggregate test flows passing through each link lj is defined by the following equation (5), the number of test flows fj when the flow entries are aggregated is expressed by the following equation (5). It can be expressed in 6). Therefore, if the entries of the test flows passing through the link lj are aggregated, the calculation is continued assuming that fj = 1, and if the entries are not aggregated, fj remains unchanged.

  Here, with respect to the aggregated flow entries, a common unique identifier is set in a new header field, so that once aggregated flow entries cannot be re-aggregated using the same header field. In other words, when aggregation is performed using one type of header field, once aggregated flow entries cannot be aggregated again with a different flow on the communication path. Therefore, bj is restricted by the following equation (7).

  Here, rj means the shortest path between the link li and the measurement terminal, and rj⊂rk in the above equation (7) is the communication path (outbound path) rj of the test packet, It is meant to be included in rk. For example, in the topology of FIG. 4, since there is an inclusion relationship of communication paths such as r8⊂r7⊂r3⊂r1, r8⊂r7⊂r2, r8⊂r7⊂r4, r8⊂r5⊂r6, the first inclusion From the relation (r8⊂r7⊂r3⊂r1), the constraint that at most one of b8, b7, b3, and b1 can be “1” is applied (similar from other inclusion relations) Restrictions apply). Assuming that the number of header fields that can be set for aggregation is M, the above equation (7) is generalized to the following equation (8).

  The above equations (1)-(8) are expressed as integer programming problems, and the optimal solution (max {F1, F2,…) is calculated using software such as a general-purpose solver (eg, IBM ILOGCPLEX software or GLPK (Gnu Linear Programming Kit). , FN} and bj (j = 1, 2,..., L)) at that time.

  After the above-mentioned optimization calculation is completed, for each link lj for which bj = 1, all test flows passing through the link are aggregated. Specifically, a new unique identifier is set in the test packet header field of the target flow, and a transfer rule using the new field is set in the switch as described with reference to FIGS. Is set instead of the existing flow entry.

  Note that the above aggregation is performed not only for the switch whose link is connected downstream but also for each switch located upstream due to the restrictions of the above equations (3) and (4). For example, in FIG. 5, when the aggregation at the link l3 is calculated as the optimal solution (b3 = 1), a rule such as SrcPort number = 100 is added to the flow entry corresponding to the routes r1 and r3 passing through the link l3. Are aggregated into one flow entry, and the setting is set to all the switches (SW8, SW7) through which the routes r1 and r3 pass in common.

  That is, according to the present embodiment, not only the switch SW7 having the link l3 calculated as the optimal solution as the outgoing link, but also the flow entries of the switch SW8 that the routes r1 and r3 pass commonly on the upstream side are collected. You.

  FIG. 7 is a diagram for explaining the function of the flow entry classifying unit 103. Here, the description will focus on the flow entry for the switch SW3.

  The source port numbers of the test flows flowing through the routes r4 and r5 (hereinafter sometimes referred to as test flows r4 and r5) are both “12”, and the outgoing link is link l4, so one flow entry It is concentrated in. The test flows r7 to r10 are all integrated into one flow entry because the outgoing link is the link l2. Other test flows are not aggregated.

  On the other hand, the test flow r1 monitors the link l1 via the switch SW1 without passing through the switch SW3, and the test flows r2 to r10 monitor the links l2 to l6 via the switches SW2 and SW3. I do.

  Each entry of the test flows r1 and r2 is classified as a “return flow entry” that is returned by the switch SW3 for a test packet that has reached the monitoring target link. Each entry of the test flows r3 to r6 is classified as a “flow entry for the forward path” that passes through the switch SW3 in the forward path. Each entry of the test flows r7 to r10 is classified as a “return flow entry” that passes through the switch SW3 on the return path.

  FIG. 8 is a diagram showing an example of the results of the aggregation and classification of the flow entries described above. The flow entries related to the ten test flows r1 to r10 are aggregated into six flow entries, and these are referred to as “return flow entries”. , "Outgoing flow entry" and "returning flow entry".

  In the first flow entry (1), the entries of the four test flows r7 to r10 are described (aggregated) as one return path flow entry, and the priority is set by the priority setting unit 104 to the lowest priority (priority). ≧ 65533). The match condition of the first flow entry (1) is a match between the source IP address and the destination IP address. As an action, the transmission port of the test packet is specified to the second IF port (SendOutPort = 2) on the upstream side. I have.

  In the second flow entry (2), the entry of the test flow r1 is described as a return flow entry, and its priority is set to the highest (priority ≧ 65535). The match condition of the second flow entry is a match between the source IP address, the destination IP address, the source port number, the destination port number, and the input port number of the test packet. In particular, the destination port number (tp_dst = 21) is unique. It is. As the action, sending out the received test packet from the same IF port (SendOutPort = IN_PORT) is specified.

  In the third flow entry (3), the entry of the test flow r2 is described as a return flow entry, and its priority is set to the highest (priority ≧ 65535). The match condition of the third flow entry is a match between the source IP address, the destination IP address, the source port number, the destination port number, and the input port number of the test packet. In particular, the destination port number (tp_dst = 22) is unique. It is. As the action, sending out the input test packet from the same IF port (SendOutPort = IN_PORT) is specified.

  In the fourth flow entry (4), an aggregation entry of the aggregated test flows r4 and r5 is described as a forward flow entry, and its priority is set to the next highest (priority ≧ 65534). The match condition of the fourth flow entry is a match between the source IP address, the destination IP address, the source port number, and the input port number of the test packet, and the destination port number (tp_dst = 12) is particularly unique. As the action, the fourth IP port (SendOutPort = 4) is specified as the packet sending IF port.

  In the fifth flow entry (5), the entry of the test flow r3 is described as a forward flow entry, and its priority is set to the next highest (priority ≧ 65534). The match condition of the fifth flow entry is a source IP address, a destination IP address, a source port number, a destination port number, and an input port number of a test packet. In particular, the destination port number (tp_dst = 23) is unique. . As the action, the third IP port (SendOutPort = 3) is specified as the packet sending IF port.

  In the sixth flow entry (6), an entry relating to the test flow r6 is described as a forward flow entry, and its priority is set to the next highest (priority ≧ 65534). The match conditions of the sixth flow entry are a source IP address, a destination IP address, a source port number, a destination port number, and an input port number of a test packet. In particular, the destination port number (tp_dst = 26) is unique. . As the action, the fourth IP port (SendOutPort = 4) is specified as the packet sending IF port.

  Next, a procedure in which the switch SW3 transfers each test packet based on each flow entry described above will be described with reference to a flowchart of FIG.

  In step S1, when the test packet of the test flow r1 is input to the switch SW3, in step S2, matching is performed on the second and third (return) flow entries having the highest priority first. In step S3, it is determined whether the matching condition is satisfied. Here, since the source IP address and the destination IP address of the test packet match the match condition of the second flow entry, the process proceeds to step S4. In step S4, a corresponding action is performed, and the test packet is transmitted from the first IP port, which is the same as the input port, to the link l1.

  Similarly, when the test packet of the test flow r2 is input to the switch SW3, in step S2, matching is performed on the second and third (return) flow entries having the highest priority. Here, since the source IP address and the destination IP address of the test packet match the match condition of the third flow entry, the process proceeds to step S4, and the test packet is transmitted from the second IP port, which is the same as the input port, to the link l2.

  Next, in step S1, when the test packet of the test flow r3 is input to the switch SW3, in step S2, matching is performed on the second and third flow entries having the highest priority. Do not match, the process proceeds from step S3 to step S5.

  In step S5, matching is performed on the fourth, fifth, and sixth (for the forward path) flow entries having the next highest priority. In step S6, it is determined whether a matching condition is satisfied. Here, since the destination port number of the test packet is “23” and matches the match condition of the fifth flow entry, the process proceeds to step S7. In step S7, the corresponding action is executed, and the test packet is transmitted from the third IF port to link l3.

  Similarly, when the test packet of the test flow r4, the test packet of the test flow r5, and the test packet of the test flow r6 are input to the switch SW3, first, in step S2, the second and third flow entries having the highest priority are added. Although matching is performed on the target, but does not match any of the matching conditions, the process proceeds to step S5, and matching is performed on the fourth, fifth, and sixth (outbound) flow entries having the next highest priority.

  Here, each test packet of the test flows r4 and r5 has a source port number of “12”, and both match the match condition of the fourth flow entry. Therefore, each test packet is transmitted from the fourth IF port. Sent to link l4.

  Also, the test packet of the test flow r6 has the destination port number “26” and matches the match condition of the sixth flow entry, so that the test packet is transmitted from the fourth IF port to the link 16.

  Next, in step S1, when the test packets of the test flows r7, r8, r9, and r10 are input to the switch SW3, in step S2, the second and third (return) flow entries having the highest priority are respectively targeted. In this case, since the matching conditions do not match, the process proceeds to step S5, and matching is performed on the fourth, fifth, and sixth (for the forward path) flow entries having the next highest priority. In the present embodiment, since the match conditions do not match, the process proceeds to steps S8, S9, and S10, where the action of the first flow entry is applied, and each test packet is transmitted from the second IF port to the link l2.

  In the above embodiment, the match condition and the action are also registered in the return flow entry. However, the present invention is not limited to this. All test packets for which a match condition is not satisfied in each flow entry may be processed based on the return flow entry without reconfirming the match condition.

  DESCRIPTION OF SYMBOLS 10 ... Link quality measurement part, 20 ... SDN network, 1 ... Flow entry determination server apparatus, 2 ... Measurement terminal, 101 ... Measurement route calculation part, 102 ... Flow entry aggregation part, 103 ... Flow entry classification part, 104 ... Priority Setting unit, 105: communication path setting unit, 106: measurement execution unit, 201: OpenFlow controller

Claims (12)

In a link quality measurement device that relays a test packet transmitted by a measurement terminal according to a flow entry registered in each switch on the network,
The flow entry registered in each switch is classified into one of a return flow entry, a forward flow entry, and a return flow entry.
A higher priority is set to the flow entry for the return, for the forward path, and for the return path in that order,
A link quality measuring device, wherein each switch processes each input test packet with a flow entry having a higher priority with matching match conditions.   The link quality measurement device according to claim 1, wherein each flow entry of the return packet is aggregated into one in the return flow entry.   The link quality measuring device according to claim 1, wherein, in the forward flow entry, each flow entry of the forward packet is aggregated according to a destination.   The source port number and the destination port number are registered in the header field of each test packet, and each switch writes each test packet into one of the flow entries based on at least one of the source port number and the destination port number. The link quality measuring device according to any one of claims 1 to 3, wherein the link quality is measured. In the flow entry determination server device of the link quality measurement device, which relays the test packet transmitted by the measurement terminal according to the flow entry registered in each switch on the network,
A measurement path calculator for calculating a communication path of the test packet;
A flow entry aggregating unit, which is registered in each switch according to a calculation result of the communication path, and aggregates flow entries of test packets passing through the switch;
A flow entry classification unit for classifying each flow entry into one of a return flow entry, a forward flow entry, and a return flow entry for each switch;
A priority setting unit that sets a higher priority in the order for each of the return, forward and return flow entries;
A communication path setting unit for registering each flow entry together with its classification result and priority in each corresponding switch,
The link quality measurement device according to claim 1, wherein in the return flow entry, each flow entry of the return packet is aggregated into one, and in the forward flow entry, each flow entry of the outward packet is aggregated according to a destination. Flow entry determination server device.   The flow entry determination server device of the link quality measuring device according to claim 5, wherein the flow entry classification unit classifies each return flow entry into a plurality of return flow entries for each incoming link of a test packet. .   7. The server according to claim 5, wherein the flow entry classifying unit classifies each flow entry on the outward route into a plurality of outward flow entries according to a destination.   The flow entry determination server device according to any one of claims 5 to 7, wherein the flow entry classification unit classifies each return flow entry into one return flow entry. In the switch of the link quality measurement device that relays the test packet transmitted by the measurement terminal according to the flow entry registered in advance,
The registered flow entry is classified into one of a return flow entry, a forward flow entry, and a return flow entry,
A higher priority is set to the flow entry for the return, for the forward path, and for the return path in that order,
A switch for a link quality measuring device, wherein each input test packet is processed by a flow entry having a higher priority with a matching condition being matched.   A source port number and a destination port number are registered in the header field of each test packet, and each test packet is processed by one of the flow entries based on at least one of the source port number and the destination port number. The switch of the link quality measurement device according to claim 9, wherein   The switch of the link quality measurement device according to claim 9, wherein, in the return flow entry, each flow entry of the return packet is integrated into one.   The switch of the link quality measuring device according to any one of claims 9 to 11, wherein, in the forward flow entry, each flow entry of the forward packet is aggregated according to a destination.