JP3777574B2 - LAN switch and test method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a LAN switch having a plurality of ports connected to a terminal device, a LAN (Local Area Network), and the like, and a test method.
[0002]
[Prior art]
Various networks including the Internet and the like for transmitting various data including images and sounds have been put into practical use. FIG. 7 shows a main part of an example of a network. 71 is a user network, 72 is an access network, and 73 is a core network. The user network 71 includes a LAN 74, a terminal device, and the like, and the access network 72 includes a line termination unit (DSU; Digital Service Unit), an optical access unit (ONU), and the like. The core network 73 has a configuration in which a plurality of core switches 77 are connected, and a configuration in which the core network 73 and the access network 72 are connected by a subscriber termination device 76 is shown.
[0003]
Conventionally, the core network 73 required to have a wide bandwidth and high reliability generally employs a transmission technology such as SDH (Synchronous Digital Hierarchy) or ATM (Asynchronous Transfer Mode). However, with the recent rapid spread of LANs, many end users often construct a user network 71 with a standardized LAN 74 according to IEEE 802.3, which is usually called Ethernet (registered trademark). The access network 72 and the core network 73 are also constructed by applying this IEEE 802.3.
[0004]
As a frame applied to such a LAN, for example, a format shown in FIG. 8 is known. (A) is Ethernet II (DIX), (b) is IEEE 802.3 (RAW), (c) is IEEE 802.3 (LLC; Logical Link Control), (d) is IEEE 802.3 (LLC + SNAP; Logical). A format specified by Link Control, Sub-Network Access Protocol) is shown, and a LAN tag when applied to a VLAN (Virtual Local Network) defined by IEEE 802.1Q can be added.
[0005]
In FIG. 8, PA is a preamble, DA is a destination address, SA is a source address, Type is a frame type, Date is a data part, FCS is a frame check sequence, TPID is a tag protocol identifier, and TCI is tag control information. , SFD is a frame start delimiter, Length is data portion length information, DSAP is a destination upper layer protocol identifier, SSAP is a source upper layer protocol identifier, Ctrl is a control unit, OUI is a management organization identifier, and PID is a protocol identifier. Each parenthesis indicates the number of bytes.
[0006]
Also, the LLC (Logical Link Control) headers of FIGS. 8C and 8D have a 3-byte structure consisting of a destination upper layer protocol identifier DSAP, a source upper layer protocol identifier SSAP, and a control unit Ctrl. 8 shows a header, and a SNAP (Subnetwork Access Protocol) header in (d) of FIG. 8 shows a 5-byte header composed of a management organization identifier OUI and a protocol identifier PID. In general, the frames shown in FIGS. 8A to 8D are generally referred to as a MAC (Media Access Control) frame.
[0007]
A LAN switch for transferring such a MAC frame includes a plurality of ports and a learning table, and associates a transmission source address with an arrival port of the MAC frame to which the transmission source address is added. sign up. Therefore, if the destination address of the received MAC frame matches the registered source address, the MAC frame can be transferred with the registered port as the transfer destination port. When a MAC frame in which the correspondence between the transmission source address and the port is not registered in the learning table is received, it is processed as an unlearned frame. That is, flooding is performed in which a transmission source address and an arrival port are newly registered in the learning table in association with each other, and a received MAC frame is copied and transmitted to all ports. By repeating such learning, the relationship between the transmission source address and the port is registered in the learning table, so that the destination address is transferred to the port that matches the registered transmission source address.
[0008]
[Problems to be solved by the invention]
A LAN switch in a communication network has an advantage that it is less expensive than an SDH node or an ATM node. However, in order to ensure the reliability of the network, it is desirable to test the normality of the LAN switch during operation, but no test means for that purpose has been proposed. When testing the normality of the network including the LAN switch of the network in operation, the test is performed by disconnecting the LAN switch from the transmission path and connecting a measuring instrument or the like. Therefore, there is a problem that the service needs to be completely interrupted. In order to prevent this service from being interrupted, it is conceivable that the LAN switch has a duplex configuration, one of which is the active system and the other is the standby system. Cost increase due to the configuration becomes a problem.
[0009]
An object of the present invention is to realize normality of a LAN switch, a continuity test between LAN switches, a bandwidth measurement test, a delay time measurement test, and the like even during network operation.
[0010]
[Means for Solving the Problems]
Referring to FIG. 1, the LAN switch of the present invention includes a plurality of ports 5-1 to 5-n, a learning table 2, and a frame distribution unit 3 that distributes frames with reference to the learning table 2. LAN switch 1 having a configuration including test frame insertion portions b and d having a function of forming and sending a test frame to ports 5-1 to 5-n, and a function test for extracting and measuring the test frame Frame extraction units a and c are provided, and at the time of a test, a source address indicating a test frame and a port number are registered in the learning table 2 in association with each other, and test frame insertion units b and d of a designated port and a test frame It is assumed that a test frame management unit 4 that performs a test by controlling one or both of the extraction units a and c is provided.
[0011]
The test frame extraction units a and c have a function of extracting a test frame and measuring at least one of the number of test frames, the test frame rate, and the number of test frame discards. The test frame insertion units b and d The learning table 2 has a function of forming and sending a test frame including a sequence number with a transmission source address registered at the time of testing as a destination address.
[0012]
The test method of the present invention also includes a plurality of ports 5-1 including a learning table 2, a frame distribution unit 3, a test frame management unit 4, test frame extraction units a and c, and test frame insertion units b and d. A test method for testing between LAN switches 1 or between LAN switches having ˜5-n, registering the learning table 2 in association with a source address indicating a test frame and a port number, and for the test frame The learning prohibition is set, and a test frame having the transmission source address registered in the learning table 2 as the destination address is formed and transmitted from the test frame insertion unit of the designated port, and the frame distribution unit 3 is registered in the learning table 2 The test frame is allocated to the port with the specified port number, the test frame is extracted from the test frame extraction unit of the specified port, and the specified port It is intended to include a process for testing between.
[0013]
Also registered in the learning table of one LAN switch connected between LAN switches via a transmission path in association with the source address indicating the test frame and the port number, and the learning prohibition for the test frame is set and registered. A test frame with the source address registered in the learning table as the destination address is sent from the outgoing side test frame insertion section of the port of the other LAN switch connected to the port with the specified port number, and one LAN switch is distributed In the process, the learning table is referred to and sent back to the other LAN switch, the test frame is extracted in the incoming test frame extraction part of the port of the other LAN switch, and the return test is performed. Is included.
[0014]
In addition, a single or a plurality of relay route LAN switches are included between the first LAN switch and the second LAN switch, and a transmission source address indicating a test frame and a test frame are stored in a learning table of the relay route LAN switch. The port number of the relay sending port is registered in association with the learning prohibition for the test frame, and from the outgoing test frame insertion unit of the port of the first LAN switch to the learning table of the relay route LAN switch The test frame having the registered source address as the destination address is transmitted, and the relay path LAN switch distribution unit relays and transmits the test frame with reference to the learning table, and the test frame arrival port of the second LAN switch The test frame is extracted by the ingress test frame extraction unit of the second and is connected via the relay route LAN switch. It is intended to include a process of performing a test between the second LAN switch.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is an explanatory diagram of an embodiment of the present invention, where 1 is a LAN switch, 2 is a learning table, 3 is a frame distribution unit, 4 is a test frame management unit, and 5-1 to 5-n are ports. Ports 5-1 to 5-n, a is an entry side test frame extraction part, b is an entry side test frame insertion part, c is an exit side test frame extraction part, and d is an exit side test frame insertion part. Each port 5-1 to 5-n is connected to another LAN switch (not shown) via a transmission line.
[0016]
The LAN switch 1 generally includes a plurality of ports 5-1 to 5-n, a learning table 2, and a frame distribution unit 3. Each of the ports 5-1 to 5-n has an input / output interface function and is assigned a port number. The frame distribution unit 3 refers to the learning table 2 and distributes the MAC frame from the arrival port to the transfer destination port. In the present invention, an input side test frame extraction unit a, an input side test frame insertion unit b, an output side test frame extraction unit c, and an output side test frame are inserted into each of the ports 5-1 to 5-n. And a test frame management unit 4 are provided. Note that when there is no need to distinguish between the entry side and the exit side, a description will be given as a test frame extraction unit and a test frame insertion unit. The test frame extraction unit has a function of identifying and extracting a test frame by destination address, frame type, etc., and the test frame insertion unit forms a test frame including a destination address indicating the test frame, a sequence number, etc. It has a function to send out.
[0017]
The test frame management unit 4 transfers various types of information to / from a device management system (operation system) (not shown) via another network (not shown) or a network including the LAN switch 1. Via the control frame or the like. The test frame management unit 4 registers the relationship between the transmission source address of the test frame and the port in the learning table 2 in accordance with the test execution instruction from the device management system, and extracts the test frame at the designated port. A function is provided for performing test frame insertion setting or extraction setting for the test section or insertion section, and for instructing test start or test hand stop.
[0018]
The incoming test frame extraction unit a and the outgoing test frame extraction unit c of the ports 5-1 to 5-n are inserted between user frames as MAC frames according to the extraction setting from the test frame management unit 4. The transferred test frame is extracted by, for example, a destination address, and has a measurement function such as counting the number of test frames, a transmission rate by the test frame, and a transmission delay time. In addition, the entrance side test frame insertion part b and the exit side test frame insertion part d are a test in which a destination address for identifying a test frame is added between user frames according to the insertion setting from the test frame management part 4. It has a function to send frames. The test frame can be identified by the frame type.
[0019]
FIG. 2 is an explanatory diagram of a test frame. FIGS. 2A and 2B show cases in which the format shown in FIG. 8B is followed, and the same reference numerals indicate the same contents. In the test frame of FIG. 2A, a 4-byte sequence number and padding (paddig) with all “0” s are inserted at the position of the data part Data. A VLAN tag is added to the VLAN. FIG. 2B shows a test frame in which a 4-byte sequence number, a 4-byte time stamp, and all “0” padding are inserted at the position of the data portion. Note that a test frame in accordance with the format shown in FIGS. 8A, 8C, and 8D can be used.
[0020]
Accordingly, the entrance side test frame insertion part a and the exit side test frame insertion part d in FIG. 1 form the frame format shown in FIG. 2 (a) or (b), and the destination address is, for example, #TEST. For example, the transmission source address is set as its own port number, and a function of incrementing the sequence number every time the test frame is transmitted is provided. Such a function can be easily realized by a memory, a control logic circuit, or the like. As for the transmission source address of this test frame, since the transmission source address of the test frame is registered in the learning table 2 and the learning prohibition for the test frame is set at the time of the test, the test frame is assigned to the designated port. Will be distributed from the beginning.
[0021]
FIG. 3 shows a case where a continuity test and a quality test between ports in the LAN switch 1 are performed. The learning table 2, the frame distribution unit 3, the test frame management unit 4, and the port numbers #PA to #PN are shown. A port, an entry side test frame extraction part a, an entry side test frame insertion part b, an exit side test frame extraction part c, and an exit side test frame insertion part c are shown.
[0022]
When the learning table 2 stores the source address #A and the port number #PN in association with each other, and the source address #B and the port number #PK are stored in association with each other, the port of the port number #PA is stored. And the port number #PJ, the device monitoring system associates, for example, #TEST with the port number #PJ as a transmission source address to the learning table 2 via the test frame management unit 4 And set a learning prohibition on the test frame.
[0023]
Also, the test frame insertion setting with the destination address #TEST is set in the ingress test frame insertion part b of the port of port number #PA, and the test frame is extracted in the egress test frame extraction part c of port number #PJ. Set up. The test frame extraction units a and c and the test frame insertion units b and d of other ports are set in an inoperative state. In this case, the port number #PA is the test frame insertion port, and the port number #PJ is the test frame end port.
[0024]
In response to the test start instruction from the test frame management unit 4, the test frame shown in FIG. 2A or 2B is formed from the entrance side test frame insertion unit b of the port number #PA, and the frame distribution unit 3 Send it out. In this case, the test frame destination address DA is set to #TEST, and a sequence number when the test frame is repeatedly transmitted is added, and the test frame is inserted and transmitted between the user frames.
[0025]
The frame distribution unit 3 searches the learning table 2, the transmission source address #TEST is registered, and learning prohibition for the test frame is set, so that the test frame is registered with the registered transmission source without performing flooding. It is distributed and sent to the port of port number #PJ corresponding to address #TEST. Therefore, the route of the test frame is indicated by a thick arrow. In this case, the test frame is not copied and sent to other ports other than the arrival port, so that the user frame traffic is not compressed. Absent.
[0026]
The outgoing test frame extraction unit c of the port of port number #PJ extracts only the test frame of the destination address #TEST according to the test frame extraction setting, and the number of test frames or test frames per unit time such as 1 second Measure transfer rate by number. Also, the number of discarded frames is measured based on the sequence number. For example, if the sequence number of the test frame extracted next to the test frame with the sequence number 100 is 103, the discard rate per unit time such as 1 second is measured with the number of discards set to 2.
[0027]
The test frame management unit 4 can collect these pieces of information to obtain a continuity test result and a quality test result between the port numbers #PA and #PJ and transfer them to, for example, a device management system as a host device. When such a test is completed, according to the instruction from the apparatus management system, the test frame management unit 4 obtains the transmission source address #TEST of the test frame registered in the learning table 2 and the port number #PJ corresponding to the transmission source. The test frame insertion process at the input side test frame insertion part b of port number #PA is stopped, and the extraction process at the output side test frame extraction part c of port number #PJ is stopped. After the test is completed, the result measured in the outgoing test frame extraction unit c can be transferred from the test frame management unit 4 to the apparatus management system.
[0028]
When the test between the port number #PA and the port number #PJ is completed, the port number corresponding to the transmission source address #TEST of the test frame in the learning table 2 is changed to #PK, for example. By performing test frame extraction setting in the outgoing test frame extraction unit c of number #PK, a test between ports of port number #PA and port number #PK can be performed. That is, by sequentially changing the test frame end port with respect to the test frame insertion port, a test between the test frame insertion port and another boat can be performed, and the test frame insertion port is also changed sequentially. As a result, it is possible to perform a quality test based on a continuity test between ports, a discard rate, and the like. In the above-described test process, normal user frame distribution processing is continued, and flooding is not performed for the first test frame, so that the user frame traffic is not compressed.
[0029]
FIG. 4 is an explanatory diagram of a test method by returning test frames between opposing LAN switches, 1-1 and 1-2 are LAN switches, 2 is a learning table, 3 is a frame distribution unit, PA to #PN indicate port numbers. The port of port number #PA of LAN switch 1-1 and the port of port number #PK of LAN switch 1-2 are connected via a transmission line, and a loopback test is performed between LAN switches 1-1 and 1-2. In the LAN switch 1-1, the test frame management unit (not shown) performs test frame insertion setting in the outgoing test frame insertion unit d of port number #PA, and the incoming test frame extraction unit. Set a to extract a test frame in a. In the LAN switch 1-2, the source address #TEST and the port number #PK are registered in the learning table 2 from the test frame management unit (not shown), and the source address and destination address of the test frame are registered. Set learning prohibition for and. It should be noted that the test frame extraction units a and c and the test frame insertion at the other ports other than the input side test frame extraction unit a and the output side test frame insertion unit d of the port number #PA of the LAN switch 1-1. The parts b and d are set in an inoperative state.
[0030]
In response to the test start instruction, for example, as shown in FIG. 2A, the destination address DA = # TEST is set from the outgoing test frame insertion unit d of the port number #PA of the LAN switch 1-1, and the source address is set. SA = # PA, and a test frame in which a sequence number is set is sent to the transmission line. The port of port number #PK of the LAN switch 1-2 transfers the arrived test frame to the frame distribution unit 3 in the same manner as the user frame. The frame distribution unit 3 refers to the learning table 2, and the test frame destination address DA = # TEST is registered as the source address #TEST, and its port number is #PK. Forward to the other port. Since this port is not set for the test frame insertion section and extraction section, the test frame is sent to the transmission path as it is. That is, the test frame is folded and sent to the transmission path.
[0031]
The incoming test frame extraction unit a of the port number #PA of the LAN switch 1-1 extracts the test frame that has arrived via the transmission path by using the destination address #TEST as described above. Therefore, the transfer path of the test frame is indicated by a thick arrow. Then, the entrance side test frame extraction unit a can perform the same measurement as the test content in FIG. 3 to obtain the frame rate, the discard rate, and the like. Similarly, a loopback test can be performed on a LAN switch connected to another boat of the LAN switch 1-1 via a transmission line. When the predetermined test process is completed, a test stop instruction is sent from the test frame management unit 4 to each unit. Therefore, a continuity test and a quality test can be performed between the LAN switches constituting the network in operation without affecting the user frame.
[0032]
FIG. 5 is an explanatory diagram for conducting a continuity test or a delay measurement test between LAN switches via a relay path. 1-1 to 1-3 denote LAN switches, and the same reference numerals as those in FIG. 1 are the same. Indicates the part. The test frame management unit 4 is not shown, and the learning table 2 is also omitted in the LAN switches 1-1 and 1-3. In this case, the LAN switch 1-1 is a first LAN switch, the LAN switch 1-2 is a second LAN switch, and the LAN switch 1-3 is a relay route LAN switch. However, the present invention can also be applied to a network in which a plurality of relay route LAN switches are connected via a transmission line between the first LAN switch and the second LAN switch.
[0033]
In FIG. 5, the port of port number #PA of the LAN switch 1-1 and the port of port number #PJ of the LAN switch 1-2 are connected via a transmission line. A network in which a port of port number #PN and a port of port number #PA of the LAN switch 1-3 are connected via a transmission line is shown, and the LAN is relayed from the LAN switch 1-1 to the LAN switch 1-2. When a test frame is transferred to the switch 1-3 and a test is performed, the outgoing side of the port of the port number #PA of the LAN switch 1-1 is sent from the test frame management unit (not shown) according to an instruction from the device management system. The test frame insertion section d is set to insert a test frame, and the test frame is input to the ingress test frame extraction section a of the port number #PA of the LAN switch 1-3. The test frame transmission source address #TEST and the port number #PN of the port through which the test frame is relayed and transmitted are registered in the learning table 2 of the relay route LAN switch 1-2. Set learning prohibition.
[0034]
Then, a test start instruction or a test stop instruction is sent from the apparatus management system to the test frame management unit of the LAN switch on the test path. According to the test start instruction, the port of port number #PA of the LAN switch 1-1 A test frame having a destination address DA = # TEST is inserted between user frames from the outgoing side test frame insertion section d and sent to the transmission path. The test frame in that case is, for example, a frame including a sequence number and a time stamp as shown in FIG.
[0035]
The test frame arriving at the port of port number #PJ of the LAN switch 1-1 refers to the learning table 2 in the frame distribution unit 3, and the destination address DA = # TEST of the test frame is registered in the learning table 2. Since it matches the source address #TEST, the test frame is assigned to the corresponding port number #PN. A test frame is transferred from the port of port number #PN to the LAN switch 1-3 via the transmission path. Therefore, the transfer path of the test frame in this case is indicated by a thick arrow.
[0036]
In the LAN switch 1-3, the test frame arriving at the port of port number #PA is extracted by the ingress test frame extraction unit a, and the number of test frames is measured, the test frame rate is measured, and the sequence number is detected. Measures the discard rate by, and measures the transfer delay time based on the test frame transmission time by time stamp. These measurement results can be transferred to the test frame management unit (not shown) in the measurement process or after the test, and transferred from the test frame management unit to the apparatus management system.
[0037]
In this case as well, the relay path can be tested in the normal user frame transmission control process. Even when a plurality of LAN switches are included as a relay route, by registering the source address of the test frame and the port number of the port that relays and transmits the test frame in the learning table of each LAN switch corresponding to the relay route In the frame distribution unit, the frame can be distributed so as to be relayed without being flooded with the test frame.
[0038]
FIG. 6 shows a case where a test of the LAN switch 1 is performed in a state in which the LAN switch 1 is disconnected from the network in operation, and the same reference numerals as those in the previous drawings indicate the same parts. In this embodiment, the test frame management unit (not shown) registers the test frame transmission source address #TEST and the port number #PJ in the learning table 2, and sets learning prohibition for the test frame. Then, it is set in the ingress test frame extraction unit a of the port number #PA to #PN port so as to discard all the arrived frames, and in the ingress test frame insertion unit b of the port of port number #PN Test frame insertion is set, and test frame extraction is set in the outgoing test frame extraction unit c of the port of port number #PJ.
[0039]
In response to the test start instruction, a test frame with a destination address DA = # TEST is transmitted from the input side test frame insertion part b of the port of port number #PN. The distribution unit 3 searches the learning table 2 and distributes the test frame to the port of the port number #PJ whose transmission source address is #TEST. The test frame extraction unit c of the port of port number #PJ extracts the test frame of the destination address DA = # TEST, and measures the number of test frames, the test frame rate, the number of discarded test frames, and the like. In this case, the entry side test frame extraction unit a extracts and discards not only the test frame but also the user frame. Accordingly, the LAN switch 1 can be tested as being disconnected from the network.
[0040]
Also, if the test frame is inserted into the ingress test frame insertion part b of the port of port number #PN and the destination address DA = # TEST is set, the distribution part 3 refers to the learning table 2 and selects this test frame. The port number #PJ is assigned. In this case, the port number #PJ can be used as a test frame termination boat to perform various tests with other ports. Further, the test frame end port can be changed to another port by changing the port number for the transmission source address #TEST in the learning table 2.
[0041]
The present invention is not limited to the above-described embodiments, and various additions and modifications can be made. For example, the test frame insertion unit and the test frame extraction unit are not all ports, It is also possible to provide only for the other ports. Also, the test frame insertion unit applies various configurations such as a configuration in which a test frame is formed by writing necessary data in a memory in which a format is stored in advance and a test frame read out from the memory is transmitted. can do. The above-described embodiment can also be applied to a test between a LAN switch and a LAN switch in a VLAN configuration network.
[0042]
【The invention's effect】
As described above, according to the present invention, the test frame insertion units b and d and the test frame extraction units a and c are provided in the ports 5-1 to 5-2, and the ports in the single LAN switch 1 are connected. Various tests, such as a test, a loopback test using another LAN switch, and a test via a relay route LAN switch between the first and second LAN switches, without compressing user frame traffic during network operation Therefore, there is an advantage that the reliability of the network using the LAN switch can be improved.
[0043]
Also, during the test process, the source address indicating the test frame and the port number of the port to be sent out are registered in the learning table 2, and the test frame is set to another port by setting the learning prohibition for the test frame. Therefore, there is an advantage that the user frame traffic is not adversely affected.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram of an embodiment of the present invention.
FIG. 2 is an explanatory diagram of a test frame.
FIG. 3 is an explanatory diagram of a test method according to an embodiment of the present invention.
FIG. 4 is an explanatory diagram of a test method using folding according to an embodiment of the present invention.
FIG. 5 is an explanatory diagram of a test method including a relay route according to the embodiment of this invention.
FIG. 6 is an explanatory diagram of a test method by external separation according to an embodiment of the present invention.
FIG. 7 is an explanatory diagram of a network.
FIG. 8 is an explanatory diagram of a frame format.
[Explanation of symbols]
1 LAN switch
2 Learning table
3 Frame sorting section
4 Test Frame Management Department
5-1 to 5-n ports
a Incoming test frame extraction section
b Entrance test frame insertion part
c Outgoing test frame extraction unit
d Outgoing test frame insertion part

Claims (5)

In a LAN switch configured to include a plurality of ports, a learning table, and a frame distribution unit that distributes frames with reference to the learning table,
The port is provided with a test frame insertion unit having a function of forming and sending a test frame, and a test frame extraction unit having a function of extracting and measuring the test frame,
At the time of a test, a transmission source address indicating a test frame and a port number are registered in the learning table in association with each other, and one or both of the test frame insertion unit and the test frame extraction unit of a designated port are controlled. A LAN switch comprising a test frame management unit for performing a test. The test frame extraction unit has a function of extracting a test frame and measuring at least one of the number of test frames, a test frame rate, and the number of test frame discards, and the test frame insertion unit stores the test frame in the learning table. 2. The LAN switch according to claim 1, wherein the LAN switch has a function of forming a test frame including a sequence number using a transmission source address registered during a test as a destination address and transmitting the test frame. In a test method for testing a LAN switch having a learning table, a frame distribution unit, a test frame management unit, a plurality of ports including a test frame extraction unit and a test frame insertion unit, or between the LAN switches.
A transmission source address and a port number indicating a test frame are registered in the learning table in association with each other, a learning prohibition for the test frame is set, and the transmission registered in the learning table from the test frame insertion unit of the designated port A test frame having a source address as a destination address is formed and transmitted, and the frame distribution unit distributes the test frame to a port having a port number registered in the learning table, and from the test frame extraction unit of the designated port. A test method comprising: extracting the test frame and performing a test between the designated ports. In a test method for testing a LAN switch having a learning table, a frame distribution unit, a test frame management unit, a plurality of ports including a test frame extraction unit and a test frame insertion unit, or between the LAN switches.
In the learning table of one LAN switch connected between LAN switches by a transmission path, a source address indicating a test frame and a port number are registered in association with each other, and learning prohibition for the test frame is set, and the port number is set. A test frame having a source address registered in the learning table as a destination address is sent from the outgoing side test frame insertion unit of the other LAN switch port connected to the port of the other LAN switch, to the distribution unit of the one LAN switch At this time, the learning table is referred to and sent back to the other LAN switch, and the test frame is extracted at the entrance side test frame extraction unit of the port of the other LAN switch to perform the return test. A test method characterized by comprising a process. In a test method for testing a LAN switch having a learning table, a frame distribution unit, a test frame management unit, a plurality of ports including a test frame extraction unit and a test frame insertion unit, or between the LAN switches.
A single or a plurality of relay route LAN switches are included between the first LAN switch and the second LAN switch, and the transmission source address indicating the test frame and the test frame are relayed to the learning table of the relay route LAN switch. The port number of the port to be transmitted is registered in association with each other, and learning prohibition for the test frame is set, and from the outgoing test frame insertion unit of the port of the first LAN switch to the learning table of the relay circuit LAN switch A test frame having a registered transmission source address as a destination address is transmitted, and the relay path LAN switch distribution unit relays and transmits the test frame with reference to the learning table, and the test frame of the second LAN switch. The test frame is extracted at the incoming test frame extraction unit of the arrival port of the relay port LA Wherein through the switch first, test method which comprises a step of performing test between the second LAN switch.

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