JP4888067B2 - Layer 2 switch and network monitoring method - Google Patents

Description

  The present invention is used for a network including layer 2 switches such as Ethernet (registered trademark). In particular, it relates to a technique for identifying a failure location when a failure occurs.

  In a network in which a VLAN (Virtual Local Area Network) is set and used, the layer 2 switch has a function of transferring packets, and terminals are connected to each other via the layer 2 switch. In the case of configuring a network using a conventional layer 2 switch, connectivity is confirmed between terminals or detected only by physical connection such as link up and down.

JP 2000-165430 A JP 2000-196647 A JP-A-10-145411

  Conventionally, when a network failure occurs, the problem is confirmed by confirming continuity by ping between terminals or investigating the router route by traceroute. In this case, the route investigation at the layer 2 level is performed. It is not possible to know where the problem is on the network.

  That is, in the case of detection at layer 1, even if a cable is connected to the wrong port, it is regarded as connected if the link is up, so it is difficult to find a connection error. Further, in the case of the layer 3 level, it is only known that a communication failure has occurred somewhere between the terminals, and the point of failure cannot be grasped.

  The present invention has been made under such a background, and an object thereof is to provide a layer 2 switch having a function of detecting a cable connection error or a VLAN setting error.

  In the present invention, a layer 2 address called a MAC (Media Access Control) address is monitored, and the MAC table is transmitted and received by each layer 2 switch, so that the location of the problem can be known in detail and can be automated.

  That is, the present invention is a layer 2 switch that transfers a packet to a terminal connected to its own device or another layer 2 switch. The feature of the present invention is that when a packet is received, Means for performing MAC learning on the port that received the packet to create a MAC table, means for transmitting the MAC table held by the own device to another layer 2 switch, and receiving from another layer 2 switch The means for holding the MAC table is compared with the MAC-related information obtained from the header information of the packet received from the other layer 2 switch and the recorded contents of the MAC table received from the other layer 2 switch held in advance. Means and the comparison result by the comparing means do not match, the network between the other layer 2 switch and its own device There is to provided with a means for determining an error in the work construction is present.

  For example, the MAC learning is learning to record the correspondence between the identification information of the VLAN to which the packet belongs and the transmission source MAC address of the packet with respect to the port that received the packet, and the MAC related information is received This is information on the correspondence between the source MAC address of the packet included in the header information of the packet and the VLAN to which the packet belongs.

  Furthermore, when the means for determining determines that an error exists, a means for notifying that can be provided.

  The present invention can also be viewed from the viewpoint of a network monitoring method. That is, the present invention is a network monitoring method executed by a layer 2 switch that transfers a packet to a terminal connected to its own device or another layer 2 switch, and the feature of the present invention is that When the layer 2 switch receives a packet, MAC learning is performed for the port that has received the packet, and a MAC table is created; and a MAC table held by the own device is transmitted to another layer 2 switch. A step of holding a MAC table received from another layer 2 switch, a MAC-related information obtained from header information of a packet received from another layer 2 switch, and a reception from the other layer 2 switch held in advance. Comparing the recorded contents of the MAC table and the comparison result of the comparing step. There when they do not match, there is to be run and determining an error of the network construction is present between the other layer 2 switch and the own apparatus.

  For example, the MAC learning is learning to record the correspondence between the identification information of the VLAN to which the packet belongs and the transmission source MAC address of the packet with respect to the port that received the packet, and the MAC related information is received This is information on the correspondence between the source MAC address of the packet included in the header information of the packet and the VLAN to which the packet belongs.

  Further, when the layer 2 switch determines that there is an error in the determining step, a step of notifying the fact can be executed.

  The present invention can also be viewed from the viewpoint of a network configured by including the layer 2 switch of the present invention.

  The present invention can also be viewed from the viewpoint of a program that, when installed in a general-purpose information processing apparatus, causes the general-purpose information processing apparatus to realize a function corresponding to the layer 2 switch of the present invention.

  By recording the program of the present invention on a recording medium, the general-purpose information processing apparatus can install the program of the present invention using this recording medium. Alternatively, the program of the present invention can be directly installed on the general-purpose information processing apparatus via a network from a server that holds the program of the present invention.

  Thereby, the layer 2 switch of the present invention can be realized using a general-purpose information processing apparatus.

  The program of the present invention includes not only a program that can be directly executed by a general-purpose information processing apparatus but also a program that can be executed by installing it on a hard disk or the like. Also included are those that are compressed or encrypted.

  According to the present invention, it is possible to easily detect a network construction error due to a cable connection error or a VLAN setting error between layer 2 switches in a network composed of layer 2 switches such as Ethernet.

  An embodiment of the present invention will be described with reference to FIG. FIG. 1 is a diagram showing a network configuration according to an embodiment of the present invention. In FIG. 1, the layer 2 switch 10 or 11 transfers a packet to the connected terminals 20 to 23 and other layer 2 switches 11 or 10. When the layer 2 switches 10 and 11 receive a packet, the layer 2 switches 10 and 11 create a MAC table that records the correspondence between the identification information of the VLAN to which the packet belongs and the source MAC address for the port that received the packet.

  The layer 2 switch 10 has a function of transmitting to the layer 2 switch 11 the MAC table held by the layer 2 switch 10 with respect to the layer 2 switch 11, and the layer 2 switch 11 transmits the transmitted layer 2 switch. It has a function of holding 10 MAC tables. Conversely, the layer 2 switch 11 has a function of transmitting the MAC table held by the layer 2 switch 11 to the layer 2 switch 10 to the layer 2 switch 10, and the layer 2 switch 10 transmits the transmitted layer 2 to the layer 2 switch 10. It has a function of holding the MAC table of the switch 11.

  Here, the abnormality determination procedure of the present embodiment will be described with reference to the flowchart of FIG. Upon receiving the packet (S1), the layer 2 switches 10 and 11 refer to the header information of the received packet (S2), and the source MAC address of the packet included in the header information and the VLAN to which the packet belongs The correspondence is extracted (S3), and the correspondence between the extracted correspondence and the MAC address and VLAN in the recorded contents of the MAC table (the MAC table of the opposite device) received from the other layer 2 switches 11 and 10 held in advance When the comparison result does not match (S5), there is a cable connection error or VLAN setting error between the other layer 2 switches 11 and 10 and the own layer 2 switch 10 and 11. It is determined that there is an error in network construction, and the abnormality is notified to the maintenance person (S6).

As means for notifying the maintenance person, for example, LED display, buzzer sound, SNMP (Simple
A notification to the management server by sending out a trap of Network Management Protocol) can be considered.

  In this way, according to the present invention, it is possible to easily detect where a mistake is made in the network by confirming the opposite connection device in each layer 2 switch.

  Next, the configuration of the layer 2 switch of this embodiment will be described with reference to FIG. FIG. 3 is a block diagram of the layer 2 switch of this embodiment. In FIG. 3, the MAC table transmission unit 30 in the layer 2 switch 10 transmits the own device MAC table 100 of the layer 2 switch 10 and the MAC address of the layer 2 switch 10 device itself to the layer 2 switch 11.

  The MAC table receiving unit 32 of the layer 2 switch 11 receives the MAC table transmitted from the layer 2 switch 10 and stores the contents in the counter device MAC table storage memory 111. Conversely, the MAC table transmission unit 33 in the layer 2 switch 11 transmits the own device MAC table 110 of the layer 2 switch 11 and the MAC address of the layer 2 switch 11 device itself to the layer 2 switch 10.

  The MAC table receiving unit 31 of the layer 2 switch 10 receives the content transmitted from the layer 2 switch 11 and stores the content in the opposite device MAC table storage memory 101.

  The MAC address comparison units 40 and 41 check whether the transmission source MAC address and the VLAN identification information of the received packet are stored in the opposing device MAC table storage memories 101 and 111.

  Although the configuration of the embodiment has been described above, the basic function of packet transfer of the layer 2 switch of FIG. 1 is well known to those skilled in the art and is not directly related to the present invention, so the detailed configuration is omitted. To do.

  Next, the operation of the layer 2 switch of FIG. 3 will be described with reference to FIG. FIG. 4 is a diagram showing the header information of the received packet and the recorded contents of the counter device MAC table storage memory. In FIG. 3, when the layer 2 switch 10 and the layer 2 switch 11 are connected, the layer 2 switch 11 sends the MAC address table from the MAC table transmission unit 33 to the layer 2 switch 10, and the layer 2 switch 10 The information is stored in the counter device MAC address storage memory 101. Similarly, the MAC address table is transmitted from the layer 2 switch 10 to the layer 2 switch 11, and the information is stored in the counter device MAC address storage memory 111.

  Next, the operation at the time of packet reception will be described with reference to FIG. The MAC address table describes correspondence between port numbers, VLAN identification information, and MAC addresses, and the situation is shown in the counter device MAC address storage memory 101.

  When the layer 2 switch 10 receives the packet, the MAC address comparison unit 40 extracts the VLAN identification information and the source MAC address of the received packet, and stores the MAC address having the same correspondence as the correspondence between the VLAN identification information and the source MAC address. Check whether it exists in the memory 101. At this time, the port number in the counter device MAC address storage memory 101 is irrelevant and is ignored.

  As a result of the confirmation, if the same correspondence does not exist in the MAC address storage memory 101, it can be determined that the network is misconfigured due to a wrong cable connection or wrong VLAN setting.

  A specific example will be given to explain the operation when a connection is made by mistake when the network configuration is normal. FIG. 1 shows an example of a normal network configuration, and FIG. 5 shows a counter device MAC address storage memory 101 in the layer 2 switch 10 in this configuration. At this time, when the packet is transmitted from the terminal 21 to the terminal 20, the same correspondence as the correspondence between the VLAN identification information of the packet and the source MAC address exists in the opposing device MAC address storage memory. Therefore, it can be regarded as a normal configuration. Note that blanks in FIG. 5 are not particularly described because they are unconscious in this operation example.

  Next, the operation when a connection error occurs will be described with reference to FIGS. FIG. 6 is a network configuration diagram when the cable connection is wrong between the layer 2 switches 10 and 11. FIG. 7 shows the opposing device MAC address storage memory 101 in the layer 2 switch 10 in the case of the configuration of FIG. At this time, when a packet is transmitted from the terminal 21 to the terminal 20, the same correspondence as the correspondence between the VLAN identification information of the packet and the source MAC address (b: the MAC address of the terminal 21) is the opposite device. Since it does not exist in the MAC address storage memory, it can be regarded as a network construction error due to a cable connection error or a VLAN setting error. Note that blanks in FIG. 6 are not particularly described because they are unconscious in this operation example.

  In this case, as a means for notifying the maintenance person, for example, a display using an LED or the like, a buzzer sounding, a notification to the management server by sending an SNMP trap, and the like can be considered.

  According to the present invention, in a network composed of layer 2 switches such as Ethernet, it is possible to easily detect a network construction error due to a cable connection error or a VLAN setting error between layer 2 switches. Efficient maintenance management can be realized. Also, by realizing efficient network maintenance management, service quality can be improved for the user.

The figure which shows the network structure of embodiment of this invention. The flowchart which shows the abnormality determination procedure of this invention. The block block diagram of the layer 2 switch of a present Example. The figure which shows the header information of a received packet, and the recording content of the opposing apparatus MAC table storage memory. The figure which shows the opposing apparatus MAC address storage memory in the layer 2 switch in the case of a normal network structure. The network block diagram when a cable connection is wrong between layer 2 switches. The figure which shows the opposing device MAC address storage memory in a layer 2 switch when a cable connection is mistaken between layer 2 switches.

Explanation of symbols

10, 11 Layer 2 switch 20-23 Terminal 30, 33 MAC table transmission unit 31, 32 MAC table reception unit 40, 41 MAC address comparison unit 100, 110 Own device MAC table 101, 111 Counter device MAC table storage memory

Claims (8)

In a layer 2 switch that forwards packets to a terminal connected to its own device or another layer 2 switch,
When a packet is received, the MAC (Media Access)
Control) means for learning and creating a MAC table;
Means for transmitting the MAC table held by the own device to another layer 2 switch;
Means for holding a MAC table received from another layer 2 switch;
Means for comparing the MAC related information obtained from the header information of the packet received from another layer 2 switch with the recorded content of the MAC table received from the other layer 2 switch held in advance;
A layer 2 switch comprising: means for determining that an error in network construction exists between the other layer 2 switch and the own device when a comparison result by the comparing means does not match. In the MAC learning, a VLAN (Virtual
Learning to record the correspondence between the identification information of (Local Area Network) and the source MAC address of the packet,
The layer 2 switch according to claim 1, wherein the MAC related information is information on a correspondence relationship between a transmission source MAC address of the packet included in header information of the received packet and a VLAN to which the packet belongs.   3. The layer 2 switch according to claim 1, further comprising means for notifying that when the means for determining determines that an error exists. In a network monitoring method executed by a layer 2 switch that transfers a packet to a terminal connected to its own device or another layer 2 switch,
When the layer 2 switch receives a packet, MAC learning is performed on the port that has received the packet, and a MAC table is created.
Transmitting the MAC table held by the own device to another layer 2 switch;
Holding a MAC table received from another layer 2 switch;
Comparing the MAC related information obtained from the header information of the packet received from another layer 2 switch with the recorded content of the MAC table received from the other layer 2 switch held in advance;
And a step of determining that there is an error in network construction between the other layer 2 switch and the own device when the comparison result of the comparing step does not match. The MAC learning is learning to record the correspondence between the identification information of the VLAN to which the packet belongs and the transmission source MAC address of the packet with respect to the port that received the packet,
The network monitoring method according to claim 4, wherein the MAC related information is information on a correspondence relationship between a transmission source MAC address of the packet included in header information of the received packet and a VLAN to which the packet belongs.   The network monitoring method according to claim 5 or 6, wherein when the layer 2 switch determines that an error exists in the determining step, a step of notifying the fact is executed.   A network comprising the layer 2 switch according to any one of claims 1 to 3.   A program that, when installed in a general-purpose information processing apparatus, causes the general-purpose information processing apparatus to realize a function corresponding to the layer 2 switch according to any one of claims 1 to 3.

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