JP5299020B2 - Data relay program, data relay method, and data relay device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To surely detect the generation of occupancy of communication band by data. <P>SOLUTION: An entry memory means 2 stores a plurality of entries correlated with identification information for identifying a last port that has received data transmitted by the same device in units of ports receiving data. An entry update means 3 updates identification information of the respective entries when receiving the data transmitted by the device from a port that is different from the last receiving port identified by the identification information. A detection means 4 detects the generation of occupancy of communication band by updating identification information for each of entries. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a data relay program, a data relay method, and a data relay device.

  A network having only one path may become unusable if the one path becomes unusable due to a failure. For this reason, securing a redundant path is generally performed.

  However, if a redundant path is secured, a loop exists in the network. If a loop exists in the network, a broadcast storm in which a communication band is occupied by broadcast data (broadcast data) occurs.

  In order to prevent this broadcast storm, STP (Spanning Tree Protocol) is known. When there is no failure, the STP keeps the redundant path from being used. Then, when a failure occurs and a used route becomes unusable, the route is switched to a redundant route.

However, when the STP falls into a state where it does not operate due to a failure of a network device or the like, a loop is formed and a broadcast storm occurs.
When a broadcast storm occurs, traffic increases. As a result, the processing capability of a device that has been operating normally may be exceeded, and a device that cannot operate the STP may be generated, which may worsen the situation. In this state, even if the device that caused the broadcast storm is restored, the network as a whole cannot operate normally.

As a method for securing a communication band, a method for determining a loop based on a reception time of a packet from a port is known.
In addition, a monitoring device is provided separately to collect information from each device that makes up the network, and by detecting the connection status of the device based on the collected information, it is possible to detect a state in which the bandwidth is being pressed by unnecessary traffic. The method is known.

JP 2004-320248 A Japanese Patent No. 3641589

  However, in the former case, it may be erroneously determined that a loop is formed even though the loop is not actually formed. For example, when a LAN cable is replaced from one port to another port, the packet reception interval varies depending on the scale of the formed loop, the load status of the switch device in the loop, and the like. If this reception interval is shortened, the loop cannot be detected, and if it is made longer, it may be erroneously determined that it has been formed. Therefore, there is a problem that it may not be possible to detect the occurrence of a broadcast storm.

  In the latter case, when a loop is already formed and a broadcast storm has occurred, there is a problem that information cannot be collected and the occurrence of the broadcast storm may not be detected.

  The present invention has been made in view of these points, and an object of the present invention is to provide a data relay program, a data relay method, and a data relay device that can reliably detect occurrence of occupation of a communication band due to data. To do.

  In order to achieve the above object, a disclosed data relay program is provided. This data relay program causes the computer to function as entry storage means, entry update means, and detection means.

The entry storage means stores, for each port that receives data, a plurality of entries that are associated with identification information that identifies the port that last received the data transmitted by the same device.
The entry update means updates the identification information of each entry when the data transmitted by the device is received from a port different from the port identified as having received the identification information last.

The detection means detects occurrence of occupation of the communication band by updating the identification information of each entry.
According to such a data relay program, a plurality of entries are stored by the entry storage means. When the data transmitted by the device is received from a port different from the port identified as having been received last by the identification information, the entry update means updates the identification information of each entry. By updating the identification information of each entry, the detection unit detects the occurrence of occupation of the communication band.

  According to the disclosed data relay program, it is possible to reliably detect occurrence of occupation of a communication band due to data.

It is a figure which shows the outline | summary of the data relay apparatus of embodiment. It is a figure which shows the structure of a system. It is a figure which shows the hardware structural example of a switch apparatus. It is a block diagram which shows the function of a switch apparatus. It is a figure which shows the structure of a Mac address table. It is a flowchart which shows the process of a switch apparatus. It is a flowchart which shows a post process. It is a figure which shows the updated Mac address table. It is a figure which shows the updated Mac address table. It is a figure which shows the updated Mac address table. It is a figure which shows the updated Mac address table. It is a figure which shows the updated Mac address table.

Hereinafter, embodiments will be described in detail with reference to the drawings.
First, the data relay apparatus according to the embodiment will be described, and then the embodiment will be described more specifically.

FIG. 1 is a diagram illustrating an overview of a data relay device according to an embodiment.
The data relay program according to the embodiment causes the computer (data relay apparatus) 1 to function as the entry storage unit 2, the entry update unit 3, and the detection unit 4.

The entry storage unit 2 stores a plurality of entries that associate identification information for identifying a port that has received data transmitted last by the same device for each port that receives data.
In FIG. 1, for a device with a physical address (for example, Mac address) “a”, an entry E1 for port P1 that has received data transmitted by the device with physical address “a” and a device with physical address “a” transmit. An entry E2 for the port P2 that has received the data is stored.

  Then, “OFF” indicating that the port P1 is not the last port that received the data is set in the identification information column of the entry E1, and the port P2 is set in the identification information column of the entry E2. “ON” indicating that the port has received data last is set.

  These entries are created and stored when the data relay device 1 receives data. Although not shown in FIG. 1, for example, when the port P1 receives data transmitted by the device having the physical address “b”, an entry that associates the physical address “b” with the port P1 and the identification information is created. And memorized.

  In addition, in FIG. 1, in addition to these pieces of information, a determination counter for determining whether or not occupation of the communication band has occurred is also associated. The initial value of the counter value is “2”, for example. The counter value of the determination counter monotonously decreases when a condition described later is satisfied.

  Here, when a device is transmitting broadcast data and the loop is formed in the network, the data relay device 1 may receive the broadcast data from a plurality of ports.

  The entry update means 3 updates the identification information of each entry when the data transmitted by the device having the physical address set in the entry is received from a port different from the port identified as having received the identification information last. To do.

The entry updating unit 3 monotonously decreases the counter value of the determination counter when data is received from a port different from the port of the entry whose identification information is set to ON.
In FIG. 1, when data is received from a port P1 different from the port P2 identified as having received identification information last, the identification information of entry E1 is set to ON and the identification information of entry E2 is set to OFF. To do. Further, the counter value of the determination counter of entry E1 is monotonously decreased.

The detecting unit 4 detects the occurrence of occupation of the communication band by updating the identification information of each entry by the entry updating unit 3.
Here, the occurrence of occupation of the communication band may be detected simply by updating the identification information of each entry. In FIG. 1, the counter value of the determination counter is a preset value (in FIG. 1, “ 0 "), it is determined that the communication band is occupied.

  Thereby, the occurrence of occupation of the communication band can be detected when a state in which broadcast data is received from a port P1 different from the port P2 that has been identified as having received identification information last time appears multiple times. False detection can be easily prevented.

  According to such a data relay device 1, when the port for receiving broadcast data is different even if the physical address is common, an entry is stored for each of these ports. When broadcast data is received from a port whose identification information is OFF, the identification information of the entry is updated, and the occurrence of occupation of the communication band is detected by this update. Therefore, it is possible to reliably detect occurrence of occupation of the communication band.

In addition, by setting a determination counter, erroneous detection can be easily prevented.
Hereinafter, the embodiment will be described more specifically.
FIG. 2 is a diagram showing the configuration of the system.

  The system 100 has a configuration in which a network area 10 and a network area 20 including at least one server device, terminal device, and the like are connected to a network 30 via switch devices SW1 to SW3, and the whole is one segment. (Layer 2 network). Here, the network 30 is a concept including the whole or a part of the Internet, an intranet, or an ISP (Internet Services Provider) network.

The network area 10 has a terminal device 10a. The network area 20 includes a server device 20a.
The Mac address of the terminal device 10a is “a”, and the Mac address of the server device 20a is “b”.

Each of the switch devices SW1 to SW3 has one or more physical ports (three ports P1 to P3 in FIG. 1) connected to other switches.
FIG. 3 is a diagram illustrating a hardware configuration example of the switch device.

  The entire switch device SW1 is controlled by a CPU (Central Processing Unit) 101. A random access memory (RAM) 102, a read only memory (ROM) 103, and a LAN port 104 are connected to the CPU 101 via a bus 105.

  The RAM 102 temporarily stores at least a part of application programs to be executed by the CPU 101. The RAM 102 stores various data necessary for processing by the CPU 101. The ROM 103 stores application programs. A program file is stored in the ROM 103.

  The LAN port 104 is connected to the network area 10 and the network 30. The LAN port 104 transmits and receives data to and from other switches and computers via the network area 10 and the network 30.

  With the hardware configuration as described above, the processing functions of the present embodiment can be realized. Although FIG. 3 shows the hardware configuration of the switch device SW1, the switch devices SW2 and SW3 can also be realized with the same hardware configuration. The following functions are provided in the switch devices SW1 to SW3 having such a hardware configuration.

FIG. 4 is a block diagram illustrating functions of the switch device.
The switch device SW1 includes an interface unit 11, a switch processing unit 12, a packet memory 13, an address table storage unit 14, and an address table management unit 15.

The interface unit 11 performs electrical processing of transmission / reception packets of the switching device SW1.
The switch processing unit 12 performs packet relay processing (switch processing).
The packet memory 13 temporarily stores the packet received from the interface unit 11. The packet stored in the packet memory 13 is transmitted from the interface unit 11 after being relayed by the switch processing unit 12.

The address table storage unit 14 stores a Mac address table for managing Mac addresses and various parameters associated with the Mac addresses.
The address table management unit 15 exchanges surrounding control information and updates the Mac address table stored in the address table storage unit 14.

The address table management unit 15 detects the occurrence of a broadcast storm based on information set in the Mac address table.
Further, the address table management unit 15 deletes the entry in the Mac address table that has not received a packet from the transmission source address for a certain period of time due to the elapse of the aging timer (time for holding the Mac address).

Next, the configuration of the Mac address table will be described.
FIG. 5 is a diagram showing the configuration of the Mac address table.
The Mac address table 14a includes columns for Mac, Port, duplication flag, update flag, and determination counter, and pieces of information arranged in the horizontal direction in one entry are associated with each other.

In the Mac column, the Mac address of the device on the network area 10 or the network area 20 that has received the packet by the switching device SW1 is set.
In the Port field, the number of the port that receives the packet of the Mac address is set.

  In the duplicate flag column, a flag indicating whether or not there is an entry in which a different port is set for one Mac address is set. Specifically, if there is an entry in the Mac address table 14a in which a Mac address is common and a different port is set, the duplication flag is set to ON. By providing the duplication flag, it is possible to easily grasp the presence / absence of an entry in which different ports are set for one Mac address.

In the update flag column, a flag indicating that the entry is the last updated among the entries having the same Mac address is set.
A counter value serving as an index indicating whether a broadcast storm has occurred is set in the determination counter column. The initial value of the counter value is “2” in the present embodiment. This initial value can be set to an arbitrary value.

  In a state where the STP is operating normally, the switch device SW3 receives only the port P1 from the terminal device 10a, so there is only one entry for one Mac address.

Next, processing of the switch device SW1 will be described.
FIG. 6 is a flowchart showing processing of the switch device.
First, the interface unit 11 receives a packet (step S1).

  The address table management unit 15 determines whether an entry including the source Mac address of the received packet is registered in the Mac address table 14a (step S2).

  When the entry including the transmission source Mac address is not registered (No in step S2), a new entry including the transmission source Mac address and information related to the transmission source Mac address is registered in the Mac address table 14a (step S3). ). That is, the Mac address of the received packet is set in the source Mac address column, the port name of the received packet is set in the port column, the duplicate flag is set to OFF, the update flag is set to ON, and the determination An entry in which the counter value of the counter is set to an initial value is registered in the Mac address table 14a.

  On the other hand, if an entry including the source Mac address has already been registered (Yes in step S2), the address table management unit 15 includes the source Mac address of the received packet and the port of the port that received the packet It is determined whether an entry including a name is registered (step S4).

  When the entry is not registered (No in Step S4), the address table management unit 15 registers an entry including the transmission source Mac address and information related to the transmission source Mac address in the Mac address table 14a (Step S5). ). That is, the Mac address of the received packet is set in the source Mac address column, the port name of the received packet is set in the port column, the duplicate flag is set ON, the update flag is set ON, and the determination An entry in which the counter value of the counter is set to an initial value is registered in the Mac address table 14a.

Further, the update flag of the entry of the same source Mac address that has already been registered is set to OFF (updated).
On the other hand, when the entry is registered (Yes in step S4), the address table management unit 15 determines whether or not the update flag of the entry is set to ON (step S6).

  When the update flag of the entry is not set to ON (No in step S6), the address table management unit 15 sets the update flag of the entry to ON, decrements the counter value of the determination counter, and transmits the same The update flag of the entry corresponding to another port of the original Mac address is set to OFF (step S7).

  On the other hand, when the update flag of the entry is set to ON (Yes in step S6), the address table management unit 15 determines whether or not the counter value of the determination counter is greater than “0” (step S8). .

  When the counter value of the determination counter is “0” (No in step S8), the address table management unit 15 determines that the broadcast storm state is set. At this time, the switch processing unit 12 performs broadcast storm processing (step S9). Specifically, one or more of the following processes are performed.

(1) Stop broadcast transmission for a certain period of time. For example, the broadcast packet is discarded.
(2) Restrict transfer only to broadcasts from specific terminal devices.

(3) Stop broadcast transfer to a specific port.
(4) Return to the previous (normal) forwarding table.
(5) Aging time extension process By performing these processes, a broadcast storm can be prevented and communication can be ensured. In addition, when the STP cannot operate normally due to the processing load, the STP function can be restored normally.

On the other hand, when the counter value of the determination counter is larger than “0” (Yes in step S8), the process proceeds to step S1 to process the next packet.
Next, processing after the broadcast storm processing (post processing) will be described.

FIG. 7 is a flowchart showing post-processing.
First, the address table management unit 15 determines whether or not there is an entry including a port that has not received a packet even after the aging timer elapses, among entries registered in the Mac address table 14a (step S1). S11).

If there is no entry including a port that has not received a packet (No in step S11), the process of step S11 is performed again after a predetermined time has elapsed.
On the other hand, when there is an entry including a port that has not received a packet (Yes in step S11), the address table management unit 15 deletes the entry from the Mac address table 14a (step S12).

Next, it is determined whether or not there is one entry including the same Mac address as that of the deleted entry (step S13).
If it does not exist (No in step S13), the post-processing is terminated.

  On the other hand, if it exists (Yes in step S13), the address table management unit 15 sets the duplication flag of the entry to OFF and returns the counter value of the determination counter to the initial value (step S14). Thereafter, the post-processing is terminated.

This is the end of the description of the post-processing.
Next, a specific example of the transition of the Mac address table 14a when a loop is formed due to an STP operation failure due to a failure of the switch device SW2 or the like will be described.

FIG. 8 shows an updated Mac address table.
When a broadcast packet is transmitted from the terminal device 10a in a state where a loop is formed, the switch device SW3 receives the packet not only from the port P1 but also from the port P2.

  At this time, the port P2 entry is added without rewriting the port corresponding to the Mac address “a” from the port P1 to the port P2, and the update flag and the counter value are set.

Note that a packet addressed to the terminal device 10a is transmitted to a port whose update flag is ON (port P2 in FIG. 8).
Since a plurality of entries are generated for the Mac address “a”, the duplication flag of each entry is set to ON. Since the port P2 last received the packet for the Mac address “a”, the update flag of the entry of the port P2 is set to ON, and the update flag of the entry of the port P1 is set to OFF.

<Monitoring broadcast storm status>
Broadcast packets transmitted in the network 30 in a state where a loop is formed start to circulate in the loop. At this time, in the switch device SW3, a state in which the packet from the terminal device 10a is received again from the port P1 occurs. At this time, the address table management unit 15 updates the Mac address table 14a.

FIG. 9 is a diagram illustrating the updated Mac address table.
Since the port P1 last received the packet for the Mac address “a”, the update flag of the entry of the port P1 is set to ON, and the update flag of the entry of the port P2 is set to OFF. Further, since the port P1 has received the packet with the duplication flag ON and the update flag OFF, the port P1 decrements the counter value of the determination counter.

  A broadcast storm occurs because there are multiple entries at the same Mac address, that is, packets are received from multiple ports with the duplicate flag set to ON (packets are received even when the update flag is set to OFF). Monitor the situation as it may have.

<Broadcast storm monitoring status>
When the switch device SW3 receives again a packet from the terminal device 10a from the port P2 in a state where the occurrence of the broadcast storm is suspected, the Mac address table 14a is updated.

FIG. 10 is a diagram illustrating the updated Mac address table.
Since it is the port P2 that last received the packet for the Mac address “a”, the update flag of the entry of the port P2 is set to ON, and the update flag of the port P1 is set to OFF. Further, the port P2 decrements the counter value of the determination counter because the packet is received with the duplication flag ON and the update flag OFF.

<Broadcast storm status>
When the switch device SW3 receives again the packet from the terminal device 10a from the port P1 in a state where the occurrence of the broadcast storm is suspected, the address table management unit 15 updates the Mac address table 14a.

FIG. 11 is a diagram illustrating the updated Mac address table.
Since the port P1 last received the packet for the Mac address “a”, the update flag of the entry of the port P1 is set to ON, and the update flag of the port P2 is set to OFF.

Further, since the port P1 has received the packet with the duplication flag ON and the update flag OFF, the port P1 decrements the counter value of the determination counter.
Here, since the counter value is “0”, it is determined that a broadcast storm has occurred.

<Post-processing>
As described above, the address table management unit 15 deletes an entry that has not received a packet from the transmission source address for a certain period of time due to the aging timer.

FIG. 12 is a diagram illustrating the updated Mac address table.
The address table management unit 15 deletes the entry when the packet having the Mac address “a” is not received from the port P2 for a certain period of time. Then, the duplication flag of the entry of the port P1 of the Mac address “a” is set to OFF, and the counter value of the determination counter is returned to the initial value.

If broadcast storm suppression processing such as transfer restriction or transfer processing is performed, it is determined that the broadcast storm state is in effect, and the suppression processing is canceled.
As described above, according to the system 100, the switching devices SW1 to SW3 detect the occurrence of the broadcast storm based on the change of the update flag value and the determination counter counter value set in the Mac address table 14a. Thereby, the occurrence of a broadcast storm can be reliably detected.

  Therefore, by suppressing broadcast packets, it is possible to reduce the traffic in the network and the processing load on the device, and to recover the device in which the STP cannot normally operate due to the processing load.

In addition, by allowing unicast packets, partial communication can be secured.
Also, traffic is not increased compared to a method of detecting a loop by transmitting a test packet to detect a loop, and detecting the occurrence of a broadcast storm.

  Also, the switch device SW1 newly creates an entry when a packet is received from a different port. As a result, it is determined that a broadcast storm has not occurred simply by changing the port that receives a packet from the same Mac address within a certain period of time. As a result, it is possible to reliably prevent erroneous detection that a broadcast storm has occurred due to fluctuations in the packet reception interval.

In addition, the switch device SW1 can detect and deal with a broadcast storm alone.
In this embodiment, the case where a packet is received from two ports (port P1 and port P2) has been described. However, even when there are three or more ports, the same processing is performed to ensure a broadcast storm. Can be detected.

  In the present embodiment, the counter value of the determination counter is decremented. However, the present invention is not limited to this, and the counter value of the determination counter is incremented (monotonically increased), and a broadcast storm occurs when the value reaches a certain value. You may make it detect.

  The data relay program, data relay method, and data relay apparatus of the present invention have been described above based on the illustrated embodiment. However, the present invention is not limited to this, and the configuration of each unit has the same function. Can be replaced with any structure having Moreover, other arbitrary structures and processes may be added to the present invention.

In addition, the present invention may be a combination of any two or more configurations (features) of the above-described embodiments.
The above processing functions can be realized by a computer. In that case, a program describing the processing contents of the functions of the switch devices SW1 to SW3 is provided. By executing the program on a computer, the above processing functions are realized on the computer. The program describing the processing contents can be recorded on a computer-readable recording medium. Examples of the computer-readable recording medium include a magnetic recording device, an optical disk, a magneto-optical recording medium, and a semiconductor memory. Examples of the magnetic recording device include a hard disk device (HDD), a flexible disk (FD), and a magnetic tape. Examples of the optical disc include a DVD (Digital Versatile Disc), a DVD-RAM (Random Access Memory), a CD-ROM (Compact Disc Read Only Memory), and a CD-R (Recordable) / RW (ReWritable). Examples of the magneto-optical recording medium include MO (Magneto-Optical disk).

  When distributing the program, for example, a portable recording medium such as a DVD or a CD-ROM in which the program is recorded is sold. It is also possible to store the program in a storage device of a server computer and transfer the program from the server computer to another computer via a network.

  A computer that executes a data relay program stores, for example, a program recorded on a portable recording medium or a program transferred from a server computer in its storage device. Then, the computer reads the program from its own storage device and executes processing according to the program. The computer can also read the program directly from the portable recording medium and execute processing according to the program. In addition, each time the program is transferred from the server computer, the computer can sequentially execute processing according to the received program.

1 Computer (data relay device)
DESCRIPTION OF SYMBOLS 2 Entry memory | storage means 3 Entry update means 4 Detection means 10, 20 Network area 10a Terminal device 11 Interface part 12 Switch processing part 13 Memory for packets 14 Address table storage part 14a Mac address table 15 Address table management part 20a Server apparatus 30 Network 100 System E1, E2 entry P1, P2, P3 port SW1, SW2, SW3 switch device

Claims (7)

Computer
Entry storage means for storing a plurality of entries associated with identification information for identifying a port that has received data last transmitted from the same device for each port that receives data;
When the data transmitted by the device is received from a port different from the port set in the entry stored in the entry storage means, a new entry in which identification information is associated with the different port is created, and the entry Entry creation means for storing in the storage means;
Entry update means for updating the identification information of each entry when the data transmitted by the device is received from a port different from the port that the identification information has been received last.
By updating the identification information of the respective entries, the end Unlike port being identified as the received data is received from a port configured from a previous reception of data entries stored in the entry storage unit Detecting means for detecting occurrence of occupation of the communication band based on the number of times;
A data relay program characterized by functioning as Each entry further includes a determination counter used for determining the occupation of the communication band,
The entry update means changes the counter value of the determination counter according to the update of the identification information of each entry,
The data relay program according to claim 1, wherein the detection unit detects occurrence of occupation of a communication band based on a change in the counter value. The entry update means monotonously increases or decreases monotonously the counter value of the determination counter when received from a port different from the port identified as the identification information received last.
3. The data relay program according to claim 2, wherein the detection unit determines that the communication band is occupied when the counter value of the determination counter reaches a preset value. Further causing the computer to function as an entry deleting means for deleting an entry having a port that has not received data for a predetermined time;
When there is one entry for the device stored in the entry storage means, the identification information for the entry is set to information for identifying the port that received the data last, and the counter value is determined in advance. claim 2 or 3 or claimed data relay program for and sets the obtained initial value.   The entry creation means sets the identification information of the newly created entry to information that identifies the port that received the data last, and the entry update means sets the identification information of the entry that has already been stored, 5. The data relay program according to claim 1, wherein the data relay program is set to information for identifying that the port is not the port that received data last.   Computer
  For each port that receives data, store a plurality of entries that associate identification information that identifies the port that received the last data transmitted by the same device,
  When the data transmitted by the device is received from a port different from the port set in the entry stored in the entry storage means, a new entry in which identification information is associated with the different port is created, and the entry storage Memorize in the means,
  When the data transmitted by the device is received from a port different from the port identified by the identification information received last, the identification information of each entry is updated,
  The number of times data is received from the port set in the entry stored in the entry storage means from before the data is received, unlike the port identified as having been received last by updating the identification information of each entry. Detecting the occurrence of communication bandwidth occupancy based on
  A data relay method.   An entry storage unit for storing a plurality of entries associated with identification information for identifying a port that has received data transmitted last by the same device for each port that receives data;
  When the data transmitted by the device is received from a port different from the port set in the entry stored in the entry storage unit, a new entry in which identification information is associated with the different port is created, and the entry An entry creation unit to be stored in the storage unit;
  An entry update unit that updates the identification information of each entry when the data transmitted by the device is received from a port different from the port that the identification information has been received last;
  The number of times data is received from the port set in the entry stored in the entry storage unit from before data reception, unlike the port identified as having been received last by updating the identification information of each entry. A detection unit that detects occurrence of occupation of the communication band based on
  A data relay device comprising:

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