KR100856216B1 - Packet switch device and bandwidth control method thereof - Google Patents

Abstract

The present invention uses a method of maintaining a database of IP addresses assigned to subscribers through DHCP, and using the packet sampling function provided by the packet switch chip to sample any packet and then deliver it to the CPU, and uses the delivered sample packet. By estimating the total bandwidth used by the user based on subscriber information (Source MAC, Source IP), if the estimated result is more than a certain threshold, the bandwidth limiting function is performed for the user. It is done. The present invention can dynamically recognize a user even for a plurality of undefined users and perform a dynamic bandwidth limiting function by tracking the bandwidth used by the user.

Packet, switch, DHCP, bandwidth, limit

Description

Packet switch equipment and its bandwidth control method {PACKET SWITCH DEVICE AND BANDWIDTH CONTROL METHOD THEREOF}

1 is a block diagram of a general packet switch equipment

Figure 2 is a block diagram of a packet switch equipment according to an embodiment of the present invention

3 is a flowchart illustrating a message transfer process between a client and a server according to DHCP of a packet switch device according to an embodiment of the present invention.

4 is a diagram illustrating statistical information calculation and update time during a bandwidth control procedure of a packet switch equipment according to an embodiment of the present invention.

5 is a flowchart of a bandwidth control operation of a packet switch equipment according to an embodiment of the present invention.

6 is a flowchart of a subscriber database management operation of a packet switch equipment according to an embodiment of the present invention.

The present invention relates to packet switch equipment of a packet-based network, such as Ethernet, and is specifically defined in DHCP (Dynamic Host Configuration Protocol; RFC 2131, Obsoletes RFC 1541) in packet switch equipment based on a packet switch chip. The present invention relates to a packet processing from a subscriber assigned with an authentication and an IP address and a bandwidth control method thereof.

DHCP is a protocol defined to efficiently use IP addresses by dynamically allocating IP addresses to subscribers joining a network using only a few IP addresses in an IP-based network structure. Although the purpose of DHCP is to efficiently use a limited IP address as described above, the parties operating the network only use packets that use IP assigned to the DHCP protocol of the equipment other than the purpose of efficient use of the IP address. In order to reduce the unnecessary bandwidth waste and authentication for the subscriber.

On the other hand, network switch devices based on packet switch chips are using functions provided by the chip itself to provide port-based bandwidth limit functions. The bandwidth limit function provided by the packet switch chip allows the user to manually set a set of control conditions regarding the chip's bandwidth limit, so that the packet switch chip can not use packets that meet a certain category according to the set method. It means a hardware limiting function. In this case, it should be noted that the user or the administrator must know the information on which categories should be limited (ie, the packet's MAC address and IP address, etc.). Information about whether to allow as much bandwidth as possible (metering information) must be set in advance by the operator directly on the packet switch chip.

In addition to the packet switch device, there is a function to apply a bandwidth limit based on all packets coming into the port based on a specific port, but in this case, a structure in which multiple users are connected to the same port can provide a desired function. none.

1 is a block diagram of a general packet switch equipment. Referring to FIG. 1, the packet switch equipment 10 first includes a packet switch chip 12 having a plurality of ports (PORT 8 to PORTN, for example). Each port may be connected to a plurality of subscriber stations 40, respectively. In FIG. 1, a plurality of subscriber stations 40 are connected through a subscriber distribution device 42 at port PORT2. In addition, the packet switch device 10 includes a memory 16 for storing information related to packet and port control via the packet switch chip 12, and the packet switch device 10 including the packet switch chip 12. It is provided with a controller (CPU) 14 for controlling the switching operation as a whole, and also provided with a communication channel unit 18 and the like for communicating with the operator terminal (30).

Taking the packet switch equipment 10 as shown in FIG. 1 as an example, in general, parties operating a network assign an IP address to a subscriber through DHCP, and the subscriber uses a allocated IP address to send a packet to a higher network. You can use the Internet by delivering. At this time, in a structure in which the network manager accommodates multiple subscribers in one port as shown in FIG. 1, it may be desired to limit the maximum bandwidth that each subscriber can use to prevent a specific subscriber from occupying the bandwidth of the corresponding port. For example, one subscriber may want to limit the use of more than 5000 PPS (Packets Per Second). In such a network configuration, the bandwidth limit function is generally as follows.

1) The number of subscribers in the structure of assigning IP address through DHCP changes over time. At one point in time, only one subscriber can use the network, and at another point, the maximum capacity can be connected to the network. Since the users of the network can change with time, the network operator presets the maximum bandwidth that each subscriber can use for all IP addresses that can be allocated. In other words, all IP addresses that can be assigned through DHCP are set in advance in the network device. In this case, if the IP used by DHCP is changed, reset is inevitable.

2) There is a disadvantage that the bandwidth of the network cannot be used efficiently when the above method is used. For example, assuming that the bandwidth of one port is 100Mbps and the maximum number of subscribers that can be accommodated on the port is 100, the bandwidth that each subscriber can use can be set to 1Mbps in case 100 users simultaneously use it. In this case, even if only one user is connected to the network, the subscriber cannot use more than 1Mbps. In order to overcome this disadvantage, the network operator does not limit the bandwidth in advance. However, the network operator may periodically monitor the network and limit the bandwidth only to a specific subscriber when a certain subscriber uses more bandwidth. In this case, there is a disadvantage that the network operator should always monitor the network, and it is not easy to find out in real time the bandwidth used by a particular subscriber in the best effort network using the network structure as shown in FIG.

3) If the IP address is assigned through DHCP, you can check the database of the assigned IP address. Based on this, the network operator may manually limit the bandwidth. In this case, it is impossible for a network operator to respond to dynamically changing IP address assignments.

As described above, when the bandwidth limiting function of the existing packet switch chip 12 is to be applied to a plurality of users assigned IP addresses using DHCP, the following problems exist.

1) In order to prevent packets from being sent from multiple users on a single port, and to prevent a specific user from using more than a certain bandwidth, it is necessary to configure the information of all subscribers that can be connected to the port. . By using DHCP to manage a database of IP addresses assigned to subscribers, it is possible to obtain subscriber information currently in use, but since this database is always changing over time, the network operator limits the bandwidth to the subscriber according to the change. It is almost impossible to do that.

2) Even if a user who can be connected to a port is predefined and the range of IP addresses that can be assigned to those users is predefined, the administrator must set the information corresponding to the predefined user directly on the device. If a user is added or deleted, administrator intervention is inevitable as well.

3) Since the number of users that can be connected to a single port is limited, there is a disadvantage that the effective bandwidth cannot be used even if the bandwidth can be set. For example, suppose that the total PPS that can be handled by one port is 10000. If 10 PPS is set to the maximum available bandwidth for each 10 users, one user cannot send more than 1000 PPS packets. If the remaining nine users are not currently using bandwidth, the subscriber will not be able to send more than 1000 PPS, which would result in wasting bandwidth.

Accordingly, an object of the present invention is to use the bandwidth limiting function of the packet switch chip in the network switch equipment based on the packet switch chip, a plurality of IP addresses assigned through DHCP without the administrator's intervention or only the administrator's basic settings It is possible to allocate bandwidth efficiently and efficiently to users in the network, to restrict the subscribers by blocking packets generated from subscribers that have not been assigned an IP address through DHCP, and to improve the bandwidth usage efficiency of the network. The present invention provides a packet switch device and a bandwidth control method thereof.

In order to achieve the above object, the present invention provides a method of maintaining a database of IP addresses assigned to subscribers through DHCP, and using the packet sampling function provided by the packet switch chip, samples an arbitrary packet and delivers it to the CPU. If the estimated value is above a certain threshold, the bandwidth limiting function is applied to the user based on the subscriber information (Source MAC, Source IP). It is characterized by using the manner of performing. The present invention can dynamically recognize a user even for a plurality of undefined users and perform a dynamic bandwidth limiting function by tracking the bandwidth used by the user.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description, specific details such as specific components are shown, which are provided to help a more general understanding of the present invention, and it is understood that these specific details may be changed or changed within the scope of the present invention. It is self-evident to those of ordinary knowledge in Esau.

2 is a block diagram of a packet switch equipment according to an embodiment of the present invention. Referring to FIG. 2, the packet switch equipment 20 according to the present invention is a packet switch chip 22 having a plurality of ports (PORT1 to PORTN) and a packet switch similarly to the prior art. Communication channel for receiving a plurality of parameters necessary for the operation of the present invention by communicating with the memory 26 for storing the packet and information related to the port control via the chip 22 and the operator terminal 30 A unit 28 and a controller (CPU) 24 for controlling the switching operation of the packet switch equipment 20, including the packet switch chip 22 as a whole. In FIG. 2, a plurality of subscriber stations 40 are connected via a subscriber distribution device 42 at port 2 of the packet switch chip 22.

In the above configuration, the packet switch chip 22 samples any packet according to a preset frequency using the packet sampling function according to the feature of the present invention and then delivers it to the controller 24, and the controller 24 The total used bandwidth of the user (subscriber) is estimated based on the subscriber information (source MAC, source IP) by using the transmitted sample packet, and if the estimated result value is above a certain threshold, the user (subscriber) Perform bandwidth limit for

More specifically, the controller 24 includes a DHCP client database management module 240, a sample packet processing module 242, and a bandwidth control processing module 244, in accordance with aspects of the present invention.

The DHCP client database management module 240 is a module for securing a database of currently used IP addresses, that is, subscriber information. When DHCP assigns an IP address to a client, DHCP delivers the time information of the assigned IP address and the IP address to be assigned to the client. The client uses the assigned IP address and then extends the usage time by re-requesting the server before the given usage time expires. These processes are defined in DHCP, the DHCP client database management module 240 of the present invention intercepts the DHCP packet exchanged between the server and the client through the DHCP protocol, the DHCP client database for the current IP address, that is, subscriber information Will be secured. In the present invention, the subscriber information registered in the DHCP client database (the DHCP client database may be provided in the memory 26) is used to determine whether to limit the bandwidth for the subscriber. If a packet with an unassigned IP address comes in, the bandwidth is limited to 0 so that the packet cannot be delivered to the upper network.

The sample packet processing module 242 analyzes the sampled packet provided from the packet switch chip 22, and classifies the packet according to a predefined field (source MAC or source IP) to determine which user the packet is from. Check it. If the user is registered in the DHCP client database, update the corresponding statistics. Statistical information for each user is stored separately for each unit time (t). If the IP address is not registered in the DHCP client database, the packet is dropped by setting the bandwidth of the packet to 0.

The bandwidth control processing module 244 calculates the total usage or average PPS during the last T time based on the statistical information stored for each unit time of each user, and when the value is more than a defined threshold, the bandwidth of the packet switch chip 22 Responsible for setting the limit function.

The packet switch chip 22 includes a packet sampling block 222 and a bandwidth control block 224. The packet sampling block 222 is part of a function provided by the packet switch chip 22, and has a settable probability. As a result, the packet is sampled and transmitted to the controller 24 according to a predetermined probability among the packets coming into the specific port. The probability that a packet is sampled by the packet sampling block 222 is p = 1 / N. The bandwidth control block 224 is a part of the function provided by the packet switch chip 22, and the operation setting is controlled by the bandwidth control processing module 244 of the controller 24, and the port is controlled according to the set contents. A hardware block that limits the bandwidth usage of packets.

The bandwidth limiting scheme proposed by the present invention performed by the packet switch equipment 20 of the present invention having the above-described configuration is only for authenticated users, that is, users who are authenticated by distinguishing between users who are not granted IP and DHCP users through DHCPf. It limits the use of this network and ensures fair use of bandwidth among authorized users. Therefore, management of the database of subscribers allocated through DHCP should be made in real time. Hereinafter, the DHCP client database update operation will be described in more detail with reference to FIG. 3.

Referring to FIG. 3, when a subscriber's terminal (DHCP client) is connected for the first time, the subscriber's terminal is assigned an IP address from a DHCP server using a DHCP protocol, as shown in FIG. 3. All the protocols intercept the switch equipment according to the present invention to check the contents of the DHCP message to update the IP address database finally assigned to the subscriber.

In more detail, according to DHCP, a DHCP client performs an initial IP address assignment process, an IP address update process, and an IP address return process with a DHCP server. In the initial IP address assignment process, since the DHCP client does not have an IP address at initial booting, the DHCP client generates a message for finding a DHCP server, that is, a "DHCP_DISCOVER" message, and transmits the message to the DHCP server through the network switch device of the present invention. Broadcast). Accordingly, the DHCP server generates and broadcasts a message containing one available IP address, that is, "DHCP_OFFER" as a response to the "DHCP_DISCOVER" message. The "DHCP_OFFER" message is also provided to the DHCP client through the network switch device. (If you have multiple DHCP servers, you can do the same for each server). The DHCP client receiving the "DHCP_OFFER" message from the DHCP server generates and broadcasts a message containing the assigned IP address and the IP address of the server that leased the IP address, that is, the "DHCP_REQUEST" message, and the "DHCP_REQUEST" message. The DHCP server sends a confirmation message, that is, "DHCP_ACK", and the DHCP client receives the final IP address assignment process. The "DHCP_ACK" message stores information such as IP address lease duration, DNS, default gateway, and the like. At this time, the DHCP server among the DHCP servers that do not accept the IP address sent by themselves will maintain its own IP database.

As such, the DHCP client assigned the initial IP address renews the IP address by periodically sending a "DHCP_REQUEST" message to the corresponding DHCP server during the IP address renewal process, and the "DHCP_RELEASE" for returning the IP address in the IP address return process. "Message will be sent to the DHCP server to return the assigned IP address.

In the network switch device according to the present invention, as shown in FIG. 3, the DHCP client database management module stores a database for a new subscriber at a time point when the "DHCP_ACK" message is transmitted from the DHCP server to the DHCP client (times ① and ② of FIG. Create and update. Similarly, at the time when the "DHCP_RELEASE" message is transmitted from the DHCP client to the DHCP server (time point 3 in FIG. 3), the database for the corresponding subscriber is updated.

Meanwhile, the bandwidth limiting operation using sampling in the packet switch device 20 of the present invention having the above-described configuration will be described in more detail below with reference to a bar line shown in FIG. 2.

① Parameter setting process

First, in the bandwidth limiting scheme proposed by the present invention, a packet sampled by a specific probability is used among packets coming into the packet switch chip 22. Therefore, information on the sampling frequency must be set in advance in the packet switch chip 22. The higher the sampling frequency, the better, but the load on the controller 24 is as much as the sampled packets have to be processed by the controller 24. Also, since sampling is not a factor of time, the more packets that enter a particular switch port for the same sampling frequency, the more packets that will be sampled. This increases the number of packets sampled as the maximum bandwidth of the switch port increases. Therefore, it is necessary to set an appropriate sampling frequency according to the maximum bandwidth supported by the switch port.

In addition to this sampling frequency, parameters to be set in advance include the maximum sampling number; Unit time t and T for updating statistical information; Bandwidth limit threshold; And the like.

Sampling frequency refers to a factor of how many percent of the total packets are to be sampled (which is an average factor for how many samples to sample). The maximum sampling number is the maximum number of packets that can be sampled when the packet using the maximum bandwidth supported by the switch port is set and the sampling frequency is set (this factor may vary depending on the length of the packet used. Therefore, it is defined as the number corresponding to the basic unit packet to be used in the statistical information.

Regarding the unit time t for updating the statistical information, the present invention updates the statistical information of each user based on the unit time t, and the updated data is stored as independent data. The unit time T (T = nt) for the final statistical mean means the time that the acquired statistical information is maintained in the system according to the unit time t for updating the statistical information, which is based on the stored statistical information for each unit time t. The unit time to average the packets sampled during the most recent T time.

As for the bandwidth limit threshold, the present invention applies the bandwidth limit function to the switch chip when the average value of the sampled packets exceeds this threshold.

Such parameters may be set in advance by an input value of the manager terminal 30 by the manager, and the manager may set an appropriate parameter value through the manager terminal 30. In the above description, all the parameter values described above are set by the administrator, but at least some of these parameters may be automatically set to appropriate values in advance. The meaning of these parameters and the operation using them will be more clearly understood by the following description.

② Packet sampling process

After the basic parameter setting of step ① is completed, all incoming packets are sampled according to the sampling frequency set in step ① and delivered to the controller 24. The forwarded packet is checked by the sample packet processing module 242 to determine whether the packet exists in the subscriber database secured through the operation according to DHCP as shown in FIG. If the packet exists in the subscriber database, the sampling information (number of packets introduced) is updated. Otherwise, it is regarded as not an IP address allocated through DHCP, and bandwidth is directly limited to 0 without going through the bandwidth control processing module 244. Perform the process.

③ Update of statistical information of sampled packet

In the sample packet processing module 242, the statistical information update operation is performed every t time (unit time for updating statistical information). First, the statistical information updated by the current time for each user is stored, and the stored statistics The average statistical information of the statistical information stored within the latest T time from the information is calculated. In FIG. 4, since the currently stored statistical information is the nth information and the T time is set to 3t, the average statistical information is obtained using the previous n-2 and n-1th stored statistical information and the present (nth) stored statistical information. Calculate. Thereafter, a memory space for storing statistical information of packets coming from the current time to the next t time is created, and a timer is set to perform the statistical information update module at the next t time.

④ Bandwidth Limit Process

After checking whether there is a source (that is, a user) exceeding the bandwidth limit threshold value among the average statistical information of all sources calculated through the step (3) above, if there is a corresponding source (user) through the bandwidth control block 224 Set the switch chip to not exceed the maximum guaranteed bandwidth. At this time, the maximum guaranteed bandwidth is automatically calculated according to the following policy to limit the bandwidth for the subscriber.

One). For a port that receives a packet that exceeds the bandwidth, if you want to guarantee the same bandwidth to all users connecting to that port, the minimum guaranteed bandwidth is

(Total bandwidth of the port) / (total number of users using the network over the port)

The bandwidth control module for the subscriber is performed as the value determined as the minimum guaranteed bandwidth.

 2). If the user wants to limit the bandwidth to a certain value regardless of the number of subscribers in use, the bandwidth is limited to a predefined value for the IP source assigned to the subscriber.

Which of the above 1) or 2) suggests a bandwidth for the subscriber is previously set by an administrator or the like.

FIG. 5 is a flowchart of a bandwidth control operation of the packet switch equipment according to an embodiment of the present invention, and the control operation of the controller 24 as shown in FIG. 2 will be described as an example. Referring to FIG. 5, the controller 24 first receives and sets various parameter values necessary for bandwidth control, such as sampling frequency, maximum sampling number, packet separator, unit time t and T, and threshold value, by the manager in step 400. Perform the action. In this case, the threshold value indicates a threshold value available for each user. When a parameter value is input from such an administrator, the bandwidth limit function may be set in advance or not. If the bandwidth limit function is activated as described above, it is checked in step 402 and then proceeds to step 404.

In step 404, the packet is currently being sampled and delivered by the packet switch chip 22, and it is checked whether the packet introduced through the sampling exists in the database. If the result is that the user already exists, proceed to step 408 to update each user statistics information, that is, the information on the number of used packets, and proceed to step 410. If the check result does not belong to an already existing user, proceed to step 406. The IP address corresponding to the "BLOCK" list is registered, and the corresponding bandwidth is set to 0 in step 407.

In step 410, if the unit time t has not expired, and if the unit time t has not expired, the process returns to step 404 and repeats the above process. If the unit time t has expired, the process proceeds to step 412.

In step 412, the average number of packets for each user is calculated during the last T time. In step 414, it is determined whether the average usage of a particular subscriber is greater than or equal to a threshold. If the result of the check is that the average usage of the subscriber is greater than or equal to the threshold, the process proceeds to step 416. In step 416, it is determined whether to limit the bandwidth according to the number of subscribers currently using the network. If so, the controller proceeds to step 418 to calculate the bandwidth value to be limited using the current number of subscribers identified by the subscriber database. In step 419, the bandwidth for the subscriber is limited to the calculated value. The calculated bandwidth limit is the minimum guaranteed bandwidth that guarantees the same bandwidth for all users, which is obtained by (total bandwidth of the port) / (total number of users using the network through the port).

In addition, in step 416, it is determined whether to limit the bandwidth according to the number of subscribers currently using the network. If not, the flow proceeds to step 417, and the bandwidth for the subscriber is limited to a preset value.

On the other hand, if it is determined that the average usage of a particular subscriber is not greater than the threshold in step 414, the process proceeds to step 420 after which it is checked whether the amount of packet use of the user whose bandwidth limit is already reflected is less than the threshold, and then 422. The bandwidth restriction function for the packet type corresponding to the user identified in the step is released.

Looking at the above process, when the average usage of a particular subscriber is above the threshold, it is understood that the bandwidth of the subscriber is limited to the minimum guaranteed band according to the total users currently using the network, or to a preset value. Can be.

6 is a flowchart of a subscriber database management operation of the packet switch equipment according to an embodiment of the present invention, and describes the control operation of the controller 24 as shown in FIG. Referring to FIG. 6, it is checked in step 502 whether the current bandwidth limit function is activated.

In step 504, an event in which a new subscriber is added by a current DHCP message has occurred, and it is checked whether the new subscriber exists in the block list described with reference to FIG. If the new subscriber exists in the block list, the process proceeds to step 506 to remove the corresponding IP address from the block list, and in step 508, the bandwidth limit for the subscriber is released and the process proceeds to step 510.

On the other hand, if the new subscriber does not exist in the block list as a result of the check in step 504, the process proceeds to step 509 to update the user database as new users are added.

Thereafter, in step 510, whether the bandwidth of the specific subscriber is limited to the port where the new user is added is checked, and if so, the process proceeds to step 512. In step 512, it is determined whether the bandwidth is previously set to be limited according to the number of subscribers currently using the network. If so, the flow proceeds to step 514.

In step 514, since the new subscriber is added, the bandwidth value to be restricted is recalculated, and in step 516, the bandwidth for the subscriber is limited to the calculated value.

As described above, the configuration and operation of the packet switch equipment and its bandwidth control method according to an embodiment of the present invention can be made. Meanwhile, in the above description of the present invention, a specific embodiment has been described, but various modifications of the present invention are made. It can be carried out without departing from the scope. Therefore, the scope of the present invention should not be defined by the described embodiments, but by the claims and equivalents of the claims.

 As described above, the packet switch equipment and its bandwidth control method according to the present invention do not need to pre-define the bandwidth setting for all the user-specific packets that can be introduced into a specific port of the packet switch chip, through packet sampling User information is dynamically added according to the incoming packet, and packet statistics information is managed, and bandwidth limiting function is dynamically performed according to the result, so that the bandwidth limiting function according to the flow of packets can be used. In particular, the present invention can provide a dynamic bandwidth limiting function according to the change of the subscriber because the bandwidth is limited based on the subscriber information allocated by DHCP.

In addition, by limiting the bandwidth to 0 for packets that are not given IP through DHCP (packets coming from unauthenticated subscribers), it is possible to efficiently use the network by preventing unnecessary packets from passing through the network.

In addition, by changing only a number of necessary parameters proposed in the present invention, it is possible to easily change and apply the bandwidth scheme and the bandwidth limit criteria.

In addition, the bandwidth is limited to the user database for each specific subscriber, thereby effectively using the entire bandwidth.

Claims (10)

Packet switch equipment, A packet switch chip having a plurality of ports for switching packets and sampling and outputting an arbitrary packet according to a preset frequency; Management of a database of subscribers allocated through Dynamic Host Configuration Protocol (DHCP) is performed, and when a sampled packet output from the packet switch chip is provided from a subscriber stored in the database, the usage of each packet of the user is determined. Packet switch equipment characterized in that it comprises a controller for performing a bandwidth limit function for each user. The method of claim 1, wherein the controller A DHCP client database management module that checks a DHCP packet exchanged between a server and a client through DHCP and secures the database of subscriber information corresponding to the currently used IP address; A sample packet processing module for analyzing the sampled packets, checking whether the corresponding user is registered in the database, and updating statistical information on packet usage for each user every predetermined time; And a bandwidth control processing module for checking the packet usage for a preset T time by using the statistical information on the packet usage for each user, and setting the bandwidth limiting function when the determined value is greater than or equal to a preset threshold. Packet switch equipment. The method of claim 2, wherein the packet switch chip A packet sampling block for sampling a packet according to a preset probability among packets coming into each port and outputting the packet to the controller; And a bandwidth control block for controlling bandwidth usage of packets entering the port under the control of the bandwidth control processing module. The packet switch device according to any one of claims 1 to 3, wherein the controller sets the bandwidth for the packet to zero when the user is not registered in the database. The packet switch device according to any one of claims 1 to 3, wherein the controller sets the bandwidth for the user of the packet to zero when the user is not registered in the database. In the bandwidth control method of the packet switch equipment, Managing the database of subscribers allocated through the Dynamic Host Configuration Protocol (DHCP); Sampling the input packets according to a preset sampling frequency; Checking whether the user of the sampled packets is registered in the database and updating statistical information on the usage amount of each user registered in the database; Identifying a user who is equal to or greater than a predetermined threshold value among the statistical information; And limiting bandwidth for a user who is equal to or greater than the identified threshold value. The method of claim 6, wherein the updating of the statistical information is performed by storing the statistical information individually every predetermined time. Identifying a user that is greater than or equal to a predetermined threshold value among the statistical information is performed through the statistical information stored for each user within a preset T time. The bandwidth limiting method of claim 6, further comprising releasing the bandwidth limiting function when a user who has already applied the bandwidth limit is less than or equal to the threshold. The bandwidth limiting method according to any one of claims 6 to 8, wherein the bandwidth of the user for the packet is set to 0 when the user of the sampled packets is not registered in the database. 9. The method of any one of claims 6 to 8, wherein limiting the bandwidth for users above the identified threshold is the minimum guaranteed bandwidth divided by the total bandwidth of the port that the packet came in from the total number of users connected through that port. Limiting or limiting to a preset bandwidth limit value.

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