JP2009081629A - Band monitoring device, and band monitoring method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress a decrease in a throughput due to the shortage of a burst size in band monitoring. <P>SOLUTION: When a decrease in a throughput occurs, a burst size is changed to a proper value in accordance with a transmission band of packet flow and quantity of water of a bucket. When the quantity of the water of the bucket is a maximum burst size or more (time t5), a band monitoring part increases the maximum burst size. Since the maximum burst size can be changed in accordance with a fluctuation in the quantity of the water of the bucket in this way, continuous discard of packets involved in the occurrence of overflow can be suppressed, and an average band can be stably output to a monitoring band. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a bandwidth monitoring device that monitors the bandwidth of a packet flowing into a network.

  With the diversification of services using the network, in addition to best-effort traffic that does not guarantee communication quality (Quality of Service), network resources such as communication line bandwidth and queue buffer capacity are reduced. A communication quality guarantee type communication mode using QoS distribution appropriately distributed is used. In a communication quality assurance type communication mode, in order to prevent a certain network user from occupying a bandwidth, for example, a MAC header, a TCP / UDP port number for identifying a communication application, etc. A bandwidth monitoring function (UPC function) for detecting a packet flow representing a series of packet flows defined as a combination of various conditions and monitoring the bandwidth of the packet is used.

  The UPC function relays, as a compliant packet, a packet that complies with a pre-defined monitoring band among received packets, and drops the packet that does not comply with the monitoring band as a violation packet or lowers the priority when relaying This is a function that suppresses network congestion.

  The UPC function setting parameter generally includes a burst size in addition to the monitoring band. The burst size is a value that allows temporary bandwidth fluctuation (burst) of the monitored packet flow. Even if the bandwidth of the packet flow temporarily exceeds the monitored bandwidth, it is the maximum that is determined as a compliant packet. The number of bytes. As a cause of occurrence of the burst, for example, there is a congestion control function of the TCP protocol of the transmitting device in TCP-IP communication.

Japanese Patent Laid-Open No. 2003-46555 “Bandwidth Monitoring Device” Japanese Patent Laid-Open No. 2004-254164 “Bandwidth Monitoring Device” The ATM Forum, Traffic Management Specification Version 4.1 IEICE technical report. Multimedia and virtual environment fundamentals Vol.102, No.661 (20030220) pp. 27-30

  Since the TCP protocol has a congestion control function that avoids network congestion by constantly increasing / decreasing the transmission bandwidth of the packet flow according to the congestion state of the network, a burst inevitably occurs. Even in the case of non-TCP-IP communication, when the network is congested, packets are accumulated in a queue in the packet relay apparatus that constitutes the network, resulting in a tight packet transmission interval and a burst.

  When the burst size of the UPC function is set to be smaller than necessary, the burst generated due to the above factors cannot be allowed, and the bandwidth of the compliant packet after application of the UPC function (hereinafter referred to as throughput in this specification) becomes the monitoring bandwidth. The problem of not being satisfied arises.

  On the other hand, when an excessive burst size is set, an excessive burst that cannot be accepted by the network flows in, resulting in a problem that communication stability is impaired.

  The present invention has been made in view of the above-described problems, and monitors when the throughput decreases by changing the burst size to an appropriate value according to the transmission bandwidth of the packet flow, the amount of data waiting to be transmitted, and the like. The purpose is to provide a stable throughput for the bandwidth.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.

[Application Example 1]
The bandwidth monitoring apparatus according to the application example 1 is disposed between the transmission device and the reception device, and monitors a bandwidth used by a packet transmitted from the transmission device to the reception device. A receiving means for receiving a packet of interest that is a packet input using a transmission band that fluctuates within a certain range, and a packet to be relayed to the receiving device among all packets input before reception of the packet of interest Virtual storage means for virtually storing the packet, transmission means for transmitting the packet to be relayed to the receiving device according to the monitoring band, and total data of the packets stored in the virtual storage means when the packet of interest is input When the amount is less than a first threshold value representing the maximum capacity of the virtual storage means, it is determined that the packet of interest is a compliance packet, and when the total data amount is greater than or equal to the first threshold, the packet of interest is A determination unit that determines that the packet is a violation packet that does not comply with the monitoring bandwidth; Was stored in the virtual storage means comprises a selection means not accumulate been noted packet determines that the violation packet, on the basis of the variation of the transmission band, and changing means for changing the first threshold value, a.

  According to the bandwidth monitoring apparatus of Application Example 1, the first threshold value can be changed according to the change in the transmission bandwidth. Accordingly, when the burst size is insufficient, a decrease in throughput can be suppressed by changing to an appropriate value.

  In the bandwidth monitoring apparatus of Application Example 1, the changing unit increases the first threshold when the total data amount that increases or decreases according to a change in bandwidth is equal to or greater than the first threshold.

  According to the bandwidth monitoring apparatus of the application example 1, the threshold value can be increased according to the total data amount of the compliance packet stored in the virtual storage unit. Therefore, when the burst size is insufficient, a decrease in throughput can be suppressed by changing to an appropriate value.

  In the bandwidth monitoring apparatus of Application Example 1, an empty state in which the compliance packet is not stored in the virtual storage unit, and an overflow state in which the compliance packet is stored in the virtual storage unit over the first threshold value And detecting means for detecting a vibration state indicating that the vibration state is alternately repeated, and the changing means increases the first threshold when the vibration state is detected a predetermined number of times within a predetermined time. Let

  According to the application example 1, when the vibration state is detected, the first threshold value can be increased, so that the occurrence of the overflow state and the empty state can be suppressed. Since the throughput decreases when an empty state occurs, the decrease in throughput can be suppressed as a result of suppressing the occurrence of the empty state.

  In the bandwidth monitoring apparatus according to the application example 1, the determination unit may further determine the total data amount when the total data amount is between the first threshold value and a second threshold value lower than the first threshold value. The packet of interest is determined as the violation packet based on a violation rate that is predetermined to increase with the increase.

  According to the bandwidth monitoring apparatus of the application example 1, since packets are discarded at a pre-specified violation rate before the first threshold of the total data amount is exceeded, a decrease in throughput of TCP-IP communication can be suppressed.

  In the bandwidth monitoring apparatus according to the application example 1, the changing unit further increases the second threshold value.

  According to the bandwidth monitoring apparatus of Application Example 1, it is possible to suppress an increase in the interval between the first threshold value and the second threshold value. Therefore, a decrease in throughput can be suppressed by changing to an appropriate value when the burst size is insufficient.

  In the bandwidth monitoring apparatus according to the application example 1, the changing unit increases the second threshold according to a predetermined increase rate. The changing unit increases the first threshold value according to a predetermined increase rate.

  According to the bandwidth monitoring device of Application Example 1, the first threshold value and the second threshold value can be easily increased, and the processing load of the bandwidth monitoring device can be reduced.

  In the bandwidth monitoring apparatus according to the application example 1, further, a transmission bandwidth calculation unit that calculates the transmission bandwidth using an integrated value of the data amount of the input packet every fixed time, and a data amount of the compliance packet every fixed time A compliance packet bandwidth that is a bandwidth of the compliance packet using the integrated value, that is, a compliance packet bandwidth calculation unit that calculates throughput, and the changing unit has the calculated transmission bandwidth equal to or higher than the monitoring bandwidth, and When the calculated throughput is less than the monitoring band, the first threshold value is increased.

  According to the bandwidth monitoring apparatus of the application example 1, the first threshold value is dynamically increased according to the actual throughput, and when the burst size is insufficient, the value can be changed to an appropriate value. The decrease in throughput can be suppressed well.

  In the bandwidth monitoring apparatus according to the application example 1, the changing unit does not change the first threshold when the first threshold is equal to or greater than a predetermined upper limit.

  According to the bandwidth monitoring apparatus of Application Example 1, it is possible to suppress an increase in load on the network due to the first threshold being increased without limit.

  The bandwidth monitoring apparatus according to the application example 1 further includes notification means for notifying the user of the total data amount. Further, the notification means further notifies the first threshold value.

  According to the bandwidth monitoring apparatus of the application example 1, the user can be notified of the amount of data stored in the virtual storage means and the first threshold value, so that it is possible to provide a means for the user to grasp the required burst size. Therefore, the convenience of the user can be improved.

  In the band monitoring apparatus of Application Example 1, the communication apparatus further includes a communication detection unit that detects the end of communication between the transmission device and the band monitoring apparatus, and the change unit is changed when the end of the communication is detected. The first threshold value and the second threshold value are respectively changed to predetermined initial values.

  According to the bandwidth monitoring apparatus of the application example 1, the first threshold value can be returned to the initial value in preparation for new communication.

  In the bandwidth monitoring apparatus of Application Example 1, the changing unit decreases the first threshold value and the second threshold value when the total data amount is equal to or less than a predetermined lower limit value.

  According to the bandwidth monitoring apparatus of Application Example 1, when the total data amount is equal to or lower than the lower limit value, it is possible to suppress the occurrence of unnecessary bursts, and thus it is possible to suppress an increase in load on the network. Therefore, it is possible to suppress the bandwidth reduction.

  In the present invention, the various aspects described above can be applied by appropriately combining or omitting some of them.

A. First embodiment:
A1-1. System configuration:
In the first embodiment, a network using TCP-IP communication will be described. FIG. 1 is an explanatory diagram illustrating the configuration of an IP network in the first embodiment. The IP network includes a site A_210, a site B_220, a site C_230, a site D_240, and a carrier network 200. Site A_210, site B_220, site C_230, and site D_240 are connected to the carrier network 200. Each site has a router and a plurality of terminals. The carrier network 200 is connected to routers 201 to 203. In the first embodiment, the router 201 has a UPC function. The UPC function is a function for monitoring the bandwidth of each flow based on the set monitoring bandwidth value and burst size. The monitoring bandwidth value represents an average bandwidth for a certain period of time that permits relaying of the flow. The burst size is a value for allowing a temporary fluctuation of the monitoring traffic, and represents the maximum number of bytes that are determined to be a compliant packet after exceeding the monitoring bandwidth. The first embodiment is an example of the UPC function provided in the router. However, since the same UPC function can be provided even if the router is used as a switch, the present invention can also be applied to the switch.

  The router at each site shapes the bandwidth of a packet transmitted by terminals in the same site into a predefined bandwidth and transmits it to the carrier network 200. For example, the site A has a router 214 and terminals 211, 212, and 213, and when the bandwidth of a packet transmitted from the terminal 211 is equal to or higher than a predetermined bandwidth, the site A is shaped into a predetermined bandwidth. To the carrier network 200. The router 201 connected to the carrier network 200 uses a bandwidth monitoring function (also referred to as a UPC function), and observes the bandwidth of the packet transmitted by the router at the site A and the router at the site B in advance. And the inflow of packets exceeding the monitoring band to the carrier network 200 is suppressed.

  FIG. 2 is an explanatory diagram illustrating the format of a packet in the first embodiment. As shown in FIG. 2, the packet used in the first embodiment includes an L2 header portion 340, an L3 header portion 310, and an L3 data portion 320. The L2 header section 340 is a packet header at the link level L2, and is composed of information that differs depending on the type of input line of the packet. FIG. 2 shows the case of an Ethernet (registered trademark) line as an example. As shown in FIG. 2, the L2 header section 340 includes a source MAC address 341 that represents the MAC address of the packet transmitting device and a destination MAC address 342 that represents the MAC address of the receiving device of the packet. The L3 data section 310 is a network level (third layer) packet header, a source IP address 311 representing the IP address of the transmission terminal, a destination IP address 312 representing the IP address of the reception terminal, and the protocol of the transmission terminal The source port number 313 representing the destination port number, the destination port number 314 representing the protocol of the receiving terminal, and the L3 packet length that is the accumulated byte length of the L3 header portion 310 and the L3 data portion 320 is included. The L3 data unit 320 includes L3 data 321 that is user data.

  FIG. 3 is an explanatory diagram illustrating the packet format inside the router in the first embodiment. The format of the packet inside the router 201 includes an L3 header part 310, an L3 data part 320, and an internal header part 330. The internal header portion 330 includes an internal L3 packet length 331 that represents the byte length of the packet, an input line number 332 that is a line number to which the packet is input, an output line number 333 that is a line number to which the packet is output, and an input And an input L2 header length 334 that is an L2 header length corresponding to the type of line.

A1-2. Function block:
FIG. 4 is an explanatory diagram illustrating functional blocks of the router 201 in the first embodiment. The router 201 has an input line 110 for packet input, a packet receiving circuit 120 that performs packet reception processing, an output line 160 for packet output for packet output, a header processing unit 180, and a packet based on the output line number. A packet relay processing unit 140 that performs switching and a packet transmission circuit 150 that reads a packet from the transmission-side buffer 190 and performs packet transmission processing are provided. The header processing unit 180 includes a route search unit 130 that determines an output line number for identifying the output line 160, a flow detection unit 170 that detects a packet flow, and a bandwidth monitoring unit 500. The router 201 is connected to the management terminal 10 for managing the router 201 and performing various settings. In FIG. 2, one input line 110 and one output line 160 are shown. However, the router 201 includes a plurality of input lines, packet receiving circuits, header processing units, transmission buffers, and packet transmitting circuits. May be.

  The packet transmitted from the transmitting terminal is input to the packet receiving circuit 120 via the input line. The packet receiving circuit 120 temporarily stores input packets in a buffer, and transmits packet header information including the internal header part 330 and the L3 header part 310 to the header processing unit 180.

  The flow detection unit 170 of the header processing unit 180 detects a flow from the packet header information. A flow is, for example, a series of packets determined by a destination IP address, a source IP address, destination port information, source port information, and the like. When the flow detection unit 170 detects a flow from packet header information, The flow identifier that is the flow identification information is transmitted to the bandwidth monitoring unit 500.

  The bandwidth monitoring unit 500 performs bandwidth monitoring of each flow based on a preset monitoring bandwidth value and burst size. The bandwidth monitoring unit 500 performs bandwidth monitoring for each flow identifier, determines whether the packet is a “compliance packet” that observes the monitored bandwidth or a violation packet, and determines the determination result. The data is transferred to the packet receiving circuit 120. The flow detection conditions and bandwidth monitoring conditions set by the management terminal 10 include, for example, “the packet flow from sites A and C is 10 Mbps and the packet flow from sites B and D is The condition “5 Mbps” is included.

  When the determination result by the bandwidth monitoring unit 500 is “compliance packet”, the packet reception circuit 120 transmits the packet stored in the buffer to the packet relay processing unit 140. On the other hand, when the determination result by the bandwidth monitoring unit 500 is “violating packet”, the packet receiving circuit 120 discards the accumulated packet.

A1-3. Bandwidth monitoring model:
A model of bandwidth monitoring performed by the bandwidth monitoring unit 500 will be described with reference to FIG. FIG. 5A is a model diagram for explaining bandwidth monitoring in the first embodiment. FIG. 5B is a graph for explaining the packet violation rate in the first embodiment. The bandwidth monitoring of the first embodiment uses an algorithm based on a bandwidth monitoring algorithm called a leaky bucket. Hereinafter, in this specification, the leaky bucket algorithm is referred to as LB. In LB, it is expressed using a bucket 1003 having a predetermined depth and having a hole in the bottom surface. The diameter of the hole vacant on the bottom surface of the bucket 1003 represents the size corresponding to the monitoring band. From the bucket 1003, an amount of water proportional to the monitoring band leaks, and when a packet is received, water corresponding to the number of bytes of the link layer length is poured.

  As shown in FIG. 5A, the bucket 1003 is preset with a minimum burst size THRMIN and a maximum burst size THR. In this embodiment, the maximum burst size THR corresponds to the “first threshold” in the claims, and the minimum burst size THRMIN corresponds to the “second threshold” in the claims.

  As shown in FIG. 5B, the violation rate P increases at a predetermined ratio when the minimum burst size THRMIN is exceeded, and becomes 100% when the maximum burst size is exceeded. It is judged as.

A1-4. Detailed configuration of the bandwidth monitoring unit:
FIG. 6 is a functional block for explaining the detailed configuration of the bandwidth monitoring unit 500 in the first embodiment. The bandwidth monitoring unit 500 stores the bandwidth monitoring information 51 for each flow corresponding to the flow identifier, and the bandwidth monitoring table control unit 50 that reads the bandwidth monitoring information corresponding to the flow identifier of the input packet from the bandwidth monitoring table 51. A water volume determination unit 52 that determines the total amount of data in the buffer packet that increases or decreases according to the packet flow rate, a packet determination unit 53 that determines whether the bandwidth of the input packet complies with the monitoring bandwidth, A burst size changing unit 54 that changes the burst size according to the total amount of data that changes according to the bandwidth fluctuation.

  The water amount determination unit 52 includes a current water amount calculation circuit 520, a monitoring band accumulation unit 522, a previous packet input time accumulation unit 523, a previous bucket water amount accumulation unit 524, and a timer 525. The monitoring band accumulating unit 522, the previous packet input time accumulating unit 523, and the previous bucket water amount accumulating unit 524 are flip-flop circuits. Hereinafter, in the present specification and drawings, the monitoring band is represented by R, the previous packet input time is represented by TLST, and the previous bucket water amount is represented by CNT.

  The packet determination unit 53 includes a packet determination circuit 530, a current bucket water amount storage unit 531, a packet frame length storage unit 532, a maximum burst size storage unit 533, a minimum burst size storage unit 534, and a previous packet input time storage unit. 523 and a post-judgment bucket water amount accumulating means 537. The current bucket water amount accumulation unit 531, the packet frame length accumulation unit 532, the maximum burst size accumulation unit 533, the minimum burst size accumulation unit 534, the previous packet input time accumulation unit 523, and the post-judgment bucket water amount accumulation unit 537 include: It consists of a flip-flop circuit. Hereinafter, in the present specification and drawings, the current bucket water amount is also referred to as NOWCNT, the packet length is LEN, the maximum burst size is THR, the minimum burst size is THRMIN, and the post-judgment bucket water amount is also referred to as CNT2.

  The burst size changing unit 54 includes a burst size changing circuit 540, a maximum burst size initial value storage unit 541, an increase rate storage unit 548, an increase rate upper limit storage unit 549, a minimum burst size initial value storage unit 557, and a post-change Burst size storage means 552. Hereinafter, in this specification and drawings, the increase rate is EXP, the changed maximum burst size is THRNEW, the changed minimum burst size is THRMINNEW, the current bucket water amount is CNT, the maximum burst size initial value is THR0, and the minimum burst size initial value is THRMIN0 and the increase rate upper limit value are also expressed as EXPLIM.

  The water amount determination unit 52 calculates the amount of water accumulated in the bucket 1003 and passes it to the packet determination unit 53. The packet determination unit 53 determines that the received packet is a “compliance packet” until the amount of water accumulated in the bucket 1003 exceeds the minimum burst size, and the amount of water accumulated in the bucket 1003 is the minimum. When the burst size starts to be exceeded, some packets are randomly selected from the received packets based on the violation rate, and are determined as “violating packets”. The packet determining unit 53 passes the determination result to the packet receiving circuit 120 and the burst size changing unit 54. A packet determined to be a received packet is relayed as it is, and a packet determined to be a violation packet is discarded by the packet receiving circuit 120.

  The burst size changing unit 54 uses the various information acquired from each storage means and the packet determining unit 53, and when the amount of bucket water after the determination of packet compliance or violation exceeds the maximum burst size, Increase the minimum burst size. In this specification, the state where the bucket water volume exceeds the maximum burst size is referred to as “bucket overflow” when the bucket overflows with water, and the bucket water volume is zero. It is also called “bucket bottoming” by comparing it to the state of not entering.

  In the communication of a response / request type protocol using the bandwidth monitoring function (the TCP-IP protocol is used in the first embodiment), when packet discard occurs continuously due to overflow of the bucket, the TCP protocol of the transmitting device is Then, it is determined that the network congestion is heavy, and the transmission bandwidth is rapidly reduced to zero. Such a process is called a slow start. When many TCP connections in the flow start slow start at the same time, the traffic on the network is reduced at a stretch. When this phenomenon occurs on a flow for which bandwidth monitoring is performed, the average bandwidth is not output up to the monitoring bandwidth, and the throughput that should be originally obtained cannot be obtained. Therefore, the bandwidth monitoring function of the present embodiment discards intermittent packets at a predefined violation rate. In this case, the TCP protocol determines that the network is lightly congested, and the transmission band is gradually reduced to about half, thereby suppressing a rapid decrease in the transmission band.

A1-5. Management terminal:
The management terminal 10 can input predetermined commands from the console screen, set various information related to bandwidth monitoring, and read values. FIG. 7 is an explanatory diagram illustrating a console screen of the management terminal in the first embodiment. As shown in FIG. 7, for example, the user inputs a command cmd1 via the console screen WD, whereby a desired value is stored in the minimum burst size storage means 534 (in the first embodiment, the maximum burst size is 12000 bytes). ) Can be set. Further, for example, the user can confirm various information such as the bucket water amount and the monitoring band at the time of command input, the maximum burst size after change, and the like by inputting the command cmd2 via the console screen. Since the bandwidth monitoring unit 500 stores various types of information in a flip-flop circuit, the management terminal 10 can easily set and reference various types of information.

A2. Burst size change processing:
A2-1. Processing flow:
8 and 9 are flowcharts for explaining the burst size changing process in the first embodiment. The burst size changing process is started when a packet is input.

  The current water amount calculation circuit 520 of the water amount determination unit 52 calculates the elapsed time ΔT from the previous packet input (step S101), and calculates the amount of water ΔDEC leaked from the hole of the bucket 1003 during the calculated ΔT (step S102). ). The water amount determination unit 52 determines whether water remains in the bucket using the calculated ΔDEC (step S103). When water remains in the bucket (step S103: YES), the current water amount calculation circuit 520 calculates the current bucket water amount and stores it in the NOWCNT accumulation means 531 (step S104). The water remains in the bucket. If not (step S103: NO), 0 is substituted into NOWCNT storage means 531 (step S105).

  The packet determination circuit 530 of the packet determination unit 53 determines whether the current bucket water amount (NOWCNT) exceeds the maximum burst size (THR) (step S106). If NOWCNT exceeds THR (step S106: YES), the packet determination circuit 530 determines that the input packet is a violation packet (step S111), and updates the bucket water amount CNT2 with the current bucket water amount NOWCNT after the determination (step S111). S112)

  If the NOWCNT does not exceed THR (step S106: NO), the packet determination circuit 530 determines whether NOWCNT exceeds the minimum burst size THRMIN (step S107). The packet determination circuit 530 determines the violation rate P determined according to NOWCNT when NOWCNT exceeds THRMIN (step S107: YES), that is, when NOWCNT is between THRMIN and THR (FIG. 5B). )), It is determined probabilistically whether the packet is a compliant packet (step S110). If the determination result using the violation rate P is a compliance packet (step S110: YES), the packet determination circuit 530 adds water corresponding to the frame length of the input packet to the bucket and updates CNT2 (step S109). .

  When the NOWCNT is less than THRMIN (step S107: NO), the packet determination circuit 530 determines that the input packet complies with the bandwidth (step S108), and proceeds to step S109.

  The bandwidth monitoring table control unit 50 updates the CNT accumulation unit 524 and the TLST accumulation unit 523 for the next input packet (steps S113 and S114).

  Subsequently, as shown in FIG. 9, the burst size changing unit 54 determines whether or not the current bucket water amount is equal to or larger than the maximum burst size (step S202). If the current bucket water amount is equal to or greater than the maximum burst size (step S202: YES), the burst size changing unit 54 determines whether the maximum burst size is equal to or less than the upper limit (step S203). If the burst size is increased without limit, the stability of communication is lost due to an excessive burst that cannot be accepted by the network. To prevent this, an upper limit is set on the maximum burst size. If the maximum burst size is less than or equal to the upper limit (step S203: YES), the burst size changing unit 54 increases the maximum burst size and the minimum burst size using a predetermined increase rate EXP (step S204). If the maximum burst size exceeds the upper limit (step S203: NO), the burst size changing unit 54 ends the process without increasing the maximum burst size and the minimum burst size.

  If the current bucket water amount is less than the maximum burst size (step S202: NO), the burst size changing unit 54 determines whether the bucket is in a bottomed out state (step S205). The burst size changing unit 54 initializes the maximum burst size and the minimum burst size with the initial values THR0 and THRMIN0 when the bucket bottoms out (step S205: YES) (step S206).

  The burst size changing unit 54 determines whether or not the current bucket water amount is less than the minimum burst size when the bucket bottom state is not reached (step S205: NO) (step S207). When the current bucket water amount is less than the minimum burst size (step S207: YES), the burst size changing unit 54 decreases the minimum burst size and the maximum burst size using the increase rate EXP (step S208). The burst size changing unit 54 ends the process when the current bucket water amount is equal to or larger than the minimum burst size (step S207: NO). Note that the process of step S208 may be omitted.

  The effect of increasing the burst size will be described with reference to FIGS. FIG. 10 is a graph illustrating the variation of the bucket water amount in the first embodiment. FIG. 11 is a graph illustrating a change in the conventional bucket water amount as a comparative example. In the graphs 710 and 720, the horizontal axis represents the elapsed time TSLT from the start of communication, and the vertical axis represents the bucket water amount CNT.

  In the conventional LB model, when the bucket water amount CNT begins to exceed the minimum burst size, as shown in FIG. 11, the input packet is determined to be a violation packet probabilistically and discarded (time t1). As a result, the TCP protocol of the transmitting device slightly reduces the transmission band, and the bucket water amount starts to decrease (time t2). When the bucket water amount is less than the minimum burst size (time t3), all the input packets are determined as observable packets, so the TCP protocol of the transmitting device increases the transmission bandwidth (time t4). When the amount of bucket water exceeds the maximum burst size, all input packets are determined as violation packets and discarded (time t5). Therefore, the TCP protocol of the transmitting device determines that the network is in a heavy congestion state because the transmitted packets are continuously discarded as violation packets, and rapidly reduces the transmission bandwidth (slow start). As a result, as indicated by a circle X1 in the graph 720, the bucket water amount becomes empty (time t6), the average bandwidth on the network does not reach the monitoring bandwidth, and the throughput decreases.

  On the other hand, the LB model of the first embodiment operates in the same manner as the conventional LB model until time t4. When the bucket water amount exceeds the maximum burst size (time t5), the bandwidth monitoring unit 500 expands the maximum burst size and the minimum burst size according to the increase rate EXP. As shown in FIG. 10, THRNEW represents a value after updating THR. By doing this, the maximum burst size and the minimum burst size can be changed according to changes in the amount of bucket water, so that continuous packet discard due to the occurrence of overflow can be suppressed, and the average bandwidth can be stably output to the monitoring bandwidth. it can.

  According to the bandwidth monitoring apparatus of the first embodiment, packets can be discarded at a predetermined violation rate before the maximum burst size of the bucket water amount is exceeded, and the burst size can be changed according to changes in the bucket water amount. Since the amount of bucket water changes according to the transmission band, according to the band monitoring apparatus of the first embodiment, the bandwidth drop according to the fluctuation of the transmission band can be suppressed by changing the burst size according to the fluctuation of the bucket water amount. Can provide a sufficient bandwidth for stable communication.

  Further, according to the first embodiment, when the bucket water amount becomes equal to or larger than the maximum burst size, the burst size can be increased, and the continuous discard of violation packets can be suppressed. Therefore, it is possible to suppress a rapid decrease in the transmission band due to the slow start of the TCP protocol of the transmission device, and to improve the throughput.

  In addition, the bandwidth monitoring apparatus according to the first embodiment is configured such that the maximum burst size does not exceed a predetermined upper limit. Accordingly, it is possible to suppress network congestion due to an unlimited increase in the maximum burst size.

  Further, according to the bandwidth monitoring apparatus of the first embodiment, the changed burst size and the current water amount can be easily referred from the management terminal, so that the user can easily check various values automatically changed. Therefore, user convenience can be improved.

B. Second embodiment:
In the first embodiment, a network using TCP-IP communication has been described. In the second embodiment, a network other than TCP-IP communication will be described.

B1. Function block:
FIG. 12 is a block diagram illustrating the configuration of the bandwidth monitoring unit 500a in the second embodiment. The bandwidth monitoring unit 500a according to the second embodiment includes a water amount determination unit 52, a packet determination unit 53a, and a burst size change unit 54a. In the bandwidth monitoring unit 500a of the second embodiment, blocks having the same reference numerals as those of the first embodiment 500 have the same configuration and operation, and thus description thereof is omitted.

  The burst size changing unit 54a includes a burst size changing unit 540a, a maximum burst size initial value storage unit 541, a detection start time storage unit 542, a detection sample time storage unit 543, a communication flag storage unit 544, and a bucket overflow. Flag accumulation means 545, water vibration frequency accumulation means 546, vibration frequency threshold accumulation means 547, increase rate accumulation means 548, increase rate upper limit accumulation means 549, communication end detection time accumulation means 550, and communication end detection Sample time storage unit 551, post-change burst size storage unit 552, post-change vibration frequency storage unit 553, post-change bucket overflow flag storage unit 554, post-change communication flag storage unit 555, post-change packet Flag accumulation means 556.

  The burst size changing unit 54a increases the maximum burst size based on the number of repetitions of “bucket overflow” and “bucket bottoming” being alternately repeated for a fixed time. In the second embodiment, a phenomenon in which the bucket overflow and the bottoming frequency are alternately repeated is referred to as “bucket vibration”.

  The vibration of the bucket will be described with reference to FIG. FIG. 13 is a graph for explaining the burst size changing process in the second embodiment. In the second embodiment, although not TCP-IP communication, it is assumed that the transmission band of the packet flow is accompanied by a burst caused by the network environment. In the graph 750 of FIG. 13, the vertical axis represents the bucket water amount CNT, and the horizontal axis represents the elapsed time from the start of communication. If the maximum burst size is less than the burst of the packet flow and the current water volume exceeds the maximum burst size in graph 750 (time t1), all input packets are discarded as violation packets (bucket overflow occurs) (time t1-t2). On the other hand, since the transmission bandwidth of the packet flow is temporarily reduced between burst traffic, the bucket water amount is also reduced to a “bucket bottom” state (time t2 to t3). In the bucket bottom state, water for the monitoring band cannot leak from the bucket, and as a result, the average band becomes less than the monitoring band.

  In the second embodiment, the burst size changing unit 54a counts the number of vibrations of the bucket as “bucket overflow” once and “bucket bottoming” once, and when the vibration occurs four times or more, the graph 750 As shown in FIG. 4, the maximum burst size THR is increased to THRNEW according to the increase rate EXP. By increasing the maximum burst size in this way, the burst size changing unit 54a suppresses the occurrence of bucket bottoming and avoids vibration, as shown by a circle X2 in FIG. 13, and suppresses a decrease in throughput.

B2. Burst size change processing:
The burst size changing process of the second embodiment will be described with reference to FIG. 14 and FIG. 14 and 15 are flowcharts for explaining the burst size changing process in the second embodiment. In the second embodiment, unlike the bandwidth monitoring algorithm described in the first embodiment, the minimum burst size is not set. Based on a bandwidth monitoring algorithm based on a general leaky bucket algorithm, if the bucket water volume exceeds the maximum burst size, the packet is discarded. The burst size changing process is started when a packet is input.

  The current water amount calculation circuit 520 of the water amount determination unit 52 calculates the elapsed time ΔT from the previous packet input (step S301), and calculates the amount of water ΔDEC leaked from the hole of the bucket 1003 during the calculated ΔT (step S302). ). The water amount determination unit 52 determines whether water remains in the bucket using the calculated ΔDEC (step S303). When water remains in the bucket (step S303: YES), the current water amount calculation circuit 520 calculates the current bucket water amount and stores it in the NOWCNT accumulation means 531 (step S304). The water remains in the bucket. If not (NO in step S303), 0 is set in the NOWCNT storage unit 531 (step S305).

  The packet determination unit 53 of the packet determination unit 53 determines whether or not the current bucket water amount NOWCNT exceeds the maximum burst size by THR (step S306). If the current bucket water amount NOWCNT exceeds the maximum burst size by THR (step S306: YES), the input packet is determined to be a violation packet (step S309), and the bucket water amount CNT2 is updated after the determination (step S310). If NOWCNT does not exceed THR (step S306: NO), the packet determination unit 53 determines that the input packet is a compliant packet (step S307), adds water corresponding to the frame length of the input packet to the bucket, CNT2 is updated (step S308).

  The bandwidth monitoring table control unit 50 updates the CNT accumulation unit 524 and the TLST accumulation unit 523 for the next input packet (steps S311 and 312).

  The burst size changing unit 54a determines whether the current water amount exceeds the maximum burst size (step S403).

  If the current amount of water exceeds the maximum burst size (step S403: YES), the burst size changing unit 54a determines that a bucket overflow has occurred and sets 1 to the bucket overflow flag (step S405) ( Time t1) in the graph 750 of FIG. When the current water amount is equal to or less than the maximum burst size (step S403: NO), the burst size changing unit 54a determines whether the current water amount is 0 (step S406).

  When the current water amount is 0 (step S406: YES), the burst size changing unit 54a sets “0” indicating that the bucket bottom has occurred in the bucket overflow flag (step S407) (graph in FIG. 13). Time t3 at 750). If the current water amount is not 0 (step S406: NO), the burst size changing unit 54a determines that there is no change in the bucket state, and sets the value of the previous bucket overflow flag in the bucket overflow flag (step S408). .

  The burst size changing unit 54a determines whether vibration has occurred using the vibration flag BFNEW and the previous vibration flag BF (step S410). If vibration has occurred (step S410: YES), the number of vibrations N Are integrated (step S412). Specifically, if the bucket overflow flag set in step S405 or step S407 is the same as the bucket shake flag (previous bucket overflow flag) at the time of the previous packet input, the burst size changing unit 54a has the same bucket status. In this state, if no vibration has occurred and the bucket overflow flag is different from the previous bucket overflow flag, it is determined that vibration has occurred and the number of vibrations N is counted.

  The burst size changing unit 54a determines whether the number of vibrations is equal to or greater than a threshold value and the maximum burst size is equal to or less than the upper limit (step S413). When the number of vibrations is equal to or greater than the threshold and the maximum burst size is equal to or less than the upper limit (step S413: YES), the burst size changing unit 54a increases the maximum burst size according to the increase rate EXP (step S414).

  Next, the burst size changing unit 54a initializes the vibration frequency N (step S414), and sets the value of the current bucket overflow flag BFNEW in the previous bucket overflow flag BF for processing at the time of the next packet input. (Step S415).

  If vibration does not occur (step S410: NO), the burst size changing unit 54a sets the value of the current bucket overflow flag BFNEW to the previous bucket overflow flag BF for processing at the time of the next packet input. Setting is made (step S415).

B3. Communication end detection processing:
FIG. 16 is a flowchart for explaining a communication end detection process for detecting a communication end in the second embodiment. The burst size changing unit 54a determines whether or not the communication time has ended (step S452). Specifically, the burst size changing unit 54a determines whether the current time (TNOW) has passed the communication end detection sample time from the previous communication end time ENDTM. When the communication time has ended (step S452: YES), the burst size changing unit 54a determines whether there is a packet that has already been input. Specifically, when the packet flag PKTF is 0, the burst size changing unit 54a determines that there is no input packet, and when the packet flag PKTF is 1, it determines that there is an input packet.

  When there is no input packet (step S453: YES), the burst size changing unit 54a initializes the burst size and the communication flag (step S454), updates the timer with the current time, and initializes the packet flag to 0 ( Step S455).

  If the communication time has not ended (step S452: NO) and the burst size changing unit 54a has an input packet (step S453: NO), the burst size changing unit 54a ends the process.

  According to the bandwidth monitoring apparatus of the second embodiment, not only the maximum burst size of the current bucket water amount, that is, not only overflowing the bucket but also bottoming out of the bucket due to a decrease in the transmission bandwidth is used for the burst size change determination. When the bucket bottoms out, the throughput decreases. Therefore, when the bucket bottoms out, the burst size is increased to suppress a decrease in the throughput. In addition, since the bucket bottom occurs even when the communication is simply ended, the bucket overflow and the bucket bottom vibration are used to distinguish it from this.

  If the burst size increased at the start of the next communication is used, an excessively large burst may flow into the network, leading to a decrease in communication quality within the network. Therefore, according to the bandwidth monitoring device of the second embodiment, the end of communication between the transmitting device and the bandwidth monitoring device is detected, and the increased maximum burst size and minimum burst size can be returned to the initial values after the communication ends. it can.

C. Third embodiment:
C1. Function block:
In the first and second embodiments described above, the bandwidth monitoring unit monitors the bandwidth using the bucket water amount and the burst size. In the third embodiment, the burst size is increased / decreased according to the reception bandwidth calculated from the total data amount of packets input within a fixed time and the throughput calculated from the data amount of observable packets within a fixed time.

  FIG. 17 is an explanatory diagram illustrating functional blocks of the router 201a in the third embodiment. In the router 201a, the statistics collection unit 12 is added to the router 201 of the first embodiment. The router 201a has the same configuration as the router 201 of the first embodiment except for the statistics collection unit 12 and the bandwidth monitoring unit 500b.

  The statistic collecting unit 12 acquires the data amount of the input packet every fixed time via the bandwidth monitoring unit 500b, and calculates the reception bandwidth using the total data amount of the input packet every fixed time. In addition, the data amount of the observing packet for every fixed time is acquired, and the throughput is calculated using the total data amount of the compliant packet for every fixed time. The statistics collection unit 12 transmits the calculated reception bandwidth and throughput to the bandwidth monitoring unit 500b.

  The bandwidth monitoring unit 500b according to the third embodiment increases the maximum burst size and the minimum burst size by using the predefined monitoring bandwidth, the reception bandwidth calculated by the statistics collection unit 12, and the throughput.

  FIG. 18 is a detailed block diagram illustrating the bandwidth monitoring unit 500b in the third embodiment. Each block of the bandwidth monitoring unit 500b of the third embodiment has the same function and configuration as each block of the bandwidth monitoring unit 500 of the first embodiment, except for the burst size changing unit 54b of the burst size changing unit 54b. Is omitted.

  The burst size changing unit 54 b transmits the packet length LEN acquired through the packet determining unit 53 to the statistics collecting unit 12. The burst size changing unit 54b receives the information on the reception band and the throughput calculated by the statistics collection unit 12, and the throughput is less than the monitoring band even though the reception band is equal to or larger than the monitoring band based on the reception band and the throughput. It is determined whether the problem has occurred. When the above condition is satisfied, the burst size changing unit 54b determines that the throughput is reduced due to the shortage of the burst size, and increases the maximum burst size THR using the increase rate EXP.

C2. Burst size change processing:
The burst size changing process of the third embodiment will be described with reference to FIG. FIG. 19 is a flowchart for explaining burst size changing processing in the third embodiment. Note that the burst size changing process of the third embodiment is a continuation of steps S3001 to S3014 of FIG. 8 described in the first embodiment, and is the process from steps S202 to S208 of FIG. 9 described in the first embodiment. Instead, the process shown in FIG. 19 is performed.

  The burst size changing unit 54 determines whether the reception band calculated by the statistics collecting unit 12 is equal to or greater than the monitoring band (step S501). If the reception band is equal to or greater than the monitoring band (step S501: YES), the burst size changing unit 54 determines whether the throughput is less than the monitoring band (step S502). When the throughput is less than the monitoring band (step S502: YES), the burst size changing unit 54 determines whether the maximum burst size is equal to or larger than the upper limit (step S503). If the burst size is increased without limit, throughput decreases due to an increase in traffic, so that the burst size is not increased beyond a certain upper limit.

  When the maximum burst size is less than the upper limit (step S503: NO), the burst size changing unit 54 increases the maximum burst size and the minimum burst size by using a predetermined increase rate EXP (step S504). If the maximum burst size is greater than or equal to the upper limit (step S503: YES), the burst size changing unit 54 ends the process without increasing the maximum burst size and the minimum burst size.

  When the reception band is less than the monitoring band (step S502: NO), the burst size changing unit 54 determines whether the reception band is equal to or less than a predetermined value (step S505). If the reception band is equal to or smaller than the predetermined value (step S505: YES), the burst size changing unit 54 initializes the maximum burst size and the minimum burst size (step S506). The burst size changing unit 54 ends the process when the reception band is not less than or equal to the predetermined value (step S505: NO).

  According to the bandwidth monitoring device of the third embodiment described above, the reception bandwidth is calculated using the total amount of input packets input to the bandwidth monitoring device at a certain time, and the bandwidth monitoring device determines compliance with the certain time. Throughput is calculated using the total amount of data of the packets, and the burst size increase is determined by determining whether the calculated reception bandwidth is equal to or greater than the monitoring bandwidth and the throughput is less than the monitoring bandwidth. Therefore, the burst size can be increased according to the actual reception band and the fluctuation of the throughput, and the decrease in the throughput can be suppressed efficiently and accurately.

D. Variations:
(1) In the first embodiment, the bandwidth monitoring unit 500 may return the maximum burst size and the minimum burst size to the initial values at the end of communication. By so doing, unnecessary bursts can be suppressed at the start of the next communication.

  As mentioned above, although the various Example of this invention was described, this invention is not limited to these Examples, A various structure can be taken in the range which does not deviate from the meaning.

Explanatory drawing which illustrates the structure of the IP network in 1st Example. Explanatory drawing which illustrates the format of the packet in 1st Example. Explanatory drawing which illustrates the format of the packet inside a router in 1st Example. Explanatory drawing which illustrates the functional block of the router in 1st Example. Explanatory drawing explaining the bandwidth monitoring in 1st Example. Explanatory drawing explaining the bandwidth monitoring in 1st Example. The functional block explaining the detailed structure of the zone | band monitoring part in 1st Example. Explanatory drawing which illustrates the console screen of the management terminal in 1st Example. Flowchart for explaining burst size change processing in the first embodiment The flowchart explaining the burst size change process in 1st Example. The graph which illustrates about the fluctuation | variation of the bucket water amount in 1st Example. The graph which illustrates about the fluctuation | variation of the conventional bucket water amount as a comparative example. The functional block which illustrates the detailed structure of the zone | band monitoring part in 2nd Example. The graph explaining the burst size change process in 2nd Example. Flowchart for explaining burst size change processing in the second embodiment The flowchart explaining the burst size change process in 2nd Example. The flowchart explaining the communication end detection process in 2nd Example. Explanatory drawing which illustrates the functional block of the router in 3rd Example. The functional block explaining the detailed structure of the zone | band monitoring part in 3rd Example. The flowchart explaining the burst size change process in 3rd Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Management terminal 12 ... Statistics collection part 50 ... Bandwidth monitoring table control part 51 ... Bandwidth monitoring table 52 ... Water volume judgment part 53 ... Packet judgment part 53a ... Packet judgment part 54 ... Burst size change part 54a ... Burst size change part 54b ... Burst size changing unit 110 ... input line 120 ... packet receiving circuit 130 ... route search unit 140 ... packet relay processing means 150 ... packet transmission circuit 160 ... output line 170 ... flow detection unit 180 ... header processing unit 190 ... transmission side buffer 200 ... Carrier network 201 ... Router 201a ... Router 211 ... Terminal 214 ... Router 313 ... Source port number 314 ... Destination port number 321 ... Data 330 ... Internal header part 332 ... Input line number 333 ... Output line number 500 ... Bandwidth monitoring part 500a ... Bandwidth monitoring unit 50 b ... Band monitoring unit 520 ... Current water amount calculation circuit 522 ... Monitoring band accumulation means 523 ... Previous packet input time accumulation means 524 ... Previous bucket water amount accumulation means 525 ... Timer 530 ... Packet judgment circuit 530 ... Determination circuit 531 ... Current bucket water amount accumulation Means 532 ... Packet frame length accumulation means 533 ... Maximum burst size accumulation means 534 ... Maximum burst size accumulation means 534 ... Minimum burst size accumulation means 537 ... Bucket water amount accumulation means after determination 540 ... Burst size change circuit 540a ... Burst size change section 541 ... maximum burst size initial value storage means 542 ... detection start time storage means 543 ... detection sample time storage means 544 ... communicating flag storage means 545 ... flag storage means 546 ... water amount vibration frequency storage means 547 ... vibration frequency threshold value storage means 48 ... Increase rate storage means 549 ... Increase rate upper limit storage means 550 ... Communication end detection time storage means 551 ... Communication end detection sample time storage means 552 ... Changed burst size storage means 553 ... Changed vibration frequency storage means 554 ... Flag accumulation unit 555 ... Communication flag accumulation unit after change 556 ... Packet flag accumulation unit after change 557 ... Minimum burst size initial value accumulation unit 710 ... Graph 720 ... Graph 750 ... Graph 1003 ... Bucket

Claims (16)

A bandwidth monitoring device that is arranged between a transmission device and a reception device and monitors a bandwidth for transmitting a packet to be relayed from the transmission device to the reception device,
Receiving means for receiving a packet of interest, which is a packet input using a transmission band that fluctuates within a certain range;
Virtual storage means for virtually storing packets to be relayed to the receiving device among all packets input before reception of the packet of interest;
Transmitting means for transmitting the packet to be relayed to a receiving device according to the monitoring band;
When the packet of interest is input, if the total amount of data stored in the virtual storage means is less than a first threshold value indicating the maximum capacity of the virtual storage means, the packet of interest is determined to be a compliant packet. Determining means for determining that the packet of interest is a violation packet that does not comply with the monitoring bandwidth when the total data amount is equal to or greater than the first threshold;
In accordance with the result of the determination, the attention packet determined as the compliance packet is stored in the virtual storage means, and the selection means that does not store the attention packet determined as the violation packet;
A bandwidth monitoring device comprising: changing means for changing the first threshold value based on fluctuations in the transmission bandwidth. The bandwidth monitoring device according to claim 1,
The change unit is a band monitoring device that increases the first threshold when the total data amount that increases or decreases according to a change in transmission band is equal to or greater than the first threshold. The bandwidth monitoring apparatus according to claim 1, further comprising:
An integration means for integrating the number of repetitions in which the total data amount is equal to or greater than the first threshold and the total data amount is 0;
The bandwidth monitoring device, wherein the changing unit increases the first threshold when the accumulated number of repetitions reaches a reference number or more at a predetermined time. The bandwidth monitoring device according to claim 2,
The determination means further preliminarily increases the total data amount when the total data amount is between the first threshold and a second threshold lower than the first threshold. A bandwidth monitoring device that determines the packet of interest as the violation packet based on a predetermined violation rate. The bandwidth monitoring apparatus according to claim 4, wherein
The bandwidth monitoring device, wherein the changing unit further increases the second threshold value. The bandwidth monitoring apparatus according to claim 5, wherein
The change unit is a bandwidth monitoring device that increases the second threshold according to a predetermined increase rate. The bandwidth monitoring apparatus according to any one of claims 2 to 6,
The change means is a bandwidth monitoring device that increases the first threshold according to a predetermined increase rate. The bandwidth monitoring apparatus according to claim 1, further comprising:
A transmission band calculating means for calculating the transmission band using an integrated value of the data amount of the input packet at regular intervals;
Complying packet bandwidth calculating means for calculating a compliant packet bandwidth, which is a bandwidth of the compliant packet, using an integrated value of the data amount of the compliant packet at regular time intervals,
The change means increases the first threshold when the calculated transmission band is equal to or greater than the monitoring band and the calculated compliant packet band is less than the monitoring band. The bandwidth monitoring apparatus according to any one of claims 1 to 7, further comprising:
The bandwidth monitoring device, wherein the changing means does not change the first threshold when the first threshold is equal to or greater than a predetermined upper limit. The bandwidth monitoring device according to any one of claims 1 to 9, further comprising:
A bandwidth monitoring apparatus comprising notification means for notifying a user of the total data amount. The bandwidth monitoring apparatus according to claim 10, wherein
The notification unit is a bandwidth monitoring device that further notifies the user of the first threshold value. The bandwidth monitoring apparatus according to any one of claims 2 to 4, further comprising:
Comprising communication detecting means for detecting the end of communication between the transmitting device and the band monitoring device;
The change unit is a bandwidth monitoring device that changes the changed first threshold value to a predetermined initial value when detecting the end of the communication. A bandwidth monitoring device according to any one of claims 2 to 4 and claim 12,
The change unit is a bandwidth monitoring device that reduces the first threshold when the total data amount is equal to or less than a predetermined lower limit value. The bandwidth monitoring device according to any one of claims 5 to 11, further comprising:
Comprising communication detecting means for detecting the end of communication between the transmitting device and the band monitoring device;
The change unit is a bandwidth monitoring device that changes the changed first threshold value and the second threshold value to predetermined initial values when the end of communication is detected. A bandwidth monitoring device according to any one of claims 5 to 11 and claim 14,
The change unit is a bandwidth monitoring device that reduces the first threshold value and the second threshold value when the total data amount is equal to or less than a predetermined lower limit value. A bandwidth monitoring method that is arranged between a transmission device and a reception device and monitors a bandwidth used by a packet transmitted from the transmission device to the reception device,
Of the packets input to the bandwidth monitoring device using the transmission bandwidth defined by the transmission device, virtually store compliance packets that comply with the predefined monitoring bandwidth,
Send the compliance packet to the receiving device according to the monitoring bandwidth,
When the packet of interest is input from the transmitting device to the bandwidth monitoring device, if the total data amount of the accumulated compliance packets is less than a first threshold, the packet of interest is the compliance packet, and the total data When the amount is equal to or greater than the first threshold, it is determined that the packet of interest is a violation packet that does not comply with the monitoring bandwidth;
Depending on the result of the determination, the violation packet is discarded,
A bandwidth monitoring method, wherein the first threshold is changed according to a change in the transmission bandwidth.

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