JP4426010B2 - Bandwidth guaranteed transmission method and apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a bandwidth guaranteed transmission method and apparatus in a communication control system.
[0002]
[Prior art]
Conventionally, when network traffic is congested, the priority of concentrated traffic is fixedly evaluated from high priority to low priority to determine the data transfer order. That is, when a priority 1 (highest priority) traffic flow and a priority 7 (lowest priority) traffic flow occur at the same time, as long as there is a priority 1 traffic flow, there is an opportunity for transmission of the priority 7 traffic flow. In some cases, it disappeared.
[0003]
[Problems to be solved by the invention]
In the prior art as described above, the transfer order is often determined by chance depending on the priority relationship between concentrated traffic flows. That is, when priority 1 and priority 7 traffic flows occur simultaneously, the priority 7 traffic flow transfer time is transmitted by priority 7 traffic flow alone by giving priority to the priority 1 traffic flow. It takes a lot of time compared to the case. As described above, in the conventional technique, the transfer time may become unstable due to the concentration of traffic flow, and the application may not operate stably.
[0004]
In view of the above points, the present invention achieves the following objects, for example.
• Enable transmission processing scheduling that guarantees transmission bandwidth for each traffic flow.
-For data queued in the transmission waiting queue, the highest priority transmission scheduling is dynamically performed for the traffic flow with the lowest guaranteed bandwidth achievement, and as long as there is data waiting for transmission, waste of the line etc. occurs. Make sure there is nothing.
-Adjust the delay time of the transmission waiting queue and the accuracy of bandwidth guarantee by adjusting the unit time for monitoring the transmission bandwidth based on the line speed and the average packet length.
[0005]
[Means for Solving the Problems]
In the present invention, the guaranteed transmission bandwidth is managed by “the number of transmission octets whose transmission should be guaranteed within a unit time” and “achievement degree for each” for each traffic flow (a certain series of data). In the transmission process, a transmission queue is provided for each traffic flow, the number of octets transmitted for each queue is managed, and the queue that achieves the lowest number of transmitted octets is prioritized for the number of octets for which transmission is guaranteed. The scheduling method is to select and transmit. At the time of transmission processing, the control variables of the number of transmission octets and the achievement level are reset every unit time in order to correct the deviation of traffic flow. A traffic flow that does not guarantee the bandwidth is handled in the same manner as a traffic flow that achieves the guaranteed bandwidth. As a result, if there is no traffic flow that does not achieve the guaranteed bandwidth in the traffic flow that should guarantee the bandwidth, either the traffic flow that achieved the guaranteed bandwidth or the traffic flow that does not guarantee the bandwidth should be sent to the line. It is possible to prevent the occurrence of a vacant line.
[0006]
According to the first solution of the present invention,
It has a transmission queue for each traffic flow that is a series of transfer data,
Said For each traffic flow Per unit time Amount of data to send Guaranteed bandwidth indicating from the transmission queue for each traffic flow Amount of data sent When Manage
Said Amount of data to send Indicating the guaranteed bandwidth Vs. To do Amount of data sent Represented by said Guaranteed bandwidth Ask for achievement, said Provided is a bandwidth-guaranteed transmission method in which a queue of a traffic flow with a low achievement level is preferentially selected and transmitted.
[0007]
According to the second solution of the present invention,
A transmission queue for each traffic flow that is a series of transfer data, a transmission queue table for queuing data according to each traffic flow, and the bandwidth guaranteed per unit time for each traffic flow in units of data The transmission bandwidth guarantee table managed in step 1, the transmission bandwidth value table for managing the number of data transmitted within a unit time for each traffic flow, and the transmission bandwidth for managing the number of wraparounds of the transmission bandwidth value table for each traffic flow A memory having a value wraparound count management table;
An input / output processing unit connected to the network;
A control unit for controlling data transmission by the input / output processing unit based on the memory;
With
The controller is
Said For each traffic flow Per unit time Amount of data to send Guaranteed bandwidth indicating from the transmission queue for each traffic flow Amount of data sent When Manage
Said Amount of data to send Indicating the guaranteed bandwidth Vs. To do Amount of data sent Represented by said Guaranteed bandwidth Ask for achievement, said Provided is a bandwidth-guaranteed transmission apparatus that preferentially selects and transmits a queue of a traffic flow with a low achievement level.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[0009]
(I) Unit time
First, consider the “unit time” for monitoring the guaranteed bandwidth and the degree of achievement. The unit time needs to be set to a time that is long enough to obtain the effect of bandwidth guarantee and short enough not to leave the effect of traffic flow bias (concentration of specific traffic flows) long.
[0010]
For example, a case is assumed in which a unit time is set to 1 second in a system that transfers packets with an average of 1,500 octets on a 9,600 bit / second line. In this case, the number of octets that can be transmitted per unit time in the transfer of one packet is exceeded, and the effect of bandwidth guarantee does not appear (actual First In First Out method). Next, for example, a case is assumed where the unit time is set to 100 seconds in such a system having a line speed and an average packet length. In this case, if the traffic flow of 96,000 bits / 100 seconds with a guaranteed bandwidth of 10% is concentrated at the beginning of the unit time, the guaranteed bandwidth is achieved by transmitting only 8 packets, and the subsequent 90 seconds are guaranteed. As long as there is another traffic flow that does not achieve the bandwidth, the traffic flow cannot be transmitted, leaving the traffic flow uneven for a long time.
[0011]
As described above, in the present invention, the optimum unit time is determined from the average packet length and line speed of the system in consideration of the accuracy of bandwidth guarantee and the delay time due to waiting in the transmission waiting queue in the following process.
[0012]
i) Calculation of the ratio of one packet to the throughput of the line per unit time
For example, if the unit time is 1 second in a system that transfers packets with an average of 1,500 octets over a 9,600 bit / second line, the ratio of one packet to the line throughput is 125% according to the following equation (1): Since the packet transfer exceeds the line throughput per unit time, the effect of bandwidth guarantee does not appear.
(1,500 (octets) x 8 (bits / octet)) ÷ (9,600 (bits / second) x 1 (seconds (unit time))) x 100 = 125 (%)-1
[0013]
Also, for example, if the unit time is 100 seconds in a system that transfers packets with an average of 1,500 octets over a 9,600 bit / second line, the ratio of one packet to the line throughput is 1.25% according to equation (2) below. The bandwidth can be guaranteed with an accuracy of about 1.25%. However, as already mentioned, the delay time due to waiting in the transmission waiting queue may be about 100 seconds.
(1,500 (octets) x 8 (bits / octet)) ÷ (9,600 (bits / second) x 100 (seconds (unit time))) x 100 = 1.25 (%)-(2)
[0014]
ii) Evaluation of bandwidth guarantee accuracy and transmission queue delay time
As described in i), the unit time represents the delay of the transmission waiting queue, and the ratio of one packet to the transmission throughput of the line per unit time represents the accuracy of bandwidth guarantee. The unit time and the accuracy of bandwidth guarantee are in a trade-off relationship.
[0015]
Considering the above, the unit time is determined by calculating / evaluating the accuracy of bandwidth guarantee and the delay of the transmission queue from the line speed (fixed value) and average packet length (fixed value).
[0016]
As shown in equation (2) in i) above, if a bandwidth guarantee with an accuracy of about 1% is performed on a system that transfers packets with an average of 1,500 octets over a 9,600 bit / second line, the delay of the transmission queue will increase. Too much. If a bandwidth guarantee with an accuracy of about 10% is performed, t = 12.5 seconds from equation (3) below, and the delay time in the transmission waiting queue is about 12 seconds. (1,500 (octets) x 8 (bits / octet)) ÷ (9,600 (bits / second) x t (seconds (unit time))) x 100 = 10 (%)-(3)
[0017]
As described above, the optimum unit time for the system is determined by calculating the accuracy of the mutually guaranteed bandwidth guarantee and the delay of the transmission queue.
[0018]
(II) Hardware configuration
FIG. 1 shows a configuration diagram of a system to which the present invention is applied. As an example of application of the present invention, a case where the present invention is applied to a transmission waiting queue of an inter-network connection device in an IP network can be considered.
[0019]
The inter-network connection device 1 is a device for connecting networks. The inter-network connection device 1 includes a CPU 2, a memory 3, and an input / output processing unit 4. The inter-network connection device 1 also holds the control tables 5 and the transmission queue 6 on the memory 3 and executes data routing processing between the networks. In the inter-network connection device 1, there are cases where networks having different line speeds are connected to each other, and when data is transmitted from a network with a high line speed to a network with a low line speed, there is a case where data transmission waiting occurs during data transmission. is there. In each network device including the inter-network connection device 1, generally, waiting control is performed using the “transmission wait queue 6” for these data transmission waits. The present invention can be applied to, for example, a scheduling process for retrieving data from the “transmission waiting queue 6”.
[0020]
FIG. 2 is an explanatory diagram of the control tables 5 and the transmission queue 6. In the present invention, the following tables necessary for processing are provided.
(1) A transmission waiting queue table 21 for queuing data according to the traffic flow type is provided. For example, the traffic flow type may be determined based on the TOS value of the IP packet and the source / destination IP address.
(2) For each traffic flow, a transmission bandwidth guarantee table 22 is provided for managing the bandwidth guaranteed per unit time in units of octets. In addition to the octet number unit, it can be managed by an appropriate value such as the number of bits.
(3) A transmission band value table 23 for managing the number of octets transmitted within a unit time for each traffic flow is provided. In addition to the number of octets, the number of bits, the ratio, etc. can be managed with appropriate values.
(4) A transmission bandwidth value wraparound count management table 24 for managing the wraparound count of the transmission bandwidth value table 23 is provided for each traffic flow. Here, one round of the counter or the like is called wrap around. For example, when a 1-byte counter is subtracted, the cycle is 1 → 0 → 255.
(5) A queue number bitmap table 25 for managing in which queue the data exists is provided according to the number of wraparounds.
[0021]
The processing method of the present invention will be described below. Band guarantee control is realized by performing the following processing using the control tables 5 as described above.
[0022]
(III) Process overview
In this embodiment, transmission data is queued in the transmission queue table 21 for each traffic flow. Then, among the queued traffic flows, the traffic flow having the lowest achievement of the transmission band with respect to the guaranteed band is preferentially transmitted.
[0023]
In the present embodiment, the achievement level is managed by the queue number bitmap table 25. The queue number bitmap table 25 may be omitted, and the transmission band value wraparound count management table 24 may be used for management. The achievement degree of the young number entry (lap round number 0) in the array of the queue number bitmap table 25 is low, and the achievement degree of the old number entry (lap round number M) is high. The oldest entry indicates that the bandwidth has been guaranteed. Each bit in the queue number bitmap table 25 entry can be mapped to a traffic flow. The oldest entry (bandwidth guaranteed) is assigned a traffic flow that does not guarantee bandwidth, and is sent only when all other traffic flows have reached the guaranteed bandwidth or there is no other traffic flow to send. It can also be used for control to do. The queue number bitmap table 25 can be configured with two entries (an entry for which the guaranteed bandwidth has not been achieved and an entry for which the guaranteed bandwidth has been achieved). However, with this configuration, the priority relationship between the traffic that has not achieved the guaranteed bandwidth cannot be precisely controlled. For this reason, the guaranteed bandwidth is divided into several stages and mapped to the entry numbers in the queue number bitmap table 25. Taking FIG. 2 as an example, entry 0 to entry M-1 are guaranteed bandwidth unachieved entries, and entry M is a guaranteed bandwidth achieved entry. In this case, M and more are handled collectively by one entry M number, but the present invention is not limited to this and can be stored as M + 1 number or an appropriate entry.
[0024]
As for the number of stages of guaranteed bandwidth, fine control is possible if there are many stages. However, when bandwidth is managed based on the number of transmission octets as in this embodiment, the line speed and the average packet An approach based on length is considered as an example. For example, in the case of a system with a guaranteed bandwidth of 16,000 octets / second and an average packet length of 1,500 bytes, the guaranteed bandwidth is achieved by transmitting about 11 packets. Therefore, by dividing the guaranteed bandwidth into 11 steps, transmission of one packet may appear as a difference in priority of one step between traffic flows (that is, a difference in one entry of values in the queue number bitmap table 25). I can expect. In this case, the value M in the queue number bitmap table 25 is 12.
[0025]
In the present invention, when the bandwidth guarantee value is divided into 11 stages as described above, the number of (guaranteed bandwidth ÷ 11) bytes transmitted is managed. In order to realize this management, each traffic flow has a table for managing the (guaranteed bandwidth / step) value and how many times the (guaranteed bandwidth / step) value is transmitted. The (guaranteed bandwidth / step) value is managed by the transmission bandwidth guarantee table 22 (FIG. 2- (2)) and the transmission bandwidth value table 23. The number of times of transmission is managed by the transmission band value wraparound frequency management table 24.
[0026]
For example, in a traffic flow with a guaranteed bandwidth of 16,000 octets, 1500 is set in each entry corresponding to the traffic flow in the transmission bandwidth guarantee table 22 and the transmission bandwidth value table 23. Each entry in the transmission bandwidth value wraparound count management table 24 is initialized with 0, and every time a packet is transmitted in a certain traffic flow, the transmission octet length is subtracted from the entry in the transmission bandwidth value table 23, and wraparound occurs. Each time the entry in the transmission bandwidth value wrap-around count management table 24 is incremented by one. The number of wraparounds for each traffic flow managed in the transmission bandwidth value wraparound number management table represents the degree of achievement of the guaranteed bandwidth and can be mapped to an entry in the queue number bitmap table 25.
[0027]
The processing in the present invention includes, for example, (1) initialization processing of the control tables 5, (2) transmission request reception processing, (3) transmission scheduling processing, (4) transmission processing, and (5) control tables 5. The re-initialization process can be broadly classified.
[0028]
The transmission request acceptance process queues a transmission packet in an entry corresponding to the traffic flow type in the transmission queue table 21 and corresponds to the achievement level (that is, the number of wraparounds) of the transmission band value wraparound number management table 24. The bit corresponding to the traffic flow type of the entry in the queue number bitmap table 25 is set to 1 to indicate that queuing has occurred in the queue. In the transmission scheduling process, bits are searched in order from the youngest entry in the queue number bitmap table 25, and a packet is extracted from the transmission queue table 21 and transmitted for a traffic flow in which the bit is set to 1.
[0029]
In the transmission process, the transmission bandwidth value table 23 is updated, and if necessary, the transmission bandwidth value wraparound count management table 24 and the queue number bitmap table 25 are updated. Further, the number of octets of the transmission packet is subtracted from the entry of the transmission band value table 23 corresponding to the traffic flow extracted by the transmission scheduling process. When wraparound occurs at this time (that is, when the transmission packet length is larger than the entry value of the transmission bandwidth value table 23), the initial value of the entry is taken out from the transmission bandwidth guarantee table 22 and the wraparound process is performed. (In other words, the entry value of the transmission bandwidth guarantee table 22 is extracted as a work variable, and the value obtained by subtracting the transmission packet length from the work variable is set in the entry of the transmission bandwidth value table 23). Further, the entry corresponding to the traffic flow in the transmission bandwidth value wraparound count management table 24 is added, the bit corresponding to the traffic flow of the wraparound count entry before the addition in the queue number bitmap table 25 is turned off, and after the addition Turn on the bit corresponding to the traffic flow of the wraparound count entry. As a result, the achievement level is increased (that is, the wraparound count is increased), so that the transmission priority is decreased (that is, the entry of the queue number bitmap table 25 is decreased).
[0030]
(IV) Processing details
Details of this processing will be described using the table state transition diagram and a flowchart, along with the following example conditions. 3 to 5 show state transition diagrams (1) to (3) of the control table 5 by each processing.
(Example)
Line speed: 9,600bps
Average packet length: 800 bytes
Unit time: 5 seconds
Amount of data that can be sent per unit time: 6,000 bytes
Achieving guaranteed bandwidth: 6 stages (6th stage is guaranteed bandwidth)
Maximum guaranteed bandwidth error: Approximately 13% ((800 × 8) ÷ (9,600 × 5) × 100)
Traffic flow type and each band: Flow 0 → 30%, Flow 1 → 70%
[0031]
The line speed, unit time, guaranteed bandwidth achievement stage, guaranteed bandwidth for each traffic flow, etc. can be set in the apparatus in advance, or means such as passing data from the outside can be used.
[0032]
(1) Initialization processing of control tables 5
FIG. 6 shows a flowchart of the control table initialization process.
[0033]
First, all entries in the transmission queue table 21 are cleared to 0 (step 400). Next, in each entry of the transmission bandwidth guarantee table 22 and the transmission bandwidth value table 23, the guaranteed bandwidth of each traffic flow per unit time / (guaranteed bandwidth achievement stage-1) is set. However, an unused entry can be distinguished from an in-use entry by setting, for example, 0 (step 410). In this example, the setting value of flow 0 that guarantees a bandwidth of 30% per unit time is 360 by the following formula, and the setting value of flow 1 that guarantees a bandwidth of 70% per unit time is 840 in the same way.
(((9,600 × 5) ÷ 8) × 0.3) ÷ (6-1) = 360
[0034]
Next, all entries in the transmission bandwidth value wraparound count management table 24 are cleared to 0 (step 420). In addition, all entries in the queue number bitmap table 25 are cleared to 0 (step 430).
[0035]
In this example, the state of various tables after execution of the initialization process is as shown in state number (1) in FIG.
[0036]
(2) Transmission request reception processing
FIG. 7 shows a flowchart of the transmission request acceptance process. Here, when a data transmission request is received, the following processing is executed for each data.
[0037]
First, transmission data is queued to the corresponding entry in the transmission queue table 21 for each transmission traffic flow type (step 500). Next, it is determined whether the traffic flow to be queued is a traffic flow whose bandwidth should be guaranteed (step 510). In order to determine this, if the guaranteed bandwidth for each traffic flow is set to 0%, a determination method is considered such that it is not necessary to guarantee the bandwidth. Next, in the case of a traffic flow whose bandwidth is to be guaranteed, an entry corresponding to the traffic flow in the transmission bandwidth value wraparound count management table 24 is extracted as a variable χ (step 520). When the variable χ is larger than M (the oldest number entry in the queue number bitmap table 25) (step 530), M is set to the variable χ (step 540). Similarly, when the traffic flow does not guarantee the bandwidth, M is set to the variable χ (step 540). Next, the bit corresponding to the traffic flow in the entry corresponding to the variable χ in the queue number bitmap table 25 is set to 1 (step 550).
[0038]
In this example, the status of various tables when receiving a transmission request for 4 data of flow 0 and 6 data of flow 1 is as shown by status number (2) in FIG.
[0039]
(3) Transmission scheduling process
FIG. 8 shows a flowchart of the transmission schedule process. This process is executed to select the next transmission data immediately after receiving the first data transmission or when one data transmission is completed.
[0040]
First, the entry counter I of the queue number bitmap table 25 is initialized to 0 (step 600). If I is less than or equal to M (stage), the following process (search process for bit “1” of variable I-th entry in queue number bitmap table 25) is executed, and if greater than M, the process is completed (step 610). ). If I is less than or equal to M, the bit counter J of the queue number bitmap table 25 entry is initialized to 0 (step 620). In FIG. 2, I indicates a vertical counter (number of wraparounds: 0 to M), and J indicates a horizontal counter (traffic flow numbers: 0 to n). If J is n (the number of traffic flow types) or less, the following processing is executed. If J is greater than n, I is incremented, and the process returns to step 610 (steps 630 and 670). If J is n or less, the I-th entry value in the queue number bitmap table 25 is searched, and if the J-th bit is non-zero, a call is made by passing I and J to the transmission processing of the relevant traffic type (step 650), if zero, J is counted up and the process returns to step 630 (step 660).
[0041]
(4) Transmission processing
FIG. 9 shows a flowchart of the transmission process. Here, the transmission process is executed in accordance with a request from the transmission scheduling process shown in FIG.
[0042]
The transmission process is called from the transmission scheduling process by designating the entry counter I of the queue number bitmap table 25 and the bit counter J of the queue number bitmap table 25 entry (step 700). Next, one packet is transmitted from the queue of the traffic flow in the transmission queue table 21 in accordance with the traffic flow number (bit counter J of the queue number bitmap table entry) designated from the transmission request process (step 710). Next, the transmission data length is subtracted from the entry of the traffic flow in the transmission band value table 23 (step 720). It is determined whether or not the transmission band value table 23 is wrapping around (step 730). If it is not wrapping around, the process is terminated, and if it is wrapping around, the following process is executed.
[0043]
First, the number of times of wraparound is added to the entry of the traffic flow in the transmission bandwidth value wraparound number management table 24 (step 740). At this time, if the transmission data length counter becomes the initial value from 0, it is considered that the wraparound occurs once, and the initial value of the counter is acquired from the entry of the traffic flow in the transmission bandwidth guarantee table 22. Then, the bit corresponding to the traffic flow of the entry corresponding to the entry counter I of the queue number bitmap table 25 is turned off (step 750). Further, the bit corresponding to the traffic flow of the entry corresponding to the updated wraparound count of the queue number bitmap table 25 is turned on (step 760).
[0044]
The (3) transmission scheduling process and (4) transmission process will be described below with reference to the examples of FIGS.
(i) In state number {circle around (2)} in FIG. 3, bit 0 of entry 0 is detected from queue number bitmap table 25, and data of flow 0 is transmitted for 800 bytes (of which 6,000 bytes can be transmitted per unit time, 800 Byte transmission). As a result, the transmission data length counter wraps to 2 and becomes 280. By updating the transmission bandwidth value table 23, the transmission bandwidth value wraparound count management table 24, and the queue number bitmap table 25, each control table 5 has a status number. The state is as shown in (3).
[0045]
(ii) In the state number {circle over (3)} in FIG. 3, bit 1 of entry 0 is detected from the queue number bitmap table 25, and 800 bytes of data of flow 1 are transmitted (of which 6,000 bytes can be transmitted per unit time, 1,600 Byte transmission). In this case, the transmission data length counter does not wrap, and by updating the transmission band value table 23, the control tables 5 are in the state shown by the state number (4).
[0046]
(iii) In state number {circle over (4)} in FIG. 4, bit 1 of entry 0 is detected from queue number bitmap table 25, and 800 bytes of flow 1 data are transmitted (of which 400 bytes can be transmitted per unit time, 2,400). Byte transmission). As a result, the transmission data length counter wraps by 1 to 80, and by updating the transmission bandwidth value table 23, the transmission bandwidth value wraparound count management table 24, and the queue number bitmap table 25, each control table 5 has a state number. The state becomes as shown in (5).
[0047]
(iv) In the state number {circle over (5)} in FIG. 4, bit 1 of entry 1 is detected from the queue number bitmap table 25, and 800 bytes of data of flow 1 are transmitted (3,200 of which 6,000 bytes can be transmitted per unit time). Byte transmission). As a result, the transmission data length counter wraps 1 to 120, and the control bandwidth table 23, the transmission bandwidth value wraparound count management table 24, and the queue number bitmap table 25 are updated so that each control table 5 has a state number. The state is as shown in (6).
[0048]
(v) In state number {circle around (6)} in FIG. 4, bit 0 of entry 2 is detected from the queue number bitmap table 25 and 800 bytes of data of flow 0 are transmitted (of which 6,000 bytes can be transmitted per unit time, 4,000 Byte transmission). As a result, the transmission data length counter wraps to 2 to 160, and by updating the transmission bandwidth value table 23, the transmission bandwidth value wraparound count management table 24, and the queue number bitmap table 25, each control table 5 has a state number. The state is as shown in (7).
[0049]
(vi) In the state number (7) in FIG. 4, the bit 1 of the entry 2 is detected from the queue number bitmap table 25, and 800 bytes of data of the flow 1 are transmitted (4,800 of which 6,000 bytes can be transmitted per unit time). Byte transmission). As a result, the transmission data length counter wraps to 1 to 160, and the control band 5 is updated by updating the transmission bandwidth value table 23, the transmission bandwidth value wraparound count management table 24, and the queue number bitmap table 25. The state becomes as shown in (8).
[0050]
(vii) In state number {circle around (8)} in FIG. 5, bit 1 of entry 3 is detected from queue number bitmap table 25, and 800 bytes of data of flow 1 are transmitted (of which 6,000 bytes can be transmitted per unit time, 5,600 Byte transmission). As a result, the transmission data length counter wraps by 1 to 200, and the control band 5 is updated by updating the transmission bandwidth value table 23, the transmission bandwidth value wraparound count management table 24, and the queue number bitmap table 25. The state becomes as shown in (9).
[0051]
(viii) In the state number {circle over (9)} in FIG. 5, bit 0 of the entry 4 is detected from the queue number bitmap table 25, and 800 bytes of flow 0 data is transmitted (of which 6,400 bytes can be transmitted per unit time, 6,400 Byte transmission, that is, the process within the unit time is terminated in this process.) As a result, the transmission data length counter wraps to 2 to 80, and by updating the transmission bandwidth value table 23, the transmission bandwidth value wraparound count management table 24, and the queue number bitmap table 25, each control table 5 has a state number. The state is as shown in FIG.
[0052]
The processing within the unit time is completed as described above, but the results are flow 0: 2,400 bytes transmission (37.5%) and flow 1: 4,000 bytes transmission (62.5%), which are within 13% error.
[0053]
(5) Control table 5 re-initialization processing
FIG. 10 shows a flowchart of the reinitialization process of the control tables 5.
[0054]
In this process, the control tables 5 are reset every unit time so as not to deviate traffic. First, all entries in the transmission bandwidth guarantee table 22 are copied to all entries in the transmission bandwidth value table 23 (step 800). Next, each entry in the transmission bandwidth value wraparound count management table 24 is cleared to 0 (step 810). Further, the logical sum operation result from entry 0 to entry M in the queue number bitmap table 25 is set in entry 0 in the queue number bitmap table 25 (step 820). Next, 0 is set from entry 1 to entry M in the queue number bitmap table 25 (step 830). In addition, in the entry 0 of the queue number bitmap table 25, the bit corresponding to the flow for which the bandwidth is not guaranteed is turned off (step 840). Then, in the entry M of the queue number bitmap table 25, the bit corresponding to the flow for which the bandwidth is not guaranteed is turned on (step 850).
[0055]
In this example, the states of the various tables after the re-initialization of the control tables 5 are as shown by the state number 11 in FIG.
[0056]
【The invention's effect】
As described above, the present invention has the following effects, for example.
-Transmission processing scheduling that guarantees the transmission bandwidth for each traffic flow must be possible.
-For data queued in the transmission waiting queue, the highest priority transmission scheduling is dynamically performed for the traffic flow with the lowest guaranteed bandwidth achievement, and as long as there is data waiting for transmission, waste of the line etc. occurs. There is nothing.
-The delay time of the transmission waiting queue and the accuracy of bandwidth guarantee can be adjusted by adjusting the unit time for monitoring the transmission bandwidth based on the line speed and average packet length.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a system to which the present invention is applied.
FIG. 2 is an explanatory diagram of control tables 5 and a transmission waiting queue 6;
FIG. 3 is a state transition diagram (1) of the control table 5 by each processing.
FIG. 4 is a state transition diagram (2) of the control table 5 by each processing.
FIG. 5 is a state transition diagram (3) of the control table 5 by each processing.
FIG. 6 is a flowchart of control table initialization processing.
FIG. 7 is a flowchart of a transmission request acceptance process.
FIG. 8 is a flowchart of transmission schedule processing.
FIG. 9 is a flowchart of transmission processing.
FIG. 10 is a flowchart of reinitialization processing of the control tables 5;
[Explanation of symbols]
1 Network connection device
2 CPU
3 memory
4 I / O processor
5 Control tables
6 Waiting queue

Claims (5)

It has a transmission queue for each traffic flow that is a series of transfer data,
The managing and guaranteed bandwidth indicating the amount of data to be transmitted per unit of each traffic flow time, and the amount of data transmitted from the transmission queue for each of the traffic flows,
Calculated achievement of the guaranteed bandwidth represented by the transmitted data amount against the guaranteed bandwidth that indicates the amount of data to be the transmission, transmitting the level of achievement of low traffic flow queues preferentially select and Bandwidth guaranteed transmission method. The bandwidth-guaranteed transmission method according to claim 1,
A bandwidth-guaranteed transmission method that corrects a traffic flow bias by reinitializing a control variable that manages the amount of data transmitted by each traffic flow and the degree of achievement of the guaranteed bandwidth every unit time. The bandwidth-guaranteed transmission method according to claim 1 or 2,
A bandwidth-guaranteed transmission method comprising adjusting the accuracy of bandwidth guarantee and the reinitialization time of a control variable based on an average data packet length and a line speed. The bandwidth-guaranteed transmission method according to any one of claims 1 to 3,
The achievement level is managed by a bandwidth-guaranteed transmission method, which is managed based on the number of times of wraparound, which is the number of times the counter for each traffic flow makes a round. A transmission queue for each traffic flow that is a series of transfer data, a transmission queue table for queuing data according to each traffic flow, and the bandwidth guaranteed per unit time for each traffic flow in units of data The transmission bandwidth guarantee table managed in step 1, the transmission bandwidth value table for managing the number of data transmitted within a unit time for each traffic flow, and the transmission bandwidth for managing the number of wraparounds of the transmission bandwidth value table for each traffic flow A memory having a value wraparound count management table;
An input / output processing unit connected to the network;
A control unit for controlling data transmission by the input / output processing unit based on the memory;
The controller is
The managing and guaranteed bandwidth indicating the amount of data to be transmitted per unit of each traffic flow time, and the amount of data transmitted from the transmission queue for each of the traffic flows,
Calculated achievement of the guaranteed bandwidth represented by the transmitted data amount against the guaranteed bandwidth that indicates the amount of data to be the transmission, transmitting the level of achievement of low traffic flow queues preferentially select and Bandwidth guaranteed transmission device.

Images