JP2003218938A - Packet communication system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent inversion of transmission sequence due to outrunning of packets in a packet communication system where a load distributor distributes and integrates packets so as to perform data conversion processing in parallel. <P>SOLUTION: The packet communication system includes: the packet distributor 1 for distributing packets on a broadband transmission line 50 into narrow band transmission lines 511 to 513; two data converters 71 to 73 or more provided corresponding to the narrow band transmission lines 511 to 513; and a packet integrator 3 for integrating the packets and transmitting the resulting packet to a broadband transmission line 51, and the transmission timing of packets in the data converters 71 to 73 is controlled on the basis of packet reception information in all the data converters 71 to 73. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a packet communication system, and more particularly, to order control of packets distributed in a data communication system in which data conversion processing is parallelized.

[0002]

2. Description of the Related Art In recent years, with the rapid development of communication networks, high-speed processing of a large number of packets on a transmission line is required. However, when a data conversion device that performs a data conversion process (for example, an encryption process) with a heavy processing load is provided in the transmission path, overflow occurs due to insufficient processing capacity of the data conversion device. That is, when the processing performance of the data conversion device is lower than the transmission speed of the transmission line, there is a problem that the data conversion device cannot be directly connected to the transmission line.

As a measure for solving such a problem, parallelization of data conversion processing can be considered. In other words, distribute the input packet to multiple data converters,
It is conceivable to use a load balancer for integrating the packets after the data conversion processing and parallelize the heavy-load data conversion processing to achieve high speed as a whole.

However, since the processing delay in the data converter and the load balancer depends on the packet length, the packet transmission order may be changed and the input packet order and the output packet order may be different. Therefore, for example, the reception performance of the terminal that receives the packet may be deteriorated.

FIG. 3 is a block diagram showing the configuration of a conventional packet communication system incorporating a load balancer.
In the figure, 1 and 3 are load balancers, 21 to 23 are data converters, 50 and 51 are broadband transmission lines, and 511 to 513.
And 521 to 523 are narrow band transmission lines.

The broadband transmission line 50 is a transmission line at the system input end, and inputs packets to the load balancer 1. The narrow band transmission lines 511 to 513 are parallel transmission lines from which packets are output from the load distribution device 1. The load balancer 1 is a packet distributor that distributes two or more packets, which are sequentially input from the wideband transmission line 50, to the narrowband transmission lines 511 to 513 and outputs the packets, and the packets are transmitted in the order of arrival.

In a load balancing system in which a packet received from a single transmission line is distributed to a plurality of transmission lines in the order in which it is received and sent out, a store-and-forward (starts transmission after the entire packet is received) There is a store and forward) method and a cut and through method that starts packet transmission at the time when the packet header is received.

The data converters 21 to 23 perform a predetermined data conversion process on the packets input from the narrow band transmission lines 511 to 513, and output the converted data as packets to the narrow band transmission lines 521 to 523. That is, the data conversion device 21 performs data conversion on the input data from the narrow band transmission line 511 on the input side and outputs the data to the narrow band transmission line 521 on the output side. In exactly the same manner, the data conversion device 22 performs data conversion on the input data from the narrow band transmission line 512 and outputs the data to the narrow band transmission line 522, and the data conversion device 23 outputs the data from the narrow band transmission line 513. Narrow band transmission line 5
It outputs to 23.

The load balancer 3 is a packet consolidator that aggregates packets on a plurality of transmission lines and outputs the packets to one transmission line, and collects two or more packets input from all the narrow band transmission lines 511 to 513. They are integrated and output to the wide band transmission line 51 at the system output end.

In this way, the load balancer 1 distributes the packets to the narrow band transmission lines 511 to 513, the data converters 21 to 23 perform the data conversion processing on the distributed packets, and the load balancer 3 In (1), by integrating the packets after data conversion, the data conversion processing can be parallelized, and high-speed processing can be realized as the entire system. Therefore, even a data converter having a relatively low processing speed can be applied to a broadband network having a high transmission speed.

However, when the length of the packet input to the system is variable, the packet order may be reversed in the load balancers 1 and 3. In addition, in the data conversion devices 21 to 23 that employ the store-and-forward method that performs processing after receiving all packets,
Packet overtaking may occur.

FIG. 4 is an explanatory diagram showing an example of the operation of the packet communication system of FIG. In this figure, a cut-and-through method is adopted as a switching method for the load balancers 1 and 3, and as a worst case in which a packet overtaking occurs, a data length after a packet (# 1) 601 having a long data length arrives. An example is shown in which a short packet (# 2) 602 of 1 arrives.

A long packet 601 on the broadband transmission line 50
And the short packet 602 are distributed by the load balancer 1, the long packet 611 is output to the narrow band transmission line 511, and the short packet 612 is output to the narrow band transmission line 512. In this case, a long packet 611 on the narrow band transmission line 511 and a short packet 6 on the narrow band transmission line 512.
The output timing with 12 becomes very close.

Since the processing time required for the data conversion of the long packet 611 is longer than the time required for the data conversion of the short packet 612, the short packet 62 is output before the long packet 621 is output from the data conversion device 21.
2 is output from the data converter 22. In other words, the output order from the load balancer 1 is normal, but at the time of output from the data converters 21 and 22, a short packet #
2 has overtaken the long packet # 1. As a result, the packets 63 integrated in the load balancer 3 are integrated.
In 2, 631, the transmission order is changed.

FIG. 5 is an explanatory diagram showing another example of the operation of the packet communication system of FIG. In this figure,
Store & as a switching method for load balancers 1 and 3
As a worst case in which the forward method is adopted and packet overtaking occurs, as in FIG.
An example is shown where two arrive.

The load balancer 1 receives all the data of the packet input from the wide band transmission line 50, and then outputs the packet to the narrow band transmission lines 511 to 513. Therefore, the long packet (# 1) 601 is
The load balancer 1 before the short packet (# 2) 602
However, the short packet 612 is output to the narrow band transmission line 512 before the long packet 611 is output to the narrow band transmission line 511. That is, at the time of output from the load balancer 1, the short packet # 2 has overtaken the long packet # 1. Furthermore, since the processing time required for the data conversion of the long packet 611 is longer than the time required for the data conversion of the short packet 612, at the time of output from the data conversion devices 21 and 22, the long packet # 1 and the short packet # 2 are output. The time lag of will expand further. As a result, the packets 632 and 631 integrated in the load balancer 3 have their transmission order changed.

[0017]

As described above, in the conventional packet communication system in which the data conversion processing is parallelized, there is a problem that packet overtaking occurs,
It is desirable to control the packet transmission order to prevent packets from overtaking. However, in the conventional packet communication system, a method of controlling the transmission order according to the packet length measured inside the exchange as disclosed in JP-A-10-271163, and JP-A-10-341258.
Most of the methods, such as the method disclosed in Japanese Patent Publication, in which the time input to the switch and the packet are associated and transmitted in that order, are applied to the packet switch.

Therefore, when these conventional techniques are applied to the load balancer, the switching performance is deteriorated due to the packet storage and transmission control processing, and the advantage of the layer 3 switching hub such as the wire speed packet switching can be utilized. There was a problem that I could not do it. In addition, because the load balancer that uses the above method is not common,
There is a problem in that a general-purpose product that is commercially available as a load balancer cannot be adopted, leading to an increase in cost.

The present invention has been made in view of the above circumstances, and in a packet communication system in which data conversion processing is parallelized by distributing and integrating packets by using a load balancer, transmission order by passing packets The purpose is to prevent the reversal of.

It is another object of the present invention to prevent the transmission order from being reversed due to the passing of packets without deteriorating the switching characteristics of the packet switch. Another object of the present invention is to provide a packet communication system in which data conversion processing is parallelized at low cost while avoiding inversion of transmission order due to overtaking of packets.

[0021]

A packet communication system according to a first aspect of the present invention is a packet distribution device for distributing two or more packets arriving from a broadband transmission line to two or more narrow band transmission lines and outputting the packets. And two or more data converters provided corresponding to each narrow band transmission line and performing data conversion for packets on the narrow band transmission line, and packets on each narrow band transmission line are integrated and sent to the wide band transmission line. A packet integration device is provided, and the packet transmission timing in each data conversion device is controlled based on the packet reception information in all data conversion devices.

In the packet communication system according to the present invention as set forth in claim 2, each data conversion device is connected via a control line to transmit and receive a token circulating in each data conversion device, and each data received the token. The conversion device is configured to add the order information of the received packet and the reception time to the token and send the token to another data conversion device.

In the packet communication system according to the third aspect of the present invention, the packet transmission timing by each data conversion device that has received the packet is determined based on the token that has circulated through all the data conversion devices. Each data conversion device is configured to circulate a token having a transmission timing, and each data conversion device transmits a packet based on the transmission timing included in the reception token.

According to a fourth aspect of the packet communication system of the present invention, the delay time for each packet in the data conversion device and the packet integration device is calculated based on the reception time in each data conversion device, and the calculated delay time is calculated. It is configured to determine the transmission timing of each packet based on

A packet communication system according to a fifth aspect of the present invention is connected to each data conversion device, receives the sequence information and the reception time of the received packet in the data conversion device, and determines the transmission timing of each packet. An apparatus is provided, and each data conversion apparatus is configured to send a packet based on a sending timing instructed by the order control apparatus.

In the packet communication system according to the present invention as set forth in claim 6, the order control device obtains a delay time for each packet in the data conversion device and the packet integration device based on the reception time in each data conversion device. , The transmission timing of each packet is obtained based on the obtained delay time.

[0027]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiment 1. 1 is a block diagram showing a configuration example of a packet communication system according to a first embodiment of the present invention. In the figure, 1 and 3 are load balancers, 50 and 51 are wide band transmission lines, 511 to 513 and 521 to 523 are narrow band transmission lines, 71 to 73 are data conversion devices, and 7 is a control line.

As in the case of FIG. 3, the load balancer 1 distributes the packets sequentially input from the wide band transmission line 50 to the narrow band transmission lines 511 to 513 and outputs them. The exchange method at this time is a store & forward method,
Either of the cut-and-through method can be adopted.

The data converters 71 to 73 are provided on the respective narrow band transmission lines between the load balancers 1 and 3 and execute the data conversion processing in parallel. The data converter 71 receives the data 611 on the narrow band transmission line 511 on the input side, performs data conversion processing on the received packet, and then outputs the data to the narrow band transmission line 521 on the output side. Similarly, the data conversion device 72 uses the data 61 on the narrow band transmission line 512.
2 is received, data conversion processing is applied to the received packet, and then the data is output to the narrow band transmission line 522. The narrowband transmission lines 521 to 523 are aggregated in the load balancer 3, and the packets 621 and 622 are output as the packets 631 and 632 on the single broadband transmission line 51.

The control line 7 is a narrow band transmission line 5 for input / output.
A signal line for token transmission / reception provided between the data conversion devices 71-73, separately from 11-513, 521-523. The token circulates through all the data conversion devices 71 to 73 via this control line 7. This token is constantly flowing on the control line 7.

Upon receiving the header portion of the packet 611, the data conversion device 71 analyzes the content and acquires the order information of the received packet 611. Also, the reception time of the packet is measured. When a token is received from the data converter 72 via the control line 7 after receiving the packet, the order information and the reception time information are added to the token and the token is sent to the control line 7 again.
Similarly, the data converter 72 that next receives the packet 612 adds the order information and the reception time information of its own received packet 612 to the token, and sends the token to the control line 7.

All tokens are data conversion devices 71 to 7
When the data converter 71 completes one round, the data converters 71 to 73 output the packets in order from the earliest packet based on the packet sequence information.
Determines the transmission order of the packets.

Further, from the relationship between the packet order information and the packet reception time information, the load balancer 1 and the data converter 7
The delay time of each packet generated between 1 to 73 is calculated. Furthermore, the transmission time of each packet is determined by adding the delay time inside the data converters 71 to 73 and the delay time of the load balancer 3 to this. That is, the packet transmission timing in each of the data conversion devices 71 to 73 is determined so that the transmission order is not reversed at the time of output from the load distribution device 3.

Information such as the transmission timing determined in this manner is put on the token and transferred to all the data conversion devices 71 to 71.
73, and is notified to each of the data conversion devices 71 to 73. Each of the data conversion devices 71 to 73 sends out a packet based on the determined transmission time information of itself.

According to the present embodiment, the packet switching equipment does not control the transmission order of the packets, the wire speed switching is maintained by the general-purpose packet switching equipment, and the packet conversion is performed by the packet length difference in the data converter. Avoiding overtaking. Therefore, it is possible to prevent the line performance from deteriorating due to packet loss. In addition, it is possible to prevent an increase in network load due to retransmission control.

In order to shorten the time required for transmission timing control, the packet transmission timing may be read from the token, and the reception information of the next packet may be added to the same token and transmitted. That is, when the data converters 71 to 73 receive the token consisting of the transmission timing information, if the next packet has already been received, the sequence information and the reception time information of the next data are added to the same token. And sends it to the control line 7.
If the next packet is not received when the token is received, the fact can be added to the token and the token can be immediately sent to complete the loop within a certain time.

Embodiment 2. In the first embodiment, when the processing performance of the data conversion devices 71 to 73 exceeds the performance of the narrow band transmission line, the data conversion devices 71 to 73 are caused to execute all of the data conversion process, the token control, and the transmission order determination process. be able to. However, the data converters 71 to 71
When the processing performance of 73 is equal to or lower than the performance of the transmission path, causing the data conversion devices 71 to 73 to perform the transmission order control causes a problem that the original performance of the data conversion processing deteriorates. Occur.

In such a case, each data conversion device 7
1 to 73 are separated from the transmission sequence control processing, and a sequence control device 80 independent of the data conversion devices 71 to 73 is provided.
By centrally managing the transmission order and time control from each data converter 71 to 73, the load on the data converter can be reduced.

FIG. 2 is a block diagram showing a configuration example of a packet communication system according to the second embodiment of the present invention. In the figure, 1 and 3 are load balancers, 50 and 51 are wide band transmission lines, 511 to 513 and 521 to 523 are narrow band transmission lines, 71 to 73 are data conversion devices, 80 is a sequence control device, and 8 is a control line. Is.

Sequence controller 80 and data converters 71-71
The server 73 and the client 73 are related to each other, and the packet transmission in each of the data converters 71 to 73 is controlled by the order controller 80. The sequence control device 80 is connected to each of the data conversion devices 71 to 73 via the control line 8, but the sequence control device 80 and the data conversion devices 71 to 71 are connected.
The connection form of 73 can be any form.

When each of the data converters 71 to 73 receives a packet from the load balancer 1 via the narrow band transmission lines 511 to 513, it acquires sequence information and reception time information based on the header information of the received packet, These pieces of acquired information are notified to the order control device 80 via the control line 8.

The sequence controller 80 includes a data converter 71.
.. to 73, the transmission order of each of the data conversion devices 71 to 73 is determined based on the transmission order and the reception time information. Further, the sequence control device 80 uses the data conversion devices 71.
A control signal is output to ~ 73 to notify the determined transmission timing. Each of the data converters 71 to 73 transmits the data-converted packet to the narrowband transmission lines 521 to 523 according to the instruction of the order control device 80.

In this way, the sequence control device 80 determines and notifies the transmission timing of each of the data conversion devices 71 to 73, so that the data conversion processing performance of each of the data conversion devices 71 to 73 is not deteriorated. , It is possible to avoid the transmission order from being reversed due to the passing of packets.

In each of the above embodiments, the packet of one wide band transmission line 50 is converted into three narrow band transmission lines 511.
To 513, and three data conversion devices 21 to 23,
Although an example of parallel processing in 71 to 73 has been described, the present invention is not limited to such a case. That is, the present invention can be similarly applied to a case where a data converter is provided in each of two or four or more narrow band transmission lines to perform parallel processing.

[0045]

According to the present invention, in a packet communication system in which a load balancer is used to distribute and integrate packets to parallelize data conversion processing, it is possible to prevent the transmission order from being reversed due to the passing of packets. it can.
Further, it is possible to avoid the reverse of the transmission order due to the passing of the packet without deteriorating the switching characteristic of the packet switch. Further, it is possible to inexpensively provide the packet communication system in which the data conversion processing is parallelized while avoiding the inversion of the transmission order due to the passing of the packet.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration example of a packet communication system according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration example of a packet communication system according to a second embodiment of the present invention.

FIG. 3 is a block diagram showing a configuration of a conventional packet communication system in which a load balancer is introduced.

FIG. 4 is an explanatory diagram showing an example of an operation of the packet communication system of FIG. 3, showing a case where a cut-and-through method is adopted as a switching method of the load balancers 1 and 3.

5 is an explanatory diagram showing an example of an operation of the packet communication system of FIG. 3, and shows a case where a store & forward method is adopted as a switching method of the load balancers 1 and 3. FIG.

[Description of Reference Signs] 1 load balancer (packet distributor) 21 to 23
Data conversion device, 3 load distribution device (packet integration device), 7 control lines, 71-73 data conversion device, 8
Control line, 80 sequence controller, 50 wideband transmission line at system input end, 51 wideband transmission line at system output end, 511 to 513 narrow band transmission line at input end of data converter, 521 to 523 output end of data converter Narrow band transmission line, 601 long packet on the wide band transmission line 50, 602 short packet on the wide band transmission line 50, 61
1 long packet on narrow band transmission line 511, 612 short packet on narrow band transmission line 512, 621 long packet on narrow band transmission line 521, 622 narrow band transmission line 5
22 short packets, 631 long packets on wide band transmission line 51, 632 short packets on wide band transmission line 51

Claims (6)

[Claims] 1. A packet distribution device that distributes and outputs two or more packets arriving from a wide band transmission line to two or more narrow band transmission lines, and a packet distribution device provided corresponding to each narrow band transmission line. Of two or more data converters that perform data conversion on the packet and a packet consolidator that consolidates the packets on each narrow band transmission line and sends the packets to the wide band transmission line. A packet communication system controlled based on packet reception information in all data converters. 2. The data conversion device is connected via a control line for transmitting and receiving a token circulating in each data conversion device, and each data conversion device that has received the token has sequence information of a received packet and a reception time. The packet communication system according to claim 1, wherein the packet is added to the token and transmitted to another data conversion device. 3. A packet transmission timing by each data conversion device that receives a packet is determined based on a token that has circulated through all data conversion devices, and a token having the determined transmission timing is circulated to each data conversion device. The packet communication system according to claim 2, wherein each of the data conversion devices transmits the packet based on the transmission timing included in the reception token. 4. A delay time for each packet in the data conversion device and the packet integration device is calculated based on a reception time in each data conversion device, and a transmission timing of each packet is calculated based on the calculated delay time. The packet communication system according to claim 3, which is characterized in that. 5. A sequence control device, which is connected to each data conversion device, receives sequence information and reception time of received packets in the data conversion device, and determines the transmission timing of each packet, each data conversion device performing sequence control. The packet communication system according to claim 1, wherein the packet is transmitted based on a transmission timing instructed by the device. 6. The sequence control device obtains a delay time for each packet in the data conversion device and the packet integration device based on the reception time in each data conversion device, and determines the delay time of each packet based on the obtained delay time. The packet communication system according to claim 5, wherein transmission timing is obtained.