JP2002185488A - Communication efficiency amplifier - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a communication efficiency amplifier which prevents competition in acquiring bands for a plurality of TCP connections to aim at realizing the amplification of the communication efficiency on the whole thereof. SOLUTION: The communication efficiency amplifier is installed at a gateway for connecting each of LANs to a network for communication between at least two LANs to be connected to the network. An inter-communication efficiency amplifier TCP connection is established between opposed communication efficiency amplifiers TBX, TBY to monitor an inter-host TCP connection established between a host in one LAN X and a host in the other LAN Y. If there are a plurality of inter-host TCP connections, IP packets for carrying the plurality of TCP connections are multiplexed to carry them as data of the TCP connection between the communication efficiency amplifiers TBX, TBY.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a LAN (Local Area) in a wide area network such as the Internet.
The present invention relates to a communication efficiency amplifying device for improving inter-network communication efficiency.

[0002]

2. Description of the Related Art Conventional TCP / IP (Transmission)
Sion Control Protocol / Int
(Ethernet Protocol) implementation, at the end of a TCP connection, if there is enough data to exchange meaningful statistics, and if the routing table entry for that destination is not the default route, it will be used for future TCP connections. , The threshold value of the slow start, the smoothed round trip time, and the average deviation of the smoothed round trip time are stored in the corresponding items of the route table. The host administrator can set the index of a specific route using the route command. They are 3 above
In addition to these values, the maximum transfer unit, the band delay product in the transmission direction, and the band delay product in the reception direction. When a new TCP connection is established, whether it is active or passive, if the routing table entry used for that connection has those values, the corresponding variables will be dependent on those values. Initialized.

[0003] As a method of avoiding a decrease in throughput due to a delay or the like at the time of TCP connection via a wide area network, an interconnect device performs processing up to TCP, a unique protocol is introduced between interconnect devices, and flow control is performed. Sending LA
N, between interconnecting apparatuses, and a receiving side LAN, a method of independently realizing each of them has already been proposed in Japanese Patent Application Laid-Open No. 7-250100.

[0004] In the method proposed in Japanese Patent Application Laid-Open No. 7-250100, the problem of buffer utilization is pointed out,
When handling a plurality of TCP connections, packets are transmitted using a unique flow control procedure between interconnecting devices and a selective retransmission procedure in the data ring layer using SSCOP so that efficient buffer utilization can be performed. A transfer method has already been proposed in Japanese Patent Application Laid-Open No. 11-340072.

[0005] A plurality of TCP connections between hosts are connected to one TC.
TIP Multiplexi realized on P connection
The method called ng Protocol is described in RFC2371.
It has already been proposed.

[0006]

In the current TCP implementation, it is not possible to use information on a network acquired by another host. That is, the information on the size of the congestion window, the threshold value of the slow start, and the round-trip time acquired by the other host cannot be used. A new TCP that would have been possible if these information could be shared
Adjusting the size of the congestion window of the connection, competing for network bandwidth caused by each host expanding the congestion window without coordinating with other hosts, resulting in unnecessary packet discard, resulting in lower throughput. Significant decline cannot be avoided.

The technique proposed in RFC 2371 can treat a plurality of TCP connections between two specific hosts as one, but cannot apply it to a set of a plurality of hosts.

In the method proposed in Japanese Patent Application Laid-Open No. 7-250100, when there are a plurality of TCP connections between hosts, there is no description of a means for preventing contention for bandwidth acquisition due to the TCP connections, and the method cannot be avoided.

In the method proposed in Japanese Patent Application Laid-Open No. H11-341072, the connection between the devices is controlled by SSCOP.
It is premised on using a data link layer using .NET, and cannot cope with a network using a data link layer using other technologies.

[0010] The present invention has been made in view of the above circumstances, and the connection between the communication efficiency amplifying devices is not limited to a data link layer by a specific technology, but is applied to communication between two LANs connected by a network. By arranging the communication efficiency amplifier opposite to the position of the gateway where the LAN connects to the network, the communication efficiency amplifier establishes a TCP connection with the communication efficiency amplifier oppositely arranged, and Monitors a TCP connection established between a host in the LAN to be connected and a partner host in the LAN adjacent to the communication efficiency amplifying device disposed in the opposite direction, and when there are a plurality of TCP connections between the hosts, IP packets carrying those TCP connections Is multiplexed and carried as data of a TCP connection between the communication efficiency amplifying devices, thereby preventing contention for bandwidth acquisition by a plurality of TCP connections beforehand. And to provide a communication efficiency amplifier toward better amplification in communication efficiency as a whole.

[0011]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a method for communicating between at least two LANs connected to a network, wherein each LAN is located at a position of a gateway connected to the network. Communication efficiency amplifying device, wherein a TCP connection between the communication efficiency amplifying devices is established between the communication efficiency amplifying device and the other communication efficiency amplifying device.
And monitor the TCP connection between the hosts established between the host in the LAN and the partner host in the opposite LAN.
When there are a plurality of P connections, the IP packets carrying the plurality of TCP connections are multiplexed, and
It is characterized by being carried as P connection data.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail.

1. Startup When the communication efficiency amplifying device is started, its own IP address, the IP address of the communication efficiency amplifying device disposed opposite thereto, the port number used for the TCP connection between the devices, the local LAN
Various settings such as the network address of the other party and the network address of the partner LAN are read.

2. Setting change Even after the operation is started, the administrator or the like performs an operation of changing various settings as needed.

3. Establishing TCP connection between communication efficiency amplifying devices When the TCP connection between the communication efficiency amplifying device and the communication efficiency amplifying device is not established, the communication efficiency amplifying device is connected to the communication efficiency amplifying device which is opposed to the communication efficiency amplifying device. Attempt to establish a TCP connection between

If the establishment of the TCP connection with the communication efficiency amplifier arranged oppositely fails, the TCP connection is attempted again after an appropriate time has elapsed.

This is repeated until a TCP connection is established between the communication efficiency amplifiers.

TCP between the opposing communication efficiency amplifying device
Until the connection is established, I
For a P packet, normal IP transfer processing is performed.

4. Communication Efficiency Amplification Processing When a TCP connection is established with the opposing communication efficiency amplification apparatus, end-side reception processing, multiplex processing, TCP connection transmission processing between communication efficiency amplification apparatuses, TCP between communication efficiency amplification apparatuses are performed. The connection reception processing, the demultiplex processing, and the end-side transmission processing are performed in parallel.

5. End-Side Receiving Process In the end-side receiving process, an IP packet input from the end-side interface is constantly monitored to determine whether the IP packet is a TCP connection between the communication efficiency amplification target hosts.

The TCP connection between the communication efficiency amplification target hosts means that the hosts in the LAN adjacent to the communication efficiency amplification device
This is a TCP connection communication with a host in a LAN adjacent to the opposed communication efficiency amplifier via the opposed communication efficiency amplifier.

In the end-side reception processing, an IP header is observed for each IP packet input from the end-side interface, and the source address is that of a host in a LAN adjacent to the communication efficiency amplifying apparatus, and the destination address is Is the host in the LAN adjacent to the communication efficiency amplifying device disposed opposite to the host, and if the upper layer protocol is TCP, the processing is further raised to the TCP layer processing, the TCP header is observed, and the source address, the source It is determined whether or not the TCP connection between the hosts recognized by the set of the port number, the destination address, and the destination port number is already registered as the TCP connection between the communication efficiency amplification target hosts.

In the end receiving process, the IP packet is
If the TCP connection has not been already registered as a TCP connection between the communication efficiency amplification target hosts and the TCP header includes a TCP segment including a SYN flag, registration processing 1 is performed.

In the end receiving process, the IP packet is
T that has already been registered as a TCP connection between the hosts to be amplified for communication efficiency and that includes a FIN flag in the TCP header
If a CP segment is included, end processing 1 is performed.

In the end receiving process, the IP packet is
If a TCP segment for a host-to-host TCP connection already registered as a communication efficiency amplification target host-to-host TCP connection is included, termination processing 1 is performed.

In the end receiving process, the IP packet is
If the above conditions are not met, it is not regarded as a TCP connection between the communication efficiency amplification target hosts, so that normal IP layer transfer processing is performed.

6. Registration Processing 1 In registration processing 1, IP packets are queued in a TCP connection transmission buffer between communication efficiency amplifying apparatuses.

In the registration process 1, the source address (RS
1), source port number, destination address (RD1), destination port number
For the host-to-host TCP connection recognized by the set, it is recorded that registration processing 1 is being executed, and the IP packet from RD1 including the TCP segment including the SYN flag and the ACK flag in the TCP header is decoded. Confirmed by the multiplex process and transferred to RS1, and the IP packet containing the TCP segment including the ACK flag in the TCP header from RS1 was confirmed by the end-side receive process and queued in the TCP connection device buffer between the communication efficiency amplifying devices. Above, the TCP connection between the hosts is registered as the TCP connection between the communication efficiency amplification target hosts.

In the registration process 1, when registering a TCP connection between hosts as a TCP connection between hosts for communication efficiency amplification,
An end-side reception buffer and an end-side transmission buffer are allocated for the TCP connection between the hosts.

7. Termination Process 1 In the termination process 1, an IP packet is exchanged between the hosts with respect to the TCP connection between the hosts recognized by a set of a source address, a source port number, a destination address, and a destination port number. All of the end connection receiving buffers for the TCP connection are queued in the TCP connection transmission buffer between the communication efficiency amplifiers by the multiplex processing, and then queued in the TCP connection transmission buffer between the communication efficiency amplifiers.

In the end processing 1, the source address (FS
1), source port number, destination address (FD1), destination port number
It records that the termination processing 1 is being executed for the host-to-host TCP connection recognized in the set, and demultiplexes the IP packet from the FD1 including the TCP segment including the ACK flag in the TCP header. The IP packet including the TCP segment including the FIN flag in the TCP header from the FD1 is confirmed and transferred to the FS1 by the demultiplex processing, and the ACK flag is included in the TCP header from the FS1. After confirming the IP packet including the TCP segment in the end-side reception processing, queuing the TCP buffer between the communication efficiency amplifying devices in the transmission buffer, and then transmitting the TCP
The connection is released from the TCP connection between the communication efficiency amplification target hosts.

In the termination processing 1, when releasing the TCP connection between the hosts from the TCP connection between the hosts to be subjected to the amplification of communication efficiency, the end receiving buffer and the end transmitting buffer allocated for the TCP connection between the hosts are released.

8. Termination Processing 1 In the termination processing 1, an end-side receiving buffer for the TCP connection between the hosts that has already been registered for communication efficiency amplification is prepared for the TCP connection between the hosts. Queue the data of the included TCP segment.

In the terminating process 1, when queuing data of a TCP segment included in an IP packet, TCP header information such as a sequence number, a data length, and an ACK sequence number is recorded so that re-packetization is possible. I do.

In the termination process 1, if the TCP segment included in the IP packet has the next expected sequence number for the host-to-host TCP connection, the host identified by the source address has an A in the TCP header.
A TCP segment including the CK flag is transmitted as a proxy response.

In the termination process 1, the window size of the TCP segment transmitted as the proxy response and including the ACK flag in the TCP header depends on how much the end-side reception buffer for the TCP connection between the hosts is queued. Adjust if possible.

In the termination processing 1, the TCP segment including the ACK flag in the TCP header, which is transmitted as a proxy response, is transmitted there when the end side transmission processing for the TCP connection between the hosts is performed within a predetermined time. Piggyback on a TCP segment.

In the termination process 1, if the TCP segment included in the IP packet does not have the next expected sequence number for the TCP connection between the hosts, the T
The TCP segment including the ACK flag in the CP header is transmitted as a proxy duplicate response.

In the termination process 1, if the TCP segment included in the IP packet includes an ACK flag in the TCP header, the ACK sequence number in the TCP header is checked, and the corresponding data is transmitted from the end side transmission buffer to
Since the transmission has already been completed, it is determined that there is no need to hold the data any more, and the data is deleted.

In the termination process 1, when congestion is detected by duplicate ACK or retransmission timeout, a TCP segment having an appropriate sequence number is retransmitted.

9. Multiplex Processing In the multiplex processing, the communication efficiency amplification target host T
For a plurality of host-to-host TCP connections registered as a CP connection, the TCP segment data queued in each end-side reception buffer is multiplexed and queued in a communication efficiency amplification device TCP connection transmission buffer.

In the multiplexing process, the data of the TCP segment and the TCP header information relating to the TCP segment are taken out from one of the end-side receiving buffers, re-packetized as an IP packet containing the TCP segment, and the TCP connection transmission buffer between the communication efficiency amplifying devices. To queue.

In the multiplex processing, for a plurality of TCP connections between hosts registered as communication efficiency amplification target TCP connections, a particular queue connection to be selected next is selected from which host connection. If not, use a simple round robin.

In the multiplex processing, for a plurality of host-to-host TCP connections registered as communication efficiency amplification-target host-to-host TCP connections, which of the host-to-host TCP connections to queue next is selected by setting. Selection by priority control or fairness control.

In the multiplex processing, when performing selection by priority control or fairness control, for example, differentiation by weighting based on port numbers or addresses, aging to prevent a specific TCP connection between hosts from becoming starved. Processing, etc.

10. TCP connection transmission processing between communication efficiency amplification apparatuses and TCP connection reception processing between communication efficiency amplification apparatuses In the TCP connection transmission processing between communication efficiency amplification apparatuses and the TCP connection reception processing between communication efficiency amplification apparatuses, multiplex processing is used. The re-packetized IP packet queued in the transmission buffer between the communication efficiency amplifying devices is transmitted as TCP data to the TCP connection reception buffer between the communication efficiency amplifying devices of the opposing communication efficiency amplifying device.
Transmit and receive by P.

In the TCP connection transmission process between the communication efficiency amplifying devices and the TCP connection reception process between the communication efficiency amplifying devices, T
Reliable data transmission / reception is performed by the CP retransmission process.

In the TCP connection transmission process between the communication efficiency amplifying devices and the TCP connection reception process between the communication efficiency amplifying devices, T
By the flow processing of the CP, data is transmitted and received with optimum efficiency between the communication efficiency amplifying devices.

In the TCP connection transmission process between the communication efficiency amplification devices and the TCP connection reception process between the communication efficiency amplification devices, T
By keeping the CP connection, the size of the congestion window is adjusted to an optimal size.

In the TCP connection transmission processing between the communication efficiency amplifiers and the TCP connection reception processing between the communication efficiency amplifiers,
A single TCP connection is provided between LANs, and when a plurality of flows exist between LANs, it is possible to prevent an increase in delay or packet discard caused by competing for bandwidth and a drop in communication efficiency as a result.

In the TCP connection transmission process between the communication efficiency amplifiers and the TCP connection reception process between the communication efficiency amplifiers, the TMT transmitted by applying the path MTU discovery is used.
The size of the CP segment is always adjusted to the optimum transfer unit.

The TCP connection transmission process between the communication efficiency amplifying devices and the TCP connection reception process between the communication efficiency amplifying devices correspond to a so-called long fat network by applying a window scale option.

11. Demultiplex processing In the demultiplex processing, the TCP between the communication efficiency amplifying devices is used.
The data in the connection reception buffer is separated in IP packet units based on the IP header information of the IP packets queued as data.

In the demultiplexing process, the separated IP packet is already transmitted to the TC between the communication efficiency amplification target hosts.
If the connection is not registered as a P connection and includes a TCP segment including a SYN flag in the TCP header, the demultiplex processing that performs registration processing 2 indicates that the separated IP packet has already been subjected to communication efficiency amplification. If it is registered as a host-to-host TCP connection and contains a TCP segment containing a FIN flag in the TCP header, termination processing 2
Perform

In the demultiplexing process, the separated IP packet is already transmitted to the TC between the communication efficiency amplification target hosts.
If a TCP segment for a TCP connection between hosts registered as a P connection is included, termination processing 2
Perform

12. Registration Processing 2 In registration processing 2, the IP packet is transmitted to the host identified by the destination address.

In the registration process 2, the source address (RS
2), source port number, destination address (RD2), destination port number
It is recorded that the registration process 2 is being executed for the host-to-host TCP connection recognized in the set, and the IP packet containing the TCP segment including the SYN flag and the ACK flag in the TCP header from the RD 2 is sent to the end. The IP packet containing the TCP segment including the ACK flag in the TCP header from the RS2 is confirmed by the demultiplexing side reception process and confirmed by the demultiplexing side reception process and transmitted to the RD2. After the transfer, the TCP connection between the hosts is registered as the TCP connection between the hosts for communication efficiency amplification.

In the registration process 2, when registering a TCP connection between hosts as a TCP connection between hosts to be amplified in communication efficiency,
An end-side reception buffer and an end-side transmission buffer are allocated for the TCP connection between the hosts.

13. End Process 2 In the end process 2, the TCP connection between the hosts recognized by the IP packet as a set of four of a source address, a source port number, a destination address, and a destination port number is determined. After all of the end-side transmission buffers for the TCP connection have been transmitted by the end-side transmission processing, they are transmitted to the host identified by the destination address.

In the end processing 2, the source address (FS
2), source port number, destination address (FD2), destination port number
For the TCP connection between the hosts recognized in the set, it is recorded that the termination processing 2 is being executed, and the IP packet containing the TCP segment including the ACK flag in the TCP header from the FD 2 is received by the end side. TCP connection between the communication efficiency amplifiers is confirmed in the transmission buffer, and the IP packet containing the TCP segment including the FIN flag in the TCP header from the FD2 is confirmed by the end-side reception processing and the TCP between the communication efficiency amplifiers is checked.
Queue in the connection transmit buffer, and
After confirming the IP packet including the TCP segment including the ACK flag in the CP header by the demultiplexing process and transferring the IP packet to the FD 2, the TCP connection between the hosts is released from the TCP connection between the communication efficiency amplification target hosts.

In the termination processing 2, when the TCP connection between the hosts is released from the TCP connection between the hosts for communication efficiency amplification, the end-side reception buffer and the end-side transmission buffer allocated for the TCP connection between the hosts are released. I do.

14. Termination Processing 2 In termination processing 2, the communication efficiency amplifying host T
For the CP connection, an end-side transmission buffer for the TCP connection between the hosts is prepared, and the TCP segment data included in the IP packet is queued there.

In the termination process 2, when queuing TCP segment data included in an IP packet, TCP header information such as a sequence number, a data length, and an ACK sequence number is recorded so that re-packetization is possible. I do.

In the termination process 2, if the TCP segment included in the IP packet includes an ACK flag in the TCP header, the ACK sequence number of the TCP header is confirmed, and the corresponding data is transmitted from the end side reception buffer to
Since the transmission has already been completed, it is determined that there is no need to hold the data any more, and the data is deleted.

15. End-Side Transmission Process In the end-side transmission process, the communication efficiency amplification target host TC
For a plurality of host-to-host TCP connections registered as P connections, TCP segment data queued in each end-side transmission buffer is repacketized as an IP packet containing a TCP segment, and the host-to-host TCP
The packet is transmitted by TCP to a host in the LAN adjacent to the communication efficiency amplifying device, which is one end of the P connection.

In the end-side transmission process, when the free space in the end-side reception buffer becomes larger than the previously advertised window size, a window update ACK is transmitted.

In the end-side transmission processing, reliable data transmission is performed by TCP retransmission processing.

In the end-side transmission processing, data transmission with optimal efficiency is performed by TCP flow control.

In the end-side transmission processing, the path MTU discovery algorithm is applied to constantly update the optimal transfer unit, that is, the size that can be transmitted as one segment.

16. Operation As described above, two LAs connected via the Internet
For N-to-N communication, the communication efficiency amplifying device is placed at the position of the gateway where the LAN connects to the Internet, so that the communication efficiency amplifying device is connected to the oppositely placed communication efficiency amplifying device by TCP connection. And the adjacent L
TCP established between a host in the AN and a counterpart host in the LAN adjacent to the communication efficiency amplifying device arranged oppositely
Monitor connections and when there are multiple TCP connections between hosts,
By multiplexing the IP packets carrying them and carrying them as TCP connection data between communication efficiency amplifiers,
The contention of band acquisition by them is prevented beforehand, and the communication efficiency as a whole is amplified.

[0071]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 shows the internal configuration of a communication efficiency amplifier according to an embodiment of the present invention. As shown in the figure, the communication efficiency amplifying device 21 includes an end-side reception processing unit 22 for processing an input packet from the LAN side, an end-side reception buffer 23 for holding data on a TCP connection subject to communication efficiency amplification, End-side receive buffer 23
Processing unit 2 for multiplexing
4. Transmission buffer 25 between communication efficiency amplifiers holding data of a plurality of TCP connections subject to amplification of communication efficiency bundled by the multiplex processing unit 24, and transmission / reception by the TCP connection established between the communication efficiency amplifiers. TCP connection between communication efficiency amplifying devices, TCP connection reception between communication efficiency amplifying devices, TCP connection between communication efficiency amplifying devices, TCP connection between communication efficiency amplifying devices holding data received by reception processing unit 27 Receive buffer 28,
TCP connection between communication efficiency amplifying devices Demultiplex processing section 29 for demultiplexing data in reception buffer 28 for each TCP connection subject to communication efficiency amplification, end for holding demultiplexed data for each TCP connection subject to communication efficiency amplification The transmission buffer 30 includes an end transmission processing unit 31 that processes output packets to the LAN.

FIG. 2 shows a case where a communication efficiency amplifier is applied to communication between two LANs connected by the Internet according to an embodiment of the present invention. As shown in the figure, a communication efficiency amplifying device is arranged at a position of a gateway where the LAN connects to the Internet. LAN
The communication efficiency amplifier TBX is arranged at the position of the gateway where X connects to the Internet 41. A communication efficiency amplifying device TBY is arranged at a position of a gateway where LAN Y connects to the Internet 41. LAN X has hosts X1 and X2, and LAN Y has hosts Y1 and Y2.
2 are provided.

FIG. 3 shows a communication efficiency amplifying device TB which sets a TCP connection between hosts established between the host X and the host Y according to the embodiment of the present invention as a TCP connection subject to amplification of communication efficiency.
9 shows a protocol stack in the case where X and the communication efficiency amplification device TBY are used. Transmission by TCP from the host X is performed in the communication efficiency amplifier TBX by TCP.
Layer, a terminating process is performed in place of the host Y, a proxy response process and the like are performed, and the multiplexing process of the communication efficiency amplifying device TBX performs another TCP connection between the hosts, which is a TCP connection subject to the communication efficiency amplification. And bundled. In the transmission / reception processing of the TCP connection between the communication efficiency amplifying devices, the bundled TCP connection for the communication efficiency amplification is treated as the TCP data as a whole, and the reliable communication by the TCP retransmission processing and the efficiency by the TCP flow control are performed. To achieve good communication. In the communication efficiency amplifier TBY, the data received by the TCP connection between the communication efficiency amplifiers is subjected to demultiplex processing to a plurality of communication efficiency amplification target TCPs bundled by the communication efficiency amplifier TBX.
The connections are separated and transferred to the host Y as individual inter-host TCP connections. Transmission by TCP from the host Y is the same as above.

FIG. 4 shows the first operation after starting the communication efficiency amplifying device according to the embodiment of the present invention. 3 shows a TCP connection between communication efficiency amplifying devices. Communication efficiency amplifier TBX
(Communication efficiency amplifying device TBY) reads each setting at the time of start-up, and in accordance with the settings, the TCP communication efficiency amplifying device TBY (communication efficiency amplifying device TBX)
Establish a connection.

FIG. 5 shows a LAN X according to an embodiment of the present invention.
Shows a case in which the host X1 within the server attempts to establish a TCP connection (hereinafter referred to as TCP connection 1) with the port y1 of the host Y1 using the port x1. FIG. 6 shows the sequence at that time. The host X1 transmits a TCP segment including a SYN flag in a TCP header. The communication efficiency amplifier TBX constantly monitors an input packet from the LAN X and finds the above TCP segment. The communication efficiency amplifying device TBX stores the entry of the registration process 1 for the TCP connection 1 (registration process 1 starts), multiplexes the packet, and executes the TCP connection transmission process between the communication efficiency amplifying devices to transmit the TCP data. Is transferred to the communication efficiency amplifier TBY. The communication efficiency amplifying device TBY receives the transmission from the communication efficiency amplifying device TBX by the TCP connection receiving process between the communication efficiency amplifying devices, and performs the TCP connection 1 by the demultiplexing process.
Discover the start of. In the communication efficiency amplifier TBY, TC
For the P connection 1, the fact that registration processing 2 has been entered is stored (registration processing 2 starts), and the packet is transferred to the host Y1. Thereafter, the communication efficiency amplifying device TBX confirms the TCP segment including the SYN flag and the ACK flag from the host Y1 for the TCP connection 1 (registration process 1 confirmation 1 in FIG. 6), and includes the ACK flag from the host X1. The TCP segment is confirmed (registration processing 1 confirmation 2 in FIG. 6), and an end-side transmission buffer and an end-side reception buffer buffer are allocated. Similarly, the communication efficiency amplifying device T
In BY, for TCP connection 1, S from host Y1
The TCP segment including the YN flag and the ACK flag is confirmed (registration process 2 confirmation 1 in FIG. 6), and the TCP segment including the ACK flag from the host X1 is confirmed (FIG. 6).
2), the end-side transmission buffer (registration processing 1 buffer allocation) and the end-side reception buffer (registration processing 2 buffer allocation) are allocated.

FIG. 7 shows that the TCP connection between the hosts <Y2, y2, X while the TCP connection 1 according to the embodiment of the present invention is being established.
2, x2> (hereinafter, TCP connection 2) is established. At this time, two LAN-to-host TCP connections, TCP connection 1 and TCP connection 2, logically exist in LAN X and LAN Y. In the communication efficiency amplifier TBX, the host X1 to the host Y1 for TCP connection 1
And the transmission from the host X2 to the host Y2 for the TCP connection 2 are stored in the respective end-side reception buffers and then multiplexed into the TCP connection transmission buffer between the communication efficiency amplifiers. The transmission rate of transmission from the host X1 to the host Y1 for the TCP connection 1 is controlled by a proxy response from the communication efficiency amplifier TBX. Specifically, the availability of the end-side reception buffer for the TCP connection 1 of the communication efficiency amplifier TBX is indicated in the window size advertised by the proxy response, whereby the transmission rate is controlled. The same applies to the transmission from the host X2 to the host Y2 for the TCP connection 2. TCP connection between communication efficiency amplifying devices The data of TCP connection 1 and TCP connection 2 multiplexed in the transmission buffer are transmitted between the communication efficiency amplifying devices TBX and the communication efficiency amplifying device TBY between the communication efficiency amplifying devices TBY.
Transferred on P connection. The TCP connection between the communication efficiency amplifying apparatuses performs reliable communication by TCP retransmission processing. When a packet on a route is discarded, the TCP connection between the communication efficiency amplifying apparatuses is retransmitted. The TCP connection between the communication efficiency amplifying devices is TC
Efficient communication is performed by P flow control.

At this time, actually, LAN X and LAN X
During Y, in addition to the TCP connection between the communication efficiency amplifying devices,
There is no TCP connection. If there is no communication efficiency amplifying device, TCP connection 1 and TCP connection 2 try to acquire the respective bandwidths and increase the transmission rates respectively.
These cause congestion, and consequently reduce the transmission rate unnecessarily.
By arranging the communication efficiency amplifying device, TCP connection 1 and T
Such a situation is prevented beforehand by treating the CP connection 2 collectively.

When the communication efficiency amplifying device TBX performs a priority control of transmitting the TCP connection 1 preferentially, in the multiplexing process, the TC is determined depending on the priority.
The probability of selection from the end-side reception buffer of P connection 1 is increased.

When the communication efficiency amplifying device TBX performs fairness control such that the TCP connection 1 and the TCP connection 2 are transmitted fairly, the selection per unit time from the respective end-side reception buffers is the same in the multiplex processing. Adjust to the extent.

FIG. 8 shows a sequence when a disconnection request is issued from the host X1 for TCP connection 1 according to the embodiment of the present invention. Communication efficiency amplifier TBX
The TCP segment including the FIN flag from the host X1 is confirmed, and the processing enters the end processing 1 (end processing 1 starts). Thereafter, the TCP segment including the ACK flag from the host Y1 is confirmed (the end processing 1 in FIG. 8 is confirmed), and the TCP segment including the FIN flag from the host Y1 is confirmed (the end processing 1 in FIG. 8 is confirmed). 2), host X1
Then, the TCP segment including the ACK flag is confirmed (end process 1 check 3 in FIG. 8), and the end-side transmission buffer and end-side receive buffer are released (end process 1 buffer release). The communication efficiency amplifier TBY confirms the TCP segment including the FIN flag from the host X1,
The end processing 2 is started (end processing 2 starts). After that, the TCP segment including the ACK flag from the host Y1 is confirmed (confirmation 1 of the end process 2 in FIG. 8), and the TCP segment including the FIN flag from the host Y1 is confirmed (confirmation of the end process 2 in FIG. 8). 2), ACK from host X1
The TCP segment including the flag is confirmed (end processing 2 confirmation 3 in FIG. 8), and the end side transmission buffer and the end side reception buffer are released (end processing 2 buffer release).

[0082]

As described above, according to the present invention, the communication between two LANs connected by a network can
By arranging the communication efficiency amplifying device at the position of the gateway connected to the network by the AN, when there are a plurality of TCP connections established between the hosts in both LANs, it is possible to prevent contention for bandwidth acquisition by those. , Realizes amplification of communication efficiency as a whole of them.

In particular, when a company having a plurality of bases performs communication between LANs at each base via the Internet, provision of an efficient communication infrastructure is considered as an application of the present invention.

[Brief description of the drawings]

FIG. 1 is a configuration explanatory diagram showing a communication efficiency amplifying device according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a case where a communication efficiency amplifier is applied to communication between two LANs connected via the Internet according to an embodiment of the present invention.

FIG. 3 is a protocol stack in a case where a TCP connection between hosts established between a host X and a host Y according to an embodiment of the present invention is handled by the communication efficiency amplifying devices X and Y as a TCP connection for communication efficiency amplification; FIG.

FIG. 4 is an explanatory diagram showing a TCP connection between the communication efficiency amplifiers, which is the first operation after the startup of the communication efficiency amplifier according to the embodiment of the present invention.

FIG. 5 shows a host X in LAN X according to an embodiment of the present invention.
Is an explanatory diagram showing a case where an attempt is made to establish a TCP connection with a host Y in LAN Y.

FIG. 6 is an explanatory diagram showing a protocol sequence in FIG. 5;

FIG. 7 shows a TCP connection between hosts according to an embodiment of the present invention <X
1, x1, Y1, y1> is an explanatory diagram showing a state in which a host-to-host TCP connection <Y2, y2, X2, x2> is established during establishment.

FIG. 8 is an explanatory diagram showing a sequence when a disconnection request is issued from the host X for a host-to-host TCP connection established between the host X and the host Y according to the embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 21 Communication efficiency amplifier 22 End-side reception processing unit 23 End-side reception buffer 24 Multiplex processing unit 25 TCP connection between communication efficiency amplification devices Transmission buffer 26 TCP connection between communication efficiency amplification devices Transmission processing unit 27 TCP connection between communication efficiency amplification devices Reception processing unit 28 TCP connection reception buffer between communication efficiency amplifying devices 29 Demultiplex processing unit 30 End transmission buffer 31 End transmission processing unit

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5K030 GA03 HA08 HC01 HD03 HD07 KX12 KX13 LC01 5K033 AA02 CB01 CC01 DA06 DB19 5K034 AA02 BB06 DD01 FF04 HH01 HH02 HH06 HH18 HH63 MM11

Claims (1)

[Claims] 1. A communication efficiency amplifying device, wherein each LAN is located at a position of a gateway connected to a network, for communication between at least two LANs connected to the network. TC between devices
A host-to-host TCP that establishes a P connection and is established between a host in one LAN and a partner host in the opposite LAN
Monitor the connection and if there are multiple TCP connections between the hosts,
A communication efficiency amplifying device characterized in that IP packets carrying a plurality of TCP connections are multiplexed and carried as TCP connection data between the communication efficiency amplifying devices.