JPH1056452A - IP packet leased line transfer system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To transfer an IP packet between specific subscriber units, between LANs or between a subscriber unit and a LAN at high speed and with low delay, to achieve low communication cost and high security. A problem-free IP packet line transfer system is provided. SOLUTION: An IP packet dedicated line device 10 is provided in a communication network.
0a to 100d are provided. In the subscriber system, I
An ATM cell is generated from the P packet and sent to the IP packet dedicated line device. The dedicated IP packet line device stores in advance a table including a plurality of specific IP addresses and intra-network route information for forming an intra-network route defined for each of the IP addresses. When the ATM cell transmitted from the dedicated IP packet line device is acquired,
Network route information corresponding to the IP address included in the ATM cell is obtained from the table, and the ATM cell is transmitted to the network route determined by the network route information.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an IP network between specific subscriber units, between LANs, or between a subscriber unit and a LAN.
The present invention relates to an IP packet leased line transfer system for transferring a packet.

[0002]

2. Description of the Related Art Conventional communication between LANs and computers L
Means for communication between the AN and a terminal device at a remote place include communication performed via the Internet, communication performed via a telephone line using a modem, and communication performed via a high-speed digital dedicated line.

[0003]

The communication via the Internet among the conventional communication techniques described above is,
Since an unspecified number of users use the transmission path jointly, the communication speed is low but the communication speed is low.
Since the transfer processing of the P (Internet Protocol) packet is performed by computer software, there is a problem that the processing delay time is long. Further, since information is transferred via a computer owned by another person, there is a security problem.

On the other hand, communication performed via a telephone line using a modem is relatively inexpensive, and does not require IP packet transfer processing on the way, so that no processing delay time is required and security can be secured to some extent. There is a problem that the communication speed cannot be increased.

[0005] In addition, communication performed via a high-speed digital leased line can perform transfer with a required communication speed and a transfer processing delay with no problem, thereby ensuring security. Is dedicated, so that there is a problem that the communication cost is extremely high as compared with others.

The present invention has been made in view of the above circumstances, and it is possible to transfer an IP packet between specific subscriber units, between LANs, or between a subscriber unit and a LAN with high speed and low delay. It is an object of the present invention to provide an IP packet leased line transfer system which can perform communication at low cost and has no problem in security.

[0007]

SUMMARY OF THE INVENTION The present invention, as a means for solving the above problems, provides an IP packet dedicated line transfer system having the following features. a. A high-speed physical line similar to a high-speed digital dedicated line is used to transfer data at a high communication speed as needed. b. In order to reduce the delay, transfer processing of IP packets on the way between the user devices is performed by dedicated hardware. Further, the transfer processing by the hardware identifies a cell including the head portion of the IP packet and performs the transfer according to the IP address included in the cell. c. In order to reduce the communication cost, IP packets are converted into cells, and cell multiplex transmission is performed in an ATM (asynchronous transfer mode) within the network, so that bandwidth can be shared with other users with a slight increase in delay.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an IP packet leased line transfer system according to the present invention will be described below with reference to the drawings.

A. IP packet dedicated line network provided by the present embodiment Currently, in a company, computer communication is performed by connecting a workstation, a personal computer, a database server, an e-mail server, and the like via a LAN (Local Area Network). As the convenience of such computer communication is recognized, there is an increasing demand for performing computer communication even in remote locations (other branch offices, homes, etc.). However, since a LAN is supposed to be used at one location, it cannot be used for communication with a remote location. For this reason,
There is a demand for computer communication capable of transferring information to a remote LAN or personal computer by connecting in the same manner as a LAN.

[0010] The IP packet leased line transfer system according to the present embodiment, as illustrated in FIG.
An object of the present invention is to provide a user with an IP packet private line network capable of transferring information between LANs or between a subscriber device and a LAN.

In communication between devices using a LAN, O
In the network layer of the SI reference model, communication is mostly performed using IP packets. Also in this embodiment,
Computer communication is performed by IP packets using the dedicated network for IP packets illustrated in FIG.

B. FIG. 2 shows a configuration of an IP packet dedicated line transfer system according to the present embodiment. In this IP packet dedicated line transfer system, an IP packet dedicated line device (reference numerals 100a to 100d in the example of FIG. 2) is provided in the network as shown. The IP packets sent from each computer device are sent to these dedicated IP packet line devices via the subscriber system. Each IP packet arriving at the IP packet leased line device is returned to the subscriber system according to each IP address, or transferred to the transfer destination via a relay network.
It is sent to the P packet dedicated line device.

Since the transfer control in the data link layer in the network is performed by the ATM, it is necessary to exchange IP packets in the form of ATM cells between the subscriber system and the IP packet dedicated line device. However, some computer devices of subscribers of the IP packet leased line transfer system do not exchange IP packets in the form of such ATM cells. Therefore, the following processing is performed in the DSU (Digital Service Unit) of the subscriber system, and it becomes possible for such a computer device or the like to use the present system.

First, on the transmitting side of a subscriber DSU, if the data link layer is other than ATM, the CLAD
(Cell Assembly and Disassembly), AIP (ATM Adaptation Layer) for each packet from the subscriber's computer etc.
ATM obtained by celling with type 5 cell
The cell is sent to the dedicated IP packet line device.

On the receiving side of the DSU, when the data link layer is other than the ATM, the VPI added to the cell is
(Virtual Path Identifier) and VCI (Virtual Channel Identifier) are used to divide the cell for each transmission source DSU, and the third bit of the payload type of the cell header is used to identify the head of the IP packet. The cell and the cell at the end are recognized, and when cells for one IP packet are completed, the cell is sent to the CLAD, and the IP packet is reproduced by the CLAD.

The function of sending out to the CLAD when cells for one packet are completed is not performed on the receiving side of the DSU, but the ATM-SLT of the IP packet dedicated line device is used.
There is also a method of performing this in the output interface unit (reference numerals 103a to 103d in FIGS. 3 and 4) which leads to.

C. IP Packet Dedicated Line Device As described above, the IP packet to be transferred is divided into a fixed length in the subscriber system, and a plurality of ATM cells each having the divided part as a payload part are generated.
The packet is transmitted to the packet line device. Each of the ATM cells transmitted from various transmission sources arrives at the IP packet dedicated line device in a multiplexed state.

IP packet dedicated line devices 100a-100
d (hereinafter, collectively referred to as an IP packet dedicated line device 100) is a means for integrally handling the incoming ATM cells for each IP packet and distributing the ATM cells to a network route determined by each IP address.

FIG. 3 shows a configuration example of the IP packet dedicated line device 100. This IP packet dedicated line device 1
00 denotes input interface units 101a, 101b,
, 101d, a cell switch unit 102, output interface units 103a, 103b, ..., 103d, and a control unit 104.

Each of the input interface units 101a to 101
d has an input processing unit 111, a cell buffer 112, and a destination table unit 113. An optical signal of a cell arrives at each of the input interface units 101a to 101d via an optical fiber. This optical signal is subjected to O / E conversion, SDH processing for recognizing an SDH frame from a bit string obtained thereby and extracting a payload portion, and ATM for recognizing a cell by establishing cell synchronization. Processing is performed, and the data is written to the cell buffer 112 in the form of a cell.

Here, focusing on one IP packet, each cell generated from the IP packet arrives at the input processing unit 111 in the same order as that in the original IP packet without being temporally exchanged. The data is sequentially written to the buffer 112. Cells generated from these identical packets are transmitted along a predetermined intra-network route by the following processing.

In the destination table unit 113, in-network route information including the following information is registered in advance corresponding to each set of the VPI of the cell to be input and the IP address of the transfer destination. a. New VPI and VCI to be assigned to the cell b. Switching information for switching the cell switch unit 102 so that the cell proceeds to a predetermined path corresponding to the IP address. Specifically, this switching information is transmitted to each of the input terminals of the cell switch unit 102. It includes the input terminal number of the cell to which the cell is input and the output terminal number of the output terminal of the cell switch unit 102 corresponding to the path of the cell. In the cell switch section 102, when this switching information is given, the input terminal and the output terminal whose number is designated by this are connected.

In the input interface unit, the third bit of the payload type of the header of the cell sequentially arriving at the cell buffer 101 is monitored, whereby the first cell and the last cell of the IP packet are recognized. . Then, when the first cell generated from the header portion of the IP packet is written in the cell buffer 112, the VPI and the IP address in the payload section are read from the first cell. Then, information corresponding to the pair of the VPI and the IP address in the intra-network route information is extracted from the destination table unit 113.

The new VPI and VCI in the extracted intra-network route information are written to the cells in the cell buffer 112. Here, the old VPI included in the cell before the writing is performed is replaced by the source VPI of the cell.
One-to-one correspondence with SU. The new VPI written in the cell is a VP (virtual path) that is the path of the cell, that is, an ATM-SLT (ATM subscriber line terminal) connected to the IP packet dedicated line device 100, or Or, the opposite I on the way to the transmission ground
This figure shows a VP set on a P packet dedicated line device.

The switching information included in the intra-network route information extracted from the destination table unit 113 is sent to the cell switch unit 102. New VPI and VCI
The cell in the cell buffer 112 in which is written is transmitted by the cell switch section 102 to an output interface section corresponding to a predetermined course of the cell. That is, if the cell is to be sent back to the ATM-SLT connected to the dedicated IP packet line device 100, the cell is sent by the cell switch unit 102 to, for example, the output interface unit 103b. In addition, the opposite IP in which the cell is on the way to the transmission destination.
If the packet is to be sent to the packet line device, it is sent to, for example, the output interface unit 103a connected to the ATM relay network.

The second and subsequent cells generated from the portion after the header portion of the IP packet do not include the IP address, but these cells have the same VPI and V as the first cell.
Has CI. For this reason, these second and subsequent cells are associated with the first cell when the VPI and VCI are the same, and new VPI and VCI are assigned and cell switching is performed using the same intra-network route information as the first cell. The control of the unit 102 is performed. As a result of such processing, the second and subsequent cells proceed to the same output interface unit as the first cell.

As described above, the cell flow sent to the output interface unit is shaped by the VP shaper 131 to the cell interval allowed for the output VP, based on the parameter instruction from the control unit 104. VP Shaper 131
Parameters include peak cell speed and CDV (Cell
Delay Variation). The shaped cell flow is subjected to SDH by the output processing unit 132.
It is embedded in the frame, E / O converted, and ATM-X
Output to C (ATM cross connector) or ATM-SLT.

The control unit 104 changes the registered contents of the destination table unit 113 and changes the parameters of the VP shaper 131 in accordance with an instruction from an operation center or a control terminal for maintenance operation.

The above is the details of the IP packet dedicated line device 100. As described above, the IP packet dedicated line device arrives in a state where each cell generated from each IP packet is multiplexed. By the above processing, each cell generated from the same IP packet is handled as one. It follows the same intra-network route determined by the IP address.

FIG. 4 shows another example of the configuration of the IP packet dedicated line device 100. In this IP packet dedicated line device, the cell switch unit 1 includes
02 is provided with a cell switch table 121 for storing information for controlling switching.

In the destination table 113, at least a new VCI is registered for a set of the input VPI and the destination IP address of the cell. When a cell is written into the cell buffer unit 112, a new VCI corresponding to the IP address of this cell is read from the destination table unit 113. Then, the new VCI is written to a cell in the cell buffer unit 112.

The cell switch table 121 of the cell switch section 102 stores information on input terminal numbers, VPIs, and output terminal numbers. These pieces of information are notified by the control unit 104 in advance so that each cell input to each input terminal of the cell switch unit 102 is output to an output terminal corresponding to each predetermined route.

When a cell is input to a certain input terminal of the cell switch section 102, the input terminal number and the V
The PI is notified to the cell switch table 121, and switch path information (input terminal number and output terminal number) and a new VPI are output. Then, the cell switch unit 10
The cell input to 2 is output to a predetermined output terminal according to the switch path information. Also, the VP in the cell
I is replaced with the new VPI. The other points are the same as those of the IP packet dedicated line device shown in FIG.

[0034]

As described above, according to the present invention,
Using a high-speed physical line similar to a high-speed digital leased line, IP packets are converted into cells, cells are multiplexed and transmitted within the network by ATM, and dedicated hardware is used for the transfer of IP packets between user devices. In this case, the transfer processing of the cellized IP packet is performed in accordance with the IP address.
There is an effect that it is possible to provide an IP packet dedicated line which is high speed, low delay, inexpensive and has no problem in security.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an IP packet leased line network provided by an IP packet leased line transfer system according to an embodiment of the present invention;

FIG. 2 is a block diagram illustrating a configuration of an IP packet leased line transfer system according to an embodiment of the present invention.

FIG. 3 is a block diagram illustrating a configuration example of an IP packet leased line device according to the embodiment;

FIG. 4 is a block diagram showing another configuration example of the IP packet leased line device according to the embodiment;

[Explanation of symbols]

100, 100a to 100d: IP packet dedicated line device, 101a to 101d: Input interface unit, 11
DESCRIPTION OF SYMBOLS 1 ... Input processing part, 112 ... Cell buffer part, 113 ... Destination table part, 102 ... Cell switch part, 103a-1
03d: output interface unit, 131: VP shaper, 132: output processing unit, 104: control unit.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hideyuki Tsuboi 3-19-2 Nishi Shinjuku, Shinjuku-ku, Tokyo Japan Telegraph and Telephone Corporation (72) Inventor Hiroyuki Fujiwara 3- 192-1 Nishi-Shinjuku, Shinjuku-ku, Tokyo No. Japan Telegraph and Telephone Corporation

Claims (2)

[Claims] A dedicated line device for IP packets is provided in a communication network, and the dedicated line device for IP packets is used by a dedicated line device between specific subscriber units, between LANs or between a subscriber unit and a LAN.
An IP packet leased line transfer system for transferring packets, wherein a subscriber system generates an ATM cell from an IP packet to be transferred and sends it to the IP packet leased line device. a. Storing in advance a table including a plurality of specific IP addresses and network route information for forming a network route defined for each of these IP addresses; b. When an ATM cell transmitted from the subscriber line or another IP packet leased line device is acquired, intra-network route information corresponding to an IP address included in the ATM cell is obtained from the table; c. An IP packet leased line transfer system, wherein the ATM cell is transmitted to an intra-network route determined by the intra-network route information. 2. Each time an IP packet is provided from a subscriber unit, the IP packet is divided into information of a fixed length, and a series of ATMs each having the divided information as a payload portion.
2. The IP packet leased line transfer system according to claim 1, further comprising cell generating means for generating and outputting cells.