JPH0918475A - Isdn terminal adapter device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To freely switch and select the use form of a B channel by a user by obtaining adapter devices by which mutual communication can be performed, regardless of the usage made of the B channel. SOLUTION: After the B channels B 1 and B 2 are separated by a separation part I3 , flag and error detections are performed for the data of each B channel B 1 and B 2 by synchronizing parts I41 and I42 . These processing results are delivered as control signals to a selector I10 , and the signals for which the error detection result is normal is selected in the selector I10 . Therefore, any of the methods communicating the single B channel B 1 or B 2, the two B channels B 1 and B 2 in parallel or the 2 B channels in which the two B channels B 1 and B 2 are made a pair can be selected according to a reception packet. This selection signal is also transmitted to the selector part I6 of a transmission part and the transmission signal having the same form as the receiving method is selected. Therefore an adapter device is automatically selected.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention is used for communication by ISDN. The present invention is used for packet communication. The present invention is suitable for use in communication using a computer terminal.
In particular, it relates to a technique for diversifying the usage pattern of B channels.

[0002]

2. Description of the Related Art As a communication method in computer communication for packetizing and transmitting data between computer terminals using a conventionally known 64 kbit / s or 128 kbit / s digital communication line called ISDN line, The Ethernet packet output from the terminal for LAN connection of the terminal is HD for ISDN line.
A method of performing frame format conversion by a protocol called LC (High-Level Data Link Control) and performing communication is widely used.

In recent years, IP (Intelligent Periferal), which is an upper layer of Ethernet packets, is used instead of Ethernet packets.
PP or other protocol packets
A method of directly transmitting and receiving by a protocol called P (Point-to-Point Protocol) is also used. PPP is also above H
It is a protocol similar to DLC, in which the same synchronization code and error detection code are added and transmitted.

On the other hand, there are two types of ISDN lines: 64 kbit / s (B channel) or 128 kbit / s (2 B channel). 128kbit / s (2B channel) to subscriber's house
And 16 kbit / s (D channel) signals are connected, and the D channel is used for signaling for the exchange. The user who wants 64 kbit / s, of the 2B channel,
Communication is performed using only one B channel. Also, 1
A user of 28 kbit / s (2B channel) can use the B channel as a set (bulk) and use it as a 2B channel, and can use it as a dedicated line, or can use the two B channels independently. it can. When passing through an exchange, it is general to use two B channels independently.

The principle of computer communication using the ISDN line will be described below with reference to FIG.
FIG. 3 is a diagram showing the principle of computer communication using the ISDN line of the conventional example. FIG. 3 shows an outline of a network device for installing a computer terminal on the subscriber side and performing computer communication using an ISDN line, and a structure of a transmission / reception signal of the ISDN line. FIG.
Reference numeral 2 _{1 in} (b) is a DSU (Digital) that terminates the subscriber line.
Service Unit) or ONU (Optical Network Uni)
t), reference numeral 2 ₂ is an ISDN line interface for LAN
ISDN terminal adapter device (hereinafter simply abbreviated as adapter device) converted into a connection interface, reference numeral 2 ₃
Computer terminal, reference numeral 2 ₄ ISDN lines, reference numeral 2
Reference numeral ₅ is a transmission line, reference numeral 2 ₆ is a reception line, and reference numeral 2 ₇ is a LAN
Each line is shown. Reference numeral 2 _{8 in} FIG. 3A is a format of the transmission signal (configuration of 250 μs time slot). Figure reference numeral 2 ₉ 3 (c) is a format of the received signal (configuration of time slots 250 [mu] s). Code B1 ₁ in the transmitted signal 2 ₈ and the received signal 2 ₉ ,
B1 ₂ is one of the B channels, the B1 channel (64 kb
it / s), codes B2 ₁ and B2 ₂ are B2 channel (64 kbit / s) which is the other side of B channel, code L is DC balanced bit, code D is D channel (16 kbit / s), code E is echo bit Indicates. There are two consecutive 125 μs time slot data in 250 μs. Each 12
Two B-channels B1 ₁ in the 5 μs time slot,
B2 ₁ (8 bits each) and D channel D and echo bit E are lined up. The data of the next time slot is stored in the B channels B2 ₁ and B2 ₂ . The D channel D is mainly used for signaling of the exchange, the echo bit E detects collision of transmission / reception signals on the subscriber line, and the DC balance bit L prevents continuation of data of logical value "0" or "1". It is a bit to do. Normally, the B channels B1 and B2 are available to the subscriber.

The configuration of an adapter device for converting the conventional ISDN line interface into a LAN connection interface will be described with reference to FIGS. FIG. 4 is a block diagram of a conventional adapter device. FIG. 5 is a diagram for explaining a procedure of mapping an HDLC packet including two different Ethernet packets to a B channel transmission signal. FIG. 6 is a diagram for explaining a state in which an HDLC packet including two different Ethernet packets is mapped to a reception signal of B channel. Reference numeral 3 _{1 in} FIG. 4 is an interface conversion unit between ISDN line data and Ethernet data, reference numeral 3 ₂ is a multiplexing unit for B channels B1 and B2, and reference numeral 3 ₃
Is a separation unit of B channels B1 and B2, and reference numerals 3 ₄₁ , 3 ₄₂
The synchronization unit to check the flag and CRC, code 3 _51, 3 ₅₂ is an additional portion for adding a flag and CRC. Reference numerals 3 ₆ and 3 _{7 in} FIGS. 5 and 6 are HDs including two different Ethernet packets in the ISDN line.
The data format of LC packet is shown. Code 2 ₈
Is a transmission signal, and reference numeral 2 ₉ is a reception signal. HDLC is generally used as a protocol for transmitting / receiving Ethernet packets via an ISDN line.

In HDLC, as shown in FIG. 5, a start flag (0111111) is added to the beginning of packetized data.
0) is added and an error detection code CRC (Cyclic Redu
ndancyCheck) and an end flag (01111110) are added and transmitted. The packet (Ethernet packet) from the computer terminal 2 ₃ is thus the start flag,
After the error detection code CRC and the end flag are added, 8 times are added to the B channel packet every 125 μs.
The HDLC packet is divided into bit units, and one HDLC packet including the Ethernet packet is mapped to the B1 channel, and the other HDLC packet is mapped to the B2 channel. FIG. 6 shows the data format of the received signal.

At the time of reception, after separating the B channels B1 and B2 by the separating unit 3 ₃ , each B channel B1 is separated.
Flags and errors are detected by the synchronizing units 3 ₄₁ and 3 ₄₂ for the B2 data and B2 data, and the normally extracted packet is passed to the interface converting unit 3 ₁ . The interface converter 3 ₁ transmits / receives Ethernet packets to / from the computer terminal 2 ₃ via the LAN line 2 ₇ . In this example, the mode in which the two B channels B1 and B2 are always used has been shown, but there is also a method in which only the B channel B1 is used in the normal state and the B channel B2 is also used when the traffic increases.

Here, as a method of using the B channel, in addition to the above, the B channels B1 and B2 are combined into one 2
There is also a method of using it as the B channel. It may be used as a dedicated line type that does not go through an exchange. This conventional example will be described with reference to FIGS. FIG. 7 is a block diagram of a conventional adapter device. FIG. 8 is a diagram for explaining a procedure for mapping an HDLC packet including one Ethernet packet to a transmission signal of the 2B channel. FIG. 9 is a diagram for explaining a state in which an HDLC packet including one Ethernet packet is mapped to a 2B channel reception signal. The adapter device 2 ₂ sets the ISDN line interface to LA.
Converted to N connection interface. Reference numeral 4 in FIG.
₁ is a synchronization unit for checking flags and CRC, code 4
₂ is an addition unit for adding a flag and CRC, and reference numeral 4 _{3 in} FIGS. 8 and 9 is an HDLC including an Ethernet packet.
Packets 2 ₈ and 2 ₉ represent 2B channel transmission signals and reception signals. Computer terminal 2 packets from ₃ (Ethernet packets) likewise start flag and 5, after the error detection code CRC and an end flag is added, it is divided into 8-bit units in accordance with the packet B channels per 125μs , An HDLC packet including one Ethernet packet is sequentially mapped to 2B channels B1 and B2 of the same time slot. During reception, the received signal of 2B-channel shown in FIG. 9 is inputted to the synchronizing unit 4 _1, 2B-channel B1 and B2
The flag and error detection are performed on the continuous data of, and the normally extracted packet is passed to the interface conversion unit 3 ₁ . The interface converter 3 ₁ transmits / receives Ethernet packets to / from the computer terminal 2 ₃ via the LAN line 2 ₇ .

[0010]

As described above, the conventional IS
Since there are a plurality of usage patterns of the DN line, even if the opposite line speed and protocol are the same (for example, HDLC), it is not possible to perform the opposite communication between the devices using different B channels as shown in FIG. 4 or 7. There is.

The present invention has been made against such a background, and an object of the present invention is to provide an adapter device which can communicate with each other regardless of the usage mode of the B channel. It is an object of the present invention to provide an adapter device that allows a user to freely switch and select a usage mode of the B channel. An object of the present invention is to provide an adapter device that can standardize hardware configurations in a unified manner.

[0012]

According to the present invention, computer terminals are connected by a B channel (64 kbit / s) or 2 B channel (128 kbit / s) digital communication line, and packet data from one computer terminal is In computer communication in which data is transmitted and received between the two by converting the frame format of a protocol of a digital communication line including a synchronization code and an error detection code and transmitting the frame format to the other computer terminal, for example, B channel alone, two channels Identification of the three methods of communicating B channels in parallel or two B channels as a set is performed by using the error detection code included in the frame format of the protocol to identify each of the two B channels and the two B channels. The header information is detected simultaneously for a set of 2B channels, and normal And mainly characterized by performing reception using the data of the B-channel or 2B channels header information is detected.

[0013] The prior art means a single B channel and two B channels.
The identification of the three methods for communicating channels in parallel or a set of two B channels is performed by using the error detection code and other header information included in the frame format of the protocol to identify each of the two B channels. B
Header information detection is performed simultaneously for 2B channels that form a set of channels, and header information is normally detected.
The difference is that reception is performed using channel or 2B channel data.

That is, the present invention provides a means for receiving a signal containing two B channels (B1, B2) from an ISDN line and converting the format of the data contained in these two B channels into a format that matches the communication terminal. It is an adapter device provided.

Here, the feature of the present invention is that the two B channels are included in the two B channels and the first receiving means for receiving in the first mode in which signal allocation is performed as one 2B channel. The second receiving means for receiving in the second mode the signal allocation of each of the data to be generated as two different series data is arranged in parallel.

By this, 64 kbit / s or 128 kbit
In the data packet communication method in computer communication in which data is packetized and transmitted between computer terminals using the / s digital communication line (ISDN line), a single B channel, two B channels in parallel or two B channels Communicate on a set of channels 3
By automatically identifying the systems, it is possible to secure the opposition between the devices of different systems.

It is desirable to provide a reception selecting means for selecting one of the first receiving means and the second receiving means having a smaller data error.

Alternatively, there is provided a reception selecting means for selecting one of the first receiving means and the second receiving means, whichever has the same packet length information included in the data and the received packet length. Is desirable.

As a result, whether the received signal is used by allocating different series data to each of two B channels or by using two B channels as one 2B channel and allocating same series data is used. It is possible to determine which of the usage forms is present and select one of the receiving means.

First transmitting means for transmitting in the first mode, second transmitting means for transmitting in the second mode, and transmission selecting means for selecting outputs of these two transmitting means and outputting them to a transmission line. It is desirable to have and.

Further, it is desirable to include a transmission selecting means for selecting either the first or the second transmitting means according to the selection result of the reception selecting means.

Thus, it is possible to select the transmitting means according to the B channel usage pattern of the communication partner determined from the received signal.

As described above, according to the present invention, B
Channel-by-channel, two B channels are identified using the error detection code and other header information included in the frame format of the protocol to identify the 3 methods of communicating two B channels in parallel or 2 B channels in which two B channels are combined. By simultaneously performing header information detection on 2B channels each of which is a set of two B channels, and automatically opposing each other using the data of the B channel or 2B channel for which the header information is normally detected. For receiving, it is possible to communicate with a device using any method.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIG. FIG. 1 is a block diagram showing an embodiment of the present invention. See Fig. 3 for the overall configuration when computer communication is performed using the ISDN line.

The present invention uses two Bs from the ISDN line 2 _4.
An interface converter 1 ₂ is provided as means for receiving a signal including channels B1 and B2 and converting a format of data included in the two B channels B1 and B2 into a format compatible with a computer terminal 2 _{3 serving} as a communication terminal. It is the adapter device 1 ₁ .

[0026] Here, it is an aspect of the present invention, a synchronization unit 1 ₅ as a first reception means for receiving the two B channels B1 and B2 in the first mode for performing signal assignment as one of 2B channels , Separation units 1 ₃ and synchronization units 1 ₄₁ and 1 ₄₂ as second receiving means for receiving the data contained in the two B channels B1 and B2 as two different series data in the second mode for signal allocation. Is provided in parallel.

[0027] In the present invention embodiment, a selector as a reception selecting means for selecting the synchronization 1 ₅ or synchronization 1 ₄₁ and 1 ₄₂ having the smaller data error of the synchronization 1 ₅ or synchronization 1 ₄₁ and 1 ₄₂ Equipped with 1 ₁₀ . Alternatively, the selector 1 _10, if it contains a packet length information in data, and a packet length received the packet length information contained in the data of the synchronization 1 ₅ or synchronization 1 ₄₁ and 1 ₄₂ You may make it select the synchronous part ₁₅ or the synchronous parts 1 ₄₁ and 1 ₄₂ which correspond.

Furthermore, an additional portion 1 ₇ of the first transmission means for transmitting in the first mode, an additional portion 1 ₆₁ and 1 ₆₂ as a second transmission means for transmitting in said second mode,
And a selector 1 ₉ as a transmission selecting means for outputting the output of the adding unit 1 ₇ or addition section 1 ₆₁ and 1 ₆₂ selected and the transmission line 2 _5.

[0029] Selector 1 ₉ selects one of addition section 1 ₇ or addition section 1 ₆₁ and 1 ₆₂ in accordance with the selection result of the selector 1 _10.

[0030]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIG. The same parts as those shown in the conventional example are designated by the same reference numerals. FIG. 1 shows an adapter configuration for converting the interface of the ISDN line 2 _{4 into} an interface for LAN connection. Reference numeral 1 ₂ is an interface conversion unit between the data of the ISDN line 2 ₄ and Ethernet data, and reference numeral 1 ₃ is Separation unit for B channels B1 and B2, reference numerals 1 ₄₁ , ₁₄₂ and ₁₅ are synchronization portions for checking flags and CRC, reference numeral ₁₇ is a start flag, error detection code C
RC and end flag imparting section, reference numeral ₁₈ indicates a multiplexing section for B channels B1 and B2, reference numeral ₂₅ indicates an ISDN line 2
₄ is a transmission line, reference numeral 2 ₆ is a reception line from the ISDN line 2 ₄ , and reference numeral 2 ₇ is a LAN line. Ethernet
The procedure for mapping the HDLC packet including the packet to the B channels B1 and B2 is as described above. An Ethernet packet as a protocol for transmitting and receiving via the ISDN line 2 ₄ illustrates the HDLC example.

Codes B1 ₁ and B1 ₂ are B1 channels (64 kbit / s), which is one of the B channels, and codes B2 ₁ and B2 ₂
Is the other of the B channels, the B2 channel, the code L is a DC balanced bit, the code D is the D channel (16 kbit / s),
The code E is an error bit. There are two consecutive 125 μs time slot data in 250 μs. Two B channels B1 ₁ and B2 ₁ (8 bits each), a D channel D and an echo bit E are arranged in each 125 μs time slot. B channel B2 ₁ ,
The data of the next time slot is stored in B2 ₂ .
The D channel D is mainly used for signaling of the exchange, the echo bit E detects collision of transmission / reception signals on the subscriber line, and the DC balanced bit L prevents continuation of data of logical value "0" or "1". It is a bit to do. Normally, the B channels B1 and B2 are available to the subscriber.

In the HDLC, the conventional example shown in FIGS.
As described with reference to FIG. 9, the start flag (01111110) is added to the head of the packetized data, and the error detection code CRC and the end flag (01111110) are added to the end of the packetized data for transmission. When using the B-channel B1 and B2 independently, a packet from the computer terminal 2 ₃ (Ethernet packets) are each in the additional unit 1 ₆₁ and 1 _62, the start flag, which is added an error detection code CRC and an end flag After that, it is divided into 8-bit units in accordance with the packets of B channels B1 and B2 every 125 μs. HDL containing one Ethernet packet
The C packet is mapped to the B channel B1, and the other HDLC packet is mapped to the B channel B2.
_{At 8} , the B channels B1 and B2 are multiplexed.

When the B channels B1 and B2 are used together as one 2B channel, after the start flag, the error detection code CRC and the end flag are added in the adding section ₁₇ , the B channels B1 and B2 are added every 125 μs. Is divided into 8-bit units according to the packet of
The B channels B1 and B2 in the same time slot are sequentially mapped. These adder ₁₇ and multiplexer 1
One of the signals from ₈ is selected by the selector ₁₉ and transmitted. The selection control in the selector ₁₉ will be described below.

[0034] Upon receipt in the present invention embodiment, as shown in FIG. 1, the separation unit 1 ₃ B-channel B1 and B
After separation of the 2, concurrently with providing synchronization 1 _41, 1 ₄₂ by a flag and an error detection for each B-channel B1 and B2 of the data, the synchronization unit for successive data of 2B channels B1 and B2 1 _The flag and error detection are performed by ₅ . These processing results are sent as a control signal to the selector 1 _10, the selector 1 _10, the error detection result to select a signal towards normal. Therefore, B channel B
Either 1 or B2 alone, two B channels B1 and B2 in parallel or two B channels in which two B channels B1 and B2 are paired can be selected according to the received packet. . Further, the above control signal is also sent to the selector _{19 of the} transmission unit, and selects the transmission signal of the same form as the reception system. The initial value of the form of the transmission signal is arbitrary. Interface converter 1 ₂
Then, transmission / reception of Ethernet packets to / from the computer terminal 2 ₃ is performed via the LAN line 2 ₇ .

Although the case where HDLC is used as the protocol has been described above, the same operation can be performed when PPP or another protocol is used. Furthermore, when using another protocol, if the header information includes information other than the error detection code, for example, packet length information, the decoded packet length and the packet length information included in the header information are used. It is also possible to compare and use the detection result instead of the error detection.

Thus, according to the present invention, B channel B
Even if the devices 1 and B2 have different usage methods, the opposite methods are automatically switched and selected, so that communication is possible.

The operation of the embodiment of the present invention is shown as a flow chart in FIG. FIG. 2 is a flowchart showing the operation of the control unit 10. First, the error detection by the synchronization unit _{1 5, 1 41, 1 42} (S1). Synchronization 1 ₅ performs first mode of error detection for signal assignment the two B channels B1 and B2 as one 2B channels. The synchronization units 1 ₄₁ and 1 ₄₂ perform error detection in the second mode in which data included in the two B channels B1 and B2 are assigned as two different series data, and the signals are assigned. It is determined which detection result is normal (S2). As a result, the synchronization units 1 ₄₁ and 1
_If the detection result of ₄₂ is determined to be normal, the secreter 1 ₁₀ selects the synchronization units 1 ₄₁ and 1 ₄₂ (S3). further,
The selector ₁₉ also selects the addition units 1 ₆₁ and ₁₆₂ (S
4). However, synchronization 1 ₉ If it is determined to be normal, select the synchronization 1 ₅ by the selector 1 ₁₀ (S13). Further, the selector ₁₉ also selects the adding unit ₁₇ (S14).

It is also conceivable that data does not exist in either one of the B channels B1 and B2 separated by the separation unit 1 _{3. In} this case, the selector 1 ₁₀ has the synchronization unit 1 ₄₁ or 1 Either one of the ₄₂ , which handles the B channel B1 or B2 in which the data exists, is selected.

[0039]

As described above, according to the present invention,
It is possible to realize an adapter device that can communicate with each other regardless of the usage mode of the B channel. As a result, the user can freely switch and select the usage mode of the B channel. Furthermore, it is possible to realize an adapter device that can standardize the hardware configuration uniformly.

[Brief description of the drawings]

FIG. 1 is a block configuration diagram showing an embodiment of the present invention.

FIG. 2 is a flowchart showing the operation of the control unit.

FIG. 3 is a diagram showing a principle of performing computer communication using an ISDN line of a conventional example.

FIG. 4 is a block configuration diagram of a conventional adapter device.

FIG. 5: H containing two different Ethernet packets
The figure for demonstrating the procedure which maps a DLC packet to the transmission signal of B channel.

FIG. 6 H containing two different Ethernet packets
The figure for demonstrating the state where the DLC packet is mapped by the received signal of B channel.

FIG. 7 is a block configuration diagram of a conventional adapter device.

FIG. 8: HDLC containing one Ethernet packet
A diagram for explaining a procedure for mapping a packet to a transmission signal of 2B channel.

FIG. 9: HDLC containing one Ethernet packet
A diagram for explaining a state in which a packet is mapped to a reception signal of 2B channel.

[Explanation of symbols]

1 ₁ , 2 ₂ Adapter device 1 ₂ , 3 ₁ Interface conversion unit 1 ₃ , 3 ₃ Separation unit 15 ₅ , 1 ₄₁ , ₁₄₂ , 3 ₄₁ , 3 ₄₂ , 4 ₁ Synchronization unit 1 ₇ , ₁₆₁ , ₁₆₂ 3 ₅₁ , 3 ₅₂ , 4 ₂ Addition section 1 ₈ 3 ₂ Multiplexing section 1 ₉ 1 1 ₁₀ Selector 2 ₁ DSU 2 ₃ Computer terminal 2 ₄ ISDN line 2 ₅ Transmission line 2 ₆ Reception line 2 ₇ LAN line 2 ₈ Transmission Signal 2 ₉ Received signal 3 ₆ , 3 ₇ , 4 ₃ HD including Ethernet packet
LC / packet 10 Control unit B1 ₁ , B1 ₂ , B2 ₁ , B2 ₂ B channel D D channel E echo bit L DC balanced bit

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Katsuhiko Sano 1-1-6 Uchisaiwaicho, Chiyoda-ku, Tokyo Nihon Telegraph and Telephone Corporation

Claims (5)

[Claims] 1. Two B channels from an ISDN line (B
In the ISDN terminal adapter device, the ISDN terminal adapter device is provided with a means for receiving a signal containing the two B channels and converting the data formats contained in the two B channels into a format that matches the communication terminal. A first receiving means for receiving in a first mode in which signal allocation is performed as a channel, and a second reception for receiving in a second mode in which data included in the two B channels are respectively allocated as two different series data. An ISDN terminal adapter device characterized in that the means and the means are provided in parallel. 2. The ISDN terminal adapter device according to claim 1, further comprising a reception selecting unit that selects one of the first receiving unit and the second receiving unit having a smaller data error. 3. A reception selection means for selecting one of the first reception means and the second reception means, which reception means has a packet length information included in the data and a received packet length that match each other. The ISDN terminal adapter device according to claim 1. 4. A first transmitting means for transmitting in the first mode, a second transmitting means for transmitting in the second mode, and a transmission for selecting the output of these two transmitting means and outputting it to a transmission line. 4. The ISDN terminal adapter device according to claim 1, further comprising a selection unit. 5. The ISDN terminal adapter device according to claim 2, further comprising a transmission selection unit that selects either the first transmission unit or the second transmission unit according to the selection result of the reception selection unit. .