WO2009003398A1

WO2009003398A1 - Asynchronous serial digital communication channel simulation method and device

Info

Publication number: WO2009003398A1
Application number: PCT/CN2008/071465
Authority: WO
Inventors: Keping Feng
Original assignee: Maipu Communication Technology Co., Ltd.
Priority date: 2007-06-29
Filing date: 2008-06-27
Publication date: 2009-01-08
Also published as: CN101090365B; CN101090365A

Abstract

Asynchronous serial data transmission method and device thereof in Packet Switched Network(PSN). The method includes: one end receives character data, break sequences and idle sequences from asynchronous serial port data signal line, and transmits the character data, break sequences and idle sequences through PSN; the other end resumes the character data, break sequences and idle sequences based on information in channel simulation data packets.

Description

Heterogeneous serial data communication channel simulation method and device

The present invention relates to data communication technologies, and in particular, to a technique for transmitting heterogeneous serial data on a PSN (Packet Switched Network).

Background technique

Heterogeneous serial data communication is one of the most widely used traditional data communication services. In the short-distance case, cable is used as the communication medium between a pair of communication interfaces; in actual use, it is also necessary to solve the heterogeneous serial data communication interface. The problems between remote communication, the currently used solutions are mainly the following:

(1) remotely transmitting heterogeneous serial data using a modem having a different serial data communication interface;

(2) remotely transmitting heterogeneous serial data using a subrate multiplexing channel of the same circuit;

(3) Remotely transmitting heterogeneous serial data directly using the peer communication circuit;

(4) Remotely transmit heterogeneous serial data on the PSN.

With the development of PSN applications such as IP (Internet Protocol) technology and MPLS (Multi-Propocol Label Switching) technology, there is an increasing demand for transmitting heterogeneous serial data on the PSN.

At present, the following two schemes are commonly used to transmit heterogeneous serial data through PSN:

(1) A protocol conversion scheme, which directly converts the application system communication protocol message into a private protocol message suitable for transmission on the PSN, and transmits it through the PSN; since the field application system has a large number of communication protocols, There is no shortage of proprietary protocols. If you want to implement a universal protocol conversion device, you must master all the application system communication protocols, which is almost impossible, so the protocol conversion solution is not a general solution.

(2) Transparent character transmission scheme, which only recognizes character data or character data and Break sequence on the signal line; the Break sequence is a continuous logical 0 of one character length (including start and stop bits), as in-band control signal. The transparent character transfer scheme only transmits character data or only character data and a Break sequence. Since the heterogeneous serial signal line includes not only character data and a Break sequence, the transparent character transfer scheme is only applicable to some application systems, and is not universal. Data transfer solution. Summary of the invention

The technical problem to be solved by the present invention is to provide a method for simulating the heterogeneous serial data communication channel and to provide a method for realizing the method, in view of the problem that the conventional method for transmitting heterogeneous serial data communication on the PSN is poor in generality. device.

The technical solution adopted by the present invention to solve the above technical problem is to provide a heterogeneous serial data communication channel emulation method, which is characterized in that the local channel emulation device receives character data and a break sequence from its heterogeneous serial data signal line. And the Idle sequence, and the character data, the Break sequence, and the Idle sequence are transmitted to the peer channel emulation device through the packet switching network; the peer channel emulation device recovers the character data, the Break sequence, and the Idle according to the information in the channel emulation data message. The sequence is sent to its isochronous serial port. Specifically, the following steps are included:

a) The local channel emulation device encapsulates the character data, the Break sequence and the Idle sequence into channel emulation data packets, and the Break sequence and the Idle sequence are composed of the sequence type and the sequence length; b) the local channel emulation device will channel the data emulation datagram The text is carried on the packet switching network message for transmission;

c) After receiving the packet switched network packet, the peer channel emulation device decapsulates the channel emulation data packet, recovers the character data, and recovers the Break sequence and the Idle according to the sequence type and the sequence length in the heterogeneous serial data packet. Sequence

d) The peer channel emulation device sends character data, break sequence and Idle sequence to the different string

□.

Specifically, the local channel emulation device receives the sequence length of the Break sequence and the Idle sequence from the different serial port data signal lines.

Further, in step a), before the local channel emulation device performs packet encapsulation, deletion processing is also performed; the deletion processing is to delete the redundant part of the Break sequence or the Idle sequence or delete the two character data. The shorter Idle sequence. The shorter Idle sequence is an Idle sequence whose segment length is less than the minimum value of the set Idle sequence.

Further, in step a), before the local channel emulation device performs encapsulation, segmentation processing is also performed; the segmentation processing is to divide the longer character data stream, the Break sequence or the Idle sequence into information segments.

Specifically, before the local channel emulation device encapsulates the packet, the connection relationship between the information segments is determined, and the connection relationship is divided into continuous and discontinuous.

Specifically, the channel emulation data packet encapsulates one or more pieces of information; When multiple pieces of information are encapsulated in a data message, the connection relationship of each piece of information must be continuous. Further, before the local channel emulation device encapsulates the message, the connection between the last information segment of the message and the first information segment of the next message is determined.

The invention also provides an isochronous serial data communication channel emulation device for realizing the above method, which is characterized in that it comprises an isochronous serial port information transmission processing unit, an interworking function unit, a packet switching network information transmission unit, and an isochronous serial port information transmission. The processing unit is connected to the packet switching network information transmission unit through the interworking function unit; the different serial port information transmission processing unit is connected to the different serial port of the application system device; the packet switching network information transmission unit is connected to the packet switching network; the different serial port information transmission processing The unit is configured to send and receive character data, a Break sequence, and an Idle sequence, and count the received sequence length when receiving the Break sequence and the Idle sequence.

An interworking function unit, configured to encapsulate the received character data, the Break sequence, and the Idle sequence into a channel emulation data message, or decapsulate the channel emulation data packet;

The packet-switched network information transmission unit is configured to send and receive packet-switched network packets carrying channel emulation data packets.

Further, the different serial port information transmission processing unit is further configured to delete the Break sequence or the Idle sequence.

Further, the heterogeneous serial port information transmission processing unit is further configured to perform segmentation processing on character data, a break sequence or an Idle sequence.

Further, the different serial port information transmission processing unit is further configured to determine a connection relationship between the pieces of information, and the connection relationship is divided into continuous and discontinuous.

Specifically, the isochronous serial port information transmission processing unit includes a sending standard horizontal line parameter register, a sending high level line parameter register, and a sending low level line parameter register.

The beneficial effects of the present invention are: a universal heterogeneous serial data communication technology independent of the application system communication protocol, achieving the effect of simulating the heterogeneous serial data communication channel on the PSN.

DRAWINGS

FIG. 1 is a schematic diagram of a network application according to an embodiment of the present invention.

detailed description

The isochronous serial data signal line includes an Idle sequence in addition to the character data and the Break sequence. The Idle sequence is a continuous logic 1, indicating that the interface data signal line is idle. In most cases, the heterogeneous serial data communication system not only needs to correctly transmit the character data stream and the Break sequence, but also The Idle sequence needs to be transmitted correctly. The basic reasons are as follows:

1) In order to avoid character escaping when a specific character is used to delimit the message, the Idle sequence is used to delimit the message;

2) In order to detect communication errors, the Idle sequence time between characters in the message frame is limited, and if it is timed out, it can be judged as a communication error.

Therefore, in order to accurately transmit the isochronous serial data signal of any application system on the PSN, all valid information of the different serial data should be transmitted: character data, Break sequence and Idle sequence.

The heterogeneous serial data communication channel emulation device comprises an isochronous serial port information transmission processing unit, an interworking function unit and a PSN information transmission unit; the heterogeneous serial port information transmission processing unit comprises a different serial port, and the interworking function unit comprises a package and a solution. The PX information transmission unit includes a PSN interface, and the channel emulation device is connected to the application system through the different serial port, and the different serial port information transmission processing unit transmits the PSN information through the interworking function unit and the PSN information. The units are connected, and the PSN interface is connected to the PSN.

In the network application diagram shown in FIG. 1, the different serial ports of the different serial data communication channel simulation device a and the different serial data communication channel simulation device b are different from the application system device a and the application system device b respectively. The serial port is connected, and its PSN interface is connected to the PSN. Through the heterogeneous serial data communication channel emulation device a and the heterogeneous serial data communication channel emulation device b information transfer to achieve remote communication between the application system device a and b serial port.

The direction in which the application system device a transmits data to the application system device b: The heterogeneous serial port information transmission processing device of the heterogeneous serial data communication channel emulation device a receives the heterogeneous serial data from the heterogeneous serial port including the character data and the Break sequence. And the Idle sequence is subjected to deletion processing and segmentation processing according to actual needs; the interworking function unit of the isochronous serial data communication channel emulation device a encapsulates the channel into the channel emulation data message; the PSN information transmission unit is used to simulate the channel data The text is carried on the standard PSN protocol message; the PSN message is transmitted through the PSN interface, and transmitted to the heterogeneous serial data communication channel emulation device b through the PSN.

The PSN information transmission unit of the isochronous serial data communication channel emulation device b decapsulates the channel emulation data message from the PSN message, and restores the message sequence; the interworking function unit of the isochronous serial data communication channel emulation device b is different The information segment is taken out in the serial data message; the different serial port information transmission processing unit of the heterogeneous serial data communication channel emulation device b processes the information segment information according to the connection relationship between the information segments, from the heterogeneous serial port to the application system device b send.

When data is transmitted from the application system device b to the application system device a, the processing steps are corresponding No longer repeat them.

The deletion processing in this embodiment refers to: deleting the redundant portion of the Break sequence and the Idle sequence, and the shorter Idle sequence between the two characters.

Define 2 parameters for the Idle sequence:

Idle_delete _{: the} minimum value of the Idle sequence;

Idle_hold: The maximum value of the Idle sequence.

1) There is an Idle sequence between the two character data, but the Idle sequence length is less than or equal to Idle_delete, then the Idle sequence is deleted. The connection between the two characters is regarded as continuous, then the Idle sequence is deleted (deleted) The Idle sequence is the shorter Idle sequence described above; in other cases, the connection between the two character data is considered to be non-contiguous;

2) If the length of the Idle sequence between the two character data is greater than Idle_delete and less than or equal to Idle_hold, then the Idle sequence is retained;

3) If the received Idle sequence is greater than Idle_hold, only the Idle sequence portion of length Idle_hold is reserved, and the portion of the Idle sequence length greater than Idle_hold is deleted (the portion of the Idle sequence information segment length greater than Idle_hold is the redundant portion of the above Idle sequence);

Idle_delete and Idle_hold can be set, Idle_delete can be set to 0, and Idle_hold can be set to infinity, so for any application system, there are a pair of parameters that do not affect normal communication.

Define 1 parameter for the Break sequence:

Break_hold: The maximum value of the Break sequence.

If the length of one of the received Break sequences is greater than the Break_hold, only the Break sequence of the length Break_hold is reserved, and the rest is deleted (the part of the Break sequence information segment whose length is greater than the Break_hold is the redundant part of the above Break sequence); if the length of the received Break sequence is less than Or equal to Break_hold, this Break sequence is completely retained.

Break_hold can also be set, the value of Break_hold should be greater than or equal to the length of one character symbol, and the maximum can be infinity.

In this embodiment, the segmentation process refers to dividing an excessively long character data stream, a Break sequence, or an Idle sequence into shorter pieces of information. One purpose of segmentation is to control the length of the channel-independent serial data message to be less than the maximum transmission unit of the PSN; another purpose is to control the delay time of the communication.

The format of the different serial data packet format in this embodiment is shown in Table 1:

Character

Tail I payload type | payload length h

Payload length

Tail I payload type | payload length h

Payload length

Character

Character character

FECO FECI Table 1

flagK flag2 : Message start delimitation flag, 2 bytes in total;

Next : The connection between the last information segment of this message and the first information segment of the next message. 1 is continuous, 0 is non-continuous;

Packet type: Packet type. 0000 is an analog data packet of a different serial data channel, and the remaining values thereof represent parameter negotiation messages, maintenance management messages, and the like;

Version: different serial data protocol version number;

DTE/DCE: Application system source serial port type;

DTR, DSR, RTS, CTS, DCD: Application system source serial port out-of-band control signal;

Packet number: The serial data packet number used to indicate the order of the packets to the end receiving the different serial data packets.

Channel dish mber : different channel number, different serial port data channel imitation Real equipment

HEC: message header check value;

Tail: The tail flag. 0: This information segment is not the last information segment of the message. 1: This information segment is the last information segment of the message.

Payload type: This type of information segment. 00: character data, 01: Idle sequence, 10: Break sequence, remaining reserved;

Payload length_h: This message segment is 5 bits long. The length of the character data information segment is in bytes; since both the Idle sequence and the Break sequence are repeated symbol sequences, the Idle sequence and the Break sequence information segment length are in units of symbols; the Idle sequence and the Break sequence are used in the text. Type (payload type) + length (payload length - h, payload length_l) to indicate;

Payload length_l: The length of this information segment is 8 bits low;

Character: The character data payload. The Idle sequence and the Break sequence information segment do not have this field information;

FEC0, FECI: Message check value.

The first information segment shown in Table 2 is a character data information segment, followed by a 197-symbol length Idle sequence information segment (payload length_l is 11000101), followed by a character data segment of the different serial data channel simulation data. In the message, the connection relationship of each piece of information in the message is continuous.

In this embodiment, the heterogeneous serial port information transmission processing unit of the heterogeneous serial data communication channel emulation device has a universal heterogeneous serial transceiver, and the main operation steps of sending the heterogeneous serial data message are:

a) the different serial port information transmission processing unit receives the character data, the Idle sequence, the break sequence and the interface control signal from the different serial port of the application system device, and collects the sequence length of the Idle sequence and the Break sequence when receiving;

b) The isochronous serial port information transmission processing unit follows the configured Idle_delete, Idle_hold and

The operation rules of the Break_hold parameter value and parameters process the received Idle sequence and Break sequence from .

c) The heterogeneous serial port information transmission processing unit of the channel emulation device divides the long continuous stream of characters, the Break sequence or the Idle sequence into shorter pieces of information; determines the connection relationship between the pieces of information, if two characters are deleted The Idle sequence is less than or equal to Idle_delete; the connection between the two character data is regarded as continuous; in other cases, the connection between the preceding and following character data is regarded as discontinuous;

d) The interworking function unit encapsulates the processed character data, the Idle sequence, and the Break sequence information segment into the channel emulation data packet in sequence, and encapsulates a single information segment in one channel emulation data message, and may also encapsulate multiple information. Segment, when a plurality of information segments are encapsulated in one channel emulation data message, the connection relationship of each information segment shall be continuous;

e) the interworking function unit fills in the message in the connection between the last information segment of the channel emulation data message and the first information segment of the next isochronous serial data message;

f) the interworking function unit fills in other fields of the channel emulation data message;

g) The PSN information transmission unit carries the channel emulation data packet on the standard PSN protocol packet;

h) The PSN information transmission unit transmits the PSN message carrying the channel emulation data message through the PSN.

The heterogeneous serial port information transmission processing unit of the heterogeneous serial data communication channel emulation device is further configured with a BD (buffer descriptor buffer descriptor) and a corresponding data buffer (buffer). Each buffer stores a segment of information received from the PSN. The contents described by the BD include the buffer operation status, the information segment type, the information segment connection relationship, the information segment length, the buffer pointer, the next BD pointer, and the like. Configure the transmit standard horizon register, the transmit high horizon register, and the transmit low horizon parameter register to accommodate the PSN delay and delay jitter.

The operation of storing data in a buffer when receiving a different serial data message is:

a) the PSN information transmission unit receives the PSN packet carrying the channel emulation data packet from the PSN, and decapsulates the channel emulation data packet, and discards the packet if the packet is incorrectly verified;

b) Check the channel emulation data message sequence number and sort the message sequence;

c) the interworking function unit of the channel emulation device decapsulates the information segment and its connection relationship from the channel emulation data packet;

d) The interworking function unit stores the received information segments and their corresponding connection relationships in the BD and the corresponding buffer.

The operation procedure of the different serial port information transmission processing unit for taking out the information segment from the BD and the corresponding buffer, and sending the information to the different serial port is:

a) extracting data from the BD and the corresponding buffer to send a character data stream, a break sequence, an Idle sequence, and an interface control signal to the application system device to control the length of the Idle and Break sequences;

b) If the current information segment _nex t=o, the data transmission can be taken out immediately;

c) If the current information segment _ne xt=l, the continuous data length that has been received must be checked backwards from the current buffer:

If the previous information segment next=0, the current information segment next=l, the received continuous data length is smaller than the transmission low horizontal line, waiting for the continuous data length to reach the transmission standard horizontal line or receiving subsequent non-contiguous data, starting to transmit, waiting for the period to be sent Idle symbol sequence;

If the previous information segment next=l, the current information segment _ne xt=l, the received continuous data length is greater than or equal to the transmission low horizontal line and less than or equal to the transmission high horizontal line, and immediately sent;

If the previous information segment next=l, the current information segment _ne xt=l, the received continuous data length is greater than the transmission high horizontal line, immediately send and raise the transmission standard horizontal line;

If the previous information segment next=l, the current information segment _ne xt=l, the received continuous data length is smaller than the transmission low horizontal line, immediately send and lower the transmission standard horizontal line.

d) If the adjustment of the transmission standard horizontal line will exceed the transmission of the high and low horizontal line range or when the previous information segment next=l, the current information segment next=l, the buffer overflows when the data is sent, an alarm event is generated and the transmission standard is automatically adjusted. Horizontal line and high and low horizontal line parameters, adjustment method The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto, and any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention. It should be covered by the scope of the present invention. Therefore, the scope of the invention should be determined by the scope of the claims.

Claims

Claim

1. The analog data communication channel simulation method is characterized in that the local channel simulation device receives the character data, the break sequence and the Idle sequence from the different serial port data signal lines, and passes the character data, the break sequence and the Idle sequence. The packet switching network transmits to the peer channel emulation device; the peer channel emulation device recovers the character data, the Break sequence, and the Idle sequence according to the information in the channel emulation data message, and sends the same to the isochronous serial port.

2. The heterogeneous serial data communication channel emulation method according to claim 1, wherein the local channel emulation device receives the break sequence and the Idle sequence from the different serial port data signal lines.

3. The heterogeneous serial data communication channel emulation method according to claim 1 or 2, characterized in that it comprises the following steps:

a) The local channel emulation device encapsulates the character data, the Break sequence, and the Idle sequence into channel emulation data packets, wherein the Break sequence and the Idle sequence are composed of the sequence type and the sequence length; b) the local channel emulation device simulates the channel The data packet is carried on the packet switching network message for transmission;

□.

The method for simulating the data transmission channel of the heterogeneous serial data communication system according to claim 3, wherein in the step a), before the local channel emulation device performs packet encapsulation, the deletion processing is further performed; The process is to delete the redundant portion of the Break sequence or the Idle sequence or to delete the shorter Idle sequence between the two character data; the shorter Idle sequence is an Idle sequence whose information segment length is smaller than the minimum value of the Idle sequence.

The heterogeneous serial data communication method according to claim 4, wherein the redundant portion of the Break sequence is a portion of the Break sequence information segment length greater than a maximum value of the set Idle sequence; The redundant portion is a portion where the Idle sequence information segment length is greater than a maximum value of the set Idle sequence.

The method for simulating the heterogeneous serial data communication channel according to claim 3, wherein in the step a), before the local channel emulation device performs packet encapsulation, segmentation processing is further performed;

1 The segmentation process is to divide a longer character data stream, a Break sequence, or an Idle sequence into pieces of information.

The method for simulating a different-sequence serial data communication channel according to claim 4, wherein in the step a), before the local channel emulation device performs packet encapsulation, segmentation processing is further performed; The segmentation process is to divide a longer character data stream, a Break sequence, or an Idle sequence into pieces of information.

8. The isochronous serial data communication channel emulation device is characterized in that it comprises an isochronous serial port information transmission processing unit, an interworking function unit, a packet switching network information transmission unit, and an isochronous serial port information transmission processing unit through an interworking function unit and a packet exchange. The network information transmission unit is connected; the different serial port information transmission processing unit is connected to the different serial port of the application system device; the packet switching network information transmission unit is connected to the packet switching network;

The different serial port information transmission processing unit is configured to send and receive character data, a Break sequence, and an Idle sequence, and count the received sequence length when receiving the Break sequence and the Idle sequence;

9. The heterogeneous serial data communication channel emulation device according to claim 8, wherein the isochronous serial port information processing unit is further configured to perform a delete process on the Break sequence or the Idle sequence.

10. The heterogeneous serial data communication channel emulation device according to claim 8 or 9, wherein the heterogeneous serial port information processing unit is further configured to perform segmentation processing on the character data, the Break sequence or the Idle sequence.

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