KR19980023733A - Error Checking Method for Call and Connection Control in Broadband Telecommunication Networks - Google Patents

Abstract

The present invention relates to an error checking method of a message for call and access control in B-ISDN, comprising: storing a received call progress message in a secured memory area after initialization; Confirming an error by detecting a bit value corresponding to the protocol discriminator (S2); Confirming an error by detecting a length bit of the call reference value (S3); Detecting an error by detecting a flag bit (S4); Detecting a call reference value (S5); Detecting a message type bit and determining that an error has occurred if the bit value does not correspond to a call progress message (S6); Detecting an error by detecting a message length bit (S7); Checking whether the received message corresponds to the first message in response to a setup message, and in case of the first message, determining whether an access identifier information element exists and confirming an error (S8); Obtaining the length information by using the sum of the number of information elements and the length of each information element, and then checking whether the message length corresponds to the length information to identify an error (S9); And a step S10 of outputting the final number of errors for the call progress message identified in each of the steps S1 to S9. By checking the error of the received message, call and connection can be controlled smoothly in B-ISDN.

Description

Method of checking error of message for controling call and connection in Broadband Integrated Services Digital Network

The present invention relates to a method of controlling a call and connection in a broadband integrated services digital network (hereinafter referred to as a B-ISDN), in particular an asynchronous transfer mode It refers to a method of checking an error in a call processing message among call processing related messages in a user-network interface (hereinafter referred to as UNI). .

Due to the rapid development of the information society, B-ISDN emerged as the next generation communication network due to the increase of user's communication service demand.

B-ISDN was formed under the influence of synchronous optical communication standard while expanding to accommodate various wideband signals utilizing the basic intent of ISDN standardization, and its basic purpose is video telephony from narrowband services such as remote meter reading, data terminal, telephone, and facsimile. It was to integrate both real-time and clustered data signals of wide band distribution into wideband services such as video conferencing, precision picture transmission, high speed data transmission, and video signal transmission.

Therefore, there is a need for an effective processing method that can handle various services as described above. The proposed solution is ATM communication that can accommodate not only narrowband but also wideband services regardless of band and speed. That's the way.

The ATM communication method is a method integrating the digital communication method and the packet mode communication method of the existing circuit mode, and for signaling of the ATM method, such as Signaling AAL, Q.2931, B-ISUP, etc. Drafts have been proposed.

That is, in the conventional ISDN (also referred to as narrowband N-ISDN), the transmission rate of a channel carrying user information was about 64 Kbps to 2 Mbps, so it was difficult to satisfy broadband services such as moving pictures.

On the other hand, B-ISDN can transmit data at high speed of 100 Mbps or more, and can use ATM technology to process various information sources such as voice, data, document and video.

In the conventional N-ISDN, a signaling method for realizing access control uses Digital Subscriber Signaling System 1 (DSS1) in the subscriber line section, and No.7 common line signaling method in the inter-station relay section. DSS1 implements Layer 2 and Layer 3 protocols on the D channel, also called Link Access Procedure on the D-channel (LAPD), and is recommended in ITU-T specifications Q.921 and Q.931. In the current B-ISDN, a Q.2931 extension is proposed into the draft by adding functional elements of ATM to Q.931 as the signaling procedure of the user network interface (UNI), and the signaling procedure of the network-node interface (NNI). B-ISUP (ISDN User Part) was proposed into the draft.

On the other hand, apart from the standardization of B-ISDN, which is centered on ITU-T, the computer and telecommunications industry, academia, government agencies, and research institutes participate to promote the development of ATM technology and accelerate the development of ATM products and services. The ATM Forum was established in October 1991 and worked closely with standardization organizations (ANSI, IEEE, ITU-T, etc.) to support ATM UNI Specification V3.0 (93.9) and ATM B-ICI Specification V1.0 ( 93.8), drafts such as ATM DXI Specication V1.0 (93.8).

The role of the ATM Forum is not to duplicate the work of international standards bodies, but to complement and speed up the standardization process by establishing standards that can be implemented in a short period of time.

The present invention implements call and connection control according to the Q.2931 standard, which is a call / access control standard in a user network proposed by the International Organization for Standardization. The purpose is to provide a method for identification.

The method of the present invention for achieving the above object, a method for checking the error in the message of the user network interface to communicate by ATM method from one terminal connected to the ATM network to the other terminal connected to the network. A method comprising: initializing to identify an error of a call progress message and storing the received call progress message in a reserved memory area; Checking an error by detecting a bit value corresponding to a protocol discriminator; Checking an error by detecting a bit value corresponding to the length of the call reference value; Checking an error by detecting a bit value corresponding to a flag; Detecting a bit value corresponding to the call reference value; Detecting a bit value corresponding to the message type and determining that an error has occurred if the bit value does not correspond to a call progress message; Checking an error by detecting a bit value corresponding to a message length; Checking whether the received message corresponds to the first message in response to a setup message, and in case of the first message, determining whether an access identifier information element exists; Obtaining the length information by using the sum of the number of information elements and the length of each information element, and then checking whether the message length corresponds to the length information to identify an error; And outputting the final number of errors for the call progress message identified in each step.

That is, by sequentially performing the steps of the present invention configured as described above it is possible to check the error in the call progress message of the call processing-related messages to realize the call and access control in the ATM user network interface.

1 is a conceptual diagram illustrating a general ATM protocol reference model;

2 is a diagram illustrating a general B-ISDN call control protocol stack;

3 is a format diagram showing the structure of an ATM cell;

4 is a view showing an example of a flow of messages related to call processing in an ATM user network interface (UNI);

5 illustrates a general format of a call processing related message in an ATM UNI;

6 shows a general format of the information element shown in FIG. 5;

7 is a block diagram showing a configuration of hardware for performing the method according to the present invention;

8 is a flowchart illustrating a method of checking an error of a received call progress message among call processing related messages according to the present invention.

* Explanation of symbols for main parts of the drawings

1: Calling Party 2: Network

3: Called Party 10: Message Generator

11: Host CPU 12: Storage

12-1: DRAM 12-2: DRAM Control Unit

12-3: ROM 12-4: Nonvolatile RAM

20: ATM card 21: packet memory

22: control memory 23: AAL unit

23-1: AAL cutout 23-2: AAL recombination

24: ATM layer and physical layer

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

First, to explain the ATM method to which the present invention is applied to facilitate understanding of the present invention.

1 is a conceptual diagram illustrating an ATM protocol reference model, which is composed of a management plane, a control plane, and a user plane, and the management plane is divided into hierarchical management and plane management.

Here, the plan management refers to the overall management of the system, and the hierarchical management refers to management and operation and maintenance (OAM) information management of resources and usage variables.

In addition, the control plane manages call control and connection control information, and the user plane manages the transfer of user information.

Protocols of the control plane and the user plane are divided into a higher layer, an ATM adaptation layer, an ATM layer, and a physical layer. The functions of each layer are shown in Table 1 below.

Functions of Each Layer in the Protocol Criteria Model Hierarchy Tier function Upper hierarchy - Higher layer function ATM Adaptation Layer (AAL) Convergence (CS) Convergence function Cut and Rejoin (SAR) Cutting function and recombination function ATM layer - General Flow Control Function Cell Header Generation and Extraction Function Cell Virtual Path Identification Number (VPI) / Virtual Channel Identification Number (VCI) Translation Cell Multiplexing and Demultiplexing Physical layer Transmission Convergence (TC) Cell rate separation function Header error control (HEC) signal generation and confirmation function Cell boundary identification function Transmission frame generation and recovery function Physical medium (PM) Bit time information function Physical media related function

As shown in Table 1, the ATM scheme is divided into vertical structures such as a physical layer, an ATM layer, an ATM adaptation layer (AAL), and a higher protocol layer, and the AAL layer is a segmentation and recombination sublayer (SAR). And Reassembly sublayers) and Convergence Sublayers (CS) are further divided into physical layers (PM) and Transmission Convergence (TC) sublayers.

In addition, the user network interface (UNI) is implemented as Q.2931 in Layer 3 of the control plane to control calls and connections between ATM networks and users, and Q.2931 is an ISDN layer. As a higher standard of Q.93B, which extends Q.931, which is a three-protocol protocol, the ITU-T proposed basic call / connection control standard (User-Network Interface (UNI) Layer 3) Network Interface Layer 3 Specification for Basic Call / Connection Control).

In addition, the network interface (NNI) is implemented as B-ISUP at layer 3 of the control plane, and related ITU-T standards are Q.2761 to Q.2764.

Next, look at the call control protocol standards of the B-ISDN to which the present invention is applied.

As shown in FIG. 2, the UNI call control protocol in the User Network Interface (UNI) is defined as Q.2931, and the Service Specific Connection Oriented Protocol (SAAL SSCOP) of the signaling AAL layer is Q.2130. And Q.2110, the AAL Service Specific Coordination Function (SSCF) is defined as I.363, the ATM layer is defined as I.361, the physical layer is defined as I.432, and the Network Node Interface (NNI). In the standard, the user part (B-ISUP: B-ISDN User Part) is Q.2761 to Q.2764, and the message sending part 3 (B-MTP: B-ISDN Message Transfer Part 3) is Q.2210, SAAL. SSCOP is defined as Q.2140 and Q.2110, respectively, AAL SSCF layer is defined as I.363, ATM layer is defined as I.361, and physical layer is defined as I.432.

Comparing these protocols with the corresponding layer of Open System Interconnection (OSI), Q.2931 and Q.2761 through Q.2764 correspond to OSI layer 3, SAAL SSCOP and AAL SSCF correspond to OSI layer 2, and ATM layer. The physical layer corresponds to OSI layer 1. That is, the Q.2931 message of layer 3 is segmented to 48 bytes (bytes, hereinafter, octets) through the SSCOP, SSCF, and CPCS of the signaling adaptation layer (Signalling AAL 5), and the ATM layer. After a 5 byte header is added in, the data is mapped and transmitted to a plurality of 53 byte ATM cells.

FIG. 3 is a diagram illustrating a format of a general ATM cell, which is divided into a 5-byte header and a 48-byte payload, and a 5-byte header structure used in a user network interface (UNI) is shown in FIG. One byte consists of four bits of Generic Flow Control (GFC) and four bits of Virtual Path Identifier (VPI), and the second byte consists of four bits of Virtual Path Identifier (VPI) and four bits. It consists of a Virtual Channel Identifier (VCI), the third byte is composed of an 8-bit virtual channel identifier (VCI), the fourth byte is a 4-bit virtual channel identifier (VCI) and three bits of pay It is composed of a load type (PT: Payload Type) and a 1 bit cell loss priority (CLP: Cell Loss Priority), and the fifth byte is composed of 8 bits of header error control (HEC).

4 illustrates an example of a call processing related message flow in an ATM user network interface (UNI), in which a calling party (1), a network (2), and a called party (3) are called. Indicates the call processing process between.

First, a virtual channel connection (VCC) is always established through the signaling adaptation layer (Signalling ALL) for call and connection control, and call / access control messages are transferred to and from the virtual channel. data) For controlling the connection for forwarding, the message used for call / access control is the message for B-ISDN call / access control as shown in Table 2 and the call between N-ISDN and B-ISDN as shown in Table 3 below. There are messages used for access control and messages used for global call references, as shown in Table 4 below.

Messages Used to Control B-ISDN Calls and Access Call establishment message: ALERTINGCALL PROCEEDINGCONNECTCONNECT ACKNOWLEDGESETUP Call release message: RELEASERELEASE COMPLETE Other: NOTIFYSTATUSSTATUS ENQUIRY

Message used to access N-ISDN service Call setup message: ALERTINGCALL PROCEEDING CONNECT ACK NOW LED GE PROGRESS SETUP ACK NO W LED GE call release message: RELEASERELEASE COMPLETE Other: NOTIFYINFORMATIONSTATUSSTATUS ENQUIRY

Messages Used to Control Global Call Reference RESTARTRESTART ACKNOWLEDGESTATUS

In FIG. 4, the messages of Tables 2 through 4 generated according to Q.2931 are transmitted using the 'AAL-DATA-REQUEST' primitive of the signal AAL (SAAL).

The originator (1) generates a SETUP message to set up the call, then transfers it to the network via the assigned signal virtual channel (VCI = 5), simultaneously starts the timer T303 and calls the call initiated state. Becomes

At this time, the setup message includes a call reference, various information elements required for call processing (for example, called part number, ATM user cell speed, broadband bearer capability, and quality of service parameter (QoSP). ), Etc.).

If there is no response for the time set by the timer T 303, the setup message is retransmitted, and if there is no response even after repeating the predetermined number of times, the call processing is stopped.

After receiving the setup message, the network 2 selects and assigns a valid connection identifier (VPCI / VCI), and then sends a setup message to the called party 3 again and then sends a CALL PROCEEDING message. Send it to (1).

At this time, when the caller 1 receives the call progress message, the caller 1 stops the timer T 303, starts the timer T310, and enters an outgoing call progress state.

The called party 3 receives the setup message and then transfers the call progressing and alerting messages to the network 2, and the network 2 receives the alerting message, and then sends it to the caller 1. ) And the caller 1 stops the timer T 303 or T 310 when the alerting message is received, and enters the call forwarding state.

When the called party 3 generates a CONNECT message to allow the connection and transmits it to the network 2, the network 2 sends it to the sender 1 and sends a CONNECT ACKNOWLEDGE message. It delivers to the called party 3 side, and receives a connection confirmation message from the caller 1.

Through the call processing process as described above, a communication path (connection) given as a connection identifier (VPCI / VCI) is formed between the originator 1 and the called party 3 so as to exchange data.

On the other hand, a user (sender or originator) who wants to disconnect from the end of the data transmission or during the transmission generates a RELEASE message and starts the timer T 308 to request the network to disconnect and then request the release. When the release message is received, the network releases the virtual channel connection, and sends a release message to the other party to inform it, and sends a release complete message to the release request side. ) State.

When the user (sender or called party) requesting the connection release receives the RELEASE COMPLETE message, the timer T 308 is stopped, the virtual channel, the call number, etc. are released, and the state is null.

At this time, the user or the network can generate a status request message at any time to request information about the network or other user's status, and the user or network that receives the status request message is the status. Create a message to tell you your status.

5 is a diagram illustrating a general format of a call processing control related message in an ATM user network interface (UNI), in which 1, ..., 8 at the top represent bits, and 1, 2, ... 9, at the right side. etc indicates octets (bytes).

As shown in Fig. 5, the first octet is a Protocol Discriminator, and when the bit value is 00000000b to 00000111b, it indicates that it is not available for the message protocol discriminator. If it is 00001001b, it corresponds to Q.2931, and if it is 00010000b to 00111111b, it is reserved. If it is 01000000b to 01001111b, it is for national use. If it is 01010000b to 11111110b, it is reserved. Meaning that values other than the bit values are reserved. In the present invention, since it is for realizing call and connection control according to the Q.2931 standard, the protocol discriminator is represented by 00001001b (Q.2931) or 00001000b (Q.931).

Bits 8 to 5 of the second octet are 0000b, and bits 4 to 1 represent the length of the call reference value in octet units and are usually 0011b.

The third to fifth octets represent the call reference value, and in particular, if bit 8 of the third octet is 0 as the call reference flag, from the side (typically, the originator side) generating the call reference (from ) Indicates the message to be sent, and a value of 1 indicates the message to be sent to the party (usually the originator) generating the call reference. If the call reference values are all 0b, it represents a global call reference, and if it is all 1b, it represents a dummy call reference for a semi-permanent virtual channel connection (SPC).

The sixth and seventh octets indicate message type related information, and messages are classified according to the sixth octet value as shown in Table 5 below.

Message coding Bit 8 7 6 5 4 3 2 1 Content (message) 0 0 0 0 0 0 0 00 0 0-----0 0 0 0 10 0 0 1 00 0 1 1 10 1 1 1 10 0 0 1 10 0 1 0 10 1 1 0 10 1 0---- -0 1 1 0 11 1 0 1 00 0 1 1 00 1 1 1 00 1 1-----1 1 0 1 10 1 1 1 01 1 1 0 11 0 1 0 10 1 1 1----1 1 1 01 1 1 10 1 1 00 1 1 11 1 1 1 1 1 1 1 Calling messages in special messages: ALERTINGCALL PROCEEDING * CONNECTCONNECT ACKNOWLEDGE PROGRESSSETUPSETUP ACKNOWLEDGE Call clearing message: RELEASERELEASE COMPLETERESTARTRESTART ACKNOWLEDGE Other messages: Message for INFORMATIONNOTIFYSTATUSSTATUS ENQUIRYSPC: UPPC STATUS STATUS UPDATE STATUS UPDATE STATUS

In addition, bit 8 of the seventh octet indicating message type related information is normally 1b as an extension, bits 7 and 6 are 00b as spares, and bit 5 is 0b as a message type flag Flag. If it indicates that the message instruction field is not important, and if 1b it is followed by an explicit instruction.

Bits 4 and 3 are spares with 0b respectively, bits 2 and 1 are Message Action Indicators, and 00b indicates a clear call, and 01b indicates Discard and ignore. 10b represents Discard and report status, and 11b represents Reserved.

In addition, the eighth and ninth octets indicate a message length and may have a maximum length of 64K (2 ¹⁶ ) octets, and from the tenth octet (etc), an information element (IE) of variable length Follows.

On the other hand, information about the call progress message of the B-ISDN can be shown as Table 6 below. In Table 6, Protocol Identifier (PD), Call Reference (CR), Message Type (MT) and Message Length (ML) represent information that must be included as Mandatory, Connection Identifier (CI) and Reporting. An indicator (NI) indicates information included as optional.

Information about call progress messages Information direction shape Length Protocol Classifier (PD) Bidirectional necessary One Call Reference (CR) Bidirectional necessary 4 Message type (MT) Bidirectional necessary 2 Message length (ML) Bidirectional necessary 2 Access identifier (CI) Bidirectional Selection 4-9 Reporting indicator (NI) Bidirectional Selection 5

6 is a diagram showing a general format of an information element (IE) included in an ATM UNI message, where 1, ..., 8 at the top represent bits, and 1, 2, 3, 4, 5, etc on the right side. … Represents an octet (byte).

In FIG. 6, the first octet is an information element identifier, and information elements are classified according to the values as shown in Table 7 below.

Information identifier coding Bit 8 7 6 5 4 3 2 1 Information Element 0 1 1 0 0 0 0 00 1 1 0 0 0 0 10 1 1 0 0 0 1 00 1 1 0 0 0 1 10 1 0 1 1 0 0 00 1 0 1 1 0 0 10 0 0 1 0 1 0 00 0 0 0 1 0 0 00 1 1 1 0 0 0 00 1 1 1 0 0 0 10 1 1 0 1 1 0 00 1 1 0 1 1 0 10 1 0 0 0 0 1 00 1 1 1 1 0 0 10 1 1 1 1 0 0 00 0 0 0 0 1 0 00 1 1 1 1 1 0 10 1 1 1 1 1 0 00 0 0 1 1 1 1 00 1 0 1 1 0 1 00 1 0 1 1 0 1 10 1 0 1 1 1 0 00 1 0 1 1 1 1 00 1 0 1 1 1 1 10 1 0 1 1 1 0 10 0 1 0 0 1 1 10 1 1 0 0 1 0 00 1 1 0 0 1 0 10 1 1 0 0 1 1 0 Broadband-Locking ShiftBroadband-Non-Locking ShiftBroadband-Sending CompleteBroadband-Repeat indicatorATM Adaptation Layer ParameterATM Traffic DescriptorCall stateCauseCalled Party NumberCalled Party SubaddressCalling Party NumberCalling Party SubaddressEnd-End Transit DelayRestart IndicatorTransit Network SelectionNarrowband Bearer Compatibility Compatibility Arrow Indicator bearer capability Broadband Low Layer Information Broadband High Layer Information Notification Indicator Transaction Number SPC status SPC Report Type

In addition, in the second octet, bit 8 is 1b as an extension, bits 7 and 6 are coding standards (CS), and bits 5 to 1 are information element command fields.

Here, the coding standard (CS) is classified into four types according to bits 7 and 6 of the second octet, and in case of 00b, ITU-T standard, in case of 01b, ISO / IEC standard, and in case of 10b, National Standard, in case of 11b, represents the defined standard.

Bit 5 of the information element command field is a flag, 0b means that the information element command field is not important, and 1b means that an explicit command follows.

Bit 4 of the information element command field is a reserved bit and is used to indicate a pass along request.

In addition, bits 3 to 1 of the information element command field are information element action indicators (IE Action Indicator), for example, 000b indicates a clear call, and 001b indicates information element abandonment and processing (Discard and Proceed), 010b indicates Discard, Proceed and Report Status, 101b Discard and Ignore, and 110b indicates Discard message, and report status.

The third and fourth octets indicate the length of information element contents (L).

From the fifth octet, information element contents are represented.

7 is a block diagram showing the configuration of hardware for performing the method according to the present invention. The hardware for performing the method of the present invention includes a message generation unit 10 of a higher layer that generates a message for call and connection. ; Receives the message generated by the message generator 10 through the CPU bus, performs the function of mapping the service signals to the effective load space of the ATM cell, performs ATM cell header related functions, and transmits the ATM cells bit The ATM card 20 transfers heat by heat.

Here, the message generator 10 is implemented as a computer system including a host CPU 11 and a storage 12, wherein the storage 12 is a DRAM for storing messages. 12-1), a DRAM controller 12-2 for controlling the DRAM 12-1, a ROM 12-3 for storing a call processing program, and the like, and storing information that is not desired to be destroyed when the power is turned off. It consists of a nonvolatile RAM 12-4.

In addition, the ATM card 20 converts a packet memory 21 for temporarily storing an ATM cell, a control memory 22 storing a control program for making data into a required form, and transfers data into an ATM cell form. Conversely, it consists of an AAL unit 23 for extracting only data from an ATM cell, an ATM cell header-related function, and an ATM layer and a physical layer unit 24 that transfer ATM cells into bit strings.

Next, operation of hardware for performing the method of the present invention will be described.

The host central processing unit 11 of the message generating unit 10 secures an area for generating a message in the DRAM 12-1 of the storage unit 12 while performing a predetermined sequence according to a request of an application or a client. A message is generated in the area according to a predetermined format.

The data input via the CPU bus is stored in the packet memory 21 of the ATM card 20, and the data is transferred to the AAL cutout 23-1 of the AAL unit 23 constituting the ATM card 20. The AAL recombination unit 23-2 of the AAL unit 23 constituting the ATM card 20 extracts only the data from the ATM cell input from the ATM layer and the physical layer unit 20. Serve At this time, the role of the packet memory 21 and the control memory 22 is necessary.

That is, the AAL layer makes user information of a higher layer into a protocol data unit (PDU), and also performs a function of cutting the protocol data unit to form a user information section of an ATM cell and recombine it. Here, the AAL unit 23 of the ATM card 20 has an AAL 5 function for Q.2931, and AAL-3 / 4 for the connection and connectionless data communication is complicated by all procedures in accordance with the protocol. The need for AAL 5 is raised because it is not suitable for communication, which is similar to AAL-3 / 4 but features a greatly simplified function.

That is, AAL 5 has sublayers of segmentation and reassembly (SAR), common part convergence sublayer (CPCS), and service specific convergence sublayer (SSCS). There is a non-guaranteed delivery method. The difference from AAL-3 / 4 is that multiplexing is not supported first, and if multiplexing is in the AAL layer, this will happen in SSCS.

Meanwhile, the ATM layer and the physical layer unit 20 of the ATM card 20 are divided into an ATM layer and a physical layer. Looking at each function, the ATM layer utilizes a general flow control (GEC) section to provide a user network interface (UNI). Control access and information flow, translate virtual path identification numbers (VPIs) / virtual channel identification numbers (VCIs) and associate them with service access points (SAPs), and multiplex and demultiplex cells Let's do it. In addition, it processes payload type (PT) or cell abandonment rank (CLP) intervals and generates and extracts headers of ATM cells.

In addition, the physical layer performs separation of cell rates, generation and confirmation of header error control bytes, detection of cell boundary points, and generation and confirmation of transmission frames in the case of transmission based on synchronous digital hierarchy (SDH). It is also responsible for the final transmission over optical fiber or coaxial cable.

8 is a flowchart illustrating a method of checking an error of a received call progress message among call processing related messages according to the present invention.

Referring to FIG. 8, the method of the present invention is initialized to identify an error of a call progress message in a first step S1, and then the received call progress message is stored in the reserved memory area m [·]. .

In the second step S2, an error is confirmed by detecting a bit value corresponding to a protocol discriminator (PD).

In the third step S3, an error is confirmed by detecting a bit value corresponding to a length of call reference value (LCRV).

In a fourth step S4, an error is confirmed by detecting a bit value corresponding to a flag.

In a fifth step S5, a bit value corresponding to a call reference value (CRV) is detected.

In a sixth step S6, if a bit value corresponding to a message type (MT) is detected and the bit value does not correspond to call proceding, it is determined that an error has occurred.

In a seventh step S7, an error is confirmed by detecting a bit value corresponding to a message length (ML).

In the eighth step S8, it is checked whether the received message corresponds to the first message in response to the setup message, and in the case of the first message, it is determined whether a connection identifier information element exists and an error is determined. Check it.

In the ninth step S9, the length information L is obtained using the sum of the number N of information elements (IE) and the length of each information element (IE Length). The error is checked by determining whether the information corresponds to the length information (L).

In the tenth step S10, the final number ErrNum of the error about the call progress message identified in each of the steps S1 to S9 is output.

Next, the steps of the present invention will be described in detail with reference to FIGS. 5 and 8 as follows.

In the first step S1, in the first step S1-1, the variable ErrNum value corresponding to the number of errors is set to 0. In the first step S1-2, the memory area m []] In the form of an array to store the received call progress message, and the reserved memory area m [·] is each of the 0th memory area to the nth memory from the first octet to the nth octet. The areas m [0], m [1], ..., m [n] are represented.

In the second step S2, in a second step S2-1, a zeroth memory area m [corresponding to the protocol identifier PD of the first octet in the format of the message (see FIG. 5). 0]), and in step 2-2 (S2-2), the bit value detected in step 2-1 (S2-1) is 00001000b, that is, Q.931 or 00001001b, that is, Q. If it does not correspond to 2931, 1 is added to the variable ErrNum value set in the first step S1, and the value is set as the new variable ErrNum value.

In a third step S3-1 of the third step S3, a first memory for the length LCRV of a call reference value corresponding to bits 4 to bit 1 of the second octet (see FIG. 5). When the bit value of the area m [1] is detected, and in step 3-2 (S3-2), the bit value detected in step 3-1 (S3-1) does not correspond to 00000011b, After adding 1 to the variable value ErrNum set in the second step S2, the value is set to the new variable ErrNum value.

In the fourth step S4-1 of the fourth step S4, in order to detect a flag bit corresponding to bit 8 of the third octet (see FIG. 5), the second memory area m [ 2]) is multiplied by 10000000b, and if the flag bit detected in step 4-1 (S4-1) corresponds to 0b in step 4-2 (S4-2), the third step After adding 1 to the variable ErrNum value set in (S3), the value is set as the new variable ErrNum value.

The fifth step S5 shifts the bit value excluding the flag bit from the bit value of the second memory area m [2] by 8 bits to the left to perform a logical OR with the bit value of the third memory area m [3]. After performing the above operation, the result of performing a logical OR on the result of shifting the result value left 8 bit again and the bit value of the fourth memory area m [4] is detected to detect a bit value corresponding to the call reference value CRV.

In step 6-1 (S6-1) of the sixth step S6, the bit value of the fifth memory area m [5] corresponding to the message type MT is detected, and in step 6-2 ( In step S6-2), if the bit value of the message type detected in step 6-1 (S6-1) does not correspond to 00000010b, that is, the call progress message (see Table 5) does not correspond to the call setup message. In this case, after adding 1 to the variable value ErrNum set in the fourth step S4, the value is set to the new variable value ErrNum.

In the seventh step S7-1 of the seventh step S7, a value obtained by shifting the bit value of the seventh memory area m [7] by 8 bits to the left and the eighth memory area m [8] The bit value corresponding to the length ML of the message is detected by performing an OR operation on the bit values, and in step 7-2 (S7-2), the length of the message detected in the 7-1 step (S7-1) is detected. If the bit value corresponding to ML) is larger than 14, 1 is added to the variable ErrNum value set in the sixth step S6, and the value is set as the new variable ErrNum value.

In step 8-1 (S8-1) of the eighth step S8, if the received call progress message corresponds to the first message in response to the setup message, the variable value first is set to 1, and Otherwise, the variable value first is set to 0, and in step 8-2 (S8-2), the variable value first is set to 1 in step 8-1 (S8-1), but the connection identifier information element (Connection Identifier) is set. IE) does not exist, then adds 1 to the variable ErrNum value set in the seventh step S7 and sets the value to the new variable value ErrNum.

In the ninth step S9, in the ninth step S9-1, the number of information elements IE is set to a variable N value. In the ninth step S9-2, the length of each information element is set. Set the sum of the value to the variable S value, in step 9-3 (S9-3) multiplies the variable N value set in the ninth step (S9-1) by 4, and then the result value The variable S set in step 9-2 (S9-2) is summed and the resultant value is set to the variable L value. In step 9-4 (S9-4), the message length detected in the seventh step (S7) ( If ML) does not correspond to the variable L value set in the ninth step S9-3, 1 is added to the variable ErrNum value set in the eighth step S8, and the value is added to the new variable ErrNum value. Set to.

Finally, in the tenth step S10, the steps S1 to S9 are sequentially performed to output the final variable ErrNum so that the number of errors in the call progress message of the call setup message can be checked.

As described above, according to the present invention, an ATM user network interface (UNI) smoothly controls a call and connection in B-ISDN by checking an error of a received message according to the Q.2931 protocol specification. You can do it.

Claims (10)

A method for checking an error in a message of a user network interface for communicating by ATM from one terminal connected to an ATM network to another terminal connected to the network, the method for initializing to confirm an error of a call progress message A first step (S1) of storing the received call progress message in the reserved memory area; A second step S2 of detecting a bit value corresponding to the protocol discriminator to identify an error; A third step S3 of detecting a bit value corresponding to the length of the call reference value to identify an error; A fourth step (S4) of detecting an error by detecting a bit value corresponding to the flag; A fifth step S5 of detecting a bit value corresponding to the call reference value; A sixth step (S6) of detecting a bit value corresponding to the message type and determining that an error has occurred if the bit value does not correspond to a call progress message; A seventh step S7 of detecting a bit value corresponding to the message length to confirm an error; An eighth step (S8) of checking whether the received message corresponds to the first message in response to a setup message, and if it is the first message, determining whether an access identifier information element exists; A ninth step (S9) of obtaining length information by using the sum of the number of information elements and the length of each information element, and then checking whether the message length corresponds to the length information to identify an error; Error in the message for call and access control in a broadband integrated information network, comprising a tenth step (S10) for outputting the final number of errors for the call progress message identified in each of the steps (S1 to S9). checking way. The method of claim 1, wherein the first step (S1) comprises: a first step (S1-1) of setting a variable ErrNum value corresponding to the number of errors to zero; And a first step (S1-2) of storing the received call progress message in the secured memory area. The method of claim 1, wherein the second step (S2) comprises: a second step (S2-1) of detecting a bit value of a zero memory area corresponding to a protocol discriminator; And when the bit value detected in the second step S2-1 does not correspond to 00001000b or 00001001b, add 1 to the variable ErrNum value set in the first step S1, and then add the value to the new variable. The error checking method of a message for call and access control in a broadband integrated information communication network, characterized in that the step 2-2 (S2-2) of setting the ErrNum value. 2. The method of claim 1, wherein the third step (S3) comprises: a 3-1 step (S3-1) of detecting a bit value of a first memory area with respect to a length of a call reference value; And when the bit value detected in step 3-1 (S3-1) does not correspond to 00000011b, add 1 to the variable value ErrNum set in step 2 (S2), and then add the value to the new variable ErrNum value. 3-2 step (S3-2) is set to the error checking method of the message for call and access control in a broadband integrated information communication network. 4. The method of claim 1, wherein the fourth step (S4) comprises: a 4-1 step (S4-1) of ANDing 10000000b with the bit value of the second memory area to detect the flag bit; If the flag bit detected in step 4-1 (S4-1) corresponds to 0b, 1 is added to the variable ErrNum value set in the third step S3, and the value is changed to the new variable ErrNum value. A method for checking error of a message for call and access control in a broadband integrated information communication network, characterized in that the fourth step of setting (S4-2). The method of claim 1, wherein the fifth step S5 performs a logical OR with the bit value of the third memory area by shifting the bit value excluding the flag bit from the bit value of the second memory area by eight bits to the left. Call and connection control is performed in the broadband integrated information network, which performs a logical OR on a value obtained by shifting the result value 8 bits back to the left and the bit value of the fourth memory area. For error checking of messages. The method of claim 1, wherein the sixth step (S6) comprises: a sixth step (S6-1) of detecting a bit value of a fifth memory area corresponding to a message type; And if the message type detected in step 6-1 (S6-1) does not correspond to the call progress message bit value 00000010b, 1 is added to the variable value ErrNum set in the fourth step (S4). A method for checking an error of a message for call and access control in a broadband integrated information network, comprising the step 6-2 (S6-2) of setting a value to a new variable value ErrNum. The method of claim 1, wherein the seventh step S7 detects a bit value corresponding to the length of the message by ORing the value obtained by shifting the bit value of the seventh memory area by eight bits to the left and the bit value of the eighth memory area. 7-1 step S7-1; If the bit value corresponding to the length of the message detected in step 7-1 (S7-1) is larger than 14, 1 is added to the variable ErrNum value set in step 6 (S6), and the value is added. A method for checking an error of a message for call and access control in a broadband integrated information network, comprising the step 7-2 of setting a new variable ErrNum value (S7-2). The variable value first of claim 1, wherein the eighth step S8 sets the variable value first to 1 when the received call progress message corresponds to the first message in response to a setup message; Step 8-1 (S8-1) of setting the value first to 0; And when the variable value first is set to 1 in step 8-1 (S8-1) but there is no connection identifier information element, 1 is added to the variable ErrNum value set in step 7 (S7). And an eighth step (S8-2) of setting the value to a new variable value ErrNum. The method of claim 1, wherein the ninth step S9 comprises: a ninth step S9-1 of setting the number of information elements to a variable N value; Step 9-2 (S9-2) of setting the sum of the lengths of the information elements to a variable S value; The variable N set in step 9-1 (S9-1) is multiplied by 4, and the result value is added to the variable S set in step 9-2 (S9-2) and the result value is set to the variable L value. A ninth step (S9-3) of setting; if the message length detected in the seventh step (S7) does not correspond to the variable L value set in the ninth step (S9-3); In the broadband integrated telecommunications network, the method comprises: a step 9-4 (S9-4) of adding 1 to the variable ErrNum value set in the eighth step S8 and setting the value to the new variable ErrNum value. How to check errors in messages for access control