KR100248148B1 - Message error confirming method for controlling call and connection of bisdn - 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 narrowband ISDN message in a reserved 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 an error by detecting a message type bit (S6); Detecting an error by detecting a message length bit (S7); Acquiring length information using the sum of the number of information elements and the length of each information element, and then determining whether the message length corresponds to the length information to identify an error (S8); And outputting the final number of errors for the messages of the narrowband ISDN identified in each of the steps S1 to S8 (S9). According to the present invention, the specification of the Q.2931 protocol in the ATM user network interface is provided. By checking the error of the received message, the B-ISDN can smoothly control the call and connection.

Description

Error Checking Method for Call and Connection Control in Broadband Telecommunication Networks

BACKGROUND OF THE INVENTION 1. Field of the Invention 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), and more particularly, to an asynchronous transfer mode. Method of checking the error of narrowband ISDN (Narrowband-ISDN) message among call processing related messages in User-Network Interface (hereinafter, UNI). It is about.

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 (hereinafter referred to as 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 defined in ITU-T specifications Q.921 and Q.931. In the current B-ISDN, a proposed Q.2931 extension to ATM is added to Q.931 as a signaling procedure for the User Network Interface (UNI). As a signaling procedure, B-ISUP (ISDN User Part) has been 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 in close cooperation with standardization bodies (ANSI, IEEE, ITU-T, etc.), "ATM UNI Specification V3.0 (93.9)", "ATM B-ICI Specification V1." Drafts such as ".0 (93.8)", "ATM DXI Specication V1.0 (93.8)", and the like.

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 access 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. Its purpose is to provide a method for identifying errors.

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 for a message of a narrowband ISDN, and then storing the received narrowband ISDN 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; Checking an error by detecting a bit value corresponding to a message type; Checking an error by detecting a bit value corresponding to a message length; 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 a final number of errors for messages of the narrowband ISDN 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 of the narrowband ISDN message among 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 diagram illustrating an example of a flow of a call processing related message 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 of a method for checking an error for a connection grant message of a narrowband ISDN received among call processing related messages according to the present invention;

9 is a partial flowchart of a method for checking an error for a release message of a narrowband ISDN received in a call processing related message according to the present invention;

10 is a partial flowchart of a method for identifying an error in a status message of a narrowband ISDN received among call processing related messages according to the present invention;

11 is a partial flowchart of a method for checking an error for a status request message of a narrowband ISDN received in a call processing related message 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.

TABLE 1

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 the ATM network and the user, and “Q.2931” is an ISDN. The basic call / connection proposed by ITU-T, which is a higher standard of Q.93B, which extends "Q.931", which is a layer 3 protocol of B. Control specification (User 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, and is divided into a 5-byte header and a 48-byte payload. The 5-byte header structure used in the 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.

TABLE 2

Messages Used to Control B-ISDN Calls and Access

TABLE 3

Message used to access N-ISDN service

TABLE 4

Messages Used to Control Global Call Reference

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), starts the timer T303 and starts the "Call initialization state (Call). Initiated state) ".

In this case, 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 parameters). (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 back to the called party 3 and then calls "CALL." PROCEEDING) "message to the sender (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 transmits the "CALL PROCEEDING" and "ALERTING" messages to the network 2, which receives the alerting message. After that, it forwards it to the caller 1 and goes to the "Call Deliver -ed" state. When the caller 1 receives the "alerting" message, it stops the timer T 303 or T 310 and the call forwarding state is stopped. do.

When the called party 3 generates a "CONNECT" message to allow the connection and transmits it to the network 2, the network 2 transmits it to the sender 1 as well as "CONNECT ACKNOWLEDGE". ) "Message is sent to the called party 3 side, and a" connection acceptance "message is received 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 sender) 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, When the "Release Request state" is received, the network releases the virtual channel connection upon receiving the "Release Request" message, and also sends a "Release" message to the other party, informing them of the "RELEASE COMPLETE" message. Is sent to the release request side and placed in the "NULL" state.

When the user (sender or called party) who requested the disconnection receives the "RELEASE COMPLETE" message, it stops the timer T 308, releases the virtual channel, call number, etc., and enters a "NULL" state. .

At this point, the user or network can generate a "STATUS ENQUIRY" message at any time to request information about the network or other user's status, and the user or network that receives a "STATUS ENQUIRY" message can Produce your status by generating a "STATUS" message.

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 the first octet is not available for the message protocol discriminator, and is "00001000b". In case of "00001001b", it corresponds to Q.2931, and in case of "00010000b" to "00111111b", it means to be reserved. In case of "01000000b" to "01001111b", For purposes of general use, the term "01010000b" to "11111110b" means reserved, and values other than the bit values are reserved. In the present invention, the protocol discriminator is represented by "00001001b" (Q.2931) or "00001000b" (Q.931) because it is for realizing call and connection control according to the Q.2931 standard.

Bits 8 through 5 of the second octet are "0000b", and bits 4 through 1 represent the length of the call reference value in octets 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 generating the call reference (typically, the calling party side). (from) Indicates the message to be sent, if "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 "1b", it is 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.

TABLE 5

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 Use of special messages Set message: ALERTINGCALL PROCEEDINGCONNECTCONNECT ACKNOWLEDGE * PROGRESSSETUPSETUP ACKNOWLEDGE Call release message: RELEASE * RELEASE COMPLETERESTARTRESTART ACKNOWLEDGE

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 a message type flag ( "0b" as a Flag indicates that the Message instruction field is not important, and "1b" 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 abandon and Discard and ignore, "10b" denotes Discard and report status, and "11b" denotes 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, the information on the message of the narrowband ISDN may be represented as shown in Table 6a to Table 6d. In the present invention, a connection acknowledgment message (CONNECT ACKNOWLEDGE) corresponding to a call establishment message among the messages of the narrowband ISDN shown in Table 5, a release message (RELEASE) corresponding to a call release message, and a status message corresponding to other messages. And STATUS ENQUIRY.

TABLE 6a

Information on the connection grant message of narrowband ISDN

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 Notification indicator (NI) Bidirectional Selection 5

In Table 6a, the Protocol Delimiter (PD), Call Reference (CR), Message Type (MT) and Message Length (ML) indicate the information to be included as Mandatory, and the Notification India (NI) is optional. Indicates information to be included.

TABLE 6b

Information on Release Messages for Narrowband ISDN

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 Cause Bidirectional necessary 6 to 34 Notification indicator (NI) Bidirectional Selection 5 Progress indicator (PI) Bidirectional Selection 4 to 6

In Table 6b, Protocol Descriptor (PD), Call Reference (CR), Message Type (MT), Message Length (ML) and Cause (Cause) indicate the information that must be included as Mandatory. Notification Indicator (PI) and Progress Indicator (PI) indicate information included as optional.

TABLE 6c

Information about status messages for narrowband ISDN

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 Call state (CS) Bidirectional necessary 5 Cause Bidirectional necessary 6 to 34

In Table 6c, protocol identifier (PD), call reference (CR), message type (MT), message length (ML), call state (CS) and cause are included as mandatory. Indicates information that should be

Table 6d

Information about status request messages for narrowband ISDN

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

In Table 6d, the protocol identifier (PD), call reference (CR), message type (MT) and message length (ML) indicate information to be included as mandatory.

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.

TABLE 7

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

Further, 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 IE element instruction fields.

Herein, the coding standard (CS) is classified into four according to bits 7 and 6 of the second octet, and in case of "00b", an ITU-T standard, and in case of "01b", an ISO / IEC standard, " 10b "indicates the national standard, and“ 11b ”indicates 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 Res.:Reserved bit and is used to indicate a "pass along request".

In addition, bits 3 to 1 in 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" for information element message abandonment, processing and report status (Discard, Proceed and Report Status), "101b" for Discard and Ignore, "110b" for message abandonment and status report (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 for an access approval message of a narrowband ISDN received among call processing related messages according to the present invention.

Referring to FIG. 8, in the method of the present invention, in the first step S1, after initializing to confirm an error of a message of a narrowband ISDN, the received narrowband ISDN message is secured (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, an error is confirmed by detecting a bit value corresponding to a message type (MT).

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, the length information L is obtained by using the sum of the number N of information elements (IE) and the length of each information element (IE Length), and then the message length ML is determined. The error is checked by determining whether the information corresponds to the length information (L).

In the ninth step S9, the final number ErrNum of the errors for the narrowband ISDN message identified in each of the steps S1 to S8 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, the memory area is set to "0". (m [·]) in the form of an array to store the received narrowband ISDN message, and the reserved memory area m [·] is the 0th memory area from the first octet to the nth octet, respectively. To n-th memory regions m [0], m [1], ..., m [n].

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, if it does not correspond to Q.2931, "1" is added to the variable ErrNum value set in the first step S1, and then the value is set to 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". Next, 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]) and the bit value of " 10000000b " and the flag bit detected in step 4-1 (S4-1) corresponds to " 0b " in step 4-2 (S4-2). After adding "1" to the variable ErrNum value set in the third step S3, the value is set to the new variable ErrNum value.

In the fifth step S5, the bit value of the second memory area m [2] except the flag bit is shifted 8 bits to the left to perform a logical sum 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 "00001111b", that is, corresponds to a narrowband ISDN access authorization message (see Table 5). Otherwise, "1" is added to the variable value ErrNum set in the fourth step S4, and the value is set to the new variable value ErrNum.

In the seventh step S7-1 of the seventh step S7, the seventh memory area m [7] is used to detect the message length bit value ML corresponding to the connection grant message of the narrowband ISDN. The value obtained by shifting the bit value 8 by 8 bits to the left and the bit value of the eighth memory area m [8] are ORed together. In step 7-2 (S7-2), the step 7-1 (S7-1) is performed. If the bit value corresponding to the detected message length (ML) is larger than "5", "1" is added to the variable ErrNum value set in the sixth step S6, and then the value is set to the new variable ErrNum value. do. In the eighth step S8, in step 8-1, the number of information elements IE is set to a variable N. In the eighth step S8-2, the length of each information element is set. Set the sum to the variable S value, in step 8-3 (S8-3) multiply the value of the variable N set in step 8-1 (S8-1) by "4", and then The variable S set in step 8-2 (S8-2) is added and the result value is set to the variable L value. In step 8-4 (S8-4), the message detected in step 7 (S7) If the length ML does not correspond to the variable L value set in the eighth step S8-3, "1" is added to the variable ErrNum value set in the seventh step S7, and then the value is added. Set to the new variable ErrNum.

FIG. 9 is a partial flowchart illustrating a method for checking an error of a release message of a narrowband ISDN received in a call processing related message according to the present invention, and shows only the sixth step S6 and the seventh step S7. The first to fifth steps S1 to S5 and the eighth to ninth steps S8 to S9 not shown in FIG. 9 are as shown in FIG. 8. Therefore, only the sixth step S6 and the seventh step S7 illustrated in FIG. 9 will be described in detail.

Referring to FIG. 9, in the sixth step S6-1 of the sixth step S6, a bit value of the fifth memory area m [5] corresponding to the message type MT is detected. In step 6-2 (S6-2), if the bit value of the message type detected in step 6-1 (S6-1) does not correspond to “01001101b,” that is, a release message of narrowband ISDN (Table 5 If it does not correspond to the reference value), "1" is added to the variable value ErrNum set in the fourth step (S4: see FIG. 8), and the value is set to the new variable value ErrNum.

In the seventh step S7-1 of the seventh step S7, the bits of the seventh memory area m [7] are detected to detect the message length bit value ML for the release message of the narrowband ISDN. The value obtained by shifting the value 8 bits to the left and the bit value of the eighth memory area m [8] are ORed together. If the bit value corresponding to the length (ML) of the message is larger than "45" or smaller than "6", "1" is added to the variable ErrNum value set in the sixth step S6, and then the value is added. Set to the new variable ErrNum.

FIG. 10 is a partial flowchart illustrating a method for identifying an error of a status message of a narrowband ISDN received among call processing related messages according to the present invention, and shows only the sixth step S6 and the seventh step S7. The first to fifth steps S1 to S5 and the eighth to ninth steps S8 to S9 not shown in FIG. 10 are as shown in FIG. 8. Therefore, only the sixth step S6 and the seventh step S7 illustrated in FIG. 10 will be described in detail.

Referring to FIG. 10, in the sixth step 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. In step 6-2 (S6-2), if the bit value of the message type detected in step 6-1 (S6-1) does not correspond to “01111101b,” that is, a status message of narrowband ISDN (Table 5 If it does not correspond to the reference value), "1" is added to the variable value ErrNum set in the fourth step (S4: see FIG. 8), and the value is set to the new variable value ErrNum.

In the seventh step S7-1 of the seventh step S7, the bits of the seventh memory area m [7] are detected in order to detect the message length bit value ML for the status message of the narrowband ISDN. The value obtained by shifting the value 8 bits to the left and the bit value of the eighth memory area m [8] are ORed together. In step 7-2 (S7-2), the detection is performed in step 7-1 (S7-1). If the bit value corresponding to the length (ML) of the message is larger than "39" or smaller than "11", "1" is added to the variable ErrNum value set in the sixth step S6, and the value is added. Set to the new variable ErrNum.

FIG. 11 is a partial flowchart illustrating a method for checking an error of a status request message of a narrowband ISDN received among call processing related messages according to the present invention, and shows only the sixth step S6 and the seventh step S7. . The first to fifth steps S1 to S5 and the eighth to ninth steps S8 to S9 not shown in FIG. 11 are as shown in FIG. Therefore, only the sixth step S6 and the seventh step S7 illustrated in FIG. 11 will be described in detail.

Referring to FIG. 11, in the sixth step S6-1 of the sixth step S6, a bit value of the fifth memory area m [5] corresponding to the message type MT is detected. In step 6-2, when the bit value of the message type detected in step 6-1 (S6-1) does not correspond to "01110101b", that is, a status request message of narrowband ISDN (Table 5), "1" is added to the variable value ErrNum set in the fourth step (S4: see FIG. 8), and the value is set to the new variable value ErrNum.

In the seventh step S7-1 of the seventh step S7, the seventh memory area m [7] of the seventh memory area m [7] is used to detect the message length bit value ML for the status request message of the narrowband ISDN. The value obtained by shifting the bit value left by eight bits and the bit value of the eighth memory area m [8] are ORed together. In step 7-2 (S7-2), in step 7-1 (S7-1), If the bit value corresponding to the detected length of the message ML is not "0", "1" is added to the variable ErrNum value set in the sixth step S6, and then the value is set to the new variable ErrNum value. do.

As described above, according to the present invention, it is possible to smoothly control call and connection in B-ISDN by checking error of received message according to Q.2931 protocol specification in ATM User Network Interface (UNI). You can do it.

Claims (5)

A method for checking an error in a message of a user network interface to communicate by ATM from one terminal connected to an ATM network to another terminal connected to the network, the method comprising: checking an error for a message of a narrowband ISDN A first step (S1) of storing the received narrowband ISDN message in the reserved memory area after initializing the received data; 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 of detecting an error by detecting a bit value corresponding to the message type (S6); A seventh step S7 of detecting a bit value corresponding to the message length to confirm an error; An eighth step (S8) of determining the error by determining whether the message length corresponds to the length information after obtaining the length information by using the sum of the number of information elements and the length of each information element; Message for call and access control in a broadband integrated information network comprising a ninth step (S9) for outputting the final number of errors for the messages of the narrowband ISDN identified in each step (S1 to S8). How to check for errors. 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 "0"; And And a first step (S1-2) of storing the received narrowband ISDN message in the reserved 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 If the bit value detected in step 2-1 (S2-1) does not correspond to "00001000b" or "00001001b," "1" is added to the variable ErrNum value set in step 1 (S1). And a second step (S2-2) of setting the value to a new variable 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 If the bit value detected in step 3-1 (S3-1) does not correspond to "00000011b," "1" is added to the variable value ErrNum set in step 2 (S2), and the value is added to the new value. A method for checking an error of a message for call and access control in a broadband integrated information network, comprising a third step (S3-2) of setting a variable ErrNum value. 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; And If the flag bit detected in step 4-1 (S4-1) corresponds to "0b", "1" is added to the variable ErrNum value set in step 3 (S3), and the value is added to the new variable. A method for checking an error of a message for call and access control in a broadband integrated information network, comprising the step 4-2 of setting ErrNum.

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