KR0158917B1 - Call and connection method at atm uni - Google Patents

Abstract

The present invention provides a method for identifying a caller's subaddress information by storing a message received through a signal adaptation layer from an ATM network in a memory and using a counter to find a calling party subaddress information element stored in the message. A first step of obtaining length information Ls of the received message; Obtaining a calling party subaddress information element compared with 109 ₁₀ by increasing the count value of the counter; A third step of detecting an error by comparing whether the counter value exceeds the message length; And a fourth step of reading a subaddress type from the calling party subaddress information element and reading and outputting a predetermined caller subaddress if it is zero.

Description

Call and connection control method in ATM user network interface

1 is a conceptual diagram illustrating an ATM protocol reference model to which the present invention is applied.

2 is a diagram illustrating a mapping structure of an ATM PDU to which the present invention is applied.

FIG. 3 is a structural diagram showing the format of an ATM cell shown in FIG. 2. FIG.

4 is a diagram illustrating an example of a flow of call processing related messages in an ATM user interface (UNI).

5 illustrates the general format of call processing related messages in an ATM UNI.

FIG. 6 shows a general format of information elements included in a message such as FIG.

7 is a block diagram schematically illustrating a hardware configuration in which the present invention is performed.

8 is a structural diagram showing the format of a sender sub-address information element to which the present invention is applied.

9 is a flowchart illustrating a method of identifying a sender's subaddress from a received message in accordance with the present invention.

* Explanation of symbols for the main parts of the drawings

10: ATM unit 20: AAL5 receiver

30: microcomputer 40: memory

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling call and connection in a user transfer network (ATM) in asynchronous transfer mode (ATM) mode. In particular, a message processing related message received from an opposite party The present invention relates to a method of controlling signals and access by reading and processing desired messages by analyzing signaling messages.

With the rapid development of information society, B-ISDN emerged as the next generation communication network due to the increase of user's communication service demand. In B-ISDN, asynchronous delivery is possible to accommodate various services of broadband as well as narrow band regardless of band and speed. The mode of ATM is the basic means of delivery. For signal processing in ATM, a draft scheme such as Signaling AAL and Q.2931, B-ISUP, etc. 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 about 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 100Mbps or more, and can process various information sources such as voice, data, document and video by using ATM technology.

In the conventional N-ISDN, a signaling method for realizing access control uses a Digital Subscriber Signaling System 1 (DSS1) in the subscriber line section and a №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), recommended by ITU-T specifications Q.921 and Q.931. In ISDN, Q.93B has been proposed into the draft, which adds the function of asynchronous transfer mode (ATM) to Q.931 as the signaling procedure of the user network interface (UNI). As a signaling procedure for the network-node interface (NNI), B-ISUP (ISDN User Part) has been proposed in the draft.

On the other hand, apart from the standardization of B-ISDN 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 accelerate the standardization process by establishing standards that can be implemented in a short period of time.

The present invention implements the Q.93B protocol for call and access control in an ATM network according to the ATM User-Network Interface Specication announced by the ATM Forum as described above, and receives a message from an ATM network. Then, the object of the present invention is to provide a method for identifying the sender's subaddress from the sender subaddress information element.

In order to achieve the above object, a sender subaddress identification method of the present invention includes a message of a predefined format including a protocol identifier field, a call number value field, a message type field, a message length field, and an information element identifier field. Communication method between a user and an asynchronous delivery mode (ATM) network according to a predetermined protocol to create a connection between a user and an asynchronous delivery mode (ATM) network. A first step of storing message data of a predetermined format received through the signal adaptation layer SAAL5 in a memory; A second step of reading data of a message length field from the memory to obtain a length information (Ls) value of a received message; A third step of obtaining a calling party subaddress information element by reading data of an information element identifier field from the memory and comparing the data of the information element identifier field with a predetermined caller subaddress information element identifier value (109 ₁₀ ); A fourth step of detecting a length error by comparing a total length in octets of the received message with a counter and a length information value of the message obtained in the second step; And reading the subaddress time value from the calling party subaddress information element obtained in the third step, and reading and outputting the subaddress of the sender if the value is 000 representing the network subaddress procedure (NSAP). It is characterized by having five steps.

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

1 is a conceptual diagram illustrating an ATM protocol reference model to which the present invention is applied, and the reference model is composed of a management plane, a control plane, and a user plane, and the management plane is again hierarchical. It is divided into management and plan management. Here, the plan management refers to the overall management of the system, and the hierarchical management refers to management of resources and usage variables and OAM information management.

In addition, the control plane manages call control and access control information, and the user plane manages the transfer of user information. Protocols of control plane and user plane are divided into upper layer, ATM adaptation layer, ATM layer, and physical layer. The functions of each layer are shown in Table 1 below.

As shown in Table 1, the ATM method is divided into vertical structures such as a physical layer, an ATM layer, an ATM adaptation layer (AAL), and a higher protocol layer. The AAL layer is divided into a segmentation and a recombination sublayer (SAR). And Reassembly sublayer (CS) and Convergence Sublayer (CS) sublayer is divided again, the physical layer is divided into physical media (PM) and Transmission Convergence (TC) sublayer.

In addition, Layer 3 of the control plane is implemented as Q.93B to control calls and connections between ATM networks and users. Q.93B is Q.931, ISDN's Layer 3 protocol. Is a Call-Bearer Control Protocol (B-ISDN User-network Interface Layer 3 Specification for Basic Call / Bearer Control) used in the User-Network Interface (UNI) for B-ISDN.

2 is a diagram illustrating a mapping structure of a protocol data unit (PDU) in an ATM scheme to which the present invention is applied, in which a Q.93B message in layer 3 passes through SSCF, SSCOP, and CPCS of a signaling adaptation layer (Signalling AAL 5). It is segmented by 48 bytes (hereinafter also referred to as octets) to show that it is mapped to multiple 53-byte ATM cells after a 5-byte header is added to the ATM layer.

FIG. 3 is a diagram illustrating the format of an ATM cell shown in FIG. 2. The ATM cell is divided into a 5-byte header and a 48-byte payload. The 5-byte header used in the User Interface Interface (UNI) consists of a 4-bit Generic Flow Control (GFC) and a 4-bit Virtual Path Identifier (VPI). Two bytes consist of a 4-bit Virtual Path Identifier (VPI) and a 4-bit Virtual Channel Identifier (VCI). The third byte consists of an 8-bit Virtual Channel Identifier (VCI). Consists of a 4-bit Virtual Channel Identifier (VCI), 3-bit Payload Type (PT) and 1-bit Cell Loss Priority (CLP), with the fifth byte being an 8-bit header error. Control (Header Error Control).

4 is a diagram illustrating an example of a call processing related message flow in an ATM user network interface (UNI), a call processing process between a calling user, a network, and a called user. Indicates.

First, a virtual channel connection (VCC) is always formed through a signaling adaptation layer (Signalling ALL) for call and connection control. As call / access control messages move through these virtual channels to control the connection for payload transfer, the messages used for call / access control are as shown in Table 2 below. As shown in Table 3, it is divided into a message used for Global Call Reference and a message used for ATM multipoint call / access control as shown in Table 4 below.

In FIG. 4, the call / access control process shows that the originator generates a SETUP message to set up a call, delivers it to the network, starts the timer T303, and enters a 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 rate, broadband bearer capability, quality of service parameters, etc.) have. If there is no response for the time set by the timer T303, the setup message is retransmitted, and if there is no response even after repeating the predetermined number of times, call processing is stopped.

After receiving the setup message, the network selects and assigns a valid connection identifier (VPCI / VCI) and then sends a setup message back to the called party.

After receiving the setup message, the called party generates a CALL PROCEEDING or CONNECT message and sends it to the network if it wants to accept the connection. If not, the receiver sends a RELEASE COMPLETE message. In this case, the call procedure message is delivered to the network when the call procedure message cannot be reached until the expiration time of timer T303 after receiving the setup message.The network stops the timer T303 when the call procedure message is received. When the called party transmits a Connect message, it starts timer T313 and enters the Connect Request state.

When the network receives the Connect message, it stops the timer T303 or T310, delivers the Connect Acknowledgment message to the called party, and then delivers the Connect message to the caller and becomes active.

When the called party receives the Connect Acknowledgment message, it stops the timer T313 and becomes active. When the called party receives the Connect Acknowledgment message, the called party transmits the Connect Acknowledgment message and becomes active.

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

On the other hand, the user (receiver or sender) who wants to disconnect after completing the data transmission or during transmission, generates a RELEASE message and starts the timer T308 to request the network to release the connection and then release the request ( When the release message is received, the network releases the virtual channel connection when the release message is received, notifies the other party, sends the release completion message to the user side, and becomes null.

When the user (sender or called party) requesting the connection release receives the RELEASE COMPLETE message, the timer T308 is stopped, the virtual channel, the call number, etc. are released, and the state is null.

At this time, 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 the STATUS ENQUIRY message is STATUS. Create a message to let you know your status.

On the other hand, when adding another party to an already existing channel connection, this is requested by an ADD PARTY message, and the user's connection in an existing point to multipoint connection. If you release it, send a DROP PARTY message.

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

As shown in FIG. 5, the first byte is a Protocol Discriminator, which is 1001 in the ATM UNI, bits 5 through 8 of the second byte are 0, and bits 1 through 4 are call reference. Indicates the length in bytes and is usually 11. The third to fifth bytes indicate the call number, in particular, bit 8 of the third byte indicates a message sent from the sender side as 0 as a flag and a message sent to the caller side as 1 if it is 1 Indicates. The sixth and seventh bytes indicate a message type and a message is allocated according to the sixth byte value as shown in Table 5 below.

In addition, the eighth and ninth bytes represent the message length, up to 64K (2 It may have a length of) bytes, and from the tenth byte is followed by an information element of variable length.

6 is a diagram showing a general format of information elements included in an ATM UNI message, where 1, ..., 8 at the top represent bits, and 1, 2, .5, etc at the right side represent bytes (octets). Indicates.

In FIG. 6, the first byte is an information element identifier, and information elements are classified according to the value shown in Table 6 below.

In the second byte, bit 8 is 1, bits 6 and 7 are coding standards, and bits 1 to 5 are IE instruction fields. The third byte and the fourth byte indicate a length of information element, and the content of the information element follows the fifth byte.

7 is a block diagram schematically showing a hardware configuration in which the present invention is performed, wherein the hardware processes an error by processing the cells received from the ATM unit 10 and the ATM unit 10 receiving the ATM cells from the ATM network. And the AAL 5 receiver 20 for restoring the message by assembling and storing the assembled message from the AAL 5 receiver 20 in the memory 40 and reading the necessary information by applying the method of the present invention to the microcomputer 30. Is done.

8 is a diagram illustrating a format of a calling party subaddress information element to which the present invention is applied, and the calling party subaddress information element has information for identifying a caller subaddress.

In FIG. 8, the first octet is 1101101, indicating that it is a calling party subaddress information element, as shown in Table 6 above, and the odd / even number of subaddress types (bits 5, 6, and 7) in the fifth octet. There is an indicator (bit 4) followed by the sender's subaddress after the sixth octet.

9 is a flowchart illustrating a method of identifying a sender's subaddress information from a calling party subaddress information element of a received message according to the present invention.

In FIG. 9, in step 100, a SETUP or ADD PARTY message is received from the ATM network by the hardware as shown in FIG. 7 and stored in memory, and then the eighth octet data (m) is stored in the temporary variable a. After storing [7]), it shifts to the left eight times and adds the result to the ninth octet data m [8] to obtain the message length Ls. In this case, the messages stored in the memory are sequentially indicated by m [0], m [1], m [2], ... from the first octet data, and the eighth and ninth octets are shown in FIG. As described above, the length Ls information of the message is contained (100 to 110).

Subsequently, after loading 9 into the counter and increasing by 1, it is determined whether the octet data indicated by the counter is 109, and the calling party subaddress information element is found. At this time, an error is detected by determining whether the counter value is greater than the length Ls + 9 plus 9 of the message obtained in step 110 (120 to 150). That is, since the caller's subaddress to be obtained in the present invention is in the calling party subaddress information element, the calling party subaddress information element is first found.

The current counter then points to the Information Element Identifier (IEI), which is the first octet of the calling party subaddress. Therefore, the current counter value is incremented by two to increase the octet data indicated by the counter. Store the temporary variable a, shift it left 8 times, and then add the temporary variable a to the octet data indicated by the counter with the count value increased by one.The length of the calling party subaddress information element (La) Obtain (160). That is, since the length La of the calling party subaddress information element is located two octets behind the information element identifier (IEI) as shown in FIG. 6, the counter value is increased by two to increase the first byte of the information length. After reading, the counter is incremented by one to read the second byte of the information length.

Subsequently, 1110000 is stored in the temporary variable b, the counter value is increased by 1, the data of the fifth octet indicated by the counter is read, and the end operation is performed with the temporary variable b to obtain the sub-address type. Store (170, 180). At this time, if the sub address type is 0, this indicates a network sub addressing procedure (NSAP).

Subsequently, if the value of the temporary variable a is 0 compared to 0, the temporary variable i is initialized to 0, and the octet data indicated by the counter is stored in the variable S [i] while increasing the counter value and the i variable by 1, If the counter value is equal to the length of the information element, the sub address and i value stored in the variable S [i] are output (190 to 260).

As described above, by analyzing the message received from the ATM network according to the present invention, it is possible to efficiently execute call and connection control according to the Q.93B protocol at the ATM user network interface by reading call and connection control related information. In particular, caller subaddresses can be easily obtained.

Claims (1)

Messages in a predefined format, including protocol identifier fields, call number fields, message type fields, message length fields, and information element identifier fields, are communicated between the user and the asynchronous delivery mode (ATM) network according to a predetermined protocol. In a call and connection control method of an asynchronous transmission mode user network interface (UNI) for creating a connection between a user and an ATM network, the message data of a predetermined format received through the signal adaptation layer SAAL5 is stored in the memory. Storing in the first step; A second step of reading data of a message length field from the memory to obtain a length information (Ls) value of a received message; A third step of obtaining a calling party subaddress information element by reading data of an information element identifier field from the memory and comparing the data of the information element identifier field with a predetermined caller subaddress information element identifier value (109 ₁₀ ); A fourth step of detecting a length error by comparing a total length in octets of the received message with a counter and a length information value of the message obtained in the second step; And reading the subaddress time value from the calling party subaddress information element obtained in the third step, and reading and outputting the subaddress of the sender if the value is 000 representing the network subaddress procedure (NSAP). Caller sub-address identification method in the ATM user network interface characterized in that it comprises five steps.