KR0133793B1 - Method of controlling call and connection in uni of atm system - Google Patents

Abstract

The present invention stores a setup message received through a signal adaptation layer from an ATM network in a memory, and uses a counter to find a BLLI information element stored in the setup message to identify Q.933 use. A first step of obtaining the length information (Ls) of the setup message, the second step of obtaining a BLLI information element compared to 95 ₁₀ while increasing the count value of the counter: The counter value exceeds the message length A third step of detecting an error by comparing the information, and the fourth step of reading user information layer 2 protocol (UIL2) data from the BLLI information element; and the user information layer 2 protocol (UIL2) data read in the fourth step. Is 6, 7, 8, 9, 10, 11, 14, or 17 ₁₀ , the fifth step of reading bit 2, bit 1 of the next octet: and the bit 2 and bit 1 read in the fifth step are 0, If it is 0 _2, Q.933 is not used. In addition, a sixth step of outputting the usage information (Q.933 USE) to Q.933 to determine that Q.933 is used is not 0,0 ₂ .

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;

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

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

5 is a diagram illustrating a general format of call processing related messages in an ATM UNI;

6 shows a general format of information elements included in a message such as FIG. 5;

7 is a block diagram schematically showing a hardware configuration in which the present invention is performed;

8 is a structural diagram showing a format of a BLLI information element to which the present invention is applied;

9 is a flow chart illustrating a method of identifying Q.933 usage from a setup message received in accordance with the present invention.

* Description of the 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) user interface, and in particular, a message processing related message received from an opposite party. The present invention relates to a method of controlling signals and connections by analyzing signaling messages to read and process desired information.

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 a wide range of services regardless of band and speed. The mode of ATM mode is the basic means of delivery, and the signal adaptation layer (Signalling AAL) and draft schemes such as Q.2931 and B-ISUP have been proposed for ATM signal processing.

That is, in the conventional ISDN (also referred to as narrowband (N) -ISDN), it is difficult to satisfy a broadband service such as a moving picture because the transmission rate of the user's information channel was about 64 Kbps to 2 Mbps. On the other hand, B-ISDN can transfer data at high speed of 100MBPS or more, and it can process various information sources such as voice, data, document, and video by using ATM technology.

In the conventional N-ISDN, the signaling method for realizing access control uses Digital Subscriber Signaling System 1 (DSSI) in the subscriber line section and the NO.7 common line signaling method in the inter-station relay section. DSSI implements the protocols of Layer 2 and Layer 3 on the D-channel, also called Link Procedure on the D-channel (LAPD), and is recommended by ITU-T's standards Q.921 and Q.931. In the ongoing B-ISDN, Q.93B has been proposed into the draft by adding an asynchronous transfer mode (ATM) functional element to Q.931 as a signaling procedure for the user network interface (UNI). As a signaling procedure, B-ISUP (ISDN User Part) was 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 (ATM Fourm) 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 is to implement the Q.93B protocol for call and access control in the ATM network according to the ATM User-Network Interface Specication announced by the ATM Forum as described above. Its purpose is to provide a way to identify the user Q.933 usage (USE) after receiving a SETUP message.

Q.933 use (ID) identification method of the present invention for achieving the above object, the setup message received from the ATM network through the signal adaptation layer stored in the memory (SETUP) message after the setup message using a counter A method for identifying Q.933 usage by finding a BLLI information element stored in the method, the first step of obtaining length information Ls of the setup message: comparing the counter with 95 ₁₀ while increasing the count value of the counter A second step of obtaining a BBLI information element: a third step of detecting an error by comparing whether the counter value exceeds the message length: a fourth step of reading user information layer 2 protocol (UIL2) data from the BLLI information element And a fifth step of reading bit 2 and bit 1 of the next octet when the user information layer 2 protocol (UIL2) data read in the fourth step is 6, 7, 9, 10, 14, or 17 ₁₀ : 5th step Document read on bit 2 and bit 1 of the output using the Q.933 information (Q.933 USE) to determine that the _second surface is used for 0,0 to ₂ am 0,0 did not use the Q.933 Q.933 Characterized in that the sixth step.

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 is composed of a management plane, a control plane, and a user plane, and the management plane is again hierarchical management and plane It is divided into 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. The protocols of control plane and user plane are divided into upper layer, ATM adaptation layer, ATM layer, and physical layer.

[Table 1] Function of each layer in protocol standard model

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, and the AAL layer is divided and recombined sublayer ( It is divided into Segmentation And Ressembly sublayer (SAR) and Convergence Sublayer (CS) sublayer, and the physical layer is further 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. The B-ISDN User-network Interface Layer 3 Specification for Basic call / bearer control is used to extend the B-ISDN User Network Interface (UNI).

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 48 bytes through SSCF, SSCOP, CPCS of a signaling adaptation layer (Signalling AAL 5). Segmented by length, a five-byte header is added to the ATM layer and mapped to a number of 53-byte ATM cells.

3 is a diagram showing the format of an ATM cell shown in FIG. 2, which is divided into a 5-byte header and a 48-byte payload, and is used in a user network interface (UNI). The header structure of the first byte is composed of 4 bits of Generic Flow Control (GFC) and 4 bits of Virtual Path Identifier (VPI), and the second byte of 4 bits of Virtual Path Identifier (VPI). VPI) and 4-bit Virtual Channel Identifier (VCI), the third byte consists of 8-bit virtual channel identifier (VCI), and the fourth byte is 4-bit virtual channel identifier (VCI). And 3-bit Payload Type (PT) and 1-bit Cell Loss Priority (CLP)

The fifth byte consists of 8 bits of header error control (HEC).

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

First, a virtual channel connection (VCC) is always formed through a signaling AAL for call and access control, and pay / load transfer messages are transferred as call / access control messages flow through these virtual channels. The message used for call / access control is the message for ATM CALL / access control as shown in the following [Table 2], and the global call reference as shown in the following [Table 3]. ) Message and message used for ATM multipoint call / connection control as shown in [Table 4].

[Table 2] Messages Used for ATM Call and Access Control

[Table 3] Message used for global call number

Table 4. Messages Used for ATM Multipoint Call and Connection Control

Referring to FIG. 4, in the call / access control process, the caller generates a SETUP message to set up the call, delivers it to the network, starts the timer T303, and the call initated state is set. do.

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.). Doing. 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, the call processing is stopped.

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

After receiving the setup message, the called party creates a CALL PROCEEDING or CONNENT message and sends it to the network if the user wants to allow the connection. If not, the receiver sends a RELEASE COMPLETE message. do. In this case, when the call procedure message cannot be reached until the expiration time of timer T303, the called party delivers to the network.When the network receives the call procedure message, the called party stops the timer T303, starts the timer T310, and becomes Incoming Call Proceeding. When the called party sends a connect message, it starts timer T313 and enters a connect request state.

Upon receiving the Connect message, the network stops the timer T303 or T310, forwards the Connect Acknowledgment message to the called party, and then delivers the Connect message to the caller and becomes active.

The called party stops timer T313 when the connect acknowledgment message is received and becomes active. When the called party receives the connect 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 data transmission is finished or in transit, generates a RELEASE message and starts the timer T308 to request the network to disconnect 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 a release completion message to the user, 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 status is null.

At this time, the user or the network can generate a status request message at any time to request information on the status of the network or another user, and the user or network that receives the status request message is the 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 is required. If you release it, a DROP PARTY message is sent.

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, ... at the right side. .., 9etc represents a byte (octet).

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

Table 5 Message Coding

In addition, the eighth and ninth bytes may indicate a message length and may have a maximum length of 64K (2 ¹⁶ ) bytes, followed by a variable length information element from the tenth byte.

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

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

[Table 6] Information identifier coding

In addition, 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, followed by the contents of the information element after the fifth byte.

FIG. 7 is a block diagram schematically showing a hardware configuration in which the present invention is performed. An ATM unit 10 receiving an ATM cell from an ATM network and cells received from the ATM unit 10 process errors and assemble an error. AAL5 receiver 20 for restoring messages, and a microcomputer 30 for storing the assembled message from AAL5 receiver 20 in memory 40 and reading out necessary information by applying the method of the present invention.

FIG. 8 is a diagram illustrating a format of a BLLI information element to which the present invention is applied, and BLLI (Broadband Low Layer Information) has information of a lower layer for checking compatibility with a higher entity accessed by an originator's address. .

In FIG. 8, the first octet is 1011111, indicating that it is a BLLI information element as shown in [Table 6] above. In the fifth octet, bit 7 and bit 6 are 1 to indicate the first layer, and users of bits 5 to 1 are shown. The protocol of information layer 1 is recorded, bit 7 and bit 6 are 10 in the sixth octet to indicate the second layer, and the protocol of user information layer 2 is recorded in bits 5 to bit 1. Also, the 6a and 6b octets are added when indicating the HDLC mode to which the protocol of the user information layer 2 of the 6th octet is applied. Bits 6 and 6 of the octet are extensions, and bits 7 and 6 are modes. Bits 5, 4, and 3 are 0, bits 2 and 1 represent the use of Q.933, bit 8 of the 6b octet represents the extension and bits 7 to 1 represent the window size. In addition, when the user information layer 2 of the sixth octet is a user specific layer 2 protocol

Denotes a sixth a * octet representing user specific layer 2 protocol information following the sixth octet. Bit 8 of the seventh octet represents the extension, bits 7 and 6 represent the ID of the third layer as 11, and bits 5 through 1 represent the user information layer 3 protocol. Layer 3 protocols of the 7a, 7b, and 7c octets are added when the protocol is based on X.25, ISO / IEC 8208, or X.223 / ISO 8878 to add bit 7, bit 6 of the 7a octet to the mode. Bits 4 through 1 of the 7b octet indicate the default packet size, and bits 7 through 1 of the 7c octet indicate the packet window size.

In addition, if the seventh octet indicates a user specific layer 3 protocol, a seventh * octet indicating the user specific layer 3 protocol information is added after the seventh octet.

In addition, when the seventh octet indicates ISO / IEC TR 9577, bits 7a ** and 7b ** octets are added. Bits 7 through 1 of the 7a ** octet correspond to ISO / IEC TR 9577 IPI (8−8). 2 bits), and bit 7 of the 7b ** octet indicates IPI (1 bit).

The eighth, 8.1, 8.2, 8.3, 8.4 and 8.5 octets are used when the seventh octet represents ISO / IEC TR 9577, and the seventh a ** and sevenb ** octets represent IEEE 802.1 SNAP. Bits 7 and 6 are SNAP IDs, 8.1 octets are OUI octets 1, 8.2 octets are OUI octets 3, 8.3 octaves are OUI octets 3, 8 octets are PID octets 1 and 8.5 octets are PID octets 2.

9 is a flowchart illustrating a method of identifying Q.933 usage (USE) from BLLI information elements of a received setup message in accordance with the present invention.

In FIG. 9, in step 100, a setup message is received from an ATM network by a hardware as shown in FIG. 7 and stored in memory, and then added to the temporary variable a with the eighth octet data m8. To get the message length (Ls).

Here, the messages stored in the memory are sequentially indicated by m0, m !, m2, ... from the first octet data, and the length (Ls) of the message is shown in the eighth and ninth octets as shown in FIG. Information is available. (100 ~ 110)

Subsequently, after loading 9 into the counter and incrementing by 1, it is determined whether the octet data indicated by the counter is 95 ₁₀ , and then the BLLI information element is searched. Then, the counter value is 9 in the message length obtained in step 110. An error is detected by determining whether the value is greater than the added value Ls + 9 (120 to 150). That is, since the Q.933 usage information, which is the object of the present invention, is located in the BLLI information element, the BLLI information element is first found.

Subsequently, since the current counter indicates an information element identifier (IEI), which is the first octet of BLLI, the data of the octet indicated by the counter is stored in the temporary variable a by incrementing 2 to the current count value. After shifting left eight times, the temporary variable a is added again to the octet data indicated by the counter having the count value increased by one to obtain the length Ls of the BLLI information element (160). Since Ls) is located two octets after the IIE, as shown in FIG. 6, the counter value is increased by two to read the first byte of the information length, and then the counter is increased by one to read the second byte of the information length. do.

Subsequently, 01100000₂ is stored in the temporary variable b1 and 00011111₂ in the temporary variable b2, the counter value is increased by 1, the octet data read by the counter is read, and the end operation is performed with the temporary variable b1. Find the ULI2 octet equal to ₁₀ (the sixth octet of FIG. 8), and end-mask the read data with b2. The result is 6, 7, 9, 10,

11, 14 or 17 ₁₀ is judged. (170 _~ 230)

Subsequently, if the ULI2 data is 6, 7, 9, 10, 11, 14, or 17 ₁₀ in step 230, the counter is incremented by 1, the data of the 6a octet pointed to by the counter is read, and 00000011₂ and masking are performed. After reading Q.933 (USE) data and comparing it with 0, if it is 0, it is judged that Q.933 is not used, and if it is not 0, Q.933 is used.

Outputs Q.933 use (Q.933USE) data. (240 ~ 280)

As described above, by analyzing the message received from the ATM network and reading the call and connection control related information, the call and connection control according to the Q.93B protocol can be efficiently executed in the ATM user network interface. have.

Claims (1)

In the method for storing the setup message received through the signal adaptation layer from the ATM network in the memory and using the counter to find the stored BLLI information element Q.933 use (USE), First step of obtaining the length information (Ls) of the setup message: A second step of obtaining a BLLI information element compared with 95 ₁₀ while increasing the count value of the counter: A third step of detecting an error by comparing whether the counter value exceeds the message length: A fourth step of reading user information layer 2 protocol (UIL2) data from the BLLI information element: A fifth step of reading bit 2 and bit 1 of the next octet when the UIL2 data read in the fourth step is 6, 7, 9, 10, 11, 14, or 17 ₁₀ ; And If bit 2 and bit 1 read in step 5 are O and O ₂ , Q.933 is not used. If O and O ₂ are not used, Q.933 usage information (Q.933) is determined. And a sixth step of outputting the USE).