KR0133795B1 - 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 finds a BLLI information element stored in the setup message using a counter. information layer 3 protocol), comprising: a first step of obtaining length information (Ls) of the setup message: a second step of obtaining a BLLI information element in comparison with 95 ₁₀ while increasing a count value of the counter A third step of detecting an error by comparing whether the counter value exceeds the message length is to increase the counter and recall User Information Layer 3 protocol (UIL3) data in which bits 7 and 8 are 11. The fourth step of reading from the BLLI information element; and the next octet if the user information layer 3 protocol data read in the fourth step is 6, 7, or 8 _10. The fifth step of reading the bit 7 to bit 6 of the mode; and if the bit 7 to bit 6 read in the fifth step is 0, 1 ₂ is the normal mode, if not 0, 1 ₂ mode (mode 3 And a sixth step of outputting the value.

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 flowchart illustrating a mode 3 identification method of a user information layer 3 protocol from a setup message received according to the present invention.

＊ Explanation of symbols for main parts of drawing

10: ATM, 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-network interface (UNI) in an asynchronous transfer mode (ATM) system. The present invention relates to a method of controlling signals and connections by reading and processing signaling messages to analyze and read 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 mode can accommodate a wide range of services regardless of band and speed. The ATM method is the basic means of delivery, and the signaling adaptation layer (Signalling AAL), and the draft schemes such as Q.2931 and B-ISUP have been proposed for the ATM 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 functional elements of asynchronous transfer mode (ATM) to Q.931 as a signaling procedure of 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.), ATM UNI Specification V3.0 (93.9), 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 published by the ARM Forum as described above, The purpose of the present invention is to provide a method of identifying a Mode 3 (Mode 3: Mode of User Information Layer 2 Protocol) after receiving a SETUP message.

In order to achieve the above object, the user information layer 3 protocol information (USL31) identification method of the present invention comprises storing a SETUP message received from a ATM network through a signal adaptation layer in a memory. A method for identifying a mode of a user information layer 3 protocol (Mode3) by finding a BLLI information element stored in the cell-up message by using a counter,

First step of obtaining the length information (Ls) of the setup message:

A second step of obtaining a BBLI information element compared with 95 ₁₀ while increasing the counter value;

A third step of detecting an error by comparing whether the counter value exceeds the message length:

A fourth step of reading a User Information Layer 3 Protocol (UIL3) data of bit 7 and bit 8 from the Blli information element by incrementing a counter:

A fifth step of reading bits 7 to 6 of the next octet if the user information layer 3 protocol data read in the fourth step is 6, 7, or 8 ₁₀ ; and

In the fifth step to read on the bit 7 and the normal mode, the bit 6 is 0, 1, _2, 0, characterized in that the ₁₂ or a sixth step of outputting a mode (mode3) value in order to determine the expansion mode do.

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. The functions of each layer are shown in Table 1 below.

Table 1

Functions of Each Layer in the Protocol Criteria 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 (SAR). Segmentation And Ressembly sublayer (CS) and Convergence Sublayer (CS) sublayer is divided again, and 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. This is a call / bearer control protocol (B-ISDNUser-networkInterfaceLayer3Specification 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 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 then 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 consists of four bits of generic flow control (GFC) and four bits of virtual path identifier (VPI), and the second byte of four bits of virtual path identifier. (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). ), 3-bit Payload Type (PT) and 1-bit Cell Loss Priority (CLP), and the fifth byte is 8-bit Header Error Control (HEC). Is done.

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

First of all, a virtual channel connection (VCC) is always established through a signaling AAL for call and access control. As the message is used to control the connection, the message used for call / connection control is the message for ATM call / connection control as shown in the following table 2 and the message used for the global call reference as shown in the following table 3. And, as shown in Table 4 below, messages are used for ATM multipoint call / access control.

[Table 2]

Messages used to control ATM calls and access

Table 3

Message used for global number

Table 4

Messages Used to Control ATM Multipoint Calls and Connections

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 initiated 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 (VPCI / 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 it wants to accept the connection. If not, the receiver sends a RELEASE COMPLETE message. . In this case, when the call cannot be reached until the expiration time of the timer T303 after receiving the call procedure message, the called party delivers it to the network.The network stops the timer T303 when the call procedure message is received, 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 as a connection identifier (VPCI / VCI) is formed between the caller and the called party.

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 the network that received the status request message is STATUS. Create a message to tell you your status.

On the other hand, when adding another party to an already existing channel connection, this is requested by an ADDPARTY message, and the user's connection is terminated at an existing point to multipoint communication. When released, 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, which 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 a message is allocated according to the sixth byte value 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 according to the values as shown in Table 6 below.

Table 6

Information identifier coding

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 the length of information element, followed by the content 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, which indicates that it is a BLLI information element as shown in Table 6, bit 5 and bit 6 are 1 in the fifth octet, indicating the first layer, and bit 5 through bit 1 in the user information layer. The protocol of 1 is recorded, bit 7 and bit 6 are 10 in the sixth octet to indicate the second layer, and the protocol of the user information layer 2 is recorded in bits 5 to 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, a 6a * octet indicating user specific layer 2 protocol information appears after 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. The 7a, 7b, and 7c octets are added when the layer 3 protocol of the seventh octet is a protocol based on X.25, ISO / IEC 8208, or X.223 / ISO 8878 to add bits 7, bit of the 7a octet 6 indicates a 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.

Further, if the seventh octet indicates the user specific layer 3 protocol, it is added after the seventh * octet indicating the user specific layer 3 protocol information.

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 for identifying a mode of user information layer 3 protocol (Mode3) from a BLLI information element of a setup message received according to 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 expressed as 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. The error is detected by determining whether the value is greater than the added value (Ls + 9) (120 to 150). That is, the user information layer 3 protocol mode (Mode 3), which is the object of the present invention, is located in the BLLI information element. .

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, 1100000 ₂ is stored in the temporary variable b1 and 11111 ₂ is stored in the temporary variable b2. The counter value is increased by 1, the octet data indicated by the counter is read, and the end operation is performed with the temporary variable b1. Finds the ULI3 octet (sixth octet of FIG. 8) having 9610, and masks the read data with b2 to determine whether the result is 6, 7, or 8 _10. (170-230) The meaning of layer 3 protocol according to UIL3 data is shown in Table 7.

TABLE 7

UIL3 protocol

Subsequently, if the ULI3 data is 6, 7, or 8 ₁₀ in step 230, the counter is incremented by 1, the data of the 7a octet pointed to by the counter is read, masked with the temporary variable b1, and the mode (mode3) data is read. After reading, lower the unit by shifting 5 times to lower the unit, and if it is 1 compared with 1, it is identified as normal mode, and if it is not 1, it is identified as extended mode and the mode (Mode 3) data is read. Output

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 using network interface. have.

Claims (1)

After storing the setup message received through the signal adaptation layer from the ATM network in the memory, a counter is used to find the stored BLLI information element, and the mode of user information layer 3 (Mode3). A 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, the counter value Detecting the error by comparing the message length with the message length; increasing user counters and extracting User Information Layer 3 Protocol (UIL3) data of bits 7 and 8 from the BLLI information element. reading out the first step 4: the user information layer 3 protocol, the data read in the step 4 is 6, 7, 8 or _10, the read bit 7, bit 6 of octet following Coming fifth step: a sixth step of outputting a mode (Mode3) value if the said first read in step 5 on bit 7 and bit 60, ₁₂ is not 0, 1 ₂ in normal mode in order to determine the expansion mode Call and connection control method in the user network interface, characterized in that.