KR980013081A - How ISDN User-Network Connections Handle Primitives at Layer 3 - Google Patents

Abstract

The present invention relates to a primitive processing method at a layer 3 of an ISDN user-network connection, comprising the steps of: discriminating a received primitive and a link ID; Confirming a minor link ID; Stopping all the timers according to the determined link ID and the minor link ID; Transmitting a release indication (RELEASE_IND) primitive to the management layer; releasing a call of the corresponding call reference according to the determined link ID and the minor link ID; A step of generating a RESTART_CFM primitive and transmitting the RESTART_CFM primitive to an entire call reference control (GCR) layer, and an entity of the layer 3 making a state thereof null, The terminal is connected to a network according to a layered protocol.

Description

How ISDN User-Network Connections Handle Primitives at Layer 3

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a connection technique between a USER and a NETWORK in an Integrated Services Digital Network (ISDN), and more particularly, RTI ID = 0.0 > RESTART ~ REQUEST < / RTI > primitive.

With the advancement of the information society, communication demands are diversified, and the media in which communication networks such as voice, data, and video are handled are diversified, making it impossible to provide efficient services for individual networks that were constructed separately for each service. Therefore, ISDN which can provide comprehensive services by integrating and digitizing individual networks has emerged. In order to uniformly accommodate various terminals, ISDN (Integrated Services Digital Network) Has been standardized as Digital Subscriber Signaling System 1 (DSSI), and the interface between network and network has been standardized as No. 7 Common Line Signaling (CCS).

DSS1, which is a signaling scheme of a user-to-network interface (UNI) of the ISDN, is implemented as layers from Layer 1 to Layer 3 by OSI (Open System Interconnection Reference Model) The relationship between the outline and the recommendations of ITU-T is shown in Table 1 below.

[Table 1]

Configuration of digital subscriber line signal system

Referring to FIG. 1, a first network terminal NT1 located in a house (or a building) is connected to an ISDN exchange located in a domestic telephone, and an ISDN terminal TE1 is connected to the first network terminal NT1 through a S / Or the second network terminal NT2 is connected to the first network terminal NT1.

In this case, 'NT1' (network terminal device 1) is a transmitting / receiving device in a house for transmitting a multi-user signal to a subscriber line, and 'NT2' (network terminal device 2) is a device corresponding to a private branch exchange (PBX) 'TE1' may be directly connected to NT1 and NT2 as an ISDN standard terminal, and 'TE2', which is an existing terminal not having an ISDN corresponding function, may be connected to the ISDN terminal And is connected to the ISDN network via the illustrated terminal adapter TA. In addition, the interface point between NT1 and NT2 is called 'T', and the interface point between NT2 and TE1 is called 'S' point. Since the interface specification of S point is determined to be based on point T, TE1 is connected to NT1 Point is called 'S / T' point.

And a subscriber terminal such as an ISDN terminal are connected according to the protocols of Layer 1 to Layer 3 described above in order to connect with an ISDN exchange, and a recommendation stipulating such connection is shown in Table 1 above.

In Table 1, layer 1 is a user-network interface of the physical layer recommended in ISDN Recommendations I.430 and I431, and has a basic interface of 2B + D connection and a primary group interface of 23B + D or 30B + D, In the basic interface, the frame structure consists of 48 bits in 250 ㎲ units.

Layer 2 is generally referred to as LAPD (Link Access Procedure on the D channel). First, the BALANCE mode of HDLC, which is the standard of the standardized data link layer, is adopted as a basis. An address field, a control field, an information field, a frame check sequence (FCS), and a flag.

Layer 3 controls the circuit-switched services provided by the network, as well as the establishment, maintenance, and release of communication paths required for packet interworking and services, as well as requests for additional services. To this end, Layer 3 and Layer 2 Analyze the received message, form a call setup related message, and transmit it to the other party through the lower layer. General information related to Layer 3 is described in Q.930, and call processing procedures for basic calls are recommended by Q.931.

However, in order to implement the ISDN terminal, the functions described above must be implemented. It is a "protocol" in which appointments are defined between the layers, and a "primitive" in which logical exchange between the upper and lower layers is defined In other words, there are entities in each layer that implement the function of the layer, and these entities exchange information vertically via primitives.

These primitives are divided into four types such as REQUEST, INDICATE, RESPONSE and CONFIRM. Most of the primitives related to data transmission are REQUEST ) Primitive and an INDICATE primitive that is passed from the lower layer to the upper layer.

The CONFIRM primitive is a primitive informing the upper layer when the lower layer has an obligation to respond to the specific request primitive from the upper layer, and the RESPONSE primitive is a primitive for notifying the upper layer It is a primitive to inform the lower layer when the layer is obliged to respond to it.

The primitives to be processed in the layer 3 (Q.931) include a setting indication (DL_ESTABLISH_IND), a setting confirmation (DL_EST_CFM), a release confirmation (DL_REL_CFM), a data indication (DL_DAT_IND ), A unit data display (DL_UDA_IND), a resume request REST_REQ received from the GCR, a resume confirmation REST_CFM transmitted to the GCR, a timer T316 and a timer T317. The call request ALERT_REQ, the disconnection request DISC_REQ, the information request INFO_REQ, the additional information request MORE INFO_REQ, the notification request NOTI_REQ, the call progress request PROC_REQ, the call progress request PROG_REQ, (REJ_REQ), a release request (RELE_REQ), a response request (RESU_REQ), a call setup response (SETUP_RES), a call setup request (SETUP_REQ), a call suspension request (SUSP_REQ) T301_EXP, T302_EXP, T303_EXP, T304_EXP, T305_EXP, T306_EXP, T307_EXP, T308_EXP, T309_EXP, T310_EXP, T313_EX P, T314_EXP, T318_EXP, T319_EXP, T321_EXP, and T322_EXP. In this case, xx_xxxx_REQ indicates a request primitive, xx_xxxx_IND indicates an indication primitive, xx_xxxx_RES indicates a response primitive, and xx_xxxx_CFM indicates an acknowledgment primitive. And PH_xxxx_xxx is a primitive between the data link layer and the physical layer, DL_xxxx_xxx is a primitive between the layer 3 and the data link layer, MPH_xxxx_xxx is a primitive between the management layer and the physical layer, and DL_xxxx_xxx is a primitive between the management layer and the data link layer . There is no prefix between Layer 3 and the management layer, and the management (MG) layer is divided into "Call Control" and "Global Call Reference Control (GCR)".

In addition, the "state" defined in the layer 3 (Q.931) is defined according to the kind of call and whether it is user side or network side. For example, in case of circuit switching call, the state at the user side is as shown in Tables 2a and 2b.

[Table 2a]

State of layer 3 (circuit switched call / user side)

[Table 2b]

On the other hand, the conventional scheme for handling such primitives in layer 3 has been proposed as SDL in Annex A (ANNEX A) of Recommendation Q.931, which is schematically shown in FIG.

Referring to FIG. 3, the conventional method receives a primitive (S1), determines a current state of the layer 3 (S2), and then drives a primitive processing routine according to the determined current state (S3). The primitive processing routine determines the received primitive (S4), and processes the received primitive according to the determined state and the primitive (S5).

That is, in processing the RESTART_REQ primitive, any primitive has been conventionally received. First, after determining the current state of the L3 layer (which state is U0 to U25), the processing proceeds to the corresponding state processing routine (RESTART_REQ) primitive by determining what the primitive is.

As described above, since the state of the layer 3 is about 15 to 20 types and the kinds of the primitives to be processed are about 30, it takes much time to determine the state and to determine the primitive. There is a problem that the code length is long in the program.

Therefore, when similar processing is repeated in different states, it is necessary to optimize the processing to shorten the processing time and to reduce the code size. Furthermore, by making it possible to construct multiple lines to widen the channel bandwidth, It is desirable to expand it.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a RESTART_REQ primitive processing method that optimizes a processing procedure to solve the above problems.

It is another object of the present invention to provide a method of processing a RESTART_REQ primitive, which enables an ISDN terminal to be connected to a network by configuring multiple lines.

According to an aspect of the present invention, there is provided a method for implementing a layer 3 for connecting an ISDN terminal to a network according to a layered protocol in an integrated information communication network, step; Determining a minor link ID; Stopping all of the timers according to the determined link ID and the minor link ID; Transmitting a RELEASE_IND primitive to the management layer; Releasing a call of a corresponding call reference number according to the determined link ID and the minor link ID; Generating a RESTART_CFM primitive and transmitting it to the entire call reference control (GCR) layer; And causing the entity of the layer 3 to set its state to a null state.

1 shows an ISDN user-network connection;

Figure 2 shows the relationship of primitives processed in the ISDN UNI layer 3;

Figure 3 is a schematic diagram illustrating a conventional method of processing primitives in an ISDN UNI layer 3;

4 is a diagram showing an example of an ISDN communication card to which the present invention is applicable;

5 is a detailed block diagram of the channel connection shown in Fig.

6 is a conceptual diagram illustrating processes that are processed in an ISDN communication card in accordance with the present invention.

7A to 7E show data formats used in the present invention.

8 is a diagram illustrating a method of processing a RESTART_REQ primitive according to the present invention.

Description of the Related Art

1: ISDN terminal

3-1 to n: Handset

5-1 to n: Network terminal device (NT1)

7: ISDN network

10: PC

12: Slot

20: ISDN communication card

21: DP RAM

22: Memory

23: CPU

24-1 to n: Codec (CODEC)

25-1 ~ n: Channel connection part (ISAC)

26: Socket

27: S bus

28: Subscriber Line

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

As shown in FIG. 4, an ISDN terminal 1 is connected to a personal computer (PC) 10 via an ISDN communication card (not shown) via a slot 12, The ISDN communication card 20 is connected to the network terminals NT1 to NT1 through an S bus 27. The network terminal devices 5-1 to 5- And is connected to the ISDN network 7 through the charity line 28. [

At this time, the ISDN communication card 20 to which the present invention is applied has n channel connection units (ISAC: 25-1 to n) for connecting 2B + D basic interfaces to n ISDN networks 7, respectively And these n channel connection units are connected to the network terminal devices 5-1 to 5-n via the S bus 27, respectively.

In this way, by expanding the number of basic interfaces to n, the host system can not transmit a large amount of data to be transmitted to one basic interface (2B + D) (for example, application to a video conference system, etc.) , The host system can transmit data by appropriately expanding the channel capacity by adding several (n) basic interfaces.

4, the ISDN communication card 20 includes a dual port RAM (DP RAM) 21, a memory 22, a CPU 23, CODECs 24-1 to n, : 25-1 to n), and functions of layers 1 to 3 are implemented so that the ISDN terminal 1 can be connected to the ISDN network 7 as described above. And is built in the memory 22.

4, the DP RAM 21 provides a physical path for transferring data to the PC 10, which is a host system, through the slot 12, and the memory 22 stores various types of data for operating the communication card 20 Programs and system data are stored and the CPU 23 controls various operations of the communication card by operating various processes according to the software stored in the memory 22. [

In the embodiment of the present invention, the IDT 71321 is used as the dual port RAM 21 and the 80C188 of Intel Corporation is used as the CPU 23. [

The codecs 24-1 to 24-n are used for connecting a voice to the basic interface. The codecs 24-1 to n encode and decode voice signals input / output through the handsets 3-1 to 3-n, And the channel connection units 25-1 to 25-n are configured as shown in FIG. 5 to connect the data terminal and the voice terminal to the network terminal devices 5-1 to 5-n.

5, the channel connection units 25-1 to 25-n include an SSI 51, an SDL 52, a B channel switching unit 53, a D channel processing unit 54, a FIFO 55, a processor connection unit 56, An IOM connection unit 57, a buffer 58, a buffer control unit 59 and an ISDN basic access layer 1 unit 60. The channel connection unit having such a configuration can be realized as a single semiconductor chip and can be purchased commercially . In the embodiment of the present invention, the channel connection units 25-1 to 25-n are implemented as an ISDN (ISDB Subscriber Access Controller Model Name: PEB2085) manufactured by SIEMENS, and the operation of the ISAC is described in detail in the Technical Manual .

6, the entities of the respective layers are divided into a LAPD process 61, an L3 common process 62 and an L3 local process 63 in order to process the primitives in the ISDN communication card 20, And operates with reference to the variable table.

Here, the L3 common process 62 includes entities for processing the primitives DL_EST_IND, DL_EST_CFM, DL_RELE_IND, DL_RELE_CFM, DL_DATA_IND and DL_UDATA_IND transmitted from the layer 2 process 61 to the layer 3 and primitives related to GCR RESTART_REQ , RESTART_CFM, T316_OUT, T317_OUT), and the L3 local process 63 consists of entities for processing the remaining primitives recommended in Q.931.

At this time, the LAPD process (layer 2) refers to the layer 2 environment variable table (L2env_tab [x]), which is identified by a link ID (Link ID or id) (L3coord_tab [x]) of the layer 3, and this environment variable table is also identified in accordance with the link ID. The layer 3 local process 63 refers to the layer 3 local environment variable table L3env_tab [x], which includes two link IDs per link ID, and stores the link ID and the minor link ID (mID) ≪ / RTI >

6, the depicted processes illustrate the case where there are three link identities id and six minor link identities (mid) (i.e., for communication cards with three channel interfaces (ISACs)).

4, when a plurality of ISACs are installed on the ISDN communication card to form multiple lines, the link ID (ID) is set to 1 to n (or 0 (MID) is an identification number of 0 or 1 for identifying the B channel on each line (there are two B channels in the 2B + D basic connection), and the minor link ID .

As described above, since a plurality of lines can be provided in the present invention, a link ID (ID) and a minor link ID (mID) are used so that they can be identified.

On the other hand, FIG. 7 shows a data format of a message or primitives processed on the ISDN communication card, in which 7a denotes a primitive without a message, 7b and 7c denote an unnumbered format, and 7d and 7e denote a numbered format, respectively.

7A to 7E, the Q.931 message field is a portion processed by Layer 3, the Q.291 Unnumbered and Numbered fields are portions (header) processed in Layer 2, and the primitive header portion includes information between layers Transmission and primitive processing in each layer.

In other words, in 7a to 7e, the primitive header is composed of a primitive id, a link id (ID), a mitter link ID (mlink_id = mID) for identifying a primitive, and a size Add2 "," n_r "," n_s ", and" n_s "in Q921 are composed of" add1 "," add2 " (4 bytes). These Q.921 fields and Q.931's message fields are described in detail in the Recommendations, and so a further description is omitted.

Figure 8 is a flow chart illustrating a method for processing a RESTART_REQ primitive according to the present invention.

First, the RESTART_REQ primitive is a primitive that is sent from an entire call reference number control (RCR) layer to an entity in layer 3, and is a primitive to transmit to clear the channel and interface to the null state (U0). Each layer 3 entity that receives this primitive stops all associated timers, releases the RELEASE_IND primitive to the management layer (CC), and releases the call if it is allocated. After sending the RESTART_CFM primitive with the link ID and the minor link ID specified by the user ID to the GCR, the state is set to a null state.

Referring to FIG. 8, in the primitive receiving step, an arbitrary primitive is received, and a received primitive and a link ID are discriminated (100, 101). In other words, since there are a primitive ID and a link ID in the header of the primitive, it is determined which primitive and which link it is based on these ID values. The link ID of the RL is for identifying the base interface on multiple lines. For example, if the link ID is "0 ", the base interface is provided through ISAC1 (25-1 in FIG. 4) 0.0 > 0 < / RTI > (Link 0).

Then, if the received primitive is a RESTART_REQ primitive, then a minor link ID is confirmed (102, 103). That is, since the resume request primitive is processed by the entity of the L3 local process shown in Fig. 6, it is processed by referring to the L3 local environment variable table (L3env__tab []) specified by the link ID and the minor link ID.

Then, all the timers on the L3 local environment variable table specified by the determined link ID and the minor link ID are stopped, and the RELE_IND primitive is transmitted to the management layer (104, 105). At this time, the link ID and the minor link ID on the release indication primitive are copied to their own IDs and transmitted.

Next, the call ID of the identified link ID and the call reference number (CR) designated by the minor link ID are released, the memory is secured, and the RESTART_CFM primitive is generated and transmitted to the GCR (106,107,108).

When all such operations are complete, the L3 local process entity makes its state null state (U0) (109).

As described above, according to the present invention, in processing the RESTART_REQ primitive, the primitive is first identified and then the appropriate processing procedure is performed according to the state to optimize the processing procedure to shorten the processing time, There is an effect that can be reduced. In addition, by enabling multi-line configuration, the channel capacity can be expanded as needed.

Claims (1)

A method for implementing layer 3 to connect an ISDN terminal to a network according to a layered protocol in an integrated information communication network, the method comprising: discriminating a received primitive and a link ID; Confirming a minor link ID; Stopping all of the timers according to the determined link ID and the minor link ID; Transmitting a RELEASE_IND primitive to the management layer; Releasing a call of a corresponding call reference number according to the determined link ID and the minor link ID; Generating a RESTART_CFM primitive and transmitting it to the entire call reference control (GCR) layer; And an entity of the Layer 3 being in a null state of the state of the ISDN user-network connection. ※ Note: It is disclosed by the contents of the first application.