KR980013101A - Information request primitive processing method in layer 3 of ISDN user network connection - Google Patents

Abstract

The present invention relates to a method for processing an information request primitive in a layer 3 of an ISDN user-network connection, comprising the steps of: determining an ID of a received primitive and a link ID; If the received primitive is an INFORMATION-REQ primitive, determining a state of the layer 3 entity by checking the minor link ID; If the state of the layer 3 entity is not null state (U0), call initiation (U1), call presence (U6), resume request (U17), release request (U19), then transmit an information message to layer 2; And activating the corresponding timer T 304 if the entity is in the superimposed transmission U2, and connects the ISDN terminal to the network according to the layered protocol in the integrated information communication network.

Description

Information request primitive processing method in layer 3 of ISDN user network connection

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, to an information request (INFORMATION-REQ) received from a management (CC) layer in Layer 3, To a method for processing a primitive.

With the advancement of the information society, communication demands are diversified, and media handled by communication networks such as voice, data, and video are diversified. Accordingly, an ISDN (Integrated Services Digital Network) has been developed for integrating and digitizing individual networks established for each service and providing a comprehensive service. In order to uniformly accommodate various terminals, Has been standardized as Digital Subscriber Signaling System 1 (DSSI), and the interface between the network and the network has been standardized as No. 7 Common Line Signaling (CCS).

DSS1, which is a signaling scheme of the user-to-network interface (UNI) of the ISDN, is implemented as a layer from layer 1 to layer 3 according to the OSI (Open Systems 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.

Herein, 'NT1' (network terminal apparatus 1) is a transmitting / receiving apparatus in a house for transmitting a digital signal to a subscriber line, 'NT2' (network terminal apparatus 2) is a device corresponding to a private branch exchange (PBX) 'TE1' may be directly connected to the NT1 as an ISDN standard terminal and may be connected via the NT2, and 'TE2', which is an existing terminal not having the ISDN corresponding function, may be connected to the terminal And is connected to the ISDN network via a terminal adapter TA.

The interface point between NT1 and NT2 is called the 'T' point and the interface point between NT2 and TE1 is called the 'S' point. Since the interface specification of S point is decided to be based on point T, The point to be connected is called the 'S / T' point.

And a subscriber terminal such as an ISDN terminal are connected according to the protocol of layer 1 to layer 3 described above in order to be connected to 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 commonly referred to as LAPD (Link Access Procedure on the D channel). It first adopts the BALANCE mode of HDLC, which is the standard of the standardized data link layer, An address field, a control field, an information field, a frame check sequence (FCS), and a flag.

Layer 3 controls the circuit-switched and packet-switched services provided by the network, such as setting, maintaining, disassembling, and requesting various additional services required for the packet-switched service. And transmits a call setup related message 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 the appointment is defined between the layers, and a "primitive" in which the logical exchange between the upper and lower layers is defined . In other words, there are entities that implement the functions of the layer in each layer, and these entities are supposed to exchange information between the top and bottom through 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 an upper layer when a lower layer is obliged to respond to a specific request primitive from an upper layer, and a RESPONSE primitive is a primitive indicating a specific indication primitive from a lower layer Is a primitive for informing a lower layer when an upper layer has an obligation to respond to it.

2, 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 And a timer T317 are present and there is a unit data display DL_UDA_IND from the MG (CC) layer and the unit data display DL_UDA_IND from the GCR, the REST_REQ received from the GCR, the REST_CFM transmitted to the GCR, (ALERT_REQ), disconnection request (DISC_REQ), information request (INFO_REQ), additional information request (MORE_INFO_REQ), notification request (NOT1_REQ), call progress request (PROC_REQ), call progress request (PROG_REQ) REJ_REQ, RELE_REQ, RESU_REQ, SETUP_RES, SETUP_REQ, and SUSP_REQ, and timers T301_EXP , T302_EXP, T303_EXP, T304_EXP, T305_EXP, T306_EXP, T307_EXP, T308_EXP, T309_EXP, T310_EX P, T313_EXP, T314_EXP, T318_EXP, T319_EXP, T321_EXP, and T322_EXP. In this case, xx_xxxx_REQ indicates the request primitive, xx_xxxx_IND indicates the indication primitive, xx_xxxx_RES indicates the response primitive, and xx_xxxx_CFM indicates the 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 MDL_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)".

The "state" defined in layer 3 (Q.931) is defined according to the type of call and whether it is user side or network side. For example, in case of circuit switching call, the state on the user side is shown in Table 2 below.

[Table 2]

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

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 (SI), 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 an information request (INFORMATION_REQ) primitive, if an arbitrary primitive is received, the current state of the L3 layer is first determined (any of U0 to U25), and then the received primitive And processed the information request (INFORMATION_REQ) primitive.

As described above, since the state of the layer 3 is about 15 to 20 types and the types of the primitives to be processed are about 30, it takes much time to determine the states and determine the primitives. 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 method of processing an information request (INFORMATION_REQ) primitive to optimize a processing procedure to solve the above problems.

Another object of the present invention is to provide an information request (INFORMATION_REQ) primitive processing method that enables ISDN terminals to be configured as multiple lines and connected to a network.

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, ; If the received primitive is an information request (INFORMATION_REQ) primitive, identifying a minor link ID and determining the state of the layer 3 entity; If the status of the layer 3 entity is not null status (U0), call initiation (U1), call presence (U6), resume request (U19), release request (U19), then transmit an information message to layer 2; And activating the corresponding timer T304 when the entity is the superposed transmission U2.

FIG. 1 shows a user-network connection of an ISDN, FIG. 2 shows a relation of primitives processed in an ISDN UNI layer 3, and FIG. 3 shows a conventional method of processing a primitive in an ISDN UNI layer 3 FIG. 5 is a detailed block diagram of the channel connection unit shown in FIG. 4; and FIG. 6 is a block diagram of an ISDN communication card according to an embodiment of the present invention. 8 is a diagram showing a method of processing an information request (INFORMATION-REQ) primitive according to the present invention. Fig. 9 is a view showing a process Is a flowchart of a procedure for processing the T304 termination primitive that occurs when the activated timer T304 terminates in accordance with the flow shown in FIG.

Description of the Related Art

1: ISDN terminal 3-1 to n: Handset 5-1 to n: NTI 7: IDSN network 10: PC 12: Slot 20: ISDN communication card 21: DP RAM 22: Memory 23: N: CODEC 25-1 to n: Channel connection unit (ISAC) 26: Socket 27: S-bus 28:

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

4, an ISDN terminal 1 is connected to a personal computer (PC) 10 via an ISDN communication card 12 through a slot 12, The ISDN communication card 20 is connected to the network terminals NT1 to NTn through an S bus 27. The network terminals 5-1 to 5n And is connected to the ISDN network 7 via the subscriber 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 base interfaces to n ISDN networks 7 respectively And these n channel connection units are connected to the network terminal stations 5-1 to 5-n via the S bus 27, respectively.

If the host system can not transmit data to one basic interface (2B + D) because the amount of data to be transmitted by the host system is large (for example, application to the video conferencing system or the like) , And 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 24-n, a channel access unit (ISAC) The 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 pathway for transferring data with the PC 10, which is a host system, through the slot 12, and the memory 22 stores various kinds of information for operating the communication card 20 Programs and system data are stored and the CPU 23 activates various processes according to the software stored in the memory 22 to control the operation of the entire communication card.

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 24-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 are connected to the SSI 51, the SDL 52, the B channel switching unit 53, the D channel processing unit 54, the FIFO 55, the 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 ISAC (ISDN Subscriber Access Controller Model Name: PEB2085) of SIEMENS, Inc. 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 primitives (DL_EST_IND, DL_EST_CFM, DL_RELE_IND, DL_RELE_CFM, DL_DATA_IND, DL_UDATA_IND) transmitted from the layer 2 proxy 61 to the layer 3 and primitives RESTART_REQ, RESTART_CFM, T316_OUT, T317_OUT), and the L3 local process 63 also includes 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 (L2nev_tab [x]), which is identified according to the link ID (Link ID or id) (L3coord_tab [x]), and the environment variable table is also identified by a 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 >

In Fig. 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 (ISAC)).

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 an ISDN communication card. FIG. 7A shows a primitive without a message, FIGS. 7B and 7C show an unnumbered format, and FIGS. 7D and 7E show a numbered format.

7, the Q.931 message field is the portion processed by Layer 3, the Q.291 Unnumbered and Numbered fields are the portion (header) processed in Layer 2, the primitive header portion is for information transfer between layers, It is the part used for 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 minor link ID (mlink_id = mID) for identifying a primitive, and a size Addr "," addr "," n_r ", and" n_s "in the non-number field of Q.921 are composed of" add1 " Quot; (4 bytes). These Q.921 fields and Q.931's message fields are described in detail in the Recommendations and will not be described further.

Figure 8 is a flow chart illustrating a method for processing an INFORMATION_REQ primitive in accordance with the present invention.

The INFORMATION_REQ primitive is a primitive that is applied to the overlapped sending procedure described in Section 5.1.3 of Q.931 when the state of layer 3 is overlapped sending (U2).

Overlap sending means that when a call is made, the SETUP message is not transmitted with all the information necessary for the call setup, but the destination address information is transmitted to the SETUP ACK after the call setup message is transmitted. The destination address information is transmitted by an INFORMATION message after receiving the message.

Therefore, the layer 3 entity receiving this primitive must transmit an information message to the other party, which includes a " Called party number information element "or a" Keypad facility information element " Side address. However, only one of these methods is used.

In addition, if the status of the layer 3 entity is not superposed transmission U2 but the information request primitive is requested, the layer 3 must transmit an INFORMATION message to the other party to inform the other party of the key operation. This state is a null state (U0), a call initiated (U1), a call present (U6), and a disconnect request (Disconnect request) among the states (U0 to U25) proposed in Q.931. U11), a resume request (U11), and a resume request (U17). The actual information element is passed in the primitive in the call control procedure (CC) which requires this primitive. Especially when the layer 3 status is overlapped sending (U2), the timer T304 is activated.

Referring to FIG. 8, when an arbitrary primitive is received in the primitive receiving step, a primitive id and a link id are discriminated (100, 101). Here, a primitive ID is recorded in a "header of a primitive" together with a link ID as an identifier defined to identify the type of a primitive. The link ID is for identifying a basic interface on multiple lines. For example, if the link ID is "0 ", it refers to the basic interface provided through ISAC1 (25-1 in FIG. 4) It can be seen that it is related to the process on Link 0.

Next, if the received primitive is an information request (INFORMATION_REQ) primitive, a minor link ID (mid) is checked and the current state of the layer 3 entity is determined (102, 103). That is, since the call progress request primitive is processed by the entity of the L3 local process 63 shown in FIG. 6, the L3 local environment variable table (L3env_tab []) specified by the link ID id and the minor link ID .

Then, the current state of the L3 entity identified is the null state U0, call initiated U1, call present U6, disconnection request U11, or resume request request: U17), the information message including the information element is generated and transmitted to the layer 2 (104, 105).

At this time, when the corresponding entity is overlaid (Overlap sending: U2), the corresponding timer T304 is activated (106,107).

If the INFORMATION_REQ primitive is received but not in the call present (U6) state, an exception handling routine is driven to indicate an error or provide information for debugging (108).

FIG. 9 is a flow chart of a procedure for processing the T304 termination primitive that occurs when the timer T304 activated according to the flow shown in FIG. 8 is terminated. FIG. Timer T304 is a timer operating in the redundant transmitting state (U2), with a default value of 15 seconds in Table 9-2 of Q.931. Therefore, when the originating user transmits an INFORMATION message to the network side and is activated and the response is not reached within 15 seconds, the T304_EXP primitive is generated.

The T304 end primitive processing procedure identifies the primitive ID and the link ID as in the other primitives, and if the T304 end primitive is selected, distinguishes the minor link ID and the state of the corresponding entity (200 to 203).

Then, if the state of the entity is a duplicate transmission (U2), a DISCONNECT message is generated and transmitted to the layer 2, the corresponding timer T303 is stopped, and a SETUP_CFM primitive containing error information is generated (CC) layer (205, 206, 207).

Subsequently, the state of the Layer 3 entity is switched to a disconnection request state (disconnect request: U11) (208). If it is not during duplicate transmission (U2), the exception processing routine is driven (209).

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

Claims (2)

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, the method comprising the steps of: determining an ID of a received primitive and a link ID: determining whether a received primitive is an information request ) Primitive, determining a state of the layer 3 entity by checking the minor link ID; If the state of the layer 3 entity is not null state (U0), call initiation (U1), call presence (U6), resume request (U17), release request (U19), then transmit an information message to layer 2; And initiating a corresponding timer T304 if the entity is a super-transmitting (U2). The method as claimed in claim 1, wherein when the activated timer T304 has elapsed after a predetermined time elapses, a disconnection message is generated and transmitted to the layer 2, the corresponding timer T303 is stopped, Primitive at the layer 3 of the ISDN user-network connection. ※ Note: It is disclosed by the contents of the first application.