KR100219226B1 - Method for processing primitives in layer 3 of isdn uni - Google Patents

Abstract

The present invention relates to a method for processing a release confirmation primitive in Layer 3 of an ISDN user-network connection, comprising: determining an ID and a link ID of a received primitive; Determining each state of Layer 3 entities if the received primitive is a Release Confirm (DL_RELEASE_CFM) primitive; All the timers are stopped for all entities whose state of the layer 3 entity is not image state (U0), overlapping transmission (U2), and overlapping number (U25), and the state of the layer 3 entity is zeroed. Releasing the call reference number after the call; Create a call setup confirmation primitive with error information for all entities whose layer 3 entity status is in overlapping transmission (U2), send it to the management layer, stop the timer T304, and then transfer the status to video status (U0). Switching and releasing the call of reference number; If the status of the layer-3 entity is in overlapping reception (U25), a release indication primitive containing error information is generated and transmitted to the management layer, and the timer T304 is stopped and then switched to the zero state (U0) and the call reference number A step of releasing the call is provided to connect the ISDN terminal to the network according to the negotiation protocol in the integrated information communication network.

Description

Method of processing release confirm primitive in layer 3 of ISDN UNI

The present invention relates to a connection technology between a user (USER) and a network (NETWORK) in an integrated information communication network (ISDN), in particular a method for processing a release confirmation (DL_RELEASE_CFM) primitive received from layer 2 in the layer 3 (LAYER 3) It is about.

As the information society has progressed, communication demands have diversified, and the media handled by communication networks such as voice, data, and video have also diversified, so that individual networks established by services cannot provide efficient services. Therefore, the ISDN, which can integrate and digitize individual networks established by services and provide comprehensive services, has emerged. These ISDNs are designed to unify various terminals in order to accommodate users and manganese. Interface is standardized by Digital Subscriber Signaling System (DSS1), and interface between network and network is no. 7 Standardized to common line signaling (CCS).

DSS1, which is a signaling method of the user-network interface (UNI) of ISDN, is implemented in layers 1 through 3 by an OSI (Open Systems Interconnection) reference model, as shown in FIG. The outline of this document and its relationship with the Recommendations of the ITU-T is shown in Table 1

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

Here, 'NT1' (network terminal device 1) is a transceiver in a house for transmitting a digital signal to a subscriber line, and 'NT2' (network terminal device 2) is a device corresponding to a private branch exchange (PBX). The terminal (TE1) can accommodate, 'TE1' is an ISDN standard terminal is directly connected to NT1 and may be connected via NT2, and the existing terminal 'TEL2', which does not have an ISDN-compliant function, is not shown. It is connected to the ISDN network through the terminal adapter (TA).

In addition, the interface point between NT1 and NT2 is called 'T' point, 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 T point, TE1 is The point to be connected is called the 'S / T' point.

In addition, a subscriber station such as an ISDN terminal is connected according to the above-described protocols of Layer 1 to Layer 3 to be connected to an ISDN exchange, and the recommendations for defining such a connection are shown in Table 1 above.

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

Layer 2 is commonly referred to as Link Access Procedure on the D channel (LAPD), which first adopts HDLC's BALANCE mode, which is the standard for the standardized data link layer, and its basic format is Flag. And an address field, a control field, an information field, a frame check sequence (FCS), and a flag.

Layer 3 controls the establishment, maintenance, and release of communication paths required by the network and packet switched services, and various additional service requests, which are received from the other side through layers 1 and 2. The message is analyzed and the call setup related message is formed and sent to the other party through the lower layer. General content related to Tier 3 is described in Q.930, and call processing procedures for basic calls are recommended by Q.931.

However, in order to implement an ISDN terminal, the functions as described above should be implemented. A protocol is defined between the same layers, and a primitive is defined to define a logical exchange between up and down measurements. That is, each layer has entities that implement the functions of the layer, and these entities are configured to exchange information between top and bottom through primitives.

These primitives are divided into four types: REQUEST, INDICATE, RESPONSE, and CONFIRM. Most of the primitives related to data transfer are REQUEST passed from the upper layer to the lower layer. ) A primitive and an INDICATE primitive passed from the lower layer to the upper layer.

And, the CONFIRM primitive is a primitive that notifies the upper layer when the lower layer is obliged to respond to the specific request primitive from the higher layer, and the response primitive is a specific one from the lower layer. Primitives to inform lower layers when the higher layer is obliged to respond to indication primitives.

On the other hand, primitives to be processed in Layer 3 (Q.931) are as shown in FIG. 2, the setting indication (DL_ESTABLISH_IND), the setting confirmation (DL_EST_CFM), the release confirmation (DL_REL_CFM), and the data indication ( DL_DAT_IND), unit data indication (DL_UDA_IND), resumption request received from GCR (REST_REQ), resumption confirmation (REST_CFM) delivered to GCR, timer (T316), timer (T317), and from MG (CC) layer. Call request (ALERT_REQ), disconnect request (DISC_REQ), information request (INFO_REQ), additional information request (MORE_INFO_REQ), notification request (NOTI_REQ), call progress request (PROC_REQ), call progress request (PROG_REQ), reject request ( REJ_REQ), release request (RELE_REQ), call resumption request (RESU_REQ), call setup response (SETUP_RES), call setup request (SETUP_REQ), foil stop request (SUSP_REQ), and timers T301_EXP sent back to itself in layer 3 , T302_EXP, T303_EXP, T304_EXP, T305_EXP, T306_EXP, T307_EXP, T308_EXP, T309_EXP, T31 0_EXP, T313_EXP, T314_EXP, T318_EXP, T319_EXP, T321_EXP, and T322_EXP. In this case, xx_xxxx_REQ represents a request primitive, xx_xxxx_IND represents an indication primitive, xx_xxxx_RES represents a response primitive, and xx_xxxx_CFM represents an confirm primitive. 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 (CC) and global call reference control (GCR).

In addition, 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 the case of a circuit switched call, the state at the user side is shown in Table 2 below.

On the other hand, it was proposed as SDL in Appendix A (ANNEX A) of Recommendation Q.931 of the conventional method of processing such pyramids in layer 3, which is roughly summarized as shown in FIG.

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

In other words, in processing a release confirmation (DL_RELEASE_CFM) primitive received from layer 2, if any primitive is conventionally received, the current state of the L3 layer is first determined (which is U0 to U25), and then the corresponding state processing routine. In order to process the release confirmation (DL_RELEASE_CFM) primitive by determining the received primitive.

As described above, since the state of layer 3 is about 15 to 20 types, and about 30 kinds of primitives to be processed, it takes a long time to determine the state and the primitive, and when processing each primitive after state determination There is a problem in that the code lengthens during programming because of a large number of processing procedures.

Therefore, if aborted processing is repeated in different states, it is necessary to reduce the processing time and reduce the code size by optimizing it, and furthermore, it is possible to configure multiple lines to widen the channel bandwidth. It is desirable to expand the sex.

Accordingly, an object of the present invention is to provide a release acknowledgment (DL_RELEASE_CFM) primitive processing method for initializing a processing procedure in order to solve the above problems.

Another object of the present invention is to provide a release acknowledgment (DL_RELEASE_CFM) primitive processing method for configuring an ISDN terminal in multiple lines to access a network.

In order to achieve the above objects, the present invention provides a method for implementing layer 3 to connect an ISDN terminal to a network according to a layered protocol in a general information communication network. Determining; Determining each state of Layer 3 entities if the received primitive is a Release Confirmation (DL_RELEASE_CFM) primitive; All the timers are stopped for all entities whose state of the layer 3 entity is not in the image state (U0), in the case of sending in the duplication (U2), and in the case of making the receipt in the U25, and the state of the layer 3 entity is zeroed. Releasing the call reference number after the call; After generating a call setup confirmation primitive containing error information for all entities whose layer 3 entity is in the state of being sent (U2), transmit it to the management layer, stop the timer T304, and display the state (U0). Switching to and releasing the call of the reference number; And if the state of the layer 3 entity is in the overlapping reception (U25), generates a release indication primitive including error information and transmits it to the management layer, stops the timer T304, and then switches to the zero state (U0) and the call reference number. It characterized in that the step of releasing the call.

1 shows a user-network connection of an ISDN.

2 shows the relationship of primitives processed in ISDN UNI Layer 3.

3 is a schematic diagram illustrating a conventional method for processing primitives in ISDN UNI layer 3. FIG.

4 is a diagram showing an example of an ISDN communication card suitable for applying the present invention.

FIG. 5 is a detailed block diagram of the channel access unit shown in FIG.

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

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

8 is a diagram illustrating a release acknowledgment (DL_RELEASE_CFM) primitive processing method according to the present invention.

* Explanation of symbols for main parts of the drawings

3-1 ～ n: Handset 5-1 ～ 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 ~ n: Codec

25-1 ～ n: Channel connection part (ISAC) 26: Socket

27: S bus 28: subscriber line

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

First, when implementing an ISDN terminal according to the present invention, looking at the schematic configuration of the hardware, as shown in Figure 4, the ISDN terminal is an ISDN communication card (slot 12) through a slot 12 in a personal computer (PC: 10) 20) is connected, the ISDN communication card 20 is connected to the network terminal device (NT: 5-1 ~ n) via the S bus 27, the network terminal device (5-1 ~ n) is subscribed It is supposed to be connected to the ISDN network 7 through the charity 28.

At this time, the ISDN communication card 20 to which the present invention is applied is provided with n channel connection parts (ISAC: (25-1 to n) so as to connect 2B + D basic interfaces to n ISDN networks 7, respectively. These n channel connections are connected to the network terminal devices 5-1 to 5-n through the S bus 27, respectively.

By extending the basic interface to n in this way, if the host system has a large amount of data to be transmitted (for example, in an application to a video conferencing system), it cannot be transmitted to one basic interface (2B + D). By adding several (n) basic interfaces, the host system can transfer data by appropriately extending the channel capacity.

Here, the ISDN communication card 20 is a dual port RAM (DP RAM: 21), memory 22, CPU 23, codec (CODEC: 24-1 ~ n), channel connection (ISAC) as shown in FIG. 25-11 to n), and implements the functions of layers 1 to 3 so that ISDN terminals can be connected to the ISDN network 7 as described above. 22).

In FIG. 4, the DP RAM 21 provides a physical path for transferring data with the PC 10, which is the host system, through the slot 12, and the memory 22 operates the communication card 20. Various programs and system data are stored, and the CPU 23 activates various processes in accordance with software stored in the memory 22 to control the operation of the entire communication card. In the embodiment of the present invention, IDT71321 is used as the dual port RAM 21, and 80C188 of Intel Corporation is used as the CPU 23.

The codecs 24-1 to n are for connecting audio to a basic interface, and the channel connection units 25-1 to n are made by incubating and decoding audio signals input / output through the handsets 3-1 to n. ), And the channel connecting portions 25-1 to n are configured as shown in FIG. 5 to connect a data terminal or an audio terminal to the network terminal apparatuses 5-1 to n.

In FIG. 5, the channel connection units 25-1 to n include the SSI 51, the SDL 52, the B channel switching unit 53, the D channel processing unit 54, the FIFO 55, and the processor connection unit 56. ), IOM connector 57, buffer 58, buffer control unit 59, ISDN basic access layer 1 unit 60, the channel connection of this configuration is implemented as a single semiconductor chip can be purchased commercially have. In the exemplary embodiment of the present invention, the channel access portions 25-1 to n are implemented as Siemens (ISDN Subscriber Access Controller Model Name: PEB2085), and the operation of the ISAC is described in detail in the corresponding Technical Manual. It is.

In order to process primitives in the ISDN communication card 20, entities of each layer are divided into a LAPD process 61, an L3 common process 62, and an L3 local process 63 as shown in FIG. 6. It works by referring to the variable table.

Herein, the L3 common process 62 may include entities for processing primitives DL_EST_IND, DL_EST_CFM, DL_RELE_IND, DL_RELE_CFM, DL_DATA_IND, and DL_UDATA_IND that are transferred from the layer 2 process 61 to layer 3, and the primitives related to the 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), and exists in a plurality of layer 3 common processes. Reference numeral 62 refers to the layer 3 common environment variable table (L3coord_tab [x]), which is also identified according to the link ID. The layer 3 local process 63 references the layer 3 local environment variable table (L3env_tab [x]), which contains two link IDs per link ID and a link ID (ID) and a minor link ID (mID). Are identified according to. In FIG. 6, the illustrated processes show the case where there are three link IDs and six minor link IDs (ie, a communication card having three channel connections (ISAC)).

Here, the link ID (ID) is shown in Figure 4, when configuring multiple lines by installing a plurality of ISAC on the ISDN communication card, from 1 to n times (or 0) to distinguish these lines Number from n-1 to n-1, and the minor link ID (mID) is 0 or 1 identification number to distinguish B channel on each line (there are two B channels in 2B + D basic connection). to be.

Thus, in the present invention, since a plurality of lines can be provided, the link ID (ID) and the minor link ID (mID) can be used.

7 is a data format of a message or primitives processed on an ISDN communication card. FIG. 7a shows a non-message primitive, 7b and 7c are non-numbered formats, and 7d and 7e are numbered formats, respectively.

In FIG. 7, the Q.931 message field is a part processed by layer 3, the Q.291 non-numbered and numbered fields are a part (header) processed in layer 2, and the primitive header part transfers information between layers. And a portion used for primitive processing in each layer.

That is, in 7a to 7e, the primitive header is composed of a 'primitive id' for identifying a primitive, a link ID (link_id = ID), a minor link ID (mlink_id = ID), and a size indicating a message size. The non-numbering field of Q921 consists of add1, add2, n_r, n_s (4 bytes). This Q.921 field and the message field of Q.931 are described in detail in the Recommendations, so further explanation is omitted.

8 is a flowchart illustrating a method of processing a release confirmation (DL_RELEASE_CFM) primitive in accordance with the present invention.

The release acknowledgment (DL_RELEASE_CFM) primitive is a primitive conveyed from layer 2 to a higher layer when the data link entity is lost due to an internal failure, and this entity conveys a release acknowledgment (DL_RELEASE_CFM) primitive to layer 3 to inform it.

Since this primitive has several Layer 3 entities associated with one Layer 2 entity, this primitive must be passed to all related Layer 3 entities.

When the layer 3 entity that has received this release confirmation primitive is in the state of overlapping transmission (U2) or overlapping reception (U25), a call clearing procedure is started internally. In case of overlapping transmission (U2), an error occurs. Transmit call setup confirmation (SETUP_CFM) primitives with information to the management (CC) layer, and in case of duplicate reception (U25), create a release confirmation (RELEASE_IND) primitive with error information to the management (CC) layer. send.

If a layer 3 entity is not in the picture state (U0), in duplication (U2), or in duplication (U25), the entity may send a DL_ESTABLISH_REQ primitive to layer 2 to request reconfiguration at layer 2 A call clearing procedure can also be performed. In zero state (U0) the call is not set and the release confirmation primitive is ignored.

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

Subsequently, if the received primitive is a release confirmation (DL_RELEASE_CFM) primitive received from layer 2, the state of the layer 3 entity designated by the call reference number CR is determined, and the minor link ID mid is initialized to 0 (102). , 103, 104).

Subsequently, if the number of minor links (mid) is smaller than the number of call reference numbers (NCR), it is determined whether the state of the layer 3 entity is not in picture state (U0), in duplicate transmission (U2), or in duplicate reception (U25). If yes, all the timers are stopped (105, 106, 107).

Subsequently, the state of the layer 3 entity is switched to a Nu11 state U0, and the call reference number CR is released (108, 109).

If the status of the layer 3 entity is in a double transmission (U2), a call setup confirmation (SETUP_CFM) primitive including error information is generated and transmitted to the management (CC) layer, and the timer T304 is stopped (110, 111, 112). ).

Subsequently, the state of the entity is switched to the null state 113, and the call of the call reference number CR is released (113).

If the status of the layer 3 entity is in duplex reception (U25), a release indication ((RELEASE_IND) primitive containing error information is generated and transmitted to the management (CC) layer, and the timer T304 is stopped (114, 115, 116). Subsequently, the state of the entity is changed to a Nu1 state U0 and the call of the corresponding call reference number CR is released (117).

When this operation is completed, the minor link ID (mid) is increased by 1 to process the next corresponding entity, and this is performed for all reference numbers (NCR), and then the buffer of the primitive is released and terminated. 118).

As described above, in processing the release confirmation (DL_RELEASE_CFM) primitive according to the present invention, by first determining the primitive and performing the appropriate processing procedure according to the state, the processing procedure is optimized to reduce the processing time and reduce the amount of code. It can be effective. In addition, by enabling a 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: determining an ID and a link ID of a received primitive; Determining each state of the layer 3 entities if the received primitive is a release confirmation (DL_RELEASE_CFM) primitive; All the timers are stopped for all entities whose state of the layer 3 entity is not image state (U0), overlapping transmission (U2), and overlapping reception (U25), and the state of the layer 3 entity is zeroed. Subtracting a call of a call reference number after switching to the call; After generating a call setup confirmation primitive containing error information for all entities whose layer 3 entity is in overlapping transmission (U2), transmit it to the management layer, stop the timer T304, and display the corresponding state (U0). Switching to and releasing the call of the reference number; And if the state of the layer 3 entity is in the overlapping reception (U25), generates a release indication primitive including error information and transmits it to the management layer, stops the timer T304, and then switches to the zero state (U0), and refers to the corresponding call. The release confirmation primitive processing method at Layer 3 of an ISDN user-network connection, comprising the step of releasing a call of number.