KR950008219B1 - Packet processing unit of isdn - Google Patents

Abstract

The ISDN packet processing equipment performs interfacing function between ISDN switch performing circuit switching function and packet network constructed for packet data communication. The ISDN packet processing equipment consists of system controller (201), PRI interface (202), memory (203), B channel processor (209), packet network interface (206), system console (207) and network management equipment (208). The B channel processor consists of B channel communication processor (204), B channel interface (205).

Description

ISDN packet processing device

1 is a diagram showing a connection relationship between an ISDN exchange using a packet handler interface (PHI) and an ISDN packet processing apparatus according to the present invention.

2 is a block diagram of an ISDN packet processing apparatus of the present invention.

3 shows a protocol to be processed in the ISDN packet processing apparatus of the present invention.

4 is a detailed block diagram of an ISDN packet processing apparatus of the present invention.

5 is an internal processing flowchart of an ISDN packet processing apparatus for establishing a virtual call by B channel from an ISDN network.

FIG. 6 is a diagram illustrating components of a table storing B channel information managed by a system controller.

FIG. 7 is a diagram illustrating components of a virtual call information table managed by a system controller.

8 is an internal processing flowchart of an ISDN packet processing apparatus for establishing a virtual call from a packet network.

9 is an internal process flow diagram of an ISDN packet processing apparatus for recovery of the last virtual call on the B channel.

10 is a diagram showing the components of the D-channel packet call information table.

11 shows an internal processing flowchart for processing a D-channel packet call request of an ISDN packet processing apparatus from outside.

12 shows an internal processing flowchart for processing D-channel packet calls from the ISDN packet processing apparatus to the outside.

* Explanation of symbols for main parts of the drawings

201: system control unit 202: PRI connection unit

203: Memory unit 204: B channel communication processing unit

205: B-channel connection processing unit 206: Packet network connection processing unit

The present invention relates to an ISDN packet processing apparatus for providing a packet switched service, and more particularly, to an ISDN switch that performs only a circuit switching function in an integrated services digital network (ISDN). An ISDN packet processing apparatus for performing an interface with packetming.

The existing communication network has been developed independently of the telephone network for telephone, packet network for data communication and telex network for telex. However, as the society develops, communication networks must be integrated into one in order to comprehensively accommodate the various communication demands that demands and emerges in various forms. The idea behind this is the Integrated Information and Communications Network (ISDN), which is being developed in a form that simplifies the structure of the network and promotes user convenience. Various standards for ISDN are recommended by the International Telephonic Advisory Committee (CCITT). . Here, the realization of the integrated information communication network (ISDN) can be basically achieved by digitizing the subscriber line. More specifically, in an ISDN, an ISDN exchange basically provides two subscribers with two B-channels and one D-channel. Here, the B channel has a speed of 64 Kbps and the D channel has a speed of 16 Kbps. The B channel is a channel through which information is transmitted. The information may be circuit switched or packet switched. Meanwhile, the D channel is a channel through which control signals are transmitted and received. The subscriber transmits and receives a call request and signals according to a circuit switched mode or a packet switched mode. The communication protocols to be carried out in this case are Q.921 and Q.931, which are recommended by the International Telegraph and Telephone Consultation Committee (CCITT). This is a protocol for performing layer 2 and layer 3 in the OSI reference model.

On the other hand, a packet communication network is a network constructed for data communication, and performs a function of assembling, transmitting, and exchanging data in a packet form. The protocol mainly adopted here is X.25 or X.75, which defines the functions of layers 1,2 and 3 in the OSI reference model.

Therefore, when the ISDN exchange does not perform a packet switching service but simply performs a circuit exchange and transmits it as the packet alone, and when the data of a packet network is to be transmitted to an ISDN subscriber through an ISDN exchange, the two communication networks are differently performed. There is a need for an interface device for translating protocols.

This functionality in the past has been developed and mounted as part of an ISDN exchange. An example of such an ISDN exchange is the TDX-10. That is, the TDX-10 can perform both circuit switched and packet. However, the TDX-1B switch, which occupies most of the exchanges in Korea, performs only the circuit switching function. Thus, in order to interwork the ISDN network based on the telephone network including the TDX-1B switch with the packet network including the packet switch, There is a need for a separate interface device to facilitate communication between exchanges. At this time, the interface device performs a packet exchange function and a management function.

If the ISDN exchange implements a block that performs packet switching and management functions in a built-in type, such as the TDX-1B switch, it may cause a problem that affects the existing circuit switching function. It is preferable to construct.

Accordingly, an object of the present invention is to provide an ISDN packet processing apparatus for smoothly communicating between an ISDN switch having a circuit switching function and a packet switch constituting a packet.

In order to achieve the above object, the present invention provides an ISDN packet processing apparatus in an external ISDN packet processing apparatus for processing a packet network connection with the ISDN exchange to provide a packet network service of a digital subscriber subscribed to an ISDN exchange without a packet switching function. A primary group (PRI) connected to the ISDN switch and for processing ISDN call control with the digital subscriber through the ISDN switch by a hierarchical protocol on the D channel through the D channel among the primary group access channels. A connecting portion; A packet network access processor for controlling packet network access by a hierarchical protocol on the packet network; A channel access processing unit for performing access processing of the B channel allocated by the ISDN call control in the primary group access channel by a data link protocol on the B channel; Controlling virtual call establishment and release through a channel communication processing unit for processing the virtual call control between the channel access processing unit and the packet network access processing unit by the packet switched network protocol on the B channel allocated by the ISDN call control, and the B A system control unit for performing channel management and packet network load management; And a memory unit in which a command program for driving the system and limited restarting of each unit is stored, wherein each protocol is integrated into a plurality of independent control modules distributed according to the degree of coupling between layers, channels, and mutual control modules. It is characterized by being able to handle the maximum load while processing the work in real time.

Hereinafter, the ISDN packet processing apparatus of the present invention will be described in detail with reference to the accompanying drawings.

1 is a diagram showing a connection relationship between an ISDN switch using a packet handler interface (PHI) and an ISDN packet processing apparatus according to the present invention together with a connection relationship between an ISDN switch and a subscriber. Although the channels are represented by different lines in the drawing, each channel is formed by substantially time-dividing one transmission line. In addition, the block diagram in the ISDN packet processing apparatus does not have a substantially corresponding relationship with the physical block diagram, and is illustrated in a communication protocol processing dimension to explain the concepts of the B channel packet service and the D channel packet service. A block diagram of the actual ISDN packet processing apparatus is configured as shown in FIG.

In FIG. 1, the ISDN switch includes a subscriber access device 119, a switch 106, a call controller 107, and a D-channel packet concentrator 110. The call controller 107 is a Q controller. And a .931 signal section 108 and a Q.931 * signal section 109. Switching unit 106 is connected to the plurality of subscribers and the B channel through the subscriber access unit 119, and the other side is also connected to the B channel to the other exchange or the ISDN packet processing apparatus according to the present invention, circuit replacement It will perform the function. The call control unit 107 is connected to a plurality of subscribers and a D channel through a subscriber access device, and the other is connected to a D channel to another switch or an ISDN packet processing device according to the present invention. Here, the connection relationship between the subscriber and the ISDN exchange and the connection relationship between the ISDN exchange and the ISDN packet processing apparatus will be described.

The connection between the subscriber and the ISDN exchange is made in the form of 2B + D as described above. On the other hand, the interface relationship between the ISDN packet processing apparatus and the ISDN exchange of the present invention is generally called a packet handler interface (PHI), which is in the form of nB + D.

In more detail, PHI is a primary group speed connection relationship, where n denotes a natural number and B and D denote B and D channels, respectively. The B channel is 64Kbps like the B channel of the subscriber line, and the D channel has a speed of 64Kbps rather than the 16Kbps, unlike the D channel of the subscriber line. Such a configuration is to increase the efficiency of the transmission path and is based on the fact that the proportion of the control signal in the inter-station signals (communication signals between the exchanges) is less than the amount of data to be transmitted. Here, n is a value of 23,30, etc., and is commonly used. 23 is selected in the US or Japan, and 30 is selected in Europe. In Korea, the European method is applied mutatis mutandis. In particular, in the PHI, the value of n is 30 when the packet service is connected to one primary group presser and the packet value is connected to a plurality of primary group subscribers. It is supposed to be a multiple of 30. In addition, the B channel of the PHI is divided into a _b (111) channel that is responsible for three B channel packets and a B _d (112) channel that is responsible for a D channel packet between the subscriber and the ISDN exchange.

Subsequently, the subscriber's request for the packet service and the route to which the subscriber is assigned will be described with reference to FIG.

In FIG. 1, a packet switching service may be of two types, one being performed through the B channel 102 between the subscriber and the ISDN exchange, and the other being performed through the D channel 103. will be.

First, the B-channel packet service will be described. The subscriber performs the signaling process according to Q.931 under the control of the call control unit 107 of the ISDN exchange using the D-channel 103 on the subscriber line to connect the B-channel on the subscriber line. Requires. In response to the request of the subscriber, the call control unit 107 of the ISDN exchange performs a signaling process according to Q.931 * through the D channel on the PHI to request the connection of the B _b (111) channel on the PHI. That is, the call control unit 107 of the ISDN exchange serves to transmit the signaling process so that the B channel 102-119-104-106-111-116 is transparently formed from the subscriber to the portion capable of performing packet service. When the B channel is established, the subscriber controls the X.25 subscriber (ie, an X.25 terminal or other terminal with an adapter for performing a communication protocol such as an X.25 terminal) using the established B channel. Signal and data are delivered to the part capable of performing packet service in ISDN network. At this time, the X.25 data and control information transmitted from the subscriber are in the form of CCITTLAPB (Line Accecc Prcpocol-Balanced), which is the frame configuration standard of worm 2.

On the other hand, if the subscriber requests the packet service to be performed through the D channel, the D. channel packet concentration unit of the ISDN exchanger directly sends an X.25 packet to the D channel 103 on the subscriber line without a channel setting process such as a B channel packet service. Forwarded to 110. In addition, unlike the B-channel packet service, the type of packet to be delivered is configured according to Q.921 (LaPD: Line Acces Protoclo-D channel), which is a standard for Layer 2 of the D-channel. The D channel packet concentrator 110 of the ISDN exchanger transmits the B _d 112 channel on the PHI to transmit the D channel packet transmitted through the D channel 103 of the plurality of subscriber stations to the ISDN packet processing apparatus 115. Will be used. In B _d (112) channels are weighted the D channel packets from the plurality of terminals. That is, the subscriber D channel concentrated by the D channel packet concentrator 110 in the ISDN exchanger is multiplexed on the B _d 112 channel, and delivered to the X.25 and Q.921 processing unit 118 of the ISDN packet processing apparatus. . As such, a plurality of D-channel packets weighted on the same channel additionally have an identification number for identifying the same. Looking at the path of the D-channel packet service in Figure 1, it is 103-119-120-110-112-118. That is, between the subscriber and the ISDN exchange, the packet service is performed through the B _d 112 channel between the ISDN exchange and the ISDN packet processing apparatus that use the D channel for packet service.

2 is a block diagram of an ISDN packet processing apparatus according to the present invention, which includes a system controller 201, a PRI connection unit 202, a memory unit 203, a B channel processing unit 209, and a packeting connection processing unit 206. . The B channel processing unit 209 is composed of a B channel communication processing unit 204 and a B channel connection processing unit 205. In addition, the ISDN packet processing apparatus may further include a system console 207 and a network management device 208 in an external configuration as shown in the figure.

In FIG. 2, the PRI connection unit 202 serves as a physical interface as a part that is connected to the ISDN exchanger through a transmission path. In addition, data transmitted on the same transmission path is separated for each channel, and the data of the B channel is applied to the B channel connection processing unit 205 of the B channel processing unit 209, and the data of the D channel is applied to the protocol required for the signal connection. According to the process. The packet network connection processing unit 206 processes the protocol of layer 1.2.3 according to X.25 or X.75 as a part connected to the packet network. When the protocol of X.25 is performed, the ISDN packet processing apparatus according to the present invention does not have a packet switching function. The ISDN packet processing apparatus is connected as a subscriber to a packet switch of a packet network, and the protocol of X.75 is performed. In the case where the ISDN packet processing apparatus according to the present invention has a concept of performing a packet switching function, the ISDN packet processing apparatus is connected to a packet switch of a packet network as a packet exchange. The B channel processing unit 209 performs a protocol for data on the B channel among the data transmitted from the ISDN exchange. The B channel access processing unit 205 performs the procedure of Layer 1.2, and the B channel communication processing unit 204 Perform the procedure of Tier 3. The memory unit 203 stores data such as subscriber number information management program, billing information, and the like, which are required to operate the ISDN packet processing apparatus.

The system control unit 201 performs a B channel communication processing unit 204, a packet network connection processing unit 206, and a memory unit 203 that perform a protocol of a layer on the B channel processing unit 209 through the first bus line 210. ISDN packet processing device is connected to the PRI connection unit 202 through the second bus line 211 and controls the flow in real time in a series of signal connection and packet data transmission processes asynchronously occurring in each block. Perform resource management, operation, maintenance. Therefore, the ISDN packet processing apparatus is composed of a plurality of functional modules that perform the functions listed above. Each module operating program of the ISDN packet processing apparatus may be stored in the memory unit 203 as described above. The system console 207 and the network management device 208 are connected to the system control unit 201 and serve as means for controlling the ISDN packet processing device from the outside. A system console (generally a terminal that can be configured as a monitor, etc.) is connected to the system control unit 201 in a non-equivalent communication manner, and an operator who uses the system console uses an ISDN packet processing device by using a command necessary for operation through the system console 207. It is possible to manage or output all the status information output from the ISDN packet processing apparatus to the screen The network management apparatus 208 is connected to the system control unit 201 in a synchronous manner by the X.25 protocol, the keyboard And monitor screen and auxiliary memory.

The network management device 208 transmits / receives the command issued by the operator or the command result from the system control unit 201 to the system control unit 201 using the X.25 protocol and can be output from the system control unit 201. Receive information (failure information, billing information, statistical information, state change information…) using the X.25 protocol and store it in the auxiliary memory device and output it to the monitor included in the network management device 208 as necessary. To be. A disk (DISK) or the like may be used as the auxiliary storage device included in the network management device 208. As described above, in the ISDN packet processing apparatus according to the present invention, the blocks for processing each communication protocol have a distributed structure and are connected to one system controller 201 using a common bus to control the overall flow. In order to more clearly explain the function, the signal flow between each block of the ISDN packet processing apparatus and its control when B channel packet communication is performed will be described.

As is well known, B-channel packet communication uses a data communication channel B channel by dividing a signal processing channel and a data communication channel, and uses a D channel to exchange control signals. In case of data communication using B channel, protocol for channel setting is first performed through B channel. The protocol used is X.25, which establishes a virtual circuit for packet switching. For this operation, each communication protocol to be processed in the ISDN packet processing apparatus is shown in FIG. That is, the I.430 / 431 protocol and the Q.921 (LAPD) protocol of the layer 2 data link layer should be implemented on the D channel that exchanges call control information with the ISDN exchange. In Layer 3, Q.931 *, which controls the call control information transfer, should be implemented. On the B channel of the physical layer according to I.430 / 431 established by the above D-channel call control information exchange, LAPB protocol and X.25 packet layer protocol, which are X.25 layer 2 protocols, for establishing virtual lines according to the X.25 protocol. An X.25 PLP should be implemented. On the other hand, in connection with the patch network, the X.21bis standard, X.25LAPB and X.25PLP protocols, which are physical layer protocols using a dedicated line, are implemented. If the ISDN packet processing apparatus performs a packet exchange and the connection of the packet network is a packet switched to packet switched as described above, the X.75 protocol is implemented instead of X.25. Each of the above communication protocols simultaneously performs predetermined communication processing protocols in response to events originating from the outside of the ISDN packet processing apparatus. Therefore, ISDN packet processing is performed to process a plurality of concurrent tasks in real time and to handle the maximum load at the same time. Configuring the inside of the device is an important issue.

Against this background, the ISDN packet processing apparatus according to the present invention has a distributed processing structure for processing each protocol, but for this purpose, the processing blocks are classified by protocol layer and channel having high functional coherency. In addition, the protocol processing modules of Layer 1 and Layer 2, which have high degree of mutual coupling, are composed of one block, and the processing block that controls the same channel with less load of the processing block compared to the performance of the processor is low. In the case of D channel, the control of layer 1, layer 2, and layer 3 is made as a separate processing block (PRI connection unit 202, which processes layer 1, layer 2, and layer 3 that process packet network access trunks. For the same reason, one independent processing block is used (packet network access processing unit 206.) and 30B for layer 2 and layer 3 that process 30B channels. In consideration of the peak loading condition of null, the processing of layer 3 is separated into one independent processing block (B channel communication processing unit 204), and a certain number of B channels are simultaneously accommodated for layer 1 and layer 2. Another independent processing block (B channel connection processing unit 205) is also used as a concept of the highest layer of the independent processing blocks, call connection control, signal transmission, driving procedure management, and B channel management between the individual processing blocks. In addition, in addition to the hatching management of the packet network trunk, another processing block (system control unit 201) for overall control and management of the ISDN packet processing apparatus, such as function realization equivalent to the operation of the ISDN packet processing apparatus, is configured through communication with the operator. Each of the processing blocks described above is constituted by a board including a microprocessor, a memory, and the like in practical configuration. In the boards to have a structure that is similar to the boards of the main system microprocessor performs a communications protocol assigned to the respective processing block.

Next, redundancy for improving scalability and stability of the ISDN packet processing apparatus will be described with reference to FIG. 4.

4 is a detailed block diagram of the ISDN packet processing apparatus of the present invention, showing a case where each block is composed of a plurality of modules. That is, the ISDN packet processing apparatus includes a memory unit 203, a system control unit 201, a PRI connection unit 202, a B channel communication processing unit 204, a packet network connection processing unit 206, a B channel connection processing unit 205, and the like. The bus line 210, the second bus line 211, the first internal serial bus 212, and the third bus line 213 are connected to each other through a communication bus.

In FIG. 4, the PRI connection unit 202, the B channel connection processing unit 205, the B channel communication processing unit 204, and the packet network connection processing unit 206 may each be composed of a plurality of modules. Bus lines for signal transmission between modules are connected as shown in the figure. Here, the dual function of the system control unit 201 will be described.

The system control unit 201 is composed of a main system control module 304 and an auxiliary system control module 305. In normal operation, the main system control module 304 reports the status to the auxiliary system control module 305 periodically. It tells you that it works without any problem. If an abnormality occurs in the main system control module 304, such a status report is not transmitted to the sub system control module 305, and the sub system control module 305 requests a reconfirmation of the state of the main system control module 304. When the abnormality of the main system control module 304 is finally confirmed, the main system control module 304 replaces the main system control module 304. At this time, since the auxiliary system control module 305 has the same status record as the main system control module 304, the ISDN packet processing apparatus continuously operates normally. When the failed main system control module 304 is accommodated and remounted, it serves as a secondary system control module, and serves as the main system control module 304 for the state of the ISDN packet processing device up to the time of installation. You will receive input from the part you are doing. In addition, the memory unit 203 also includes a main memory 306 and an auxiliary memory 307 connected to the respective modules through the first bus line 210, and if an error occurs in the operating memory, another memory is replaced and used. do.

In FIG. 4, the PRI connection unit 202 also includes a plurality of PRI connection modules 301, each of which independently performs a physical interface function and a D-channel protocol processing function. Similarly, the packet network connection processing unit 206, the B channel connection processing unit 205, and the B channel communication processing unit 204 also serve as the plurality of packet network connection modules 308, the B channel connection module 302, and the B channel communication module 303. Each of the plurality of B channel modules 302 is connected to one B channel communication module 303. In the ISDN packet processing device configured as described above, the failure of some component modules of the system, the failure of the connection link key to the outside, etc., can be performed by replacing the function by another module that does not show a fault because each part is composed of a plurality of modules. It increases the stability of the system. If this is explained in more detail as follows.

The duplication of the PRI connection unit 202 functions by configuring a plurality of PRI connection modules 301 when the B channel processing capacity is 30 B channels or more. Here, one PRI connection module 301 becomes a module capable of constructing a PRI connection unit 202 that performs a complete operation as one. For example, if the ISDN packet processing apparatus processes 60B channels, there are two PRI connection modules 301, and the D channel of one PRI connection module 301 serves as a main signal channel, so that the ISDN switch and call control are performed. Send and receive information. The 60B channels are multiplexed on the first internal serial bus 212 and applied to the B channel connection processing unit 205. In this case, when one B channel connection module is configured to process eight B channels, the 60B channel is distributed and processed by eight connection modules. If an abnormality occurs in one PRI connection module 301, the system control unit 201 detects this and B of the B channel communication processing unit 204 in charge of the 30B channel of the PRI connection module 301 is not abnormal. This situation is communicated to the channel communication module 303. The B channel communication module 303, which has received such a situation, prevents the malfunction of the system by causing the corresponding B channel connection module 302 to stop processing for the abnormal 30B channel. In addition, the operation of the remaining B channel without any abnormality is to be made normally. Therefore, even if one PRI connection module fails, the overall B-channel processing capacity is reduced, and the overall operation of the ISDN packet processing device is not affected. At this time, if the call control signal was exchanged with the ISDN exchanger using the D channel of the failed PRI connection module, the system can be continuously operated by using the new call control signal exchange channel using the D channel of another PRI connection module.

If a failure occurs in the B channel communication module or B channel connection module, the B channel used by the failed module is processed or accepted by another module so that the system can operate normally with the reduced processing capacity without stopping the system. .

Likewise, the packet network access processing unit 206 is composed of a plurality of packet network access modules 308 that can be configured as a packet network access processing unit 206 alone, and when a failure occurs in one module, a module that has failed in another module is performed. It can be replaced with a function.

As described above, the operation of the ISDN packet processing apparatus is stabilized by duplexing the B channel communication processing unit 204, the B channel connection processing unit 205, the packeting connection processing unit 206, the system control unit 201, and the PRI connection unit 202. You can do it.

Subsequently, the B-channel packet call service is performed for the signal flow and its role performed to perform the signal setting process and the release process when the call request is released by the ISDN packet processing apparatus using FIGS. 5 to 9. The explanation will be centered.

5 shows an internal processing flow diagram of an ISDN packet processing apparatus for virtual call setup by B channel from an ISDN network. Prior to explaining the signal flow, for convenience of explanation, an ISDN packet call requested from an ISDN terminal is called an incomong call, and an ISDN packet call is generated by a virtual call establishment request from the packet network to an ISDN booster terminal. It is called an outgoing call and the signals transmitted and received when connecting other signals will use the name used in the CCITT Recommendation.

Referring to FIG. 5, the start of processing of the first call (incomong call) in the ISDN packet processing apparatus of the present invention starts from receiving a Q.931 * SETUP message using the D channel of the PRI connection unit 202. FIG. In the figure, the part indicated by note 1 indicates that the signal link setting process is omitted, which is a case where the signal link has already been set. The PRI connection unit 202 connects 30 64 Kbps B channels to the B channel connection processing unit 205 by connecting the primary group of the pressure to the ISDN exchanger and exchanges call control information with the ISDN exchange through the 64 Kbps D channel. . The call control information is information for allocating, connecting, and disconnecting the B channel. In addition, the PRI connection unit 202 is composed of PRI connection modules 301 for processing call control information for the 30B channel. If one PRI connection module 301 is added to increase the processing capacity, the 30B channel unit is used. It will be expanded to. In this case, in the PHI, when the B channel is set to a multiple of 30, the D channel belonging to one of the PRI connection modules 301 constituting the PRI connection unit 202 is the common signal channel. It selects and exchanges call control information with ISDN exchange. The 30B channels input to the PRI connection modules 301 constituting the PRI connection unit 202 are multiplexed on the first internal serial bus 21 by a time division multiplexing method. Since the B channel access processing unit 205 is responsible for the allocated B channel among the multiplexed B channels, the B channel access module should be equipped to handle more than the total number of B channels in the ISDN primary group connected to the ISDN packet processing system.

The Layer 3 (Q.391 *) protocol processing portion of the PRI connection unit 202 is a call control module of the system control unit 201, and the B channel, originating address (E.164), and identifier identified in the SETUP call ' Report on the message 'Receipt of setup' and wait for the response. The call control module of the system control unit 201 determines whether the received b-channel information is a preferred B channel or an exclusive B channel. As a result of the determination, in the case of the preferred B channel, the idle channel B is allocated among the 30B channels, and the call identifier is transmitted to the layer 3 of the PRI connection unit 202 together with the call identifier. In this case, the call control module uses data information for each B channel stored in its memory to allocate the idle B channel, and the B channel in a round robin manner for the idle B channels. Will be assigned. You can also use other allocation schemes here. In addition, it is possible to give priority to a predetermined B channel in order to provide operational flexibility in allocating the B channel. In other words, the round robin method is basically used to give equality to each B channel, but the priority is given to a specific B channel by the operator's command operation. On the other hand, if the result of the determination and the exclusive (exclusive) B channel, whether or not the status of the channel B is idle or not, it sends a success or error message to the call setup acknowledgment message. In addition, the call control module of the system control unit 201 sends a successful 'call establishment acknowledgment' message and stores the information received from layer 3 and the state value of the call as a table called 'B channel information' so that the signal is completely Keep until released. FIG. 6 is a diagram illustrating components of a table storing B channel information, and is referred to in the above-described respective processes.

Layer 3 of the PRI connection unit 202, which receives a response from the control module of the system control unit 201, performs the Q.931 * protocols such as connection and transmission and reception of a connection confirmation message through an IS-DN exchange and a D-channel signal. If an error occurs, the layer 3 release process is performed by itself, and the system control unit 201 requests the preparation of the call so that the call is completely released. If the ISDN call is established by Layer 3 of the PRI connection 202, the work for establishing an X.25 virtual call from the X.25 stack is performed through the procedures of Layer 2 and Layer 3, and as shown in FIG. The LAPB protocol (Layer 2) for establishing the X.25 data link with the channel access processing unit 205 proceeds first, and when the data link setting is completed, the virtual call setting process of the packet layer (X.55 PLP) is performed. The channel communication processing unit 204 is mainly made. The B-channel communication processing unit 204 issues a 'routing request' message to connect a trunk wire to be received when an X.25 virtual call request (X.25CR) packet is received from an X.25 terminal. It carries the called address and the virtual call identifier and requests the call control module of the control unit 201 and waits for a response.

The call control module of the system control unit 201 inspects the load state of the current ISDN packet processing apparatus and releases it when the number of virtual calls in progress is greater than or equal to a predetermined level of the maximum processing capacity of the system. For example, if the number of virtual calls currently in progress is more than 90% of the capacity of the system, the B channel communication processing unit 204 sends a 'release request' message to release the message. Otherwise, the routing process is performed. do. The routing process consists of two stages. The first step is to check whether the called address of the X.25 CR packet is registered in the routing table. The routing table refers to the registration of the destination line to be allocated to specific destination addresses by the operator's command in the table. In this case, the routing result is automatically determined by the destination circuit line registered in the table. Proceed to step 2 only if the destination address is not registered in the routing table. In the second step, one circuit is selected from the available trunk lines of the packet network access processing unit 206. In this case, the selection method basically selects a circuit whose load is the best according to the principle of load sharinfg. do. However, in the case of an operator's command, it may be selected using a round robin method. If the routing result as described above is the trunk line of the packet network access processing unit 206, the call control module of the system control unit 201 routes the message 'routing information' to the B channel communication processing unit 204, which is waiting for the routing result. Send the trunk line of the result.

7 is a diagram illustrating the components of a virtual call information table for recording virtual call information. The call control module of the system control unit 201 transmits the message 'routing information' to the B channel communication processing unit 204, and thereafter. The related information is recorded in the virtual call information table. In addition, the call control module stores the caller address in the area corresponding to the address information of the B channel information table as shown in FIG. The B-channel communication processing unit 204 then sends a 'virtual call setup request' message (same as an X.25 CR packet) to the packet network connection processing unit 206, which causes the packet network connection processing unit 206 to transmit the packet network and the X.25. When a call is set up, and a 'virtual call setup confirmation' (X.25 call connected packet) message is received from the packet network connection processing unit 206, indicating that an X.25 virtual call has been established, the system control unit 201 and the X.25 terminal are received. Each send a 'Virtual call setup confirmation' message and a 'call connected' packet to indicate that the incomong call is completed. Herein, the X.25 CR transmitted from the packet network access processing unit 206 to the packet network allows the X.75 protocol to proceed when the ISDN packet processing apparatus has a packet switching function.

Here, if the ISDN packet processing apparatus has a packet switching function and the routing result is an ISDN network subscriber, the process of 1-2 according to FIG. 8 is performed. In case of progress, the communication is performed by switching to the burr through the B channel communication processing unit 204 and the B channel connection processing unit 205 to the X.25 terminal.

That is, if the result of the routing is not one of the trunk lines of the packet network access processing unit 206 but one of the 30B channels which are the ISDN exchange lines, the call control module performs the B channel communication processing unit 204 after the process of steps 1-2 of FIG. Send the routing result to the message 'routing information', and the B channel communication processing unit 204 establishes an X.25 virtual call. After the X25 virtual call is established, a transparent data transfer step is performed so that only the X.25 data link layer (layer 2) and the X.25 packet layer (layer 3) control data transmission. That is, only the packet network connection processing unit 206 or the B channel connection processing unit 205 and the B channel communication processing unit 204 perform the operation, and the system control unit 201 does not become involved in this operation. The call control module transitions the state information of the B channel information table as shown in FIG. 6 to a 'virtual call active' state.

8 is an internal processing flowchart of an ISDN packet processing apparatus for establishing a virtual call from a packet network, which will be described with reference to FIG.

In FIG. 8, when the packet network connection processing unit 206 receives an X.25 'call request' packet from the packet switch, processing for the second call is started. The packet network access processing unit 206 reports the call request module to the call control module of the system control unit 201 and waits for the response. The call control module of the system control unit 201 checks the load state of the current ISDN packet processing apparatus as in the first case, and if the number of virtual calls currently in progress is equal to or greater than a predetermined maximum processing capacity of the ISDN packet processing apparatus, for example. If it is 90% or more, the packet network access processing unit 206 sends a 'call release request' message to release the message. Otherwise, the routing process is performed. Routing here is routing for the 30B channel connected to the ISDN exchange, which is the routing table for the call address of the X.25 'call request' packet as in the first call (incoming call). Check if you are registered at. If there is a B channel registered only in the result of the investigation, the B channel is allocated, the routing is terminated, and if the routing is not registered, the second step is performed. The second step compares the address information in the B channel information table of FIG. 6 with the destination address of the X.25 call request packet for each 30B channel, and selects the corresponding B channel if there is a matching B channel. In this case, one of the idle B channels is allocated. The allocation of the idle B channel is the same as the preferred B channel allocation method in the ISDN call setup process of the first call. If the state of the B channel selected in this process is the active state of the virtual call, the call control module of the system control unit 201 allocates the allocated B channel and the virtual call to the packet network access processing unit 206 which is waiting for a response. Send the identifier in a message called 'routing information'.

The address information and the number of virtual calls are recorded in the B channel information table, and all information is recorded in the virtual call information table. In addition, the call control module of the system control unit 201 sends an 'ISDN call setup request' message to the layer 3 of the PRI connection unit 202 to establish an ISDN call if the selected B channel state is idle. Then, the call control module receives the 'ISDN call setup confirmation' message from the PRI connection unit 202, and when the establishment of the ISDN call is completed, the B channel connection processing unit (B) is passed through the B channel communication processing unit 204 to establish the X.25 call. Send an 'X.25 link setup request' message to the X.25 terminal and the B-channel connection processing unit 205 to set up the X.25 link. The packet network access processing unit 206, which has been waiting for the transmission, sends a message of 'routing information' to the B channel and the virtual call identifier of the routing result. The process after this is the same as in the case of the first incoming call, only the direction of progress is reversed. X. CR performed in the part indicated by Note 4 of FIG. 8 becomes X.75 CR or X.75 CC when the ISDN packet processing apparatus has a packet switching function, and the part indicated by Note 5 is already D channel signal link. Indicates that the signal link process is omitted. In note 6, in the case of a call request for a B channel that has already established a virtual call, all steps between 1 and 2 immediately preceding are omitted.

Next, the recovery and release processing that occurs after the X.25 virtual call is established and the data transfer step is performed will be described with reference to FIG.

9 is an internal process flow diagram of the ISDN packet processing apparatus for the recovery of the last virtual call on the B channel.

In FIG. 9, the B channel communication processing unit 204 or the packet network connection processing unit 206 receives a 'call release request' (X.25 CLR) packet, which is a release packet of an X.25 virtual call, from an X.25 terminal or a packet network. Then, it sends a 'call release' message to the call control module of the system control unit 201 and performs their own X.25 PLP release processing. The call control module of the system control unit 201 initializes this table after extracting B channel information from the second item of the virtual call information table of FIG. Next, the number of virtual calls is reduced by accessing the B channel information table. At this time, if the number of reduced virtual calls is 0, the timer is operated. If none of the virtual calls are established on the above B channel until the end of the timer, the B channel connection processing unit 205 sends a message to release the X.25 link. ) And then send a 'release signal' message to the PRI connection unit 202 for ISDN call control so that the ISDN release process is processed and then initialize the contents of the B-channel information table. If the release of the ISDN call occurs first, or the X.25 link from the X.25 terminal occurs, it is notified to the call control module of the system control unit 201, where the same or similar release processing is performed. The release process on each communication protocol is performed in the block in charge of that protocol. The part indicated by Note 7 of FIG. 9 becomes a part which can be replaced by the process of releasing the link to the X.25 terminal after the timer runs out in the ISDN packet processing apparatus. In addition, the part marked 8 is generally unnecessary when the connection with the ISDN network is always maintained.

Next, D channel packet communication processing in the ISDN packet processing apparatus of the present invention will be described with reference to FIGS.

In D-channel packet communication, SAPI value is set to 16 after link connection according to LAPD protocol with SAPI (Service Access Point Identifier) value of 16 as service identifier in D channel, which is the signal link provided when ISDN intruder is connected. This is achieved by loading X.25 packets in one LAPD frame. The D-channel packet thus collected is collected by the ISDN line exchanger and delivered to the ISDN packet processing apparatus of the present invention for processing. At this time, the connection between the ISDN line exchange and the ISDN packet processing device follows the following procedure according to the PHI standard. Makin first place, the procedure for allocating the primary groups the subscriber connection line D channel packet B _d channel, a data transmission on the PHI ^* according to the Q.931 protocol, as in normal B-channel assigned to the B-channel packet by the network management Prior to this, the B _d channel is determined. In these B _d- channels, D-channel packets sent from a plurality of ISDN-suppressor terminals are collected and multiplexed at the ISDN circuit switch. Therefore, a procedure for distinguishing each D channel packet on the B _d channel for each subscriber is needed. This is specified in the PTI to solve by putting an identifier called Data Link Connection Identifier (DLCI) in the LAPD frame. According to the PTI, a special virtual signal data link with a DLCI value of 0 is first established on the B _d channel (if the DCLI value is 0, this is called a signaling DLCI, or SDLCI), and the link between the ISDN exchange and the ISDN packet processing device is established. DLCI is allocated for the D-channel packet.

The data link by this DLCI value is performed by LAPD procedure. On top of this, the virtual circuits of the X.25 packet layer are connected to D-channel packet exchange. The internal operation of the ISDN packet processing apparatus for the D channel packet communication processing is the same as between the B channel packets. However, instead of exchanging messages such as call establishment, connection, and connection confirmation between the ISDN exchange and the PRI connection unit 202 in order to allocate the B channel on the primary group access link during the B channel packet, the DLCI on the link having the above-described DLCI value is 0. It is replaced with a connection message (CONNECT) for allocating a request call setup message (SET-UP) and a DLCI value, and then a SABM for establishing a LAPB link with the B-channel access processing unit 205, a SABME for establishing a LAPD link instead of a UA message, The difference is that UA message exchange takes place.

11 shows an internal processing flowchart for processing a D-channel packet call request from the outside to the ISDN packet processing apparatus.

Referring to FIG. 11, the internal operation processing will be described first. In the B channel access processing unit 205, a virtual signal data link having a DLCI value of 0 is established on the B _d channel from the ISDN exchange, and is allocated at the ISDN exchange through the link. When the B channel access processing unit 205 receives the SETUP message including the received DLCI value, the B channel communication processing unit 204 sends a message, 'DLCI allocation request', to inform the BCI communication processing unit 204. After checking the validity, the B-channel access processing unit 205 sends a 'DLCI assignment' message. The B channel access processing unit 205 sends a CONNECT, which is a response message for DLCI allocation, through ISDN exchange. Then, when the layer 2 data link connection process is completed by SABME and UA signals, the B channel access processing unit 205 performs B channel communication. The link setting notification message is sent to the system control unit 201 via the processing unit 204 to inform the fact that the link is established. In this process, the system controller 201 receives the B _d channel number, the DLC value, and the address information, stores the received information in the D channel packet call information table as shown in FIG. To manage. Subsequently, the X.25 virtual call request packet is received from the X.25 terminal. After the ISDN call is established through the PRI connection 202 during the B channel packet communication processing, the X.25 virtual call request is established. This is the same process as when an X.25 virtual request (X.25 CR) is received from an X.25 terminal after the completion of the layer 2 process. However, only using the D-channel packet call information table as shown in FIG. 10 instead of the B-channel information table is different. The note 9 in FIG. 11 indicates that the signal data link is already established (SDLCI), and the process is omitted.

12 shows an internal processing flowchart for processing a D-channel packet call from the ISDN packet processing apparatus FH to the outside.

As shown in FIG. 12, it can be seen that the processing of the outgoing call of the D-channel packet call is almost similar to the processing of the second call of the b-channel packet call. However, the process from the system control unit 201 to receiving the 'routing request' message until sending the 'routing information' message to the package network access processing unit 206 is different. In other words, in the call control module in the system control unit 201, the routing request, upon receiving the message, to select a B _d channels available to a routing process for a B _d channel in the same way as when B channel processing B channels The processor 204 sends a 'link setting request' message.

At this time, the call control module stores all the contents of the virtual call information table as shown in FIG. 6 and all data except the data link identifier element of the D-channel packet information table as shown in FIG. At this time, the B channel communication processor 204 receives the destination address and the B _d channel number from the call control module, and sends a SETUP message for requesting DLCI allocation using the information to the ISDN exchange via the B channel connection processor 205. . When the B channel connection processing unit 205 receives the CONNECT message from the ISDN exchange, and the B channel communication processing unit 204 receives, the B channel is used to extract the assigned DLCI value from this message and carry out the LAPO protocol with the value. After receiving a command to the access processing unit 205 and receiving a 'link setting notification' message from the B channel access processing unit 205 indicating that the link connection to the corresponding DLCI was successful, the DLCI value is transmitted to the call control module of the system control unit 201. Sends 'Link setup notification' message with B _d channel value. The call control module stores the allocated DLCI value in the data link identifier of the D-channel packet call information table as shown in FIG. 10, transitions the state element value, and selects the B _d channel information selected by the packet network access processing unit 206 waiting for the routing result. And DLCI values are sent in the 'routing information' message. Subsequent process It is the same as the process of B-channel packet processing, and there is only internal point that DLCI value is added to the identifier element for each call.

The portion indicated as note 10 in FIG. 12 is also the case where the signal data link has already been established, similarly to the portion indicated as note 9 in FIG. 11, indicating that the process is omitted. Next, the present invention maintains a system given additionally in addition to packet communication processing which is a basic function of the ISDN packet processing apparatus. The management function will be described.

ISDN packet processing apparatus according to the present invention, the maintenance of the system. It can have synchronous and asynchronous ports for maintenance and network management functions. Keep these via. The diagnostic command function for maintenance is the same service from both ports. In the synchronous port, X.25 packet communication can be used to form multiple virtual calls to issue diagnostic commands not only for own system but also for systems in other regions. have. The network management device 208 connected to the synchronization port has an auxiliary memory device for storing all information output from the system, for example, a disk, and has an X.25 protocol processing function. The system console that connects to the asynchronous port keeps its own system. As a dedicated device for maintenance, a display unit such as a monitor for outputting a screen and a key input unit such as a keyboard for inputting an operator's signal are provided. In order to communicate with the network management device 208, the system control unit 201 has a network management module, which processes the X.25 protocol, and thus the remote ISDN packet processing device from the network management device 208. Even when a virtual call is established, the network management module acts as a call control module to make a routing request for the virtual call so that the X.25 virtual line is connected to the remote ISDN packet processing device.

The synchronous and asynchronous ports can be configured to be enabled after logging in by entering a password to use diagnostic commands. This is to prevent unjust access by the network operation due to the large impact on the public.

Functions that can be performed by the network management device 208 may include a statistical function for each B channel or trunk circuit, a communication protocol variable change function, such that failure occurrence information, billing information, statistical information, state change information, and the like are output. can do. The network management device 208 stores all the software programs for operating the respective blocks of the ISDN packet processing device. When the first ISDN packet processing device is installed, the network management device 208 communicates the software program with the system control unit 201 and the memory unit. (203). The memory unit 203 is designed to be backed up to a battery so that its contents are preserved even when power is delivered. In this configuration, after the initial system installation, the system operation is performed by the system control unit 201 without the help of the network management device 208. It is driven to load. In addition, when a partial software program of each block is to be changed, the contents thereof can be loaded through the network management device 208 so that a new program can be installed even during system operation. In this case, when the memory 203 is configured using a memory device of RAM type, which is free to write and read, it is possible to change the software program for driving each block from the outside so that the overall performance of the system can be expected. do. Such a program loading function may be achieved by establishing a virtual call for a remote system in the network management device 208, and thus collective software management may be performed for systems in various regions. In addition, the system console 207 or the network management device 208 may have a function to automatically log out when there is no input from outside.

As described above, the present invention provides an ISDN packet processing apparatus that performs an interface between an ISDN switch and a packet network in order to provide a packet service function to a subscriber connected to an ISDN switch having only a circuit switching function. The advantage is that it is possible to establish an ISDN network using the exchange without replacing it with a new exchange.

Claims (11)

An external ISDN packet processing apparatus for processing a packet network connection with the ISDN switch for providing a packet switching service of a digital subscriber subscribed to an ISDN switch having no packet switching function, the primary group being connected to the ISDN switch and the primary group. A primary group (PRI) connection for processing ISDN call control with the digital pressurizer via the ISDN switch by a hierarchical protocol on the D channel through the D channel of the access channel; A packet network access processor for controlling packet network access by a hierarchical protocol on the packet network; A channel access processing unit for performing access processing of the B channel allocated by the ISDN call control in the primary group access channel by a data link protocol on the B channel; Controlling the virtual call establishment and release through a channel communication processing unit for processing the virtual call control between the channel access processing unit and the packet network access processing unit by the packet switched network protocol on the B channel allocated by the ISDN call control, and the B A system control unit for performing channel management and packet network load management; And a memory unit in which a command program for system driving and limited restart of each unit is stored, wherein each protocol is formed by independent control modules distributed according to the degree of coupling between layers, channels, and mutual control modules. External ISDN packet processing device, characterized in that to handle the real-time work at the same time handling the maximum load. The system of claim 1, wherein the device is connected to the system control unit in an asynchronous communication manner to input a command required for operating the system through a keyboard and to output all status information output from the system through a monitor to a screen to manage the system. External ISDN packet processing device characterized in that it further comprises a system console. 3. The apparatus of claim 2, further comprising a network management device connected to the system control unit in a synchronous manner by a packet switched network protocol, and storing all state output information of the system in an auxiliary memory device to manage the network. External ISDN packet processing device, characterized in that. The external ISDN packet processing apparatus of claim 1, wherein the memory unit is backed up to a battery. The external ISDN packet processing apparatus of claim 3, wherein the status output information is failure occurrence information, billing information, statistical information, status change information, and the like. 4. The system of claim 3, wherein the system control unit comprises a network management module for connecting a virtual line with a remote packet processing system by a routing request for a virtual call when a virtual call is established from a network management unit to a remote system. External ISDN packet processing device characterized in that. The method of claim 1, wherein the primary group (PRI) connection, the packet network connection processing unit, the channel connection processing unit, the channel communication processing unit, the system control unit is structured in a distributed manner, to provide a packet service to the ISDN oppressor mutually 'call setup receiving passage ',' Call setup acknowledgment ', X.25 link setup notification', 'routing request', 'routing information', 'virtual call setup request', 'virtual call setup check', 'ISDN call setup request', 'ISDN Call setup confirmation ',' X.25 link setup request '. 'Release', 'Virtual Call Release Request', 'X.25 Link Release', 'Signal Release', 'DLCI Assignment Request', 'DLCI Assignment', 'Link Setting Notification', 'Link Setting Request', etc. External ISDN packet processing device, which allocates channels in exchange and sets up X.25 virtual interaction. 8. The ISDN packet processing apparatus of claim 7, wherein the ISDN packet processing apparatus sets up a call for each channel, a channel state for use in releasing a call, address information, virtual call number, virtual call identifier, and ISDN call identifier in performing B channel packet communication processing. External ISDN packet processing device, characterized in that the table to store and manage the timer information. 8. The ISDN packet processing apparatus of claim 7, wherein the ISDN packet processing apparatus performs channel number, data link identifier, virtual call identifier, packet network line number, and address information for use in setting up and releasing a call for each channel in performing D-channel packet communication processing. External ISDN packet processing device, characterized in that for storing and managing the table of the channel status. The apparatus of claim 7, wherein the ISDN packet processing apparatus stores and manages a virtual call identifier, a line or channel number, a virtual call address, and a virtual call state for all virtual calls from virtual call setting to virtual call release. External ISDN packet processing apparatus, characterized in that. An external ISDN packet processing apparatus for processing a packet network connection with the ISDN exchange to provide packet network services of a digital subscriber subscribed to an ISDN exchange without a packet switching function, the primary group being connected to the ISDN exchange, and the primary group connection. A plurality of primary group (PRI) connection modules for processing ISDN call control with the digital pressurizer via the ISDN exchange by a hierarchical protocol on the D channel through the D channel of the channel; A plurality of packet network connection modules for controlling the packet network connection by means of a hierarchical protocol on the packet network; In order to perform the connection processing of the B channel allocated by the ISDN call control of the primary group access channel by the data link protocol on the B channel, the plurality of primary group access modules are connected through an internal serial bus and the internal serial. A plurality of channel access modules for allocating B channels among a plurality of B channels that are time-division multiplexed on a bus; A subsidiary system independent of a predetermined number of channel access modules for processing virtual call control between the channel access processing modules and packet network access processing modules according to the packet switched network protocol on the B channel allocated by the ISDN call control. A plurality of channel communication modules connected through a bus; A plurality of memory units which store a command program for system driving and limited restraining for each unit; The primary connection modules are connected through an auxiliary system bus and the memory units, channel communication modules, and packet network connection modules are connected through a main system bus to control the ISDN call setup and release, and the virtual call setup and release. And a plurality of system control modules for controlling the system by performing the B-channel management and the packet network load management, and in the event of a failure, to control the system by exchanging main / units with each other so that the system operation can be operated without stopping in the event of a failure. External ISDN packet processing device characterized in that.