KR0150034B1 - Atm ring node apparatus - Google Patents

Abstract

The present invention relates to an asynchronous transmission mode (ATM) ring node device for performing a real-time line switching when a failure occurs by applying a conceptual failure recovery method to an ATM ring applied to a broadband integrated information network (B-ISDN). The management line receiving physical media matching unit; A management line transmission physical medium matching unit; One physical layer and two physical layer performing the physical layer functions recommended by ITU-T SG.13; A line switching unit for routing the service cell data provided by the physical layer unit to the ATM layer; An ATM layer unit that performs an ATM layer function; And a network / subscriber connection unit performing a protocol for connection with a network or subscriber and an upper layer unit performing AAL or a higher protocol.

Description

Asynchronous transfer mode ring node device

1 is a schematic diagram of a ring network.

2 is a block diagram of a ring node device.

3 is a functional block diagram of a line transfer part.

4 is a ring node signal flow diagram in the case of steady state.

5 is a flow diagram of a ring node signal when a failure occurs on the transmission operation line.

6 is a signal flow diagram at node 2 in case of ring node 3 failure.

7 is a flow diagram of a ring node signal when a failure occurs in the reception operation line.

8 is a signal flow diagram at ring node 2 when ring node 1 fails.

9 is the signal flow throughout the network in normal network operation.

10 is a signal flow diagram of the entire network upon failure of ring node 2. FIG.

The present invention relates to an asynchronous transmission mode (ATM) ring node device configured to have a recovery function for line and node failures in a ring-type distributed access network applied to a broadband integrated information network.

The standardization of broadband integrated telecommunication networks is actively progressing and a new data transfer method called Asynchronous Transfer Mode (ATM) is applied to successfully build it. This is a fixed packet (ATM cell) of limited data length (53 bytes) in order to compensate for the disadvantage of using the variable length packet used in the existing data network and to compensate for the disadvantage of bandwidth inefficient use of the conventional synchronous multiplexing transmission method. ), The hierarchical concept is applied for each protocol processing, and the method of multiplexing the cells of multiple sources for their transmission is applied. Its hierarchical structure is divided into physical layer, ATM layer, AAL layer, etc. Especially, in the physical layer, cell-based or STM-1-based (Synchronous Transfer Mode type 1) according to a format for transmitting data to a physical medium. : 155.520Mbps). And even though the demand for broadband service is more diverse and distributed or concentrated locally, it is economical to have a ring or point-to-multipoint network rather than a point-to-point network in a network that mainly uses distributed services such as broadcast type services. Will be. In addition, in the case of many internal processing services that enable broadband information communication from a business building to a private network, the ring-type network configuration has many advantages over point-to-point. For this reason, many countries have been researching recovery methods for failures in ring-structured networks. However, this paper describes the schematic flow of tracks for failure recovery methods in data packet networks and synchronous optical networks (SONET). I just do it.

Accordingly, the present invention provides an asynchronous transmission mode (ATM) ring node device for applying a conceptual failure recovery method to an ATM ring applied to a broadband integrated information network (B-ISDN) to perform real-time line switching when a failure occurs. There is a purpose.

In order to achieve the above object, the present invention provides an operation line receiving physical medium matching unit; Management line transmission physical media matching unit; One physical layer and two physical layer performing the physical layer functions recommended by ITU-T SG.13; A line switching unit for routing the service cell data provided by the physical layer unit to the ATM layer; An ATM layer unit that performs an ATM layer function; And a network / subscriber connection unit performing a protocol for connection with a network or subscriber and an upper layer unit performing AAL or a higher protocol.

Hereinafter, the present invention will be described in detail with reference to FIGS. 1 to 10.

FIG. 1 is a diagram illustrating a shared medium network configuration in a ring form. As illustrated, a plurality of ring nodes RN1 to RNn are connected in a double ring structure.

2 is a block diagram of a ring node device. The ring node device includes a management line receiving physical medium matching unit 201, a management line transmitting physical medium matching unit 202, and a physical layer recommended by ITU-T SG.13. Physical layer 1 unit 203 and physical layer 2 unit 204 which perform a function, a line switching unit 205 for routing service cell data provided by two physical layer units to an ATM layer, and an ATM layer function. ATM layer 206, upper layer 207 performing AAL or higher protocols (multiplexing, switching, ...) and network / subscriber connection 208 performing protocols for connecting to the network or subscriber. do.

This means that each ring node forming a ring has a double ring structure consisting of an operation line and a spare line to maintain the OAM signal flow of the physical layer, and is used to isolate the failure part so as to prevent the disconnection of the service path due to the failure. Perform a function that supports.

The receiving unit of the operation line receiving physical medium matching unit 201 receives the service cell data from the preceding node through the operation line as an optical signal 210 and converts it into an electrical signal and reproduces a clock from the signal to physical layer 1. Monitors the power transmitted to the unit 203 and the optical power of the received optical signal to provide the input signal loss information 226 of the operation line to the layer management unit 209 and the line switching unit 205 when it is less than the threshold power. Perform a function to apply to maintenance.

The transmitter converts an electrical signal transmitted from the physical layer first unit 203 into an optical signal 225 and supplies a basic physical layer OAM flow by supplying it to a node delivering a service through a preliminary line.

The management line transmission physical medium matching unit 202 receives the optical signal 211 of the spare line provided from the next node of the operation line, converts the signal into an electrical signal, and reproduces a clock from the signal to the physical layer 2 unit 204. By monitoring the optical power of the received optical signal and the function provided to the input signal loss information 226 of the reserve line to the layer management unit 209 and the line switching unit 205 in the case of less than the threshold power for operation / maintenance Perform the function to apply. Its transmitter performs a function of converting an electrical signal provided by the physical layer 2 unit 204 into an optical signal 212 and providing it to the next ring node of the operation line 212.

The receiving unit of the physical layer unit 203 receives the electrical bit stream provided by the operating line receiving physical medium matching unit 201 and converts it into parallel data, and the reframing function by section A1 and A2 byte data, section and path over. Function and operation of processing head and extracting 53 bytes of ATM cell from VC4 container, checking header error, classifying abnormal cell, and transmitting this cell data and its control signal 213 to line transfer unit 205. Extracts information on the preliminary line 225 of the current ring node provided by the previous line node from the data channel of the path overhead, and provides the information to the line switching unit 205 and conversely, the physical layer 1 unit 203. Receives the cell data transmitted from the line switching unit 205 and its control signal 214 to the transmitter of the transmission line and provides it to the management line receiving physical medium matching unit 201 as the reverse process of the above process. It performs a function. At this time, if there is no cell data transferred from the line transfer unit 205, the VC4 container in the STM-1 frame is filled with an idle cell, and propagation information of the operation line failure information is transmitted to the operation line transfer ring node through a communication channel of path overhead. It also has a function to propagate whether the input operation line has a failure state to the previous ring node using the data channel of the path overhead. Here, the operation line is used as a path for providing service cell data, and the backup line provides basic OAM information flow of the physical layer in normal operation, and in case of failure, performs fault isolation to deliver the returned service cell data to the next stage of the failure location. Performs a function that provides a path.

The receiving unit of the physical layer 2 unit 204 receives an electrical bit stream provided by the operating line transmission physical medium matching unit 202 and converts it into parallel data, and reframing function and section and path over by A1 and A2 byte data. Function and operation of processing the head, extracting 53 bytes of ATM cells from VC4 container, checking header errors, classifying cells with no abnormality, and transmitting this cell data and its control signal 215 to the line transfer unit 205. Extracts the operation line 212 failure information of the current ring node provided by the ring node next to the line from the data channel of the path overhead and provides it to the line switching unit 205 and conversely, the physical layer 2 unit 204. ) Transmits the cell data transmitted from the line transfer unit 205 and its control signal 216 and provides it to the management line transmission physical medium matching unit 202 in the reverse process of the above process. It performs a function. The input of the line switching unit 205 receives the transmission ATM service cell data 213, 215, 218 inputted from the physical layer 1 unit 203, the physical layer 2 unit 204, and the ATM layer unit 206 through three input ports. Combination of the respective line failure information provided by the physical layer first unit 203, the physical layer second unit 204, the operating line transmission physical medium matching unit 202, and the operating line receiving physical medium matching unit 201, and The path control signal is generated by the control signal of the layer management unit 209 and the function of routing each input port to the three output ports 214, 216, and 217 based on the signal and its operation state and the control of the layer management unit Perform the function.

The transmitting unit of the ATM layer unit 206 receives service data provided from the upper layer 207 and primitives for controlling the same, thereby establishing connection setter conversion, ATM cell generation, ATM OAM cells provided by the layer management unit 209, The multiplexing function of the service cell and the unassigned cell provided by the upper layer 207 is performed to provide the multiplexed cell data and its control signal 218 to the input port of the line switching unit 205. The receiver of the ATM layer unit 206 receives ATM cell data provided from the line switching unit 205 and its control signal 217 to extract / analyze a header of 5 bytes, and according to this information, the layer manager 209 or higher. The hierarchical portion 207 delivers 48 bytes of service data and its primitives 219 and 228.

The transmitting unit of the upper layer unit 207 receives the service data and its primitives 222 provided by the network / subscriber connection unit 208 and performs the corresponding functions of the upper layer to provide them to the ATM layer (220). Such upper layer functions may be, for example, ATM switching function, AAL function, N-channel multiplexing function or interworking function. The receiving unit of the upper layer unit 207 performs a function of processing the functions of the upper layer and providing the service data and primitives 221 provided in the ATM layer 206 to the network / subscriber connection unit 208 (221).

The network / subscriber connection unit 208 performs a function for transmitting service data output to the network or subscriber side in accordance with a transmission protocol. It is provided with payload information of cell data to be transmitted to the network / subscriber and its primitive 221 at the interface with the upper layer unit 207, and performs the ATM layer function and the physical layer function, and performs a network through a physical medium matching function. Or converts the optical signal or the line coded electrical signal 223 to the subscriber and transmits it to the network or the subscriber, and receives the optical signal or the line coded electrical signal 224 provided from the network or the subscriber. It performs the function and ATM layer function and delivers the resulting service data and its primitives 222 to the upper layer unit 207. At this time, the network / subscriber access unit 208 exchanges the management information and the OAM flow information 230 of the ATM layer and the physical layer with the layer management unit 209. The layer management unit 209 supports management information collection and control functions of each layer (ATM, physical layer, upper layer, etc.) generated in the ring node RN, and various OAM functions. They also provide communication with the system management functions that govern the ring node system.

3 is a functional block diagram of a line switching unit 205 which performs a function of routing service cell data between two physical layer units and an ATM layer, and is controlled by the path switching controller 303. The path providing unit 301 having a function of routing the output port, the physical layer alarm processing unit 302 which collects information on the presence or absence of operation lines and spare lines provided by the physical layer, and the failure provided by the physical layer alarm processing unit 302. The path switching control unit 303 for controlling the routing of the line switching unit 205 according to the information and the control information provided by the layer management unit 209, the CPU connection unit 304 that is in charge of the connection with the layer management unit 203, and the physical layer. And a physical layer connection unit 305 for controlling input / output signals to and from the ATM layer, and an ATM layer connection unit 306 for controlling input / output signals with the ATM layer.

The route providing unit performs a basic 3x3 router function, and control thereof is performed by the route control signal 317 provided by the route switching controller 303. These are input signals 312 and 311 which are input signals provided by the receiver of the physical layer 1 unit 203 and the receiver of the physical layer 2 unit 204 and the transmitter of the ATM layer unit 206. To be input to the transmitter of the physical layer 1 unit 203, the transmitter of the physical layer 2 unit 204, or the receiver of the ATM layer 206 according to the routing control signal 317 of the path switching controller 303. Do this. The physical layer alarm processing unit 302 receives the failure information of the reception management line in the operation line receiving physical medium matching unit 201, the failure information of the reception spare line in the management line transmission physical medium matching unit 202, and the physical layer 1 part. In operation 203, failure information of the transmission preliminary line, and failure information of the reception operation line are collected in the physical layer 2 unit 204, and the failure information signal 314 of a format that can be used by the path switching controller 303 is used. Perform the function provided.

The path switching controller 303 receives the failure information signal 314 provided by the physical layer alarm processing unit 302 and the control information 316 of the layer management unit 209 provided by the CPU connection unit 304. ) Provides a signal to control according to the control procedure.

The central processing unit (CPU) connection unit 304 receives the operation mode information of the line switching unit 205 and various control register input information 315 provided by the layer management unit 209 and provides it to the path switching control unit 303. And various status information of the line switching unit 205 and the interrupt signal 315 are generated.

4 shows a service signal flow in a steady state in a ring type network composed of ring nodes of the above structure.

In the drawing, the management line receiving physical layer unit 401 performs a function including the entire management line receiving physical medium matching unit 201 and the physical layer first unit 203 mentioned in FIG. 2. First, the service data flow transmitted through the ring node 1 is received by the receiver of the operating line receiving physical layer unit 401 to process the transmission convergence function. It is provided to the line switching unit 205 in units of ATM cells, and the line switching unit 205 provides it to the ATM layer unit 206 and determines whether or not to establish a connection and converts the connection recognizer. The upper layer unit 207 and the network / subscriber connection unit 208 combine the functions of the SB connection processing unit 403 and serve to transmit the corresponding service data to the corresponding SB interface.

The SB access processor 403 performs a multiplexer / demultiplexer function and a subscriber interface function of four subscribers. In addition, the transmitter flow of the service signal provided by the ring node 2 multiplexes the cell data provided from each of the four SB interfaces by the SB connection processing unit 403 to provide the ATM layer unit 206, which undergoes the connection identifier conversion and the CPU. After performing the OAM and multiplexing with the signal cells and the general flow control (GFC) function to provide the ATM transmission access port of the line switching unit 205.

The line switching unit 205 routes the service cell data inputted to the ATM transmission connection port to an output port corresponding to the transmission unit of the management line transmission physical layer unit 402 and receives the signal and receives the operation line transmission physical layer unit 402. Provides a signal flow by placing it in an STM-1 frame, converting it into an optical signal form, and transmitting it to ring node 3. At this time, the line transfer unit 205 is the ATM transmission connection port in the normal state to provide a connection to the transmission connection port of the management line transmission physical layer unit 402 ATM receiving connection port of the management line receiving physical layer unit 401 Performs the function of providing a connection with a receiving access port. The receiving port of the management line transmission physical layer unit 402 to which the reception unit of the management line transmission physical layer unit 402 which receives the spare line signal is connected to the management line reception physical layer unit 401 having the backup line transmission function. It is responsible for routing to the egress port. It is normal that there is no signal flow in the routing path in this case. This is because the idle line is terminated by the preliminary line receiving unit of the management line transmitting physical layer unit 402.

5 and 6 illustrate the flow of service signals in ring node 2 when the management line transmitting side line or ring node of ring node 2 is a failure 501 in a ring-shaped network. This situation occurs when a failure occurs in the operating line between ring node 2 and ring node 3, a failure occurs in the spare line, a failure occurs in ring node 3, and a failure occurs in both the operation line and the spare line.

First, if a failure occurs only on the operating line, the operating node receiving physical layer unit at the ring node 3 transmits the input signal loss information through the allocated data channel in the STM-1 frame and transmits the remote input signal loss information between the ring node 2 and the ring node 3. Transmission is through the reserve line. This signal is extracted from the preliminary line receiving function of the management line transmitting physical layer unit 402 of the ring node 2, and the signal 502 is provided to the layer management unit 209 and the line switching unit 205. do. The line changer 205 changes the route routing according to the collected alarm information. Next, when a failure occurs only on the spare line, when a failure occurs not only on the spare line but also on the operation line, and when a failure occurs in the ring node 3, the input signal is received by the spare line reception function of the management line transmitting physical layer unit 402 of the ring node 2. Loss information is generated to provide this signal 502 to the layer management unit 209 and the line switching unit 205. The line changer 205 changes the route routing according to the collected alarm information. At this time, the route routing causes the operation connection receiving physical layer unit 401 to use the transmission connection port of the ATM layer unit 206 at the transmission port of the operation line transmission physical layer unit 402 to isolate the management line transmission physical layer unit 402. Route routing to the egress port to provide service signaling.

7 and 8 illustrate the service signal flow in ring node 2 when the line receiving side line or ring node of ring node 2 is a fault 601 in a ring-shaped network. This situation occurs when a failure occurs in the operation line between the ring node 1 and the ring node 2, or a failure occurs in the spare line, when the ring node 1 fails, and both the operation line and the spare line fail.

First, if a failure occurs only on the operating line, the operating node receiving physical layer unit at the ring node 3 transmits the input signal loss information through the allocated data channel in the STM-1 frame and transmits the remote input signal loss information between the ring node 2 and the ring node 3. Transmission is through the reserve line. This signal is extracted from the preliminary line receiving function of the management line transmitting physical layer unit 402 of the ring node 2, and the signal 502 is provided to the layer management unit 209 and the line switching unit 205. do. The line changer 205 changes the route routing according to the collected alarm information.

Next, when a failure occurs only on the spare line, when a failure occurs not only on the spare line but also on the operation line, and when a failure occurs in the ring node 1, the input signal is received by the spare line reception function of the management line transmitting physical layer unit 402 of the ring node 2. Loss information is generated to provide this signal 502 to the layer management unit 209 and the line switching unit 205. The line changer 205 changes the route routing according to the collected alarm information. At this time, the route routing uses the transmission connection port of the ATM layer unit 206 at the transmission port of the management line transmission physical layer unit 402 to isolate the management line transmission physical layer unit 402. Route routing to the egress port to provide service signaling.

FIG. 9 shows the service signal flow of the entire network when normal network operation is performed in a ring type network composed of four ring nodes. In this case, the path provided by the line switching unit 205 of each ring node connects the transmission port of the ATM layer unit 206 to the transmission port of the management line transmission physical layer unit 402 and the management line receiving physical layer unit 401. The receive port of is connected to the receive port of the ATM layer unit 206. The reception port of the management line transmission physical layer unit 402 is connected to the transmission port of the management line reception physical layer unit 401 so that service data can be provided in a single ring form immediately even in the event of a line failure.

When the data received from the management line receiving physical layer unit 401 at the ring node 3 is provided to the receiving port of the ATM layer unit 206 by providing a path of the line switching unit 205, the ATM layer unit 206 recognizes the connection. In this case, the cell data 902 having the connection identifier belonging to the current node is delivered to the upper layer, and the cell data 903 not present in the connection identifier table of the current node is multiplexed with the ATM cell data 904 provided at the upper layer. And input to the ATM layer connection transmission port of the line switching section 205. In this case, the cell data 903 delivered and passed in the previous ring is preferentially provided rather than the ATM cell data 904 provided in the upper layer.

FIG. 10 shows the flow of service signals throughout the network when ring node 2 fails. First, the line switching unit 205 in the ring node 1 sets the path 1001 to isolate the operating line receiving physical layer unit according to the input signal loss information provided by the optical receiver of the operating line receiving physical layer unit connected to the ring node 2. do. If the state of the management line transmission physical layer unit is normal, the spare line receiving port of the management line transmission physical layer unit is connected to the reception port of the ATM layer unit 206, and the transmission port of the ATM layer unit 206 is connected to the management line transmission physical layer unit. Provides a connection with a send port. At this time, the ATM layer unit 206 searches the input signal of the receiving port provided by the line switching unit and provides the cell data belonging to the connection recognition table of the current node to the upper layer (1002). It is provided to the ATM connection transmission port of the line switching unit 205 to pass to the next ring node, and multiplexed with the transmission cell data 1004 provided at the upper layer (1003) to the ATM connection transmission port of the line switching unit 205. Will be sent. Next, in ring node 3, the line switching unit 205 isolates the operation line transmission physical layer unit according to the input signal loss information provided by the spare line optical receiver of the management line transmission physical layer unit connected to the ring node 2. Will be set. If the status of the management line receiving physical layer unit is normal, the receiving port of the operating line receiving physical layer unit is connected to the receiving port of the ATM layer unit 206, and the transmitting port of the ATM layer unit 206 is a transmitting port of the spare line transmitting physical layer unit. To provide connectivity. At this time, the ATM layer unit 206 searches the input signal of the receiving port provided by the line switching unit and provides the cell data belonging to the connection recognition table of the current node to the upper layer (1002). It is provided to the ATM connection transmission port of the line switching unit 205 to pass to the next ring node (1003) and multiplexed with the transmission cell data 1004 provided from the upper layer to the ATM connection transmission port of the line switching unit 205. Will be sent. In the ring node 4, the line switching unit 205 maintains the connection with the upper layer through the ATM layer normally, and the spare line provides the path passing through the line switching unit 205, thereby providing it through the spare line. The service data is provided only the path without any processing to guarantee the same signal flow sequence as the original network configuration. This type of network configuration is a single ring-like configuration that maintains the service data flow even in the event of a failure, and immediately reconfigures the configuration of the double ring with immediate recovery in the event of a failure.

The present invention made as described above is a self-healing method for enabling network maintenance by minimizing the interruption of service provision in response to line failure and ring node failure in a ring-type shared media network, control of signal flow and support at this time The ring configuration to facilitate the configuration of the ATM access network in the form of a ring through this.

Claims (2)

A management line receiving physical medium matching means for receiving the service cell data from the preceding node through the management line as an optical signal, converting the service cell data into an electrical signal, reproducing a clock, and providing input signal loss information of the management line according to the received optical signal; First physical layer processing means for receiving an electrical bitstream from the operating line receiving physical medium matching means and converting the electrical bitstream into parallel data and providing the same to the operating line receiving physical medium matching means; A management line transmission physical medium matching means for receiving an optical signal of a spare line provided from a next node of the operation line and converting the optical signal into an electrical signal to reproduce a clock; Second physical layer processing means for receiving the electrical bitstream from the management line transmission physical medium matching means and converting the data into historical data to process reframing and section and path overhead; Line switching means for routing the service cell data provided by the first and second physical layer processing means to an asynchronous delivery mode layer; Upper layer processing means for performing an asynchronous delivery mode adaptation layer (AAL) or a higher layer protocol; Asynchronous delivery mode layer processing means for receiving service data provided from the upper layer and multiplexing a service cell and an unassigned cell; And a network / subscriber access means for providing service data to the upper layer processing means and performing a protocol for connection with a network or a subscriber. 2. The apparatus of claim 1, wherein the line switching means comprises: a path providing unit for routing three input ports and three output ports by path switching control; A physical layer alarm processing unit collecting failure information of the operation line and the preliminary line provided by the physical layer; A path switching controller controlling the routing line according to the failure information and the control information provided by the physical layer alarm processing unit; A central processing unit connecting portion responsible for connecting to the first physical layer portion; A physical layer connection unit controlling an input / output signal with the first and second physical layer units; And an asynchronous delivery mode layer connection unit controlling an input / output signal with the asynchronous delivery mode layer unit.