KR100237883B1 - Efficient method for cell routing in atm vp cross connector using the method - Google Patents

Abstract

The present invention relates to an efficient cell routing method of the asynchronous transmission method (ATM) and a virtual path (VP) cross-connector for the same, by integrating the video service, voice and dedicated line signal to simplify the information using ATM to subscribers in multiple regions As a technology that can be provided quickly through cell routing, the use of an ATM VP cross-connector having a routing structure of the present invention enables the minimization of service delay due to routing even in the presence of multiple ATM nodes in an access device. The advantages of fast service provision and the simple routing structure are accompanied by economic advantages in designing all the implementation circuits such as memory for routing.

Description

An Efficient Cell Routing Method for Asynchronous Transmission Method and Virtual Cross-Connector

The present invention relates to a virtual path (hereinafter referred to as VP) cross-connector of an asynchronous transmission method (hereinafter referred to as ATM), and integrates video service, voice, and dedicated line signals to transmit information using ATM to subscribers in multiple regions. The present invention relates to an ATM VP cross-connector implementation of an ATM access device having a simple ATM routing structure.

In general, an ATM access device supports two types of ATM connections: a switched virtual channel (hereinafter referred to as SVC) or a permanent virtual circuit (hereinafter referred to as PVC).

In order to deliver the ATM cells inputted to the device to the corresponding destinations correctly with this support, the routing information includes the virtual path identifier / virtual channel identifier (hereinafter referred to as VPI / VCI) that is allocated from the ATM switch through a signaling procedure. It is stored in the routing table with the subscriber information until the call is released for use.In case of PVC, the VPI / VCI information promised between the ATM switch and the subscriber is pre-assigned without signaling procedure and stored in the routing table with the subscriber information. It is used as a means to determine.

Here, the routing table means providing both routing and conversion functions.

However, such a conventional scheme requires that the routing table be managed by the number of ATM nodes in the device, that is, the number of VPI / VCI endpoints, in an access device supporting SVC or PVC. It is becoming.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems, and an object of the present invention is to provide an ATM access device supporting a PVC having a simple and efficient routing structure. .

1 is a network diagram showing the basic configuration of an ATM access device and an ATM VP cross connector according to the present invention.

Figure 2 is a detailed block diagram illustrating the inter-module operation associated with the routing table of the ATM VP cross connector implemented by the present invention.

FIG. 3 is a diagram illustrating an up-down cell header form between an optical transmitter and a subscriber access device in an ATM VP cross connector of the present invention.

4 (A) is a diagram showing a cell header form for a broadband service cell.

4B is a diagram illustrating an example of a cell header form for a CES cell.

Fig. 4C is a diagram showing a cell header form for IPC cell processing.

<Description of Symbols for Major Parts of Drawings>

100: ATM access device 10: ATM VP cross connector

11: DS1E processing unit 12: DS1L processing unit

13 ATM matching unit 14 optical transmission unit

15: Selbus 16: E-VPI (External VPI)

17: I-VPI (Internal VPI) 20: Subscriber Access Device

30: ATM Switching Network 40: General Line

50: Dedicated line for DS1 / DS1E 60: STB (set top box)

70: Public Switched Telephone Network (PSTN) 80: Most significant bit 4 bits

90: least significant 4 bits

In order to achieve the above object, an ATM cell routing method proposed by the present invention is a downstream process of determining a corresponding subscriber access means to be accessed from a cell header through a first routing table stored in an ATM matching means connected to an ATM switching network. and;

After storing the second routing table of the same format as the routing table in the optical transmission means connected to the subscriber side,

The upstream process of determining the corresponding ATM matching means to be accessed through the table in the cell header is characterized in that the ATM node routing in the ATM system is performed quickly.

In addition, the apparatus for ATM cell routing implemented in the present invention to achieve the above object comprises a DS1E processing unit for performing the function and the reverse function to emulate the DS1E signal input from the exchanger AAL1 line to make an ATM cell to the optical transmitter;

A DS1L processing unit for performing a function and a reverse function of emulating DS1E and DS1 signals inputted from a dedicated line network into an ATM cell and transmitting them to an optical transmission unit;

A routing table for converting the VPI value of the switching network side to the VPI value of the subscriber access device stores the VPI value in the ATM cell received from the ATM switching network, and accepts four STM-1 signals. Matching unit;

Stores a routing table for converting the VPI value of the subscriber access device into the VPI value of the switching network side, and selects and maps a cell corresponding to its address from each of the DS1E / DS1L processing units and the ATM matching unit, and thus the pointer and over. An optical transmission processing unit which performs a function of transmitting a light to a corresponding subscriber access device through an electrical / optical (E / O) conversion and a reverse function after processing the head; And

ATM VP cross-connector is located on the backplane (plane), characterized in that it comprises a cell bus that is connected to each processing unit in common to enable each information transmission.

The above objects, features and advantages will become more apparent from the following detailed description taken in conjunction with the accompanying drawings. Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a network diagram showing the basic configuration of an ATM access device 100 and an ATM VP cross connector 10 according to the present invention, wherein the access device 100 is an ATM VP cross connector 10 and an apartment located in a telephone station. There are a plurality of subscriber access devices 20 located in the high demand area such as a general line 40, a DS1 / DS1E dedicated line 50, and a set-top-box (STB) for video-on-demand (VOD) service ( A device for optically transmitting a broadband service such as 60) between the ATM VP cross connector 10 and the subscriber access device 20.

That is, the ATM VP cross connector 10 performs a function and a reverse function of integrating subscriber service at a telephone station and performs an inverse function, and the subscriber access device 20 receives an optical signal transmitted from the ATM VP cross connector 10 to each subscriber. It performs the function and the reverse function to provide the service to the user.

As shown in FIG. 1, the ATM access apparatus 100 uses a fiber optic cable to the subscriber's adjacent area, and each subscriber's inlet line uses a copper wire to connect a service with an 'FTTC (Fiber-To-The-Curb') structure. It is a star structure that forms a network and connects a plurality of subscriber access devices 20 to a single ATM VP cross connector 2 in a point-to-multipoint manner.

The ATM VP cross connector 10 integrates the public switched telephone network (hereinafter referred to as PSTN) 70 service provided by the telephone company to the subscriber side and the VOD service provided by the ATM switching network 30 to the plurality of subscriber access devices 20. It performs optical transmission and reverse function at the transmission speed of 'STM-4c (622Mbps)'.

The ATM VP cross-connector (2) is connected to the PSTN (70) network as DS1 and DS1E. DS1 is a dedicated circuit, and DS1E can be connected to a digital loop carrier (DLC) and integrated digital loop carrier (NDLC). .

FIG. 2 is a detailed block diagram illustrating the inter-module operation related to the routing table of the ATM VP cross connector 10 implemented by the present invention. The optical transmission is performed by emulating a DS1E signal input from an IDLC or DLC switch to an AAL1 circuit to form an ATM cell. A DS1E processing unit 11 for performing a function of transmitting to the unit 14 and a reverse function;

A DS1L processor (12) for accommodating DS1, DS1E dedicated lines, emulating an AAL1 line to form an ATM cell, and transmitting the same to the optical transmission unit 14;

Stores a routing table for converting the VPI value of the switching network 30 to the VPI value of the subscriber access device 20, thereby processing the VPI value in the ATM cell received from the ATM switching network 30, An ATM matching unit 13 for receiving STM-1 level signals;

A routing table for converting the VPI value of the subscriber access device 10 side into the VPI value of the switching network 30 side is stored and sent to each of the DS1E / DS1L processing units 11 and 12 and the ATM matching unit 13. Selects cells that match their own addresses, maps them to payloads of the 'STM-4c (622Mbps)' signal, processes pointers and overhead, and accesses the subscribers through electrical / optical (E / O) conversion. An optical transmission processor 14 for performing optical transmission and reverse functions to the apparatus 20;

ATM VP cross-connector 10 is present on the back-plane (plane), and is configured to include a cell bus (15) connected to each of the processing units (11 to 14) to enable each information transmission.

The operation of transmitting information between each subscriber device 20 and networks 30 and 70 through the ATM VP cross connector 10 configured as described above is as follows.

As shown in FIG. 1, a plurality of services are integrated to the subscriber access device 10 so as to accurately transfer each service cell to a corresponding subscriber, and to easily and quickly process the routing at each ATM node. The access device 100 according to the present invention uses two types of VPI.

This refers to the VPI provided by the ATM switching network 30 as an external VPI (hereinafter referred to as an external VPI) 16, and a VPI defined for the purpose of the present invention is referred to as an internal VPI (hereinafter referred to as an internal VPI). (17).

Here, the E-VPI 16 is a value initially assigned to the subscriber from the ATM switch 30.

In addition, two ATM matching units 13 exist in the ATM VP cross-connector 10, and the routing table of the present invention performs routing and conversion functions for ATM cells received from the ATM switching network 30. Used.

That is, the ATM matching unit 30 determines the output port of the optical transmission unit 14 and the I-VPI 17 from the corresponding port of the input cell and the E-VPI 16 of the cell header.

At this time, the most significant bit (hereinafter referred to as MSB) of the I-VPI 17 is referred to as the least significant bit (hereinafter referred to as LSB) in the corresponding unit identification number (hereinafter referred to as Id) of the subscriber access device 20 to which the broadband subscriber is connected. ) In the 4 bits, the port Id information in the unit is inserted instead of the 8 bits of the E-VPI 16.

The ATM cell thus converted is transmitted to the optical transmission unit 14 through the cell bus 15 and optically transmitted to the connected subscriber access device 20.

On the other hand, the DS1E processing unit 11 accommodates 12xDS1E (360 star subscriber) and is mounted 12 per ATM VP cross-connector 10, DS1E processing unit 11 and DS1L processing unit 12 is the E-VPI (16) It does not have a separate routing table, so it only performs routing function for ATM cell that emulates circuit using VPI / VCI table of AAL-1 chip in module.

That is, the corresponding unit Id of the subscriber access device 10 to which the voice or dedicated line subscriber is connected to the MSB 4 bits of the I-VPI 17, and the port Id information in the unit as the VPI field value of the cell header in the LSB 4 bits. Filled and transmitted to the optical transmission unit 14 through the cell bus 15.

In addition, the optical transmitter 14 is designed to be connected to the two subscriber access devices 10 so that a total of eight optical transmitters 14 are connected to 16 subscriber access devices 10.

The routing table of the optical transmission unit 14 is used to perform routing and conversion functions for ATM cells flowing from the subscriber access device 10.

That is, the service module and the port information are determined using the I-VPI 17 of each service cell and transferred to the corresponding module through the cell bus 15.

In addition, the subscriber access device 10 can easily distinguish the destination port of the destination unit by using only the MSB 4-bit and LSB 4-bit values of the cell I-VPI 17 that are received without a separate routing table. By integrating the service cell of the optical transmission unit 14 is also transmitted to the same I-VPI 17 at the time of ATM transmission.

Hereinafter, the cell header form used for the routing structure of the present invention will be described in detail with reference to FIG. 3.

FIG. 3 is a diagram illustrating an up-down cell header form between the optical transmission unit 14 and the subscriber access device 10 in the ATM VP cross connector 10 of the present invention.

'GFC (Generic Flow Control)' is a field for general flow control, 8 bits of the VPI field means MSB 4 bits (80) and LSB 4 bits (90) of I-VPI (19), MSB 4 bits The 80 and the LSB 4 bits 90 are used to view a broadband service cell, a circuit emulation (CES) cell, an IPC (Inter Processor Communication) cell, and an OAM cell when looking at the subscriber access device 10 from the ATM VP cross-connector 10. This corresponds to a unit Id 80 that can be processed and a specific port Id 90 of the various ports that the unit accepts.

The IPC cell is a communication between main control units for remotely controlling the subscriber access device 10 in the ATM VP cross connector 10, and the LSB 4 bits 90 are fixed to '0'.

And 'PTI (Payload Type Identifier)' is a field indicating the payload type, 'P (Priority)' is a field indicating the priority.

4 is a diagram illustrating an example of actually using a cell header form used in the above format, FIG. 4 (A) shows a cell header form for a broadband service cell, and FIG. 4 (B) shows a cell for a CES cell. 4 illustrates a cell header form for IPC cell processing.

In FIG. 4 (A), 'VCU #' and 'STB #' indicate a corresponding unit Id of a subscriber access device 10 to which a broadband service subscriber is connected, and a port Id connected to a specific port of the unit, respectively.

In addition, 'FRU #' and '1channel #' of FIG. 4 (B) show corresponding CES unit Id of the subscriber access device 10 to which the PSTN subscriber is connected and port Id connected to a specific port of the unit, respectively.

In the MSB 4 bits of the I-VPI of FIG. 4C, the Id of the control unit for processing the IPC cell in the subscriber access device 10 is inserted, and the lower 4 bits are filled with '0'.

By using the actual physical location information of each service line as the VPI value, routing at the destination of the cell can be handled very simply.

In addition, since the VPI values of the up-down cell headers are kept the same as in FIG. 4, the routing structure of each ATM node is simple, and memory can be efficiently used for table management.

As described in detail above, the use of an ATM VP cross-connector having a routing structure proposed in the present invention enables the minimization of service delays due to routing even when a plurality of ATM nodes exist in an access device. In addition, since the routing structure is simple, it has economic advantages in designing a general implementation circuit such as a memory for routing.

In addition, preferred embodiments of the present invention are disclosed for the purpose of illustration, those skilled in the art will be able to various modifications, changes, additions, etc. within the spirit and scope of the present invention, such modifications and modifications belong to the following claims Should see

Claims (7)

In the cell routing method of the optical communication between the network and the subscriber access means, A downstream process of determining a corresponding subscriber access means to be connected in the cell header through a first routing table stored in an ATM matching means connected to an ATM switching network; After storing the second routing table of the same format as the routing table in the optical transmission means connected to the subscriber side, A method of cell routing in an asynchronous transmission method (ATM), characterized in that the routing of ATM nodes in an ATM system is performed quickly, including an upstream process of determining a corresponding ATM matching means to be accessed through the table in a cell header. The method of claim 1, The 4-bit value of the most significant bit of the VPI bits in the cell header transmitted in the downstream process and the upstream process represents the unit identification number of the corresponding means to be connected. The least significant bit 4-bit value indicates a corresponding port identification number in the corresponding unit. The method of claim 2, Each identification number in the VPI is an identification number used in the downstream process and the identification number used in the upstream process is characterized in that the asynchronous transmission method (ATM) cell routing method. A DS1E processor for emulating the DS1E signal input from the exchanger in an AAL1 line to make an ATM cell and transmitting it to the optical transmitter; A DS1L processor for emulating DS1E and DS1 signals inputted from a dedicated line network, emulating an AAL1 line to make an ATM cell, and transmitting them to an optical transmission unit; A routing table for converting the VPI value of the switching network side to the VPI value of the subscriber access device stores the VPI value in the ATM cell received from the ATM switching network, and accepts four STM-1 signals. Matching unit; Stores a routing table for converting the VPI value of the subscriber access device into the VPI value of the switching network side, and selects and maps a cell corresponding to its address from each of the DS1E / DS1L processing units and the ATM matching unit, and thus the pointer and over. An optical transmission processing unit which performs a function of transmitting a light to a corresponding subscriber access device through an electrical / optical (E / O) conversion and a reverse function after processing the head; And ATM VP cross-connector on the back-plane (plane), a common transmission for the asynchronous transmission (ATM) cell routing characterized in that it comprises a cell bus that is connected to each processing unit to enable each information transmission Virtual path (VP) cross connector. The method of claim 4, wherein The ATM matching unit is a virtual path (VP) cross-connector for the asynchronous transmission (ATM) cell routing, characterized in that the basic unit is to receive four STM1 class signals, two per unit is mounted in the ATM VP cross connector. The method of claim 4, wherein The routing table used when the DS1E signal is emulated by an AAL1 circuit to make an ATM cell uses a VPI / VCI table of an AAL-1 chip in a DSLE processor. ) Cross connector. The method of claim 4, wherein The optical transmission unit is connected to two subscriber access units per unit, virtual path (VP) cross connector for asynchronous routing (ATM) cell routing, characterized in that the eight units are mounted in the ATM VP cross connector.

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