KR20010045645A - Apparatus For V5.2 Protocol Application Of A Base ATM - Google Patents

Abstract

PURPOSE: An ATM(Asynchronous Transfer Mode)-based V5.2 protocol application apparatus is provided to match access network and local exchange system to ATM link as a light transmission line, and define protocols of ATM application layers, thereby providing reliability and stability to subscribers. CONSTITUTION: A local exchange system and an access network based on the ATM V5.2 protocol include connection ports of an analog general terminal, a PABX(Private Branch Exchange), an ISDN BA observed by the recommendation of ITU-T G.960 and I.430, and an ISDN PRA observed by the recommendation of ITU-T G.962 and I.431. ATM-based V5.2 protocols(110,210) are defined to an access network(100) and a local exchange system(200), respectively. The protocols(110,210) includes synchronous digital hierarchy(SDH)s(111,112) for interfacing with the physical layers. ATM layers(112,221) perform a cell multiplexing function loading cells generated by several virtual path(VP)s and virtual channel(VC)s to one line in transmission, a cell separation function for separating cells from one line and then distributing it to various VP and VC, and a selection function of VP and VC of a cell and cell header production and deletion function. AAL layers(113,213) includes AAL 2 type for providing error restoring and non-restoring service to the upper layer and AAL 5 type for performing efficiently cell segmentation and reassembly function. Also, the system includes V5.2 interface protocol.

Description

Apparatus For V5.2 Protocol Application Of A Base ATM}

The present invention relates to a V5.2 protocol. Specifically, the V5.2 interface matching between a local exchange system and an access network is performed based on asynchronous transfer mode (ATM), thereby enabling broadband. The present invention relates to an ATM based V5.2 protocol application apparatus and method for stably performing high-speed data communication.

In general, a communication network is composed of a plurality of subscriber stations 1, an access network 2, and a local switching system 3, as shown in FIG. 1, which is connected to a general terminal 1a for voice call and Internet communication. The subscriber terminal 1 and the access network 2, which are made up of a personal computer 1b for transmission, a facsimile 1c for simulation transmission, an internet television 1d, are connected via an optical transmission line, and are based on the V5.2 protocol. It maintains the transmission and reception of voice and data at transfer rates from hundreds of Mbps to several Gbps.

The access network 2 and the local switching system 3 are connected through the V5.2 interface protocol through the physical layer and data link layer of the multiple E1 links, layer 2 and the network layer, layer 3.

In more detail with reference to FIG. 2, the subscriber port of the access network 2 and the local switching system 3 includes an analog general terminal connection port and an access port of a private private switching system (PABX), recommendation ITU-T G. ISDN Integrated Services Digital Network Basic Rate Access (BA) compliant port .960 and I.430 and ISDN Integrated Services Digital Network Primary Rate Access (PRA) access port compliant with ITU-T G.962 and I.431 It is provided.

In addition, in the case of a connection between the access network 2 and the local switching system 3, a physical layer and a data link layer that match a plurality of E1 links through the V5.2 protocol interface are connected through a protocol of LAPV5 (Link Access Procedure V5). It is interconnected via Layer 3, which provides the interface, and Layer 3, which provides the interface through the protocol of L3 to the network layer.

In Layer 1, which defines an interface with a physical transmission medium, an E1 link has a transmission rate of 2 Mbps per link, manages 32 channels per link, and a rate of 64 Kbps per channel, with a Public Switched Telephone Network (PSTN) subscriber and an ISDN PRI. It is composed of maximum 16 E1 links to provide V5.2 interface service to subscriber and ISDN BRI subscriber.

In addition, Layer 2, which maintains stable data transmission between physical links, uses LAPV5 to establish and terminate data links for V5.2 protocol interfaces consisting of PSTN protocol, CONTROL protocol, LINK CONTROL protocol, PROTECTION protocol, and BCC protocol. Layer of LAPV5 that manages and manages the Termination of TEI (Terminal Endpoint Identifier) for ISDN calls and the termination, and enables information transfer between upper layers to be provided regardless of data transmission or exchange. 3 consists of PSTN protocol, CONTROL protocol, LINK CONTROL protocol, PROTECTION protocol, and BCC protocol. The PSTN protocol works in conjunction with NP (National Protocol) to initialize the PSTN subscriber port based on the functions of call establishment and termination of PSTN subscribers. By performing a function relating to the call, substantially the access network 2 It is responsible for the call processing function of transmitting analog state information to the protocol entity of the local switching system 3 without controlling the progress.

The CONTROL protocol includes the PORT CONTROL Protocol, Reprovisioning, and Interface ID that perform functions related to enabling / disabling blocks or unblocks of PSTN and ISDN subscriber ports or enabling or disabling ISDN subscribers. And COMMON CONTROL protocol to check variable ID and block / unblock of all ports.

The LINK CONTROL protocol is responsible for the block or unblocking procedure and the link ID identification procedure for the E1 link used in the V5.2 interface.

The Bearer Channel Connection (BCC) protocol allocates and releases time slots on the E1 link when ISDN and PSTN calls are established and terminated.

PROTECTION protocol is to protect data link to provide continuous service in case of data link link failure of PSTN, CONTROL, LINK CONTROL, BCC, PROTECTION, ISDN_Ds, ISDN_f, ISDN_p using the protocol of V5.2. It is responsible for protecting the data link through switch-over in case of demands or other link and data link failures.

The frame structure of the V5.2 protocol that connects the access network 2 and the local switching system 3 in charge of the above functions is formed as shown in FIG. 3, and as shown in the drawing, DL-address and EF. The value of the address is configured to have the same value.

In the conventional communication network as described above, the subscriber and the access network are connected to the optical line through the FLC (Fiber Loop Carrier), and the access network and the local switching system are connected by the E1 level link so that the subscriber and the access are accommodated through the FLC. In the process of interfacing hundreds of Mbps to several Gbps of network over the E1 link having a transmission rate of 32 Mbps (2048 × 16), data loss occurs due to the mismatch of transmission speeds. In case of use, more E1 link resources and up to 16 E1 link resources are required for a stable interface between the access network and the local switching system.

In addition, the structure of the V5.2 protocol interface as described above cannot accommodate B-ISDN subscribers in a broadband band and is not suitable for call processing of data having burst traffic characteristics, and for CATV users. When using the compression technology, a flexible bandwidth of several Kbps to several Mbps is used. There is a problem in that it is not economical to accommodate the V5.2 protocol interface structure using a fixed bandwidth.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned general problems, and an object thereof is to match an access network and a local switching system to an ATM link which is an optical transmission line, and to match an ATM link through a V5.2 protocol. Defines the protocols of ATM Layer 2 and Layer 3 ATM Adaptation Layers, AAL2 and AAL5, which perform multiple separations, selection of Virtual Channels and Virtual Paths, and creation and deletion of cell headers. It provides reliability and stability in providing broadband subscriber service, and makes it easy to measure the amount of transmission per cell to facilitate billing according to the amount of data.

1 is a conventional general network configuration diagram.

2 is a block diagram showing a V5.2 interface registration between a local switching system and an access network in a conventional communication network.

3 is a block diagram of a conventional V5.2 protocol frame format.

4 is a block diagram of a local switching system and an access network to which the ATM-based V5.2 protocol is applied according to the present invention.

5 is a structural diagram of a frame format configuring level 3 in the ATM-based V5.2 protocol according to the present invention;

6 is a block diagram of a primitive and a message for providing PSTN subscriber service in an ATM-based V5.2 protocol according to the present invention.

7 is a state table for PSTN subscriber service of a local switching system in an ATM based V5.2 protocol according to the present invention.

8 is a frame format state diagram of a control protocol in the ATM-based V5.2 protocol according to the present invention.

9 is a state table of a common control protocol and a port control in the ATM-based V5.2 protocol according to the present invention.

10 is a state table of a user port by a control protocol in the ATM-based V5.2 protocol according to the present invention.

11 is a block diagram of a primitive and a message of the BCC protocol in the ATM-based V5.2 protocol according to the present invention.

12 is a state table for performing VPI and VCI allocation and revocation functions of the BCC protocol in the ATM-based V5.2 protocol according to the present invention.

13 is a layer 3 frame format configuration diagram of an ATM-based V5.2 protocol and an ISDN protocol according to the present invention.

FIG. 14 is a diagram illustrating a frame format analysis apparatus for call establishment and termination in a local exchange system and an access network to which an ATM-based V5.2 protocol is applied according to the present invention; FIG.

<Explanation of symbols for main parts of drawing>

100: access network 200: local exchange system

The present invention for achieving the above object comprises an optical transmission line interface between the access network (AN) connected to the subscriber and the local switching system (LE) for connecting the inter-station switching system, and the access network (AN) and It provides an ATM-based V 5.2 interface application device that implements the ATM-based V5.2 protocol interface between the local switching system (LE).

The ATM-based V5.2 protocol is a synchronous digital hierarchy for the interface of the physical layer, an ATM layer that performs cell multifunction and cell distribution, cell virtual channel and virtual path selection, and decomposes data into cells. The ATM adaptation layer, which reports the information to the upper layer, and the V5.2 protocol as the upper layer, are implemented as an ATM-based V5.2 protocol.

In addition, the V5.2 protocol of the layer 3 includes a PSTN protocol for providing services of a PSTN subscriber, an interface ID for all ports and an activation / deactivation of the PSTN and ISDN subscriber ports and activation / deactivation of the assigned subscriber ports. BCC responsible for allocating / cancelling / monitoring virtual channel identifiers and virtual path identifiers for assigning / removing traffic channels to user ports of access networks in the CONTROL protocol and the local exchange system. Characterized in that the protocol.

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

As shown in FIG. 4, the local switching system and the access network applying the ATM-based V5.2 protocol according to the present invention are analog general terminal access ports and connection ports of the private private switching system (PABX), and recommendation ITU-T. Subscriber ports such as ISDN BA access ports and G.960 and I.430 compliant ISDN PRA access ports and ITU-T G.962 and I.431 compliant ports, including access network 100 and local switching systems In each of 200, an ATM based V5.2 protocol 110, 210 is defined.

The ATM-based V5.2 protocols 110 and 210 are synchronous digital hierarchy (hereinafter referred to as 'SDH') 111 and 211 for the interface of the physical layer, and multiple virtual paths during transmission. Cell multi function that loads cells generated in (VP) and virtual channel (VC) on one line, and cell separation function that separates cells from one line when receiving and distributes them to multiple virtual paths and virtual channels. Variable ATM layer 112 (221) 221 which performs selection of virtual channel (VC) and virtual path (VP) and generation and deletion of cell header, and user-service data unit (U-SDU) which is real time AAL2 type for delivering error recovery and unrecovered error services to upper layers and mainly used in data applications, and delivering the function of cell segmentation and reassembly. Done with AAL5 AAL layer 113 (213) which is layer 3 which consists of a type, and V5.2 interface protocol.

In the ATM-based V5.2 protocol having the above structure, the SDH 111 for the physical layer interface provided to the access network 100 and the SDH 211 for the physical layer interface provided to the local switching system 200 are It is connected via the optical line.

As described above, in the ATM-based V5.2 protocol having the optical line matching structure between the SDHs 111 and 211, three protocol messages are transmitted through the layer 3 between the access network 100 and the local switching system 200. A control channel must be secured.

At this time, the secured control channel provides a basis for determining the state of the V5.2 interface by determining whether the data transmission path and the data link are abnormal.

For example, the switching point of the out of service is determined by the switching of the data link, and the switching point of the in service is determined as whether the data link can be set.

Management of allocation and release of control channel in V5.2 interface using ATM link uses Meta Signaling which has a procedure of setting up, checking, and releasing a virtual channel for signaling. The administration is handled by the Operation Administration and Maintenance (OAM) cell in the management plane for the network monitoring function.

In V5.2 protocol based on ATM link, Layer 3 protocol consists of PSTN protocol, BCC protocol and CONTROL protocol. Each protocol has its own message, internal primitive and finite state machine (FSM). Information exchange with the NP and the access network 100 and the SM (System Management) of the layer 3 and the layer 2 is performed.

The frame format of the layer 3 performing the above function is a protocol discriminator and two layer 3 address fields (LAYER 3 address, LAYER 3 address [lower]) as shown in FIG. It has a structure consisting of a message type (Message type) and other information element, the message of each protocol is determined by the message type.

In addition, the PSTN protocol, which is one of layer 3 protocols in the V5.2 protocol based on the ATM link, includes a message and a primitive used as a protocol used to provide a service of a PSTN subscriber, and a function thereof is attached. As shown in FIG. 6, status information of the PSTN protocol FSM table in the local exchange system 200 and a function thereof are performed as shown in FIG. 7.

In addition, the CONTROL protocol, which is one of layer 3 protocols in the ATM link-based V5.2 protocol, is divided into a PORT CONTROL protocol and a COMMON CONTROL protocol. The PORT CONTROL protocol is a block for subscriber ports of PSTN and ISDN. / Unblock function, and enable / disable the ISDN subscriber port only.The COMMON CONTROL protocol provides the function of block / unblock for all ports, the function of block / unblock for all ISDN ports, It is responsible for the block / unblock function of the PSTN port, restart of the PSTN protocol, and verification of the interface ID and variant ID.

When the access network 100 or the local exchange system 200 receives the PORT CONTROL protocol or the COMMON CONTROL protocol of the CONTROL protocol, the access network 100 transmits a CONTROL PROCOL ACK in response to each of them, and the PORT CONTROL protocol is a control function element (Control Function). Element) as a distinguisher to perform each function defined above, and the COMMON CONTROL protocol performs each function as defined above as a Control Function ID as a distinguisher.

The frame format of the CONTROL protocol to perform the function as described above is made as shown in Figure 8 attached, the state and state transition diagram of the PORT CONTROL protocol and the COMMON CONTROL protocol is made as shown in Figure 9 attached.

In addition, the state of the user port maintained by the CONTROL protocol, that is, the PSTN port and the N-ISDN port, the N-ISDN and B-ISDN port is made as shown in FIG.

In addition, the BCC protocol, which is one of the layer 3 protocols in the V5.2 protocol based on the ATM link, is used to allocate or release a traffic channel to a specific access network 100 user port in the local switching system 200. It is responsible for allocating, removing, and monitoring the virtual path identifier (VPI) and the virtual channel identifier (VCI).

In the above BCC protocol, the function of allocating, canceling, and monitoring the virtual path identifier (VPI) and the virtual channel identifier (VCI) is performed by a unique processing operation. Therefore, multiple processing operations may be activated on the same user port. The processing operations of can be distinguished by their unique BCC reference numbers.

In addition, the processing operation provided by the BCC protocol is a processing operation used to assign a virtual path identifier (VPI) and a virtual channel identifier (VCI) to a traffic channel to a specific user port. Allocation Complete ',' Allocation Reject ', which is a processing operation used to terminate the Virtual Path Identifier (VPI) and the Virtual Channel Identifier (VCI) assigned as a traffic channel to a specific user port. 'Deallocation Complete' and 'Deallocation Reject' are included.The processing action used to examine the virtual path identifier (VPI) and virtual channel identifier (VCI) assigned to the user port is related to the message 'Audit', Audit Complete '. When the local exchange of the virtual path identifier (VPI) and the virtual channel identifier (VCI) information is disconnected due to a failure in the access network 100. System is included in a message used to notify (200) 'AN FAULT', 'AN FAULT ACKNOWLEDGE'.

In the BCC protocol as described above, primitives and messages between the RM (System Management), the SM (System Management) and the BCC protocol (BCC_PE) in the locale exchange system (LE) and the channel between the access network 100 and the local exchange system 200 Related primitives and messages are configured as shown in FIG.

In addition, as described above, the status and messages of the BCC protocol for performing the allocation and release functions of the virtual channel identifier (VPI) and the virtual channel identifier (VCI), which are traffic channels, are configured as shown in FIG. 12.

In addition, when the V5.2 interface between the access network 100 and the local switching system 200 is used as an ATM-based link, multiple interfaces are formed on one link. Service to the interface will be disabled.

Therefore, when a link failure is detected, switching of the detected link failure is performed using the OAM function provided in the management plane of the ATM.

As described above, the frame format of the layer 3 for providing the ATM-based V5.2 protocol and the broadband ISDN service in the access network 100 and the local switching system 200 matched with the ATM link has a structure as shown in FIG. 13. As shown in FIG. 4, it is positioned on the top of the AAL adaptation layer, which is layer 2. FIG.

As can be seen in FIG. 13, the ATM-based V5.2 protocol consists of two address fields consisting of an EF-address and a DL-address, a protocol discriminator, an address field of layer 3, a message type, and a field of other information elements. EF-address is a factor that distinguishes between V5.2 protocol interface control message and ISDN message, and DL-address is used as a factor that distinguishes PSTN protocol, CONTROL protocol and BCC protocol, which is an ATM-based V5.2 protocol. The frame structure of the PSTN protocol, the CONTROL protocol, and the BCC protocol, which is an ATM-based V5.2 protocol, is composed of the same EF-address and DL-address as those of the conventional V5.2 protocol frame.

However, in the case of the message for ISDN call connection, as shown in the above-described frame structure, a virtual value that does not use the setting values of the EF-address and the DL-address in the V5.2 protocol, for example, '0'. Set to so that it is possible to determine that the frame required for call connection is an ISDN message.

Hereinafter, a process of setting up an ISDN call through an ATM based V5.2 protocol interface will be described with reference to FIG. 14.

When a setup message requesting call setup from an ISDN subscriber is applied to the frame connection analyzer 310 of an access network (AN), the frame connection analyzer 310 analyzes the frame structure of the received setup message and then analyzes the analyzed value. It applies to the map value analysis part 320 side.

The map value analysis unit 320 extracts the information of the EF-address and the DL-address from the received frame, and then sends a setup message requesting call setup according to the information of the EF-address through the EF-address processing unit 330. It applies to the address processing part 410 side of the switching system LE side.

At this time, the EF-address processor 410 of the local switching system LE applies a frame format applied from the access network AN to the map value analyzer 420 to request the analysis of the DL-address. The analyzer 420 analyzes the DL-address information of the received frame format and applies a setup message requesting call setup to the analyzed ISDN call manager block 430 when it is determined that the signal is a request for ISDN call setup. .

The ISDN call manager block 430 sends a virtual path identifier (VPI) and a virtual channel identifier (VCI) between the access network (AN) and the local switching system (LE) through the BCC protocol processing unit 450 according to a message requesting call establishment. And then transmits the data to the BCC protocol processing unit 370, which is the V5.2 protocol interface of the access network, and transmits the data to the access network (AN) side between the access network (AN) and the local switching system (LE). 2 Set the channel and path for data transmission / reception through protocol.

As described above, in the case of transmitting / receiving a message through the V5.2 protocol in a state in which a channel and a path for data transmission and reception are set according to a setup message from an ISDN subscriber, information of a frame format as shown in FIG. 13 is transmitted from a subscriber station. When applied to the map value analyzer 320 through 310, the map value analyzer 320 analyzes the information of the DL-address and the EF-address in the applied frame format and receives the message format of the subscriber station. 2, after determining that the information is through the protocol, activates the PSTN protocol processing unit 350, the control protocol processing unit 360, and the BCC protocol processing unit 370, which are the V5.2 protocol processing means, and sends the corresponding message to the local exchange system (LE). BCC protocol processing unit which is a V5.2 protocol processing unit on the local exchange system (LE) side by applying to the map value analysis unit 420 through the EF-address processing unit 410 on the At step 450, the control protocol processor 460 and the PSTN protocol processor 470 are activated.

Therefore, the V5.2 message, which is the general data and voice data between the access network AN and the local switching system LE, is carried out by the V5.2 protocol interface processing means which maintains the activation state.

When the ISDN message is transmitted and received while the call is established between the access network (AN) and the local switching system (LE) as described above, the ISDN frame format having the structure as shown in FIG. 13 from the ISDN subscriber station is connected to the frame of the access network (AN). When applied to the map value analyzer 320 through the analyzer 310, the map value analyzer 320 analyzes the EF-address information and the DL-address information in the applied frame format.

At this time, if it is determined that the analyzed DL-address is set to a dummy value which is an arbitrary digit, it is determined that the received information is ISDN data, and the map is determined through the EF-address analysis unit 410 of the local exchange system (LE). It applies to the value analyzer 420 side.

Accordingly, if the map value analyzer 420 of the local switching system LE applies the received information to the ISDN call manager block 430 according to the analysis of the DL-address in the received frame format, the ISDN call manager block 430 is provided. As described above, the BCC protocol processor 450 performs data transmission and reception with the access network (AN) through the virtual channel and the virtual path.

As described above, the present invention connects the link between the access network and the local switching system by using an optical fiber as a physical link, and implements the V5.2 interface using the ATM-based V5.2 protocol to transmit and receive ISDN data having a large data capacity. It can be performed stably, and the billing can be easily performed according to the increase of the data call service by measuring the transmission amount per cell.

Claims (6)

The interface between the access network (AN) connected to the subscriber and the local switching system (LE) connecting the switching system between stations is composed of optical transmission lines, and the interface between the access network (AN) and the local switching system (LE) is ATM-based. A V based V 5.2 interface application device, characterized in that the implementation of the V5.2 protocol. The method according to claim 1, The ATM based V5.2 protocol includes a synchronous digital hierarchy for an interface of a physical layer; An ATM layer for performing cell multifunction, cell distribution, and cell virtual channel and virtual path selection; An ATM adaptation layer that decomposes data into cell units and reports information on the information to a higher layer; V 5.2 protocol application apparatus characterized in that the implementation of the V5.2 protocol based on ATM by applying the V5.2 protocol to the upper layer. The method according to claim 1, The ATM-based V5.2 protocol consists of two address fields consisting of an EF-address and a DL-address, a protocol discriminator field, an address field of layer 3, a message type field, and a field of other information elements. ATM based V 5.2 protocol application device. The method according to claim 2, The layer 3 V5.2 protocol includes a PSTN protocol for providing a service of a PSTN subscriber; A CONTROL protocol that is responsible for allocating / removing PSTN and ISDN subscriber ports, activating / deactivating assigned subscriber ports, and identifying interface IDs and bearer IDs for all ports; AMB based V is composed of BCC protocol which is responsible for allocating / cancelling / monitoring virtual channel identifier and virtual path identifier for allocating / removing traffic channel to user port of access network in local switching system. 5.2 Protocol Applicator. The method according to claim 3, The EF-address is a factor for distinguishing between a V5.2 protocol interface control message or an ISDN message, and the DL-address is a factor for distinguishing a PSTN protocol, a CONTROL protocol, and a BCC protocol from an ATM-based V5.2 protocol. ATM based V 5.2 protocol application device. The method according to claim 3 or 5, The EF-address and the DL-address for the ISDN call is set to any virtual bit value that is not used in the V5.2 protocol.