KR100238432B1 - Frame relay pvc management interworking method in an atm switching system - Google Patents

Abstract

The present invention is an essential function for implementing the interworking function between ATM and frame relay, and is divided into one-way / two-way and event-driven methods according to UNI / NNI, network / service interworking, and one-to-one / many-one interworking function in network interworking. The present invention relates to a method of applying ITU-T Q.933 Annex A's PVC state management procedure in an interworking function structure implemented in an ATM exchange. It is a unidirectional, bidirectional, event-driven mode in the case of service interworking for protocol conversion. Refer to PVC status information table in case of Permanent Virtual Access (PVC) status management interworking. In case of network interworking for connecting two FR networks with ATM network as main network, PVC status management interworking of unidirectional, bidirectional, event-driven mode In case of, refer to the relevant FR side status information management table or ATM side status information table, and use the information of the received status message to Is to change the state table.

Description

Frame Relay Permanent Virtual Connection Status Management in Asynchronous Transfer Exchange

The present invention belongs to a subscriber or network matching function implementation technology in an ATM (Asynchronous Transfer Mode) exchange, and in particular, a permanent virtual connection (Permanent Virtual Connection; PVC ') refers to a method of interlocking state management.

In the early stages of the introduction of ATM into the national network, interworking between ATM networks and existing networks has emerged as an important issue.

Among the existing networks, especially frame relay (hereinafter referred to as 'FR') network is used in various fields such as file transfer, database access, e-mail, banking, and video data transmission to provide various bandwidths from low speed to 45Mbps. The simplicity of the protocol enables the high-speed service at a much lower cost than the leased line or the ATM.It is an optimal network as a service providing network that responds to the natural increase in user demand in the middle evolutionary stage from the existing network to the ATM network. It is pointed out.

The present invention is an essential function for implementing an interworking function between ATM and FR, and includes a user-network interface (hereinafter referred to as a “UNI”) / network and a node-to-node interface (hereinafter referred to as “NNI”). PVC status of ITU-T Q.933 Annex A, which is divided into one-way / two-way and event-driven methods according to network / service interworking and one-to-one / many-one interworking function in network interworking. The purpose of this paper is to provide a method that can be applied in the interworking function structure implemented in ATM switch.

1 is a configuration diagram of an ATM / FR interworking scenario;

2 is an ATM / FR PVC state management interworking procedure diagram,

3 is a PVC state management interworking protocol stack configuration,

4 is a block diagram of a FRIM in an ATM switch to which the present invention is applied;

5 is a bidirectional PVC state management interworking procedure for service interworking;

6 is a unidirectional PVC state management interworking procedure diagram for service interworking;

7 is an event-driven mode PVC state management interworking procedure for service interworking;

8 is a bidirectional PVC state management interworking procedure diagram in the case of network interworking;

9 is a unidirectional PVC state management interworking procedure diagram in case of interworking with a network;

10 is an event-driven mode PVC state management interworking procedure diagram in the case of network interworking;

<Explanation of symbols for main parts of drawing>

401: Frame Relay Interworking Module (FRIM) 402: Frame Relay Connection (FAP)

403: Multiplexer (M) 409: Connection Switching Subsystem (ALS)

411: ATM Switch

One feature of the present invention for achieving the above object is a frame in the case that the permanent virtual access (PVC) state management interworking between the frame relay network connected to the frame relay (FR) terminal and the ATM network connected to the ATM terminal is a service interworking A FR connection (FAP) that receives a status management entity (Q.933 Annex A) message on each state management interworking protocol from the relay side (FR) and transmits the corresponding change state through the IPC bus, and the corresponding transmission transmitted from the FR connection. ATM switch including a multiplexing unit (MDP) connected to an ATM switch and mapping to ATM OAM cells with reference to the change state information, and a module clock distribution unit for generating and distributing clocks required by the FR connection unit and the multiplexing unit. In the PVC state management interworking method of the frame relay interworking module (FRIM) structure in the connection exchange subsystem (ALS) of the state, the state (S) to the frame relay (FR) side. When a message or a status request (SE) message is received in the FR connection in one of two-way, one-way, and event-driven modes, a status message is generated by referencing or changing a PVC status information table in the FR connection. And responding to the FR side and transmitting the state change of the PVC received through the IPC bus from the multiplexer to a corresponding continuity check, loopback or alarm indication signal (AIS) ATM OAM (operation, maintenance and management) cell. After receiving the RDI ATM OAM cell in response to the ATM, the related PVC state information table is transferred to the FR connection through the IPC bus again for use in changing.

In the above, the status message or the status request message is transmitted and received in both directions in the bidirectional direction during service interworking, the status request message is received in one direction in the one-way direction, and the status message is received in the event-driven mode.

Another feature of the present invention is that both of frame relay (FR) / ATM when a permanent virtual access (PVC) state management interworking function between a frame relay network connected to a frame relay (FR) terminal and an ATM network connected to an ATM terminal is network interworking. Receives the status management entity (Q.933 Annex A) message on each state management interworking protocol from the FR connection unit (FAP) for transmitting and receiving the corresponding message through the cell bus, and the FR status message which is the ATM cell transmitted from the FR connection unit. Interworking frame relay in the connection switching subsystem (ALS) of the ATM exchanger including a multiplexing unit (MDP) transmitting and receiving and connected to the ATM switch, and a module clock distribution unit for generating and distributing the clock required by the FR connection unit and the multiplexing unit. In the PVC state management interworking method in the module (FRIM) structure, the state management entity on both sides of the FR / ATM operating independently in the FR connection; (S) When a message or a status request (SE) message is received in the FR connection in one of two-way, one-way, and event-driven modes, the FR side sends the ATM side PVC status information table or the ATM side according to the direction. A status message for the received status request message is generated with reference to each of the FR status information tables, and the status information management table of the own side is changed using the information of the received status message.

In the case of the unidirectional direction above, this table is changed with reference to one PVC state information management table.

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

FR / ATM interworking scenarios can be classified into two types: network interworking and service interworking.

First, network interworking is a function of transparently transmitting FR user traffic and PVC signal traffic through the ATM network as in the case of the path A 101 of FIG. 1. In other words, the interworking function provides the function of connecting the two FR networks 105 to the ATM network 104 as a backbone network. One FR PVC can be mapped and delivered (one-to-one) to one ATM PVC, or all FR PVCs can be multiplexed and delivered (one-to-one) to one ATM PVC.

Next, the service interworking is a case of the path B 102 of FIG. 1, unlike the network interworking, user and signal traffic are not transmitted transparently, and a protocol conversion function that provides communication between devices having different protocols. Has

In the Interworking Function (hereinafter, referred to as 'IWF') 103, the FR user premises device (FR-CPE (FR-CPE) by mapping traffic sent from one FR PVC to the ATM PVC and transmitting it to the ATM network. Customer Premises Equipment, 107) and ATM subscriber premises equipment (ATM-CPE, 106). Of course, in the IWF 103, mapping / conversion of header information in the FR frame and ATM cell header occurs, and the conversion of the FR PVC status management message to an ATM OAM (Operations, Administration, Management) cell is also generated.

The PVC maintenance function handled according to this divided interworking scenario is divided into one-to-one and many-to-one in network interworking again. Unlike service interworking where FR status management messages are mapped to ATM OAM cells, DLCI 0 (Data Link Connection) With Identifier 0), the status request / status message is sent transparently to the end.

Q.933 The functions for maintenance of PVC in FRs, as recommended in Annex A, use status requests (SE) and status messages (S).

In the case of UNI (User-to-Network Connection), when the periodic status request message is transmitted from the FR TE to the network side, the network transmits the status message to the FR TE side in response. The content of the status message includes the status or Link Integrity Verification (LIV), single PVC asynchronous status, etc. for all PVCs on that bearer channel. Unidirectional mode is defined as the main mode of UNI, and bidirectional mode is defined as a selection mode.

In the case of NNI (network connection), the bidirectional mode is defined as the main mode, and the event driving mode is defined as the selection mode. In particular, only the status message is used for the event driving mode.

2 is a PVC state management interworking procedure in service interworking, wherein the FR side or the ATM side independently performs the PVC maintenance function, and the status request or status message 201 of the FR side is transferred to the OAM cell 202 of the ATM side. It must be converted and delivered. In case of failure of FR side, it transmits Alarm Indication Signal (AIS) F5 OAM cell to all ATM PVC concerned and stops AIS F5 OAM cell transmission when FR side failure recovery.

Network interworking is divided into one-to-one and many-to-one interworking. Figure 3 shows the PVC state management interworking protocol stack of network linkage. The FR side 301 and the ATM side (FR-SSCS (FR-SSCS) state management) operate independently of each other. In particular, the ATM side has a FR-SSCS state management entity (Q.933 Annex A) per VCC. 302 is generated and the FR PVC status management message is forwarded to ATM using DLCI 0. Also, in case of one-to-one network interworking, FR-SSCS state management entity does not apply LIV related message, but refers to the state of ATM VCC (Virtual Channel Connection) LIV provided by ATM OAM F5. Is applied.

In order to apply the aforementioned processing function for interworking of the PVC state management to the implementation of the interworking function of the ATM exchanger, we first describe the interworking module in the system and propose a method proposed by the present invention.

4 illustrates a structure of a FR Relay Interworking Module (FRIM) in an ATM switch, and is largely connected to an ATM switch 411 and a module in an ALS (ATM Local Switching Subsystem) 409. A ATM switch 413 in an ATM Central Switching Subsysem 412 is connected. In this case, the ATM switch 411 is connected to a call control processor (CCP) 410, and the ATM switch 413 is connected to an operation and administration processor (OAP) 414.

The Frame Relay Access Part (FAP) 402 in the FR interworking module 401 has a function of matching two DS1 / E1s 405, a function of transmitting / receiving a FR frame for each channel, and sending it to an ATM cell. ATM Adaptation Layer 5 (AAL5) processing function for conversion is the main function, ATM cell is transmitted to the multiplexer (MDP) 403 through the cell bus 407, maintenance information, FR subscriber registration / deletion, FR PVC Information such as connection establishment / release is communicated with the multiplexer (MDP) 403 via an Inter-Prcocessor Communication (IPC) bus 407 using DPRAM (Dual Port RAM). In case of SVC, call processing signal is easily distinguished from user information because DLCI = 0 is input from FR. Call processing message is also treated as IPC message and transmitted to multiplexer through IPC bus. The multiplexer 403 provides a User Parameter Control (UPC) function and a Virtual Path Identification (VPI) / Virtual Channel Identification (VCI) function for an ATM cell transmitted from the FR access unit 402. ), The function of inserting routing information, the function of multiplexing / demultiplexing cells by connecting to the IMI 408, the OAM processing function, and the like, and controlling the FR connection, It becomes the IPC master of FR interlocking module. The multiplexer 403 is connected to an Access Local Switch (ALS) 409 through an intermodule connection (IMI). The module clock distribution part (CDP) 404 receives a network synchronizer clock from the ATM switch 411 to generate and distribute a clock required by the multiplexer 403 and the FR connection unit 402. As a key feature, PLL (Phase Synchronous Loop) is used to generate 155.52 MHz from the network synchronizer clock derived from 155.52 MHz, which is then divided to generate the clock needed for ATM cell transmission. The module clock distribution unit 404 is connected to the ALS 409 by a mini-coaxial cable.

As described above, in order to implement the state management interworking function, it is necessary to distinguish several cases to be applied first, and this is a bidirectional, unidirectional, event-driven method for each UNI / NNI in each case of service / network interworking. And so on. The state management entity (Q.933 Annex A) on the state management interworking protocol is implemented in the FR connection unit (FAP) 402 in the FR interworking module, and the mapping of the FR state messages to the ATM OAM cell is performed by the multiplexer (MDP) 403. Is suggested to be performed in

5 is a diagram illustrating a bidirectional case during service interworking.

The status (S; 502) or status request message (SE; 501) is transmitted and received in both directions to the FR side based on the FR connection (FAP) 402, and the generation or reference of the status message transmitted and received in response to the status request message is related to the PVC. This is made possible by referencing or changing the state information table 503 information. The state change (new, active / inactive) 504 of the associated PVC is passed to the multiplexer (MDP) 403 via the IPC bus and mapped to the corresponding continuity check, loopback or AIS ATM OAM cell 505 and the ATM switch 411 When the RDI (Remote Defect Indication) ATM OAM cell 506 is received in response to the RPC, it is transferred to the FR connection 402 through the IPC bus and used to change the related PVC state information table.

6 is a diagram illustrating a one-way case during service interworking.

When the status request message 601 is received on the FR side based on the FR connection unit 402, the status message 603 is generated with reference to the information in the status information table 602, and a response is transmitted to the FR side. The state change (new, active / inactive) 604 of the relevant PVC is transmitted to the multiplexer 403 via the IPC bus and mapped to the corresponding continuity check, loopback or alarm indication signal (AIS) ATM OAM cell 605. When the RDI ATM OAM cell 606 is received in response to the ATM switch 411, the RDI ATM OAM cell 606 is transmitted to the FR connection 402 through the IPC bus and used to change the relevant PVC state table.

FIG. 7 illustrates a case of an event-driven method during service interworking.

When the status message 701 on the FR side is received based on the FR connection portion 402, the information in the PVC status information table 706 is changed, and when there is a status change by the ATM side, a status message 702 is generated to the FR side. Send a response. The state change (new, active / inactive) 703 of the related PVC is transmitted to the multiplexer 403 via the IPC bus and mapped to the corresponding continuity check, loopback or alarm indication signal ATM OAM cell 704, and forwarded to the ATM side. When the RDI ATM OAM cell 705 is received in response, the RDI ATM OAM cell 705 is transferred to the FR connection 402 through the IPC bus and used to change the related PVC state table.

8 is a diagram illustrating a bidirectional case during network linkage.

Since the state management entities on both sides of the FR / ATM operate independently in the FR connection unit 402, the state information management table is implemented accordingly, and ATM is generated when the state message 802 is generated for the state request message 801 on the FR side. Reference is made to the side status information management table 805 and the information in the received status message 803 is used to change the FR side status information table 804. The status request message 806 transmitted from the ATM state management entity to the ATM side is transmitted through the multiplexer 403, the ATM switch 411, and the wireless data communication interworking device (IWF) 815 to the other side FR network 807 or FR. The information in the status message 808, which is transmitted transparently to the connection 403 and received in response, is used to change the ATM side status information management table 805. The FR side status information management table 804 is also referred to for generating the status message 810 to be transmitted in response to the status request message 809 received from the counterpart.

Fig. 9 is a diagram showing a case of unidirectional during network linkage.

In the FR connection 402, the state management entity on both sides of the FR / ATM operates independently but is unidirectional so that one state information management table 903 is implemented, and the state message 902 for the state request message 901 on the FR side. When generating, reference is made to the PVC state information management table 903, and the information in the received state message 905 is used to change the state information table. The status request message 904 transmitted from the ATM state management entity to the ATM side is transmitted through the multiplexer 403, the ATM switch 411, and the wireless data communication interworking device (IWF) 915 to the other side FR network 906 or FR. The information in the status message 905 transmitted transparently to the connection 403 and received in response is used to change the status information management table.

FIG. 10 is a diagram illustrating a case of an event-driven method during network linkage.

As in the bidirectional case, the status information management table is divided and implemented, and when generating the status message 1001 to be delivered to the FR side, the ATM side status information management table 1004 is referred to, and the information in the received status message 1002 is the FR side. It is used to change the state information table 1003. The status request message 1005 transmitted from the ATM state management entity to the ATM side is transmitted through the multiplexer 403, the ATM switch 411, and the wireless data communication interworking device 1015 to the other side FR network 1009 or FR connection unit ( Information in the status message 1006, which is transmitted transparently to 402 and received in response, is used to change the status information management table 1004. The FR side status information management table 1003 is also referred to for generating the status message 1007 to be transmitted in response to the status request message 1008 received from the counterpart.

In the present invention as described above, the interworking between the ATM network and the existing network is an inevitable function, and when interworking with the FR network capable of providing various data services at low cost and high efficiency among the existing network is necessary, In order to implement the interlocking function, it is expected that the interlocking of the PVC status management procedure is necessary. In addition, the present invention may be applicable to the implementation of ATM / FR PVC state management interworking function as well as the related functions of other systems.

Claims (4)

State management entity on each state management interworking protocol from the frame relay side (FR) when the permanent virtual access (PVC) state management interworking between the frame relay network to which the frame relay (FR) terminal is connected and the ATM network to which the ATM terminal is connected is service interworking. Receives the message (Q.933 Annex A) and performs mapping to the ATM OAM cell with reference to the FR connection unit (FAP) transmitting the state change information through the IPC bus and the corresponding change state information transmitted from the FR connection unit. Frame relay interworking module in the connection switching subsystem (ALS) of the ATM exchanger including a multiplexing unit (MDP) connected to the ATM switch and a module clock distribution unit for generating and distributing the clock required by the FR connection unit and the multiplexing unit ( In the PVC state management interworking method in the FRIM) structure, PVC status information table in the FR connection when a status (S) message or a status request (SE) message to the frame relay (FR) is received in the FR connection in any one of a bidirectional, unidirectional, event-driven mode. After generating or generating a status message by referring to or changing, the response and transmission to the FR side and the status change of the PVC received through the IPC bus are performed by the multiplexer in a continuity check, loopback or alarm indication signal (AIS). Mapping to ATM OAM (operation, maintenance and management) cell and forwarding it to ATM side, and when receiving RDI ATM OAM cell in response, it reconnects through IPC bus to use relevant PVC state information table when changing. Frame relay PVC state management interworking method in the ATM exchange, characterized in that the transfer to the FR connection. The method of claim 1, During the service interworking, a status message or a status request message is transmitted and received in both directions in one-way direction, a status request message is received in one direction in one-way direction, and an status message is received in event-driven mode. Frame relay PVC status management interworking method in exchange. If the permanent virtual access (PVC) state management interworking function between the frame relay network to which the frame relay (FR) terminal is connected and the ATM network to which the ATM terminal is connected is network interworking, A FR connection (FAP) that receives a state management entity message (Q.933 Annex A) and transmits and receives a corresponding message through a cell bus, and transmits and receives a FR status message, which is an ATM cell transmitted from the FR connection, and is connected to an ATM switch. In the frame relay interworking module (FRIM) structure of the ATM switch exchange system (ALS) including a multiplexer (MDP) and a module clock divider for generating and distributing clocks required by the FR connector and the multiplexer. In the PVC state management interworking method, A status (S) message or a status request (SE) message is received from the FR connection in one of two-way, unidirectional, and event-driven modes from state management entities on both sides of the FR / ATM operating independently in the FR connection. In this case, the FR side generates the status message for the received status request message by using the FR side PVC status information table or the ATM side referring to the FR side status information table, and uses the information of the received status message according to the direction. Frame state PVC interworking management method of the ATM switch, characterized in that for changing the state information management table of its own side. The method of claim 3, wherein The frame relay PVC state management interworking method of the ATM switch, characterized in that for changing the table with reference to one PVC state information management table in the case of the one-way.

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