KR100252514B1 - Clear packet processing method in all electronic switch for packet exchange - Google Patents

Abstract

PURPOSE: A method of processing a clear packet in a full electronic exchange for packet exchanging is provided to quickly process a call canceling procedure according to a state of a present PLP(Packet Level Procedure), when a clear packet is received from a terminal while a call for packet exchanging is set up in the full electronic exchange. CONSTITUTION: If a clear packet is received from an originating terminal during a call setup, and if a present state of an originating PLP(Packet Level Procedure) is an origination ready state, the PLP is transitted to a PLP ready state(PLPReady) to cancel a call. If the present state is a CR(Clear Request) packet confirm ready state, the PLP transmits an abnormal cancellation request confirm(AbnCgLcRelRQ) signal to an originating packet call processing(BPCC) block to transit to the PLP ready state(PLPReady), and cancels the call. If the call is transmitted to a receiving side, the PLP transmits a clear confirm request(ClrCgLcRelRQ) signal to the originating BPCC block. If a clear confirm response(ClrCgLcRelRP) signal is received from the originating BPCC block, the PLP transmits a CLC(Clear) packet to an originating terminal, and transmits a clear request packet to the receiving side. If the present state is an incoming call confirm ready state(IcPktValRqState), a receiving PLP transmits a cancellation confirm request(NclrCdLcRelRQ) signal to a receiving BPCC block, and transits to a response ready state(NclrValRq_1_State). If a cancellation confirm response(NclrCdLcRelRP) signal is received from the receiving BPCC block, the receiving PLP transmits a clear confirm packet to an originating side, and transits to a PLP ready state(PLPReadyState).

Description

Method of processing clear packet for packet switching in electric exchange

The present invention relates to a method for handling a clear packet when a clear packet is received during call setup in an electronic switchboard that provides a packet switching function.

As is well known, the switching functions are broadly classified into circuit switching for normal telephone service and packet switching for data communication. In order to satisfy various services required by the user, the existing switching circuit can accommodate the packet switching function. Is gradually being improved. That is, in the related art, a dedicated packet exchanger was used for packet exchange, but as the network evolved to ISDN and B-ISDN, it was required to be able to access various networks with one exchange.

As such, for packet exchange, it is necessary to establish a procedure for promptly processing a clear packet when a clear packet is received in order to abnormally release the packet call during the setup of the packet call according to the request of the calling terminal.

Accordingly, the present invention has been proposed to meet the above requirements, and provides a method for processing a clear packet when a clear packet is received while setting up a call for packet switching in an electronic switchgear for providing circuit switching. There is this.

In order to achieve the above object, the present invention, the terminal (DTE) is respectively connected to the source exchange and the destination exchange with a packet exchange function, the source exchange and the destination exchange is interconnected through a network, In a switch network in which a link layer (LAPB), a packet layer (PLP), and a packet call processing (BPCC) block are implemented at each exchange, when a clear packet is received from an originating terminal during call setup, If the state is a call waiting state, immediately transitioning to a PLP ready state (PLPReady) to release the call; If the CR packet check wait state is transmitted, an abnormal release request acknowledgment (AbnCgLcRelRQ) signal is transmitted to the calling BPCC block, and then transitioned to the PLP read state (PLPReady) to release the call; If the call is forwarded to the called party, the calling party PLP sends a clear confirmation request (ClrCgLcRelRQ) signal to the calling party BPCC block and sends a CLC packet to the calling party when a clear acknowledgment (ClrCgLcRelRP) signal is received from the calling party BPCC block. Transmitting a clear request packet to a called party; And if the incoming call confirmation wait state (IcPktValRqState), the called party PLP transmits a release confirmation request (NclrCdLcRelRQ) signal to the called party BPCC block, and then transitions to the answer waiting state (NclrValRq_1_State), and releases the acknowledgment response from the called party BPCC block. When the NclrCdLcRelRP) signal is received, and transmitting a Clear Confirm packet to the sender, and transitioning to the PLP Ready state (PLPReadyState).

1 is a schematic structural diagram of a packet switched network to which the present invention is applied;

2 is a protocol stack of a source side and a destination side exchange during packet exchange according to the present invention;

3 is a state transition diagram showing a change of state in a packet layer (PLP) according to the present invention;

4 is a flowchart illustrating a case where a clear packet is received in an outgoing standby state according to the present invention;

5 is a flowchart illustrating a case where a clear packet is received from a DTE in a CR packet confirmation wait state according to the present invention;

6 is a flowchart illustrating a case where a clear packet is received from a DTE after forwarding a call to a called party according to the present invention;

7 is a flowchart illustrating a case where a clear packet is received from an originating party in an incoming call confirmation waiting state according to the present invention.

＊ Explanation of symbols for main parts of drawing

100,300: Terminal (DTE) 200: Switching network

210,220: Subsystem

211,221: main processor 212,222: ISDN subscriber module

213,223: packet subscriber module 230: IPC network

240: packet network 250: switch network

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

1 is a schematic structural diagram of a packet switched network to which the present invention is applied. As shown in FIG. 1, the switching network 200 to which the present invention is applied is composed of a plurality of subsystems including an originating subsystem 210 and a destination subsystem 220 or exchangers connected to the network. In addition, the originating subsystem 210 and the destination subsystem 220 are composed of subscriber modules 212 and 222, packet subscriber modules 213 and 223, and main processor modules 211 and 221, respectively, to communicate with each other or between each module. There is an IPC network 230, a packet network 240, a switch network 250 to tie the whole system in one. The main processor modules 211 and 221 process resource management, state management, subscriber number management and translation of the entire system, the IPC network 230 and the packet network 240 have an HDLC structure, and the switch network 250 has time. Has a slot structure.

Referring to FIG. 1, the main processor modules 211 and 221 are modules in which software such as operation, maintenance, maintenance, statistics, call processing, and database of the system reside, and other processors or subscribers through the IPC network 230. In communication with the module, performs a packet call processing (BPCC) block according to the present invention.

The ISDN subscriber module (212, 222) is a module connected to the ISDN terminal (100, 300) satisfying the protocol conditions of the ISDN physical layer through the terminal interface, the packet subscriber module (213, 223) through the switch interface 250 B channel on the ISDN terminal interface Function (ie, providing a route)

The packet subscriber modules 213 and 223 relay the packet frames received in HDLC form from one time slot of the switch network interface to the packet switch network, the function of the link layer (LAPB), and the data flow control function of the packet layer (PLP). do. In addition, communication with the packet call processing (BPCC) block in the main processor (211,221) through the IPC interface 230, the connection, disconnection, switch of the LAPB connected to the ISDN terminal by the command from the packet call processing (BPCC) block Allocates, connects, and releases specific time slots in the network.

2 is a protocol stack of an originating and terminating exchange during packet exchange according to the present invention. Referring to FIG. 2, the source exchange 210 and the destination exchange 220 are composed of a physical layer, a link layer (LAPB), a packet layer (PLP), and a packet call processing application (BPCC) layer. As described, the link layer (LAPB) and the packet layer (PLP) are processed in the packet subscriber module, and the packet call processing application (BPCC) is processed in the main processor.

3 is a state transition diagram showing a change of state in a packet layer (PLP) according to the present invention. Referring to FIG. 3, a waiting state (ReadyState: S10) is a state in which a program starts and waits for an event after initialization.

The user link setup wait state (UserL2EstWaitState: S20) is a link setup request (LinkSetupRQ) signal having a call type (Cell type = Org) signal from a packet call processing (BPCC) block in a waiting state (S10) during an outgoing call processing. When you receive a transition state. Upon receiving a LinkSetupRQ signal, the PLP sends a LinkModeSetup Signal to the LAPB. Here, the link setup request (LinkSetupRQ) signal may be omitted. If this signal is omitted, the LAPB operates as 'modulo 8'. If the LAPB is to be operated as 'Modulo 128', the LinkSetup Request (LinkSetupRQ) signal cannot be omitted. After the link mode setup signal is sent to the LAPB, if the link is not set up until the timer T100 expires, the LAPB transitions to the ready status.

The network link setup waiting status (NetL2EstWaitStatus: S20) is a link setup request with the parameter that the call type is called (cell type = destination) from the packet call processing (BPCC) block in the waiting state (ReadyState: S10) during incoming call processing. Transition when a LinkSetupRQ) signal is received. When this signal is received, the destination PLP sends a LinkEstRQ signal to the LAPB to establish a link. In this case, the information required for the mode (modulo 8 or modulo 128) is also transmitted to the link establishment request (LinkEstReq) signal.

The PLP standby state (PLPReadyState: S41) is included in the L2 active state (L2 ActState: S40), and the L2 link is established.

The call waiting state (OrgWaitState: S42) is an outgoing call processing process. When a call request (CR) call is received from the user in the PLP waiting state (PLPReadyState: S41), the CR packet checking request (CrPktValRQ) signal is sent to the BPCC block. It is waiting for a signal called PID (InitCgPid) from BPCC. The PID (InitCgPid) signal then includes the ID of the child process of the BPCC to process the packet using the same call reference ID (the identifier that distinguishes the call of the packet) as the call request packet. The BPCC block has the destination address contained in the CR Packet Acknowledgment Request (CrPktValRQ) signal and locates the subsystem and PLP to be processed at the destination.

The CR packet acknowledgment wait state (CrValRqstate: S43) is a state of waiting for a CR packet acknowledgment (CrPktvalRP) signal when an InitCgPid signal is received from a BPCC block in an outgoing standby state (OrgWaitState).

The DTE wait state (DTEWaitState: S44) receives a CR packet acknowledgment (CrPktValRP) signal from the BPCC block in the CR packet acknowledgment wait state (CrValRqState: S43) during outgoing call processing. The CR Packet Acknowledgment (CrPktValRP) signal contains all the information about the destination (ie, subsystem location, required subscriber boards, etc.) and therefore calls the call to the corresponding PLP layer of the subsystem. Deliver the packet and wait for a response from the called process. This state is also present in ITU-T X.25.

CC packet check wait state (CcValRqState: S45) is a DAC wait state (DTEWaitState: S44), when a call accept (CA) packet is received from the destination, the CC packet is sent to the BPCC block to query the validity and usefulness of this packet. It sends a CcPktValRQ signal and waits for a response.

In the data active state (FlowcontrolReadyState or DataActState, S49), the CC packet acknowledgment (CcPktValRP) signal is received in the CC packet acknowledgment wait state (CcValRqState: S35) or the CA packet acknowledgment response (CaPktValRqState: S48). Receives CaPktValRP) signal and delivers call accept (CA) packet to calling party. From this point on, flow of user data begins.

Incoming call packet acknowledgment wait state (IcPktValRqState: S46) is a call request (CR) packet received from the calling party in PLP waiting state (PLPReadyState: S41), and the incoming call packet acknowledgment request (IcPktRQ) signal to the BPCC block. Wait for an incoming call packet acknowledgment (IcPktValRP) signal. If the call request (CR) packet received from the calling party is a valid value, the " IcPktValRP " signal is received. If it is invalid, the " IcPktValNok " signal is received.

DCE waiting state (DCEWaitState: S47) receives an incoming packet acknowledgment (IcPktValRP) signal from the BPCC block in the incoming call packet acknowledgment wait state (IcPktVal RqState) and sends an incoming call (IC) packet to the called terminal. This state is also described in ITU-T X.25.

CA packet confirmation wait state (CaPktValRqState: S48) receives a Call Accept (CA) packet from the destination terminal in DCE standby state (DCEWaitState), and requests CA packet confirmation to the BPCC block to confirm the validity and validity of this packet. Sending a (CaPktValRQ) signal and waiting for a response, which is one of incoming call processing.

The DTE release wait state (DTEClrRqState: S51) is a state in which a call clear (CLR) packet has been received from the terminal in DataActState, CcValReqState, DTEWaitState, DCEWaitState, and CaPktValRqState. This state is a state in the release process that sends a ClrCgRelRQ (if called) or ClrCdLcRelRQ (if called) signal to the BPCC block to verify the validity / validity of the received call release (CLR) packet. to be.

Release response wait state (NclrRqState: S52) receives ClrCgLcRelRP (if calling party) or ClrCdLcRelRQ (if calling party) signal from BPCC block in DTEClrRqState (S51), and clear confirm (CC) packet to DTE side. It sends a clear request packet to the other side of the network and waits for the response. When it receives a Clear Confirm (CC) packet from the other side of the network, it enters the PLP waiting state (PLPReadyState: S41). Transition

The release packet check wait state (NclrValRqState: S54) is a state in which a clear packet is received from the other side of the network in DTEWaitState, CcValReqState, DataActive, DCEWaitState, and CaPktValRqState.The NclrCgRelRQ It is in the process of releasing a signal (if called) or NclrCdLcRelRQ (if called) and waiting for a response. The DCE release indication state (DCEClearIndState: S55) sends a clear indication (CI) packet to the terminal when NclrValRqState (S54) receives NclrCdLcRelRP (if called) or NclrCgLcRelRP (if called). Waiting for the response. This state is also indicated in ITU-T X.25, and is a state during the release process. When a clear confirm (CC) packet is received from the terminal side, the state transitions to the PLP waiting state (PLPReadyState: S41). LinkRelWaitState sends LinkRelReq signal to LAPB when it receives LinkRelRQ signal to release link layer from BPCC block in any state of PLP, and waits for the response. Transition to the state (ReadyState).

As such, the signals transmitted between the PLP and BPCC blocks are shown in Tables 1a and 1b.

Signal notation Signal direction function LinkSetupRQ BPCC-> PLP The signal to establish the link LinkSetupRP PLP-> BPCC Signal that the link is established LinkRelRQ BPCC-> PLP Signal to unlink LinkDiscRP PLP-> BPCC A signal that the link has been released InitCgPid BPCC-> PLP Notice that a BPCC child process has been allocated to handle the call CrPktValRQ PLP-> BPCC Signal that the CR packet has been received CrPktValRP BPCC-> PLP Signal confirming that the CR packet is normal and valid IcPktValRQ PLP-> BPCC Signal that a CR has been received from the other side of the network IcPktValRP BPCC-> PLP Signal from the other side of the network confirming that the CR is normal and valid CaPktValRQ PLP-> BPCC Signal that the CA packet is received from the terminal CaPktValRP BPCC-> PLP Signal confirming that the received CA packet is a normal and valid packet CcPktValRQ PLP-> BPCC Signal that a CA packet has been received from the other side of the network CcPktValRP BPCC-> PLP Signal confirming that CA packet received from the other side of network is normal and valid ClrCgLcRelRQ PLP-> BPCC Signal that clear packet is received from calling terminal ClrCgLcRelRP BPCC-> PLP Signal confirming that clear packet received from calling party is normal and valid NclrCgLcRelRQ PLP-> BPCC Signal that the calling party has received a clear packet from the other side of the network. NclrCgLcRelRP BPCC-> PLP Signal that confirms that the clear packet received from the other side of the network on the calling side is normal / valid

Signal notation Signal direction function ClrCdLcRelRQ PLP-> BPCC Signal indicating that clear packet is received from terminal at called party ClrCdLcRelRP BPCC-> PLP Signal confirming that clear packet received from terminal is normal and valid at called party NclrCdLcRelRQ PLP-> BPCC Signal that the receiving party receives clear packet from the other side of the network. NclrCdLcRelRP BPCC-> PLP Signal that confirms that the clear packet received from the other side of the network on the called party is normal and valid CrPktValNokRP BPCC-> PLP Response that the received CR packet is not normal CaPktValNokRP BPCC-> PLP Response that received CA packet is not normal IcPktValNokRP BPCC-> PLP Reply that the Encrypting Packet is not normal CcPktValNokRP BPCC-> PLP Response that received CC packet is not normal

On the other hand, if a clear packet for abnormally requesting call release is received during the process of setting up a call according to a predetermined procedure in the PLP layer, a procedure for processing the same according to the present invention is illustrated in FIGS. 4 to 7. It is.

4 is a flowchart illustrating a case where a clear packet is received in an originating wait state (OrgldWaitState) according to the present invention. Referring to Figure 4, the source exchange includes a DTE, LAPB, PLP, BPCCo, the PLP receives the CR packet from the DTE, transmits the CrPktValRQ signal to the BPCCo, and then transitions from PLPReadyState to OrgldWaitState and waits for the InitCgPid signal have.

In this state, when the clear (CLR) packet is received from the calling terminal, the PLP transfers the CLC packet to the terminal and then transitions to PLPReadyState.

5 is a flowchart illustrating a case where a clear packet is received from a DTE in a CR packet check wait state (CrValRqState) according to the present invention. Referring to FIG. 5, an originating exchange includes a DTE, LAPB, PLP, and BPCCo. The PLP receives an InitCgPid signal from OrgldWaitState and then transitions to CrVarRqState and waits for a CrPktValRP signal after receiving a CR packet from the DTE.

In this state, when a clear (CLR) packet is received from the terminal, the PLP sends an AbnCgLcRElRQ signal to the BPCCo block, transmits a CLC packet to the terminal, and then transitions to PLPReadyState. The ClrCgLcRelRP signal received from BPCCo is then ignored.

6 is a flowchart illustrating a case where a clear packet is received from a DTE after forwarding a call to a called party according to the present invention. Referring to FIG. 6, when the calling party PLP receives the CrPktValRP signal from the BPCCo while performing a normal call setup procedure, the calling PLP transmits a Call Request packet (TxLcn = x, RxLcn = y) to the called party. In this way, when a clear (CLR) packet is received from the calling terminal after forwarding the call to the called party, the PLP sends a ClrCgLcRelRQ signal to the BPCCo block and starts the timer T400. When the ClrCgLcRelRP signal is received from the BPCCo block, the timer starts T410. After sending the CLC packet to the terminal, it sends the ClearRequest packet to the called party and transitions to NclrRqState.

7 is a flowchart illustrating a case where a clear packet is received from an originating party in an incoming call confirmation wait state (IcPktValRqState) according to the present invention. Referring to FIG. 7, after the calling PLP receives the clear packet in the DTEWaitState, the calling PLP transmits a ClrCgLcRelRQ signal to the BPCCo block and transitions to the DTEClearRqState. When the ClrCgLcRelRP signal is received from the BPCCo block, the CLC packet is transmitted to the calling terminal and the clear request signal is sent to the called party.

At this time, when the destination PLP transitions to IcPktValRqState in the BPCCt block, when a Clear Request packet is received from the calling party, the destination PLP transmits the NclrCdLcRelRQ signal to the BPCCt block and then transitions to NclrValRq_1_State. Subsequently, when the NclrCdLcRelRQ signal is received from BPCCt, the transmitter transmits a Clear Confirm packet to the calling party and then transitions to PLPReadyState. The calling PLP transitions to PLPReadyState when a Clear Confirm packet is received.

As described above, if a clear packet is received from the terminal while setting up a call for packet exchange in the electronic switch according to the present invention, the call release procedure can be promptly processed according to the current state of the packet layer (PLP). have.

Claims (1)

A terminal (DTE) is connected to an originating exchange and a destination exchange each equipped with a packet switching function, and an originating exchange and a destination exchange are interconnected through a network, and each exchange has a link layer (LAPB) and a packet layer ( PLP), in a switching network in which a packet call processing (BPCC) block is implemented, If a clear packet is received from the calling terminal during call setup, If the current state of the calling party PLP is the calling waiting state, immediately transitioning to the PLP waiting state (PLPReady) to release the call; If the CR packet check wait state is transmitted, an abnormal release request acknowledgment (AbnCgLcRelRQ) signal is transmitted to the calling BPCC block, and then transitioned to the PLP read state (PLPReady) to release the call; If the call is forwarded to the called party, the calling party PLP sends a clear confirmation request (ClrCgLcRelRQ) signal to the calling party BPCC block and sends a CLC packet to the calling party when a clear acknowledgment (ClrCgLcRelRP) signal is received from the calling party BPCC block. Transmitting a clear request packet to a called party; And If the incoming call acknowledgment wait state (IcPktValRqState), the called party PLP transmits the release confirmation request (NclrCdLcRelRQ) signal to the called party BPCC block, and then transitions to the answer waiting state (NclrValRq_1_State), and releases acknowledgment (NclrCdLcRRP) from the called party BPCC block. Transmitting a clear confirmation packet to the calling party when the signal is received, and then transitioning to a PLP ready state. 2.

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