KR20010028108A - Method of Interfacing PRI for AODI Service in the Exchange System - Google Patents

Abstract

PURPOSE: The PRI(Primary Rate Interface) interfacing method for an AODI(Always On Dynamic ISDN) service in an exchange, is provided to recognize a PRI(Primary Rate Interface) line and a channel number having an AO(Analog Output) channel through an independent AO channel table, so that an AO call and a DI(Digital Input) call can be simultaneously included in one PRI. Accordingly, a network service provider can distribute the AO channel to many RASs(Remote Access Servers). CONSTITUTION: A table for storing an AO(Analog Output) B-channel configured in a PRI(Primary Rate Interface) for an AODI(Always On Dynamic ISDN) service is generated for management(S1). Hunting for an AO channel is performed according to a characteristic of a packet call, to selects the PRI B-channel for AO(S2). If the AO call is attempted to the PRI B-channel for AO in an RAS(Remote Access Server), a nailed up function is supported(S3).

Description

Method of Interfacing PRI for AODI Service in the Exchange System}

The present invention relates to a PRI matching method for AODI services in an exchange, and more particularly, to a PRI matching method for an AODI service in an exchange in which a matching form with a RAS (Remote Access Server) for supporting AODI in an exchange is matched using PRI. will be.

In general, AODI is implemented based on the existing exchange and Bandwidth Allocation Control Protocol (BACP). AO is implemented in the form of X.25 packet, and the calling party connects with D-channel packet and works directly with the exchange to transmit TCP (Transmission). The RAS side acting as a server for Control Protocol / IP (Internet Protocol) is connected by B-channel packet, DI is connected by general ISDN data call, and short data is always connected according to user's purpose. To be delivered. Here, the existing exchange that can handle the ISDN subscriber includes an X.25 packet handler function.

The basic idea behind the AODI is that ISDN D-channel X.25 calls occur between clients and Internet service providers (ISPs). Multilink Protocol (MLP) and TCP / IP are delivered by D-channel. It is encapsulated in a logical circuit.

In this case, the B-channel does not use the Q.921 and X.25 encapsulation used in the D-channel, but directly uses the MLP, that is, a circuit switched connection between the subscriber and the ISP is performed on the corresponding B-channel. The IP packet is generated and delivered over this B-channel through Point to Point Protocol (PPP) encapsulation.

The use of X.25 on the D-channel is, of course, not the most efficient protocol stack, but the use of existing packet handlers in the switchboard to implement AODI. Used as PL (Primary Link).

Then, a simple configuration for the conventional AODI service, as shown in Figure 1, the personal computer (PC) 11, the local exchange 12, the ISP 13, the Internet network 14, the packet network ( 14). Here, AO uses Packet Data Capability (PDS), which is part of the ISDN standard, and the subscriber establishes a packet connection to the ISP 13 on the D-channel, and the bidirectional connection is established by the subscriber. 11) on, and when the connection is established, the subscriber can exchange data such as e-mail.

If there is a lot of information that cannot be handled by a 16K D-channel packet connection, the line connection is established using one or two ISDN B-channels, which are automatically established without subscriber involvement. Kbps) is guaranteed.

When the transmission of data ends, the line connection is released and the subscriber is online again on the D-channel.

Meanwhile, there is a technology using an X.25 dedicated link, that is, a T1 / E1 link, for AODI service, in which case it is used separately from the call path of the DI. In this case, when performing matching between the exchange and the RAS using a dedicated T1 / E1 dedicated link for the AO, the AO call is concentrated on a specific SSP (Switching Subsystem Processor) linked to the RAS in a form used separately from the PRI for the DI. Also, because it is a dedicated link, one PRI cannot accept both AO and DI calls at the same time. And, when using the B channel packet RAS can only support nailed up B channel access.

However, in the packet access scenario of the local exchange, the channel information required by the network is delivered to the destination subscriber in the Q.931 Set-up message, and is transferred from the ISDN modem used by the destination subscriber to the Q.931 Connect message. On-demand B that establishes a Link Access Procedure Balanced (LAPB) data link in the network and attempts to make a package call to the called party in order to respond with an available channel and attempt a packet call on an agreed B channel. Follows the channel connection type, which does not match the RAS

In other words, the conventional on-demand B channel connection type is not supported by the RAS and thus is not interworked with the exchange, and the conventional exchange does not use the nailed up procedure for the B-channel packet. In addition, the conventional exchange must deliver the AO call to the nailed-up B-channel, but if the AO call is not delivered to the nailed-up B-channel, the RAS releases the AO call. There is a need for a scheme for distinguishing up B-channels, but there is no description of such schemes and management in conventional networks.

And, if B-channel packet is used for interworking with RAS, the scheme of nailed-up configuration can generate a lot of network changes, and it can flexibly cope with RAS supporting on-demand B-channel connection. There was no.

In order to solve the problems or disadvantages described above, the present invention is to match the form of matching with the RAS using PRI to support AODI in the exchange and to manage the AO channel according to the corresponding PRI matching, the RAS is on demand By applying to the B-channel method, it is possible to distribute the AO channel to multiple RASs when the network service provider provides AODI service, and to assign a single PRI line to a small ISP. It can be configured to reduce the cost and to focus the AO channel to a specific RAS or PRI as needed.

1 is a block diagram showing a simple configuration for a conventional AODI (Always on Dynamic ISDN) Service (Service).

2 is a flowchart illustrating a PRI matching method for an AODI service in an exchange according to an embodiment of the present invention.

FIG. 3 is a block diagram illustrating a process of selecting a primary rate interface (PRI) B-channel for AO in FIG. 2; FIG.

4 is a flowchart illustrating a process of providing a nailed-up function in FIG. 2.

Explanation of symbols on the main parts of the drawings

21: Outgoing Packet Subscriber Call Control (PSC)

22: NTR (Number Translation)

23: Private Branch Exchange Control (PBXC)

24: Incoming PSC

PRI matching method for AODI service in an exchange according to an embodiment of the present invention for achieving the above object comprises the steps of creating and managing a table for storing the B-channel for AO configured in PRI for the AODI service; Selecting the PRI B-channel for the AO by performing hunting of the AO channel according to the characteristics of the packet call; When the AO call to the RAS to the PRI B-channel for the AO characterized in that it comprises a process of supporting the nailed up function. In this case, the table consists of a dual circular link list to perform a search for performing the addition, deletion and hunting of the AO channel.

The AO PRI B-channel selection process is characterized in that the AO channel is not hunted for DI in association with the PBX hunting table. In addition, the PRI B-channel selection process for AO includes the step of notifying the result after performing the number translation according to the packet number translation request; Requesting hunting of the AO channel using the group number of the corresponding line when the type of the called subscriber line is a group line or a separate line in the PBX group and receives a packet number translation request; Selecting a channel having a small number of calls being performed in each channel among the AO channels in the group, and hunting using the selected channel; And specifying the AO channel as a result of the hunting, and connecting the AO call to the corresponding channel to notify the occupant subscriber occupancy. Alternatively, the PRI B-channel selection process for AO may further include requesting rehunting of the AO channel by confirming receipt of the hunting request when the channel call of the circuit cannot proceed.

In addition, the process of providing the nailed up function may include: performing link setting according to a link setting request and notifying the result; Determining whether to forward the restart packet according to the presence or absence of the call when the data link transitions to the up state after the link establishment is completed; Receiving the restart packet and transmitting a restart confirmation packet according to a restart confirmation packet transmission request; Transmitting an IC packet over the established link in accordance with an IC packet transmission request; And receiving the CA packet.

Alternatively, in the switch according to the embodiment of the present invention, the PRI matching method for the AODI service, when interworking with the RAS and the PRI for the AODI service, finds the line and channel number of the PRI having the AO channel in the table, and then uses one PRI. It characterized in that it further comprises the step of receiving the AO call and the DI call at the same time.

Also, alternatively, the PRI matching method for the AODI service in the exchange according to an embodiment of the present invention further comprises the step of setting the PRI B-channel for the AO to a plurality of specific channels of any line in the same PBXC group. It features.

The present invention broadly supports AODI services and provides AODI services with the same level as existing data network access services, and can be applied even after RAS enhancement. In addition, the present invention creates and manages an independent table that can manage the B-channel for AO for AODI, and does not hunt the channel for AO for DI in association with an existing exchange hunting table, and AO in one PRI. It is possible to accept both call and DI call at the same time, and it is possible to set AO channel to several specific channel of any line in the same PBXC group, and to try RAS to RAS with B-channel for AO. It allows you to support nailed up. Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

The PRI matching method for the AODI service in the switch according to the embodiment of the present invention is largely a process for creating an independent table that can manage the PRI B-channel for the AO for AODI, and the AO to select the PRI B-channel for the AO. It includes three steps of hunting channel and providing nailed up function when attempting AO call with PRI B-channel for AO.

Then, referring to the flowchart of Figure 2 as follows.

First, create and manage an independent table that can store the B-channel for AO configured in PRI for AODI service (step S1), and the generated table is composed of a double circular linked list (AODI). A search for adding, deleting, and hunting channels is made easy.

In addition, the operator creates and deletes an AO B-channel in the generated table as needed in consultation with the RAS operator and checks the same information as the call count of the AO channel currently being used.

Next, the scheme for selecting the channel for AO is performed in the PBXC block as with the channel hunting of the existing PBXC, but the difference from the existing scheme is that it can accommodate 10 calls in one AO channel according to the characteristics of the packet call. Since it is possible to perform the hunting of the AO channel in order to select the PRI B-channel for the AO in accordance with this meaning (step S2). At this time, the AO channel is not hunted for DI in connection with the existing PBX hunting table.

After that, when the AO call is attempted to RAS with the PRI B-channel for AO, the nailed up function is supported (step S3). The operation to omit the IC packet is transmitted through the link of the PH interworking with the RAS, and the packet setting is performed in the same manner as the conventional technology.

Here, when interworking with RAS and PRI for AODI service, find out the line and channel number of PRI with AO channel as independent AO channel table so that AO call and DI call can be simultaneously accepted in one PRI. The AO channel can be set to a number of specific channels of any line in the same PBXC group.

Referring to the block diagram of FIG. 3, the AO PRI B-channel selection process of the second process S2 is as follows.

First, the originating PSC 21, which is a packet subscriber high call control block in the exchange, sets the AO flag (ao_flag) in the Packet Number Translation Request Message (PNTRQ) to True and sends it to the NTR 22. You will be asked to translate the packet number.

Accordingly, the NTR 22 generates a packet number translation response message (PNTRP) after the packet number translation is performed and applies it to the originating PSC 21. At the same time, the type of the called subscriber line is a group line. gln) or an individual line (iln) and the AO flag (ao_flag) in the packet number translation request message (PNTRQ) of the originating PSC 21 is set to true, and the group number of the corresponding line. Packet PBX Term Request Message for requesting hunting of AO channel to PBXC 23 performing Idle line hunting in PBX group in exchange by using NTR 22 PPTRQ1) is applied to the PBXC 23.

In addition, the PBXC 23 that receives the first packet PBX term request message PPTRQ1 hunts an AO channel in the group, and selects a channel having a small number of calls being performed in each channel among the AO channels in the group, The hunt flag (hunt_flag) in the Term Set-up Request Message (TSRQ) is set to true using the selected channel, and the AO channel is designated and sent to the destination PSC 24 as a result of the hunting. .

Accordingly, the incoming PSC 24 checks whether the hunt flag (hunt_flag) in the tum setup request message (TSRQ) of the PBXC 23 is set to true and performs a procedure for connecting an AO call to the corresponding channel. On the other hand, when the hunt flag (hunt_flag) in the tum setup request message (TSRQ) of the PBXC 23 is set to false, the processing is performed in the same manner as the existing call processing procedure and the called party is called. A tum setup response message (TSRP) is sent to the originating PSC 21 to indicate that the occupancy was performed.

If the terminating PSC 24 that has received the terrestrial setup request message (TSRQ) cannot proceed to the corresponding channel call of the terminating line, the terminating setup request message (TSRQ) of the PBXC 23 is received by the terminating PSC 24. In the case where the hunt flag (hunt_flag) is set to true, a second packet PBX term request message (PPTRQ2) is generated to request hunting of an AO channel from the incoming PSC 24 to the PBXC 23 in the SNP. It transmits to the corresponding PBXC 23 to perform rehunting of the channel.

Looking at the nailed up function providing process of the third process (S3) with reference to the flow chart of FIG.

First of all, Q.931 Call Offering operation is omitted to support nailed-up connection. LAPB data link establishment request is requested by network or RAS, and the processing for the requested partner is made first.

That is, when the PSC applies the link establishment request to the packet handler (PH), which is a packet subscriber matching device in the exchange, via the PCIM (Packet Call Interface Module), the PH is interworked with the RAS and thus the LAPB link establishment request L2 primitive. A Primitive Set Asynchronous Balanced Mode Extended (SABM) is applied to the RAS. In addition, the RAS sends a UA (Unnumbered Acknowledgement), a LAPB link establishment complete L2 primitive, to the PH, and the PH notifies the PSC via the PCIM.

At this time, in the RAS, after receiving or transmitting UA, the data link transitions to an up state, and after the state transition, the RAS determines whether to transmit a restart packet according to its presence and state. do.

Accordingly, when the restart packet needs to be delivered, the RAS applies the restart packet to the PH, and the PH notifies the PSC of the restart packet reception through the PCIM.

Then, the PSC requests the PH to send a restart acknowledgment packet through the PCIM, and the PH transmits a restart acknowledgment packet to the RAS, and then transmits an IC (Incoming Call) packet, which is an X.25 call transfer L3 message. Is requested to the PH via the PCIM, and the PH transmits an IC packet to the RAS via a link.

Accordingly, the RAS applies a Call Accept (CA) packet, which is a call reception L3 message of X.25, to the PH, and the PH notifies the PSC of the CA packet reception through the PCIM.

As described above, when interworking with RAS and PRI for the AODI service according to the present invention, it is possible to know the line and channel number of the PRI with the AO channel as an independent AO channel table. In addition to providing the flexibility to distribute and process AO channels to multiple RASs when network operators provide AODI services, the network can be configured by assigning only one PRI line to a small ISP. The AO channel can be concentrated to a specific RAS or PRI as needed.

In addition, the conventional RAS supports only nailed-up B-channel packets. When the B-channel packet is reserved in the network, the exchange not only has various limitations but also many parts have to be modified. It works as if it is nailed up by the network, but the actual application connects the PH and PRI AO channels to the switch at the time of the call to make it identical to the on-demand B-channel packet, so that the network can use another LAPB for the same link. It has the effect of not setting.

In addition, AO channel hunting according to the present invention can be distributed processing within the exchange while applying the advantages of the existing PBXC hunting as it is, and can also select the channel again after concentrating on one channel according to the needs of the operator.

Claims (8)

Creating and managing a table storing a B-channel for AO configured in PRI for the AODI service; Selecting the PRI B-channel for the AO by performing hunting of the AO channel according to the characteristics of the packet call; A method for matching PAI eye for EIA service in a switch, characterized in that it comprises a process of supporting a nailed up function when an AO call is attempted to RAS by the PRI B-channel for AO. The method of claim 1, In the case of interworking with RAS and PRI for the AODI service, the table further includes a process of finding the line and channel number of the PRI having the AO channel and simultaneously accepting the AO and DI calls in one PRI. PAI eye matching method for AIODIA service in a switchboard characterized by the above-mentioned. The method of claim 1, And setting the PRI B-channel for the AO as a plurality of specific channels of an arbitrary line in the same PBXC group. The method of claim 1, The table consists of a double circular link list to perform the search for performing the addition, deletion and hunting of AO channel to the PIA eye matching method for the EIA service. The method of claim 1, The PRI B-channel selection process for the AO is to connect the PBX hunting table so that the AO channel is not hunted for DI. The method of claim 1, The PRI B-channel selection process for AO includes: notifying a result after performing number translation according to a packet number translation request; Requesting hunting of the AO channel using the group number of the corresponding line when the type of the called subscriber line is a group or a separate line and receives a packet number translation request; Selecting a channel having a small number of calls being performed in each channel among the AO channels in the group, and hunting using the selected channel; And specifying the AO channel as a result of the hunting and notifying the occupied subscriber occupancy by connecting the AO call to the corresponding channel. The method of claim 6, The PRI B-channel selection process for AO further comprises the step of confirming receipt of the hunting request when the channel call of the circuit cannot proceed and requesting re-hunting of the AO channel. PI eye matching method for service. The method of claim 1, The process of providing the nailed-up function may include performing link setting according to a link setting request and notifying a result thereof; Determining whether to forward the restart packet according to the presence or absence of the call when the data link transitions to the up state after the link establishment is completed; Receiving the restart packet and transmitting a restart confirmation packet according to a restart confirmation packet transmission request; Transmitting an IC packet over the established link in accordance with an IC packet transmission request; Receiving a CA packet comprising a method for matching the PIA eye for EIA services in the exchange.