KR20020034524A - Apparatus and method of call processing in switching system which provides idlc service - Google Patents

Abstract

PURPOSE: An apparatus and method for processing a call in a switch system for providing an IDLC(Integrated Digital Loop Carrier) service is provided to perform a PSTN(Public Switched Telephone Network) call process with several AN(Access Network) devices using one interface ID to satisfy a V5.2 standard proposed in an ITU(International Telecommunication Union). CONSTITUTION: A plurality of AN-Rts(AN-Remote terminals)(500) install subscriber boards connected to IDLC subscribers and manage subscribers according to a message command transmitted from a switch(200), An AN-Cot(AN-Central office terminal)(300) connects between the switch(200) and a plurality of AN-Rts(500), performs bandwidth management and sets a channel for transmitting and receiving a call establish/release message for channel assignment between the switch(200) and plurality of AN-Rts(500).

Description

Apparatus and method for call processing in exchange system providing IDC service {APPARATUS AND METHOD OF CALL PROCESSING IN SWITCHING SYSTEM WHICH PROVIDES IDLC SERVICE}

The present invention relates to a call processing apparatus and method in a switching system for providing IDLC subscriber service with a V5.2 switch.

Recently, Integrated Digital Loop Carrier (IDLC) exchange function has been developed to provide broadband service to remote subscribers. In other words, the implementation of IDLC in an electronic exchange is being developed to provide basic Plain Old Telephone Service (POTS) and ISDN services to remote broadband subscribers, and based on the V5.2 interface, access network (AN) and Connected. The IDLC exchange function of the electronic exchange exchanges the FTTC by connecting an access network (AN) such as a Fiber Loop Carrier-Curb (FLC-C) optical subscriber transmission device and a wireless local loop (WLL) system through a V5.2 standard interface. It aims to provide public network services in the form of Fiber to the Curb.

In general, FTTC (Fiber to the Curb) has emerged as one of the carrier's subscriber network optical cable evolution methods to provide broadband multimedia services by connecting optical fibers to residential entrances and small and medium-sized buildings in commercial areas. Evolution to FTTH (Fiber to the Home), the ultimate goal of high-speed network construction, is expected.

1 is a diagram illustrating a configuration of a conventional IDLC PSTN call service.

V5.2 interface structure used as IDLC interface, communication between subscriber network and electronic exchange is handled by V5.2 protocol, and each layer is composed of physical layer that transmits protocol information on physical link and use of adjacent line. It consists of a data link layer that improves efficiency, functions for flow control and error control, and a network layer that handles call establishment / release and routing. In addition, the network layer protocol of V5.2 consists of a number of protocols, each consisting of a subprotocol of PSTN, bearer channel connection (BCC), control, link control and protection protocols.

Referring to FIG. 1, since the two AN systems 400 must process the V5.2 protocol, each of the two AN systems 400 is given one different V5.2 interface ID per AN system 400. Therefore, if the number of subscribers who want to receive PSTN service increases, the AN system should be expanded at a remote location. Accordingly, the number of V5.2 interface IDs for communication between the V5.2 switch (LE) 200 and the AN system is also increased. It should be increased by the number of AN systems.

The LE 200 manages a V5.2 interface ID as a basic unit to manage subscribers used by all AN systems linked to different V5.2 interface IDs. That is, the LE 200 cannot infinitely accommodate the increase in the number of V5.2 interface IDs to be managed, that is, there is a structural limitation in the serviceable LE itself. Furthermore, managing the number of V5.2 interface IDs that are changing according to the interworking network configuration of AN and LE requires more management tools, performance considerations, and additional hardware in the LE system. do. For example, when an AN system is newly established in several regions where the number of serviced subscribers is small, each AN has a V5.2 interface ID even though the actual number of LEs can be serviced with one V5.2 interface ID. Since it has to be set differently, the case where the LE apparatus needs to be expanded sometimes occurs, and since it must manage this, it may adversely affect the management of the LE, and the maintenance and the expansion were expensive.

In summary, in the conventional IDLC exchange system, when the number of subscribers increases, the number of V5.2 interface IDs increases, so that the limited V5.2 interface IDs may be consumed early. In addition, when adding a few subscribers, additional equipment of a switching device is required.

Accordingly, an object of the present invention is to perform PTSN call processing as a voice subscriber while satisfying the V5.2 standard proposed by several access network apparatuses (ANs) and ITU (International Telecommunication Union) with one interface identification. To provide a way.

Another object of the present invention is to provide efficient bandwidth management in addition to the aggregation function in the end subscriber AN device.

1 is a diagram showing a configuration diagram of a conventional IDLC PSTN call service;

2 is a diagram showing a configuration diagram of an IDLC PSTN call service according to the present invention;

3 is a block diagram showing the main configuration of the AN-Cot system 300 according to the present invention,

4 is a block diagram showing the main configuration of the AN-Rt system 500 according to the present invention.

In order to achieve the above object, the present invention provides a call processing method for setting up a call in a central station subscriber transmission device provided between an exchange and a remote subscriber transmission device to provide an interface for an IDLC subscriber. Determining one of a plurality of remote subscriber transmitters connected to the IDLC subscriber upon receiving; searching for a free channel on a link connected to the determined remote subscriber transmitter; and determining the determined remote subscriber transmitter and the central subscriber subscriber apparatus. And providing link / channel information and subscriber information for connecting to the determined remote subscriber transmission apparatus, and connecting the determined remote subscriber transmission apparatus and the exchange.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description and the annexed drawings, detailed descriptions of well-known functions and configurations that may unnecessarily obscure the subject matter of the present invention will be omitted.

The present invention continuously provides the PSTN call service while performing all the functions of the existing AN system that uses the V5.2 switch (hereinafter referred to as LE) for the existing IDLC call service and accepts subscribers. This will allow you to accommodate more subscribers.

2 is a diagram illustrating a configuration of an IDLC PSTN call service according to the present invention.

Referring to FIG. 2, the switching system according to the present invention receives one interface ID from the existing LE system to the central station subscriber transmission apparatus (hereinafter referred to as AN-Cot (Access Network-Central Office Terminal) system). Interface with LE while performing V5.2 (IDLC) protocol. In other words, the exchange system accepts all the functions of protocol entities (PEs, hereinafter called PEs) such as PSTN, control, BCC, link control and protection, which are V5.2 protocols. And some V5.2 protocol techniques are distributed to AN-Cot system and remote subscriber transmission device (hereinafter referred to as AN-Rt (Access Network-Remote Terminal) system) to provide existing IDLC call service.

As described above, in the conventional switching system illustrated in FIG. 1, a V5.2 interface ID is separately assigned to each AN system linked to the LE so that the LE and the AN correspond to each other in a 1: 1 correspondence. In the present invention, as shown in FIG. 2, the AN-Cot system is added between the LE and the AN system so that the exchange function with the LE is performed by the AN-Cot system, and the AN of the Remote Site to which the AN-Rt system is connected to the subscriber The system is configured to accommodate one AN-Cot system and a plurality of AN-Rt systems. As shown in FIG. 2, the exchange system according to the present invention installs the AN-Cot system 300 and the AN-Rt system 500 between the LE 200 and the real subscriber 200. The V5.2 interface ID is set between the LE 200 and the AN-Cot system 300. In addition, the AN-Cot system 300 is connected to the real subscriber 600 through the AN-Rt system 500. That is, since the AN-Rt system 500 is connected to the real subscriber 600, when the number of subscribers increases, increasing the number of AN-Rt systems 500 may correspond to this.

In other words, if the capacity and performance of the AN-Cot system is sufficient, the number of AN-Rt systems can be added more, so that a PSTN call service can be provided to an increased subscriber with only a small number of V5.2 interface IDs. Can provide.

Referring back to FIG. 2, the AN-Cot system consists of two types of links that communicate with devices LE and AN-Rt that are interfaced using different types of communication channels.

The first link type physically satisfies the IDLC protocol established by the ITU with the LE 200 and the V5.2 interface ID using E1, and communicates with the LE 200 with the actual IDLC communication message type, while communicating with the PSTN call. Perform the overall function for the service. It has the same type of IDLC call service that is being used.

The second type of link is a link that interfaces with the AN-Rt system and acts as a path for acting for direct call connection with the actual subscriber 600. Perform the aggregation function on this second link. To this end, the AN-Cot system 300 manages bandwidth, and designates a channel capable of transmitting and receiving messages for channel allocation to communicate with the AN-Rt system through this communication channel.

That is, the AN-Cot system 300 must deliver the message received from the LE 200 to the AN-Rt system 500, and the message received from the AN-Rt system 500 can be delivered to the LE 200. Thus, the main role of the AN-Cot system 300 is the aggregation function and the message relay function between the exchange and the subscriber. In order for the AN-Cot system 300 to perform such a relay function smoothly, the AN-Cot system 300 has information on a plurality of AN-Rt systems connected thereto. These information include link information (AN-Cot, link of AN-Rt system), AN-Rt system information, subscriber information, and the like.

In addition, when describing the AN-Rt system, the AN-Rt system 500 has a Subscriber Loop Carrier-Terminal (SLC-T) that can be connected to a link that interfaces with the AN-Cot system 300 and the actual PSTN subscriber. The system is equipped to monitor subscriber information and signal types. The AN-Rt system 500 manages subscribers according to the V5.2 message command transmitted from the LE 200, and when a change or event that needs to be notified to the LE occurs, the AN-Rt system 500 establishes a communication channel established with the AN-Cot system. Inform the AN-Cot to allow the AN-Cot system to send a message to the LE.

2, a call setup and release method between an LE and a subscriber according to the present invention will be described.

First, a procedure for setting up a call from an LE to a subscriber in the switching system according to the present invention will be described.

When the LE 200 receives a call establishment request by another LE or a corresponding subscriber, the LE 200 transmits a call establishment message to the AN-Cot system 300. When the AN-Cot system 300 receives the call setup message from the LE 200, the AN-Cot system 300 sends a setup response message accordingly to the LE 200. The LE 200 provides an allocation message to the AN-Cot system 300 according to this configuration response message. This assignment message includes subscriber information, link ID (Link_id), channel ID (Channel_id), etc., associated with the LE. The AN-Cot system 300 determines whether the call setup request subscriber is a subscriber belonging to a plurality of AN-Rt systems connected to the AN-Cot system 300 based on the assignment message. The AN-Cot system 300 manages information of all subscribers belonging to a plurality of AN-Rt systems connected to each database by AN-Rt system (hereinafter, referred to as DB). If the subscriber required by the LE is a subscriber belonging to the AN-Rt system 500 connected to the AN-Cot system 300, the subscriber searches for the AN-Rt system 500 to which the subscriber is configured, and the connected link. Find available free channels in. At this time, if there is no free channel on the link connected to the AN-Rt system 500, the AN-Cot system 500 transmits an allocation rejection message (Allocation_reject Message) to the LE 200. In this case, the AN-Cot system 300 terminates the procedure of calling from the LE 200 to the subscriber 600. Again, if the AN-Cot system 300 has a free channel on the link connected to the AN-Rt system 500, the AN-Cot system 300 frees the link / channel connected from the LE 200 and the free found on the link connected to the AN-Rt system 500. Mark the channel / link. In addition, the AN-Cot system 300 messages the subscriber information provided from the LE 200 and link / channel information connecting the AN-Cot system 300 and the AN-Rt system 500 to the AN-Rt system ( 500). At this time, the AN-Cot system 300 knows the physical link number information of the actual AN-Rt system 500 for each link connected to the AN-Rt system 500.

When both the AN-Cot system 300 and the AN-Rt system 500 receive a provision such as call setup and release, the AN-Cot system 300 sends and receives information at each link L2 to find a relative link number. At this time, transmission and reception of a message is performed using a specific channel on a link as a communication channel, and communication can be performed regardless of the type (type) of the communication channel. Upon receiving the assignment message, the AN-Rt system 500 determines whether the corresponding link / channel and the subscriber are normal. If the link / channel and the subscriber are not normal, the AN-Rt system 500 transmits an Allocation_Reject Message to the AN-Cot system 300. When the AN-Cot system 300 receives this assignment rejection message, it retransmits this message back to the LE and disconnects the switching associated with the LE. Again, if the link / channel and subscriber is normal, the AN-Rt system 500 connects the subscriber with the link / channel and causes the ring to ring on the subscriber side. In addition, the AN-Rt system 500 transmits an Allocation Complete message to the AN-Cot system 500. When the AN-Cot system 500 receives the allocation completion message, the AN-Cot system 500 transmits the message to the LE and switches the marked link and channel.

The following describes a procedure for releasing a call setup set from the LE to a subscriber in the switching system according to the present invention.

When the LE 200 receives a call release request from another LE or a corresponding subscriber, the LE 200 transmits a disconnect message to the AN-Cot system 300. This disconnect message has information such as subscriber information, link ID (Link_id) and channel ID (Channel_id) associated with the LE. The AN-Cot system 300 determines whether the subscriber is in the AN-Rt system 300 connected to the subscriber based on this information included in the truncation message. If the requested subscriber is a subscriber belonging to the AN-Rt system 500 connected to the AN-Cot system 300, the AN-Cot system 300 is the AN-Rt system 500 that the subscriber is set up. ), And find the channel occupied by the subscriber on the connected link. At this time, if there is no channel occupied by the subscriber on the link connected to the AN-Rt system 500, the AN-Cot system 300 transmits a Deallocation Complete message to the LE. Otherwise, the AN-Cot system 500 transmits a Deallocation_Reject Message to the LE when another subscriber uses the corresponding channel on the link connected to the AN-Rt system 500. The AN-Cot system 300 terminates the call release procedure in both of these cases.

If the channel occupied by the subscriber is on a link connected to the AN-Rt system 500, the AN-Cot system 300 is connected with the AN-Cot system 300 and the subscriber information transmitted from the LE 200. Link-channel information connected between the AN-Rt system 500 is messaged to transmit an unassignment message to the AN-Rt system 500. The AN-Rt system 500 determines whether the corresponding link / channel and the subscriber are normal based on the information included in the received deassignment message.

If the link / channel and the subscriber are normal, the AN-Rt system 500 disconnects the link / channel and the subscriber. Subsequently, the AN-Rt system 500 transmits a deallocation completion message (Deallocation_Complete Message) to the AN-Cot system 300. Then, the AN-Cot system 300 receives the deassignment completion message, retransmits it to the LE, and releases the connected switching.

This call setup and release procedure will be described again with a focus on subscribers.

First, the call setup procedure from the subscriber to the LE is described, and the AN-Rt system periodically monitors the subscriber off / on hook status at an interval of, for example, 50 msec. Cot system 300 is transmitted. Then, the AN-Cot system 300 retransmits the subscriber information and the off-hook information to the LE. In transmitting the subscriber's information, the AN-Rt system 300 also provides information of its site ID (Site_id). The site ID information enables the AN-Cot system 500 to determine which AN-Rt system 500 subscriber information is transmitted, thereby signaling the subscribers of the plurality of AN-Rt systems connected thereto. The transition state can be managed. The following procedure is performed almost similarly to the call setup procedure from the LE to the subscriber described above.

In addition, when describing a call release procedure from the subscriber to the LE, the AN-Rt system 500 periodically monitors the subscriber off / on hook state, and if the on-hook state is detected, the AN-Cot system 300 To send. Then, the AN-Cot system 300 retransmits this subscriber information and on-hook information to LE. The following procedure is performed almost similar to the call release procedure from the LE to the subscriber described above.

Meanwhile, if the AN-Rt system 500 detects the removal of the subscriber board, the AN-Rt system 500 transmits the message to the AN-Cot system 300 by messaging the subscriber board removal information. In this case, only the card information is transmitted as a message. Here, subscriber unavailable status propagation is done on a per subscriber basis according to the V5.2 protocol. Subsequently, the AN-Cot system transmits a block message to the LE for the corresponding port of the received subscriber board disconnection information. At this time, the AN-Cot system transmits the block release message to the LE for each corresponding subscriber, the mounting information of the received subscriber board. In the case of such mounting information, a message is periodically transmitted at intervals of 100 msec between ports at the time of dismounting and 500 msec between ports at the time of dismounting in order to prevent congestion of the message. Subsequent processing is performed according to the existing IDLC protocol.

On the other hand, the operator may give a block / block release command of the subscriber port to the AN-Cot system and AN-Rt system. If the AN-Cot system provides a block / unblock command, it passes this command to the AN-Rt system. Conversely, when the AN-Rt system gives these commands, they are passed to the LE through the AN-Cot system. Since subscribers exist in the AN-Rt system, acting on real subscribers takes place only in AN-Rt.

3 is a block diagram showing the main configuration of the AN-Cot system 300 according to the present invention.

The AN-Cot system 300 includes an OAMP interface module 332, a subsportmgmt module 334, a bccrm module 336, a bandwidth management unit 340, and a switching unit 350.

The OAMP interface module 332 receives a link related provision connected to the V5.2 link and the AN-Rt system from the MMI or the EMS 310, and receives a subscriber related command belonging to the AN-Rt system to the LE. send.

The subsportmgmt module 334 manages subscribers in communication with the LE and AN-Rt systems by receiving subscriber-related V5.2 messages, which manages the subscribers of all connected AN-Rt. In addition, the subsportmgmt module 334 of the AN-Cot system communicates only protocols with the LEs because the subscribers are connected to the AN-Rt system, and the functions related to the actual subscribers retransmit the message for the AN-Rt system to perform.

The Bccrm module 336 performs channel assignment and release. In detail, the Bccrm module 336 cross-connects / disconnects the corresponding channel in the AN-Rt system to which the subscriber to which LE is directed / connected and the link connected to the link / channel indicated to LE. Subsequently, the Bccrm module 336 transmits an allocation / release message to the AN-Rt system for accessing and releasing the corresponding subscriber. In this case, the Bccrm module 336 checks the bandwidth and not the value of the link / channel transmitted from the LE. Message the value of the link / channel connected to the system.

In fact, the number of user channels of the physical link between the AN-Cot system and the AN-Rt system is smaller than the number of subscribers belonging to the AN-Rt system. Accordingly, the bandwidth manager 340 manages the channels currently being used and the empty channels in order to assign a channel only to the subscriber.

The switching unit 350 controls the switching. In particular, the switching unit 350 performs channel-to-link switching between the V5.2 link and the AN-Rt system.

4 is a block diagram showing the main configuration of the AN-Rt system 500 according to the present invention.

The AN-Rt system 500 includes an OAMP interface module 522, a subsportScan module 524, a subsport demounting module 526, a subsportmgmt module 528, a bccrm module 532, and a switching unit 530.

OAMP interface module 522 receives commands for subscribers and links from MMI or EMS and performs IDLC call switching commands.

The subsportmgmt module 528 manages only subscribers in its own system while receiving subscriber related V5.2 messages and communicating with the LE and AN-Cot systems. The subscriber information should be identical to the subscriber information of the AN-Cot system.

The subsportScan module 524 manages the signal status of the subscriber and transmits a message change signal to the AN-Cot system.

The subsport off-market module 526 monitors the unmounted state of the subscriber board and transmits information to the AN-Cot system when an event occurs.

The bccrm module 532 manages the switching and performs channel assignment and release according to commands sent from the AN-Cot system.

The switching unit 530 controls switching, and performs switching between links connected to the actual subscriber and the AN-Cot system.

As such, the existing AN system is equipped with the V5.2 protocol for each system, and communicates with the LE of IDLC in a one-to-one concept. However, in the present invention, the AN-Cot system is equipped with a V5.2 protocol to process IDLC messages with the LE, and in the AN-Rt system, some IDLC protocols for managing IDLC subscribers are not installed without the entire IDLC protocol. I use it.

As can be seen from the call setup and release as described above, the V5.2 message delivery order is done in a similar order to the PSTN call setup / release of the existing IDLC. In the existing AN system, all these procedures were carried out in consultation with the LE in the system itself, and only the LE had the aggregation function. However, in the present invention, the roles of the AN-Cot system and the AN-Rt system are divided, and the aggregation function contained only in the LE is also included in the AN-Cot system. That is, more subscribers than AN-Rt system, AN-Cot system, and physical link (E1) can be configured in the AN-Rt system, and when a call is connected, a free channel is found and assigned a subscriber to an arbitrary channel. Play a role. Of course, subscriber access in the entire network is limited to the number of channels in the V5.2 links connected to the LE and AN-Cot systems.

As described above, when the number of subscribers who want network services increases and the number of AN systems increases due to the continuous growth of the access network, the increase of the AN system may increase the use number of V5.2 interface IDs when interworking with the exchange. As a result, a limitedly available exchange would require a large number of LE devices and management tools to manage them.

According to the present invention, the AN-Cot system has the aggregation function and the message relay function between the exchange and the subscriber, thereby reducing the number of V5.2 interface IDs, which had to increase according to the number of AN systems to be added. Accordingly, the present invention leads to efficient use of the limited number of V5.2 interface IDs available on the LE side, and can accommodate more subscribers as one LE with a smaller number of V5.2 interface IDs. Can facilitate subscriber management.

Claims (6)

A call processing method for setting up a call in a central station subscriber transmission device provided between an exchange and a remote subscriber transmission device to provide an interface for an IDLC subscriber, Determining one of a plurality of remote subscriber transmission devices associated with an IDLC subscriber upon receiving a call setup request from the exchange; Searching for a free channel in a link connected to the determined remote subscriber transmission device; Providing the determined remote subscriber transmission apparatus with link / channel information and subscriber information connecting the determined remote subscriber transmission apparatus and the central station subscriber transmission apparatus; Connecting between the determined remote subscriber station and the switch. The call processing method according to claim 1, further comprising: receiving an ID and subscriber information from a remote subscriber transmission device when the call establishment request is received from the subscriber and transmitting the ID and subscriber information to the exchange. A call processing method for releasing from a central station subscriber transmission device provided between an exchange and a remote subscriber transmission device to provide an interface for an IDLC subscriber. Upon receipt of a call release request from the remote subscriber transmission device, determining one of the remote subscriber transmission devices connected to the plurality of real subscribers; Searching for a subscriber occupancy channel on a link connected to the determined remote subscriber transmission device; Providing the determined remote subscriber transmission apparatus with link / channel information and subscriber information connecting the determined remote subscriber transmission apparatus and the central station subscriber transmission apparatus; And disconnecting between the determined remote subscriber station and the exchange. 4. The call processing method according to claim 3, further comprising the step of receiving the ID and subscriber information from a remote subscriber transmission device when the call cancellation request is received from the subscriber and transmitting the ID and subscriber information to the exchange. A switching system for interfacing a call between an exchange and an IDLC subscriber, A plurality of remote subscriber transmission apparatuses equipped with a subscriber board connected to the IDLC subscriber and managing subscribers according to message commands transmitted from an exchange; A central station subscriber transmission device connected between the switch and a plurality of remote subscriber transmission devices, performing bandwidth management, and setting a channel for transmitting / receiving call establishment / release messages between the exchange and the remote subscriber transmission devices for channel allocation; Exchange system, characterized in that provided. 6. The switching system as claimed in claim 5, wherein the central station subscriber transmission apparatus has a database of information for all subscribers belonging to a plurality of remote subscriber transmission apparatuses connected thereto for each remote subscriber transmission apparatus.