JPH04100351A - Broad band exchange network - Google Patents

Abstract

PURPOSE:To attain sure and efficient call connection control by ensuring a forward transfer route and a return transfer route integrally at the call connection request of forward and return transfer routes and setting formally the forward and return transfer routes. CONSTITUTION:An ATM ring (ATMR) 2, a broad band ISDN terminal equipment 3, a broad band ISDN trunk line 4 and a narrow band ISDN PBX 5 are connected to a broad band exchange node (ATMT) 1, and forward and return transfer routes are ensured integrally at a call connection request of the forward and return transfer routes by the ATMT 1 and then the forward and return transfer routes are set formally. Thus, the connection control in 2-ways is set efficiently and an event that a transfer route for a caller terminal equipment is ensured in the system setting the route in one way each independently but the transfer route at the called terminal equipment is not ensured is avoided and efficient connection control in terms of quality and performance is implemented.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention provides an ATM (Asynchronous
TransferMode) technology, wideband l
This invention relates to a broadband switching network based on 5DN and aimed at corporate use.

(Conventional technology) Individual service networks such as telephone networks, data networks, and FAX networks that have been developed, constructed, and put into operation over a period of more than 100 years are now integrated into ISDN (Integrated Technology).
5services Digital Network
), efforts are being made in various parts of the world to integrate them into a single network system.

As the first step toward ISDN, narrowband I5DN began operating in Japan and other developed countries in 1988, and wideband ISDN based on ATM technology led to the completion of the I5DN network, including integration with broadcasting networks. 1, and its technological development is being actively pursued at major research institutes around the world, led by the CCITT (Consultative Committee for International Telegraph and Telephone). As for the technological development that is being carried out mainly by CCITT, CCITT is conducting standardization work and is scheduled to make a basic recommendation as broadband I5DN in 1992.

According to the broadband ISDN standardization being promoted by CCITT, meta-signaling procedures or fixed/
A signaling multi-cell channel is set up semi-fixed, call control signals are sent and received based on the multi-cell channel (VC), a VP/VC connection for user information cell transfer is set up, and the band to be used is allocated. This enables the transfer of user information cells.

By the way, in broadband 15DN, there are communication forms such as bidirectional communication, unidirectional communication, and broadcasting, but unlike conventional voice communication, bidirectional channels and usage bands are fixedly allocated when requesting a call connection. Since this reduces line usage efficiency, CCITT is currently considering setting up VP/VC connections for user information cell transfer in each direction, that is, independently of origin and arrival.

For this reason, by setting the V P/VC connection for user information cell transfer and the necessary band to be used on both the originating and receiving sides as described above, it is possible to avoid allocating unused bands. Furthermore, the VP/VC connection for transferring user information cells from the destination terminal and its usage band may be set as necessary during communication, thereby improving the efficiency of the line.

However, if call connection control is performed using the method described above for users who request bidirectional communication, connection control that sets the VP/VC connection and its usage band required for bidirectional user information cell transfer is difficult. Improvement measures that require time and can be set efficiently are desired.

(Problem to be Solved by the Invention) As described above, in response to a call connection request from a terminal connected to a broadband switching node, the If the method of setting is applied to all communication forms, there will naturally be no problem in the case of one-way communication or broadcasting, but the following problem will occur in the case of interactive two-way communication.

First, in a method where settings are set independently for each direction, if the transfer route for the calling terminal is secured but the transfer route for the receiving terminal cannot be secured, a means of notification is required, and bidirectional communication becomes impossible. It will take time to make a decision.

Second, since each direction is configured independently, the inbound and outbound transfer routes are physically separate routes, which creates a strange situation where if one route goes down in the event of a failure, the other route remains normal ( (for example, one-way conversation).

The present invention was made based on the above-mentioned circumstances, and an object of the present invention is to provide a broadband switching network that can efficiently (and reliably) control call connections in the case of bidirectional communication.

[Structure of the Invention] (Means for Solving the Problems) In order to achieve the above object, the present invention provides a plurality of wideband input/output ports that multiplex transmit cells consisting of a fixed length information field and a header, and In a broadband switching network, the broadband switching node has a switching function that multiplexes and demultiplexes the cell to the broadband input/output port by identifying a label value in the broadband switching node. , After securing the outbound transfer route and the return transfer route,
This method is characterized by formally setting a round-trip transfer route.

(Function) In the present invention, when a broadband switching node requests a call connection for a round trip transfer route, the forward transfer route and the return transfer route are integrally secured, and then the round trip transfer route is formally set. Call connection control in the case of two-way communication can be performed efficiently and reliably.

(Example) Hereinafter, details of embodiments of the present invention will be explained based on the drawings.

FIG. 1 is a diagram showing the configuration of a broadband switching network according to an embodiment of the present invention.

In the figure, 1 is a broadband switching node (hereinafter referred to as ATMT).
It is called. ) is shown. This ATMTl has ATM
Ring (hereinafter referred to as ATMR) 2, wideband I SD
N terminal 3, wideband l5DN office line 4 and narrowband l5DN
PBX5 is connected.

The interface between ATMTI and broadband ISDN terminal 3 terminates at 88 points. In addition, ATMTl and wideband l
Since the interface with the 5DN office line 4 terminates at point T3, the wideband 15DN user/network interface specified by CCITT and the JT-Q, 931+ protocol are applied.

This protocol configuration is shown in FIG. Also, narrow band l5
DN P B is terminated as

FIG. 3 is a diagram showing the configuration of the above-mentioned ATMT.

The ATM I/F processing section 7, trunk 1/F processing section 8, and extension 1/F section 9.10 (these are collectively referred to as the terminal interface processing section 11) shown in the same figure are used to control the meta-signaling VCI cell. It has a drop/insert function and a signaling VCI idle management assignment function, and sets up a signaling VC using a meta-signal procedure.

The call control unit (TCP) 12 also includes an ATMR control unit 13.
, a trunk control unit 14, an extension control unit 15, a resource management unit] 6, a path control unit 17, a database 18, and a service control unit 19, which analyzes call connection requests from the terminal interfaces it accommodates and transfers them to the other party. It has a route selection control function and a band management function. This route selection control function selects the outgoing route. The route selection control function is separated by the terminal interface section 11, analyzes address information included in the received call control signal message, selects the outgoing route of the transfer destination, and assigns a VCI. On the other hand, the band management function manages the bandwidth allocation for the outgoing line selected by the route selection function and the VCI of the selected outgoing line.
It is determined whether or not the ATM switch internal route can be accepted from among the candidate routes, a possible route is selected, and a routing tag is attached to the route.

The ATMR control section 13, trunk control section 14, and extension control section 15 (collectively referred to as the terminal control section 20) perform single-party calls, multi-party calls, etc. in response to call connection requests from the terminal interface section]1. In order to efficiently perform connection control for calls, single connection calls, multi-connection calls, etc. individually or in combination, we provide instructions and notifications to the service control function in response to call control development and additional service connection requests, and collect detailed call information. It has a call control function that performs processing and a bearer control function that performs resource management and setting up a single bearer connection.

The resource management unit 16 has a bandwidth management function that determines whether the bandwidth necessary for cell transfer can be allocated based on a call connection request from the terminal interface to be accommodated, and allocates an appropriate bandwidth.

The database 18 has user and system data necessary for performing call control using ATMTI.

Next, call connection operations in the broadband switching network configured as described above will be explained based on the flowcharts shown in FIGS. 4(a) to 4(c).

First, layer 3 is applied to the terminal side connected to ATMTI.
In order to terminate the connection, the connected terminal side and the ATMTI, for example, use a meta-signaling procedure to
After setting the CI, the terminal side sends a call setup request to ATMTI.

Then, the terminal interface section 11 in ATMTI
separates the signaling cell using the signaling cell drop-insertion function and notifies the higher-level terminal control unit 20 of a call setup request in a frame structure compliant with LAPD.

Then, the terminal control unit 20 determines the LAPD of this call setup request.
Converts a compliant frame structure into a layer 3 message.

First, analyze the content of the layer 3 message.5401
), the resource management unit 16 having a bandwidth management function performs the following processing based on the bearer attributes declared by the originating terminal user.

The bandwidth management function in the resource management unit 16 checks the bandwidth for the VP/VC connection on the outbound ingress route to the originating terminal (5402), secures the bandwidth for the outbound ingress route (5403), and then checks the bandwidth for the VP/VC connection on the outbound ingress route (5403). is temporarily captured (S404).

Then, if it is impossible to secure the bandwidth for the outbound inbound route, a disconnection notification is sent to the originating terminal (340B).

Next, it is determined whether or not it is a connection request for bidirectional communication based on the identifier indicating bidirectional communication written in the layer 3 message (3407).

If it is a bidirectional communication connection request, check the bandwidth for the VP/VC connection on the inbound route on the return side (S40g), secure the bandwidth for the inbound route on the return side (S409') 1') Temporarily acquire the VP I/VCI (5410).

Then, if it is impossible to secure the bandwidth for the return route, a disconnection notification is similarly sent to the originating terminal (S41
1).

Then, if the round-trip bandwidth on the incoming route can be secured, the terminal control unit 2 on the outgoing route uses the address information in the call setup message.
0 of the connection request.

The terminal control section 20 on the outgoing road side performs the following processing in conjunction with the resource management section 16 or the bus control section 17.

First, the route selection control function in the bus control unit 17 selects the outgoing route circuit (S412), and then the bandwidth management function in the resource management unit 16 selects the VP of the outgoing route for the outgoing route. /Check the bandwidth for the VC connection (5413), and secure the usage bandwidth for the outbound route (S4
14) Temporarily capture the VP I/VCI (5415)
.

As a result, the route selection inside the ATM switch for the outward exit route is performed (S4LB), and the ATM switch for the outward exit route is selected (S4LB).
Routing tag (R
T) is determined.

Then, if it is impossible to secure the band for the outbound route, a disconnection notification is sent to the originating terminal (5417).

Next, it is determined whether the request is a connection request for bidirectional communication based on the presence or absence of a bidirectional communication identifier (S418).

If it is a bidirectional communication connection request, check the bandwidth for the VP/VC connection on the outgoing route on the return side (5419), secure the bandwidth for the outgoing route on the return side (5420) (-( 7) Temporarily capture VP I/VC1 (5421).

As a result, the route inside the ATM switch for the return route is selected (S422), and the ATM switch for the return route is selected (S422).
Routing tag (RT
) to determine.

If it is not possible to secure the band for the outgoing route on the return route, a disconnection notification is similarly sent to the originating terminal (S42
3).

Thereafter, the terminal control unit 20 sends a call setup request via the outgoing road side (terminating side) terminal interface processing unit 11 (S424).

Here, similarly to the terminal interface processing section 11 on the originating side, the terminal interface processing section 11 on the destination side sets a signaling VCI with the connected terminal or another store's band switching node through a meta-signaling procedure, and the terminal control section 20 returns a response signal.

The terminal control unit 20 that received this response signal (S425
), identifies whether it is bidirectional communication from the identifier that indicates the presence or absence of bidirectional communication included in the response signal message (
54213).

In the case of two-way communication, the bearer attributes (
(S42g)

If a change is necessary, the used band is reacquired (84
29-431), if not possible, notify disconnection (
S432).

On the other hand, if they match, formally set the VP I/VCI and usage band of the ingress and egress routes obtained as described above (5433), the egress route (7) VPI/VC■ and the routing tag. (RT) in the routing table, returns a response signal to the originating terminal (5434), and transitions to communication (S435).

With the above, it becomes possible to transfer user information cells between originating and receiving terminals.

Thus, according to the system of this embodiment, whether the ATMTl or
When requesting a call connection for a round-trip transfer route, the forward and return transfer routes are secured together and then the round-trip transfer route is officially set, so connection control for both directions can be set efficiently. As with the method of configuring each direction independently, it is difficult to ensure whether the transfer route for the calling terminal is secured or if the transfer route for the receiving terminal cannot be secured, or when the incoming and outgoing transfer routes become physically separate routes and there is a failure. There is no longer a strange situation where one route is down but the other is normal, and it becomes possible to provide efficient connection control in terms of quality and performance.

Note that although the bidirectional usage band explained above is based on a method in which the round trip is secured separately, it is also possible to set it simultaneously for the round trip.

[Effects of the Invention] As explained above, according to the present invention, when a broadband switching node requests a call connection for a round-trip transfer route, after integrally securing an outbound transfer route and a return transfer route, Since a round-trip transfer route is set in , call connection control in the case of bidirectional communication can be performed efficiently and reliably.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the configuration of a broadband switching system according to an embodiment of the present invention, FIG. 2 is a diagram showing the communication protocol in this system, and FIG. 3 is a diagram showing the configuration of the broadband switching node shown in FIG. 1. 4(a) to 4(c) are flowcharts showing call connection operations in the broadband switching network of the present invention. 1...Broadband switching node (ATMT), 2...A
TM ring (ATMR), 3... Wideband I5DN terminal, 4... Wideband I5DN office line, 5... Narrowband I
PBX for SDN, 6...Terminal adapter (B-T
A), 7... ATMRI/F section, 8... TB 8 points 1/
F, 9.10... SB point 1/F section, 11... Terminal interface section, 12... Call control section (TCP), 1
3... ATMR control unit, 14... Trunk control unit,
15... Extension control unit, 16... Resource management unit, 1
7... Path control unit, 18... Database, 19.
...Service control unit, 20...Terminal control unit.

Claims (1)

[Claims] (1) Multiple broadband input/output ports that multiplex transmit cells consisting of fixed-length information fields and headers, and a switching function that multiplexes and demultiplexes the cells to the broadband input/output ports by identifying label values in the headers. In a broadband switching network having a broadband switching node equipped with A broadband switching network characterized by setting transfer routes.