JPH0799541A - Communication system and communication method utilizing cross connect network - Google Patents

Abstract

PURPOSE:To attain dynamic band allocation even in the case of a relay exchange having no exchange function by allowing the relay exchange having a band management state to secure a band for each call. CONSTITUTION:A virtual path value VP is in advance revised and set between subscriber exchanges. For example, in the case of communication from a subscriber exchange 11 to a subscriber exchange 32, a VP=1 is set between the exchange 11 and a multiplexer 1, a VP=2 is set between the multiplexers 1, 2, a VP=5 is set between the multiplexers 2, 3, and a VP=3 is set between the multiplexer 3 and the exchange 32 respectively. In the case of communication between the subscriber exchanges 11, 32, a destination number and a required band are transferred to the relay exchange 10 through a signaling network 4 to request the security of the required band. The exchange 10 reserves the requested band while referencing to a table representing a transmission line between the exchange 11 and the multiplexer 1 and the operating state of a link 5 and transfers a control signal to the exchange 20. Similarly the exchange 30 reserves the band between the multiplexer 3 and the exchange 32 and makes a call reception request to the exchange 32.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication system including a cross connect network and a control signal transmission network and a communication method.

[0002]

2. Description of the Related Art An ATM (Asynchronous Transfer Mode) communication system using fixed-length cells as a transfer unit has an excellent feature of being able to integrate multiple communication and multimedia communication, and has a wide band ISDN (B-ISDN). Recognized as a suitable system.

[0003]

However, replacing all of the conventionally used cross-connect systems and relay switching systems with the ATM cell system requires too much investment. For this reason, there is a demand for stepwise ATM conversion while utilizing the conventional system.

ATM even in such a transitional stage
The features of the communication system should not be impaired. For example, dynamic path control and management cannot be realized only by replacing the existing STM (synchronous transfer mode) communication system with the ATM communication system for the cross-connect system that fixes the bandwidth allocated to each path, and It cannot be used efficiently. In this case, in order to realize dynamic resource management, it is necessary to make the transit switching system ATM.
It requires a lot of investment.

An object of the present invention is to provide a communication system and a communication method which can realize efficient use of a transmission line band of a cross-connect network even in a transit switching system having no ATM switching function.

Another object of the present invention is to provide a highly economical communication system by reducing the size and function of the transit switching system.

Still another object of the present invention is to provide a communication system and a communication method for reducing the delay time in ATM cell transmission.

[0008]

A communication system according to the present invention includes a cross-connect network including a plurality of channels, a control signal transmission network for transmitting a control signal including at least a channel designation signal and a band request signal, and a cross-connect network. In a communication network consisting of a plurality of local switching nodes connected to each other and capable of communicating with each other through one of the channels, the control signal transmission network comprises a plurality of relay switching nodes for transferring control signals, each relay switching node comprising: The switching node has a switch means for transferring a control signal between the local switching nodes via at least one other relay switching node and a transmission path of a predetermined cross-connect network managed by the relay switching node. Band management means for allocating bands according to the band request signal included in the control signal. The features.

According to the communication method of the present invention, a control signal is transferred between a calling local switching node and a destination local switching node through a control signal transmission network, and within a range determined for each relay switching node based on the control signal. A request band is secured between the calling local switching node and the destination local switching node, and data is transmitted between the calling local switching node and the destination local switching node through a band-secured transmission path. To do.

[0010]

The band management of the cross connect network is performed between the relay switching nodes via the control signal transmission network. First, the calling local switching node sends a control signal to the relay switching node to which the local switching node belongs, thereby notifying the information specifying the channel in the cross-connect network to the destination local switching node and the band usage information thereof. The control signal is transferred between the relay switching node and the relay switching node to which the destination local switching node belongs, so that the bandwidth used for the transmission line in the cross-connect network managed by each relay switching node is secured and the bandwidth is secured. Enable communication between the calling local switching node and the destination local switching node over the reserved channel.

[0011]

1 is a schematic block diagram showing an embodiment of a communication system according to the present invention, and FIG. 2 is a block diagram of a concrete ATM communication network thereof.

In FIG. 1, the ATM cross-connect network comprises a plurality of multiplexers (cross-connect systems) MUs.
It consists of X1-3. The subscriber exchanges LS11-LS13 are connected to one another via a multiplexer MUX1.
The subscriber exchanges LS21-LS23 are multiplexers MUX2.
The subscriber exchanges LS31-LS33 are connected to one another via a multiplexer MUX3.

The multiplexers MUX1 and MUX2 are connected by a link 5, and the multiplexers MUX2 and MUX3 are connected by a link 6, respectively. Therefore,
The subscriber exchanges LS are connected to each other via multiplexers MUX1-3.

Further, the subscriber exchange LS and the transit exchange 1
0, 20 and 30 are connected by the signaling network 4. Specifically, as illustrated in FIG. 2, the subscriber exchanges LS11-13 are the transit exchanges TS10, the subscriber exchanges LS21-23 are the transit exchanges TS20, the subscriber exchanges LS31-33 are the transit exchanges TS30, respectively. It is connected. Further, the transit exchange TS10 is connected to the transit exchange TS20, and the transit exchange TS20 is connected to the transit exchange TS30.

FIG. 3 shows the transit exchange TS in this embodiment.
3 is a block diagram showing a schematic configuration of FIG. Each relay exchange T
S includes a switch 101, a control unit 102 that performs switch control and band securing control, and a table 103 that indicates the usage status of transmission lines and links. Calling subscriber exchange LS
Alternatively, when the control signal (destination, used band, etc.) from the repeater exchange TS is input, the control unit 102 refers to the table 103 indicating the use status of the transmission path and the link specified in advance and refers to the transmission path and the link. Secure the requested bandwidth for. When the required band is secured, the switch 101 sends the control signal to the next transit exchange TS or the destination subscriber exchange LS.

In the configurations shown in FIGS. 1 and 2, for example, the relay exchange TS10 includes a transmission line between the subscriber exchange LS11-13 and the multiplexer MUX1 and the multiplexer MUX1.
And a use state table for managing the link 5 connecting the MUX 2 and the MUX 2. Similarly, the relay exchange TS20
Has a table for managing the use status of the link 6, and the transit exchange TS30 has a table for managing the use status of the transmission path between the multiplexer MUX3 and the subscriber exchanges LS31-33.

FIG. 4 shows an example of the structure of the multiplexer MUX which constitutes the ATM cross connect network. A buffer 41 and a header translator 42 are provided corresponding to the input ports, and an address filter 43 and a buffer 44 are provided corresponding to the output ports. The input port and the output port are connected by a bus 40.
The ATM cell input to the buffer 41 from the input port is
The cell header is updated by the translator 42, the output port number is added, and the cell header is transmitted to the bus 40. The address filter 43 detects the port number added to the cell and performs address filtering. The cell is stored in the buffer 44 and then transmitted from the output port.

Next, the flow of control signals and ATM cells of this embodiment will be described with reference to FIG.

First, a VP (virtual path) value is assigned in advance between the respective subscriber exchanges. For example, for communication from the subscriber exchange 11 to the subscriber exchange 32, the subscriber exchange 11
VPI = 1 between the multiplexer 1 and the multiplexer 1, VPI = 2 between the multiplexer 1 and the multiplexer 2, VPI = 5 between the multiplexer 2 and the multiplexer 3, and multiplexing It is assumed that VPI = 3 is assigned between the device 3 and the subscriber exchange 32.

Upon communication with the subscriber exchange 32, the subscriber exchange 11 first transfers a control signal (destination number and required bandwidth) to the transit exchange 10 through the signaling network 4 and requests to secure a required bandwidth. The relay exchange 10
The requested bandwidth is reserved with reference to a table showing the transmission path between the subscriber exchange 11 and the multiplexer 1 and the usage status of the link 5, and the control signal is transmitted to the relay exchange 20.
Transfer to. The repeater exchange 20 reserves the requested band with reference to the table showing the usage status of the link 6, and similarly, the repeater exchange 30 reserves the band between the multiplexer 3 and the subscriber switch 32. , Subscriber exchange 32
Make an incoming call request to.

Then, when the repeater exchange 30 receives the response signal (ACK) from the subscriber exchange 32, it registers the reserved band in the table. This response signal is transferred in the reverse route through the signaling network 4, and the transit exchanges 20 and 1
In 0, the same band registration is performed, and securing of all bands of the channels to be used is completed. And FIG. 5 (B)
As shown in, communication is performed between the subscriber exchange 11 and the subscriber exchange 32 via a channel in which a band is secured.

The bandwidth thus secured can be assigned to other communications by performing release control when the communications are completed.

5A and 5B show the case of symmetrical communication in which the communication band from the subscriber exchange 11 and the communication band from the subscriber exchange 32 are the same. In this case, the communication band can be secured from the subscriber exchange 32 at the same time as the control communication for securing the bandwidth from the subscriber exchange 11. Of course, the transmission from the subscriber exchange 32 may be subjected to similar band securing control independently of the transmission from the subscriber exchange 11.

Since the allocated bandwidths of the respective transmission lines and links are predetermined, each transit exchange TS creates a new one when the sum of the used bandwidth and the new requested bandwidth exceeds this allocated bandwidth. The requested bandwidth cannot be secured. In this case, the repeater exchange TS notifies the transmission source to that effect via the signaling network 4, and the repeater exchange TS having received this notification releases the secured band.

In the present embodiment, a VCI / VPI-based mesh-like logical link is preset between the subscriber exchanges by the cross-connect network. Therefore, the transit exchange TS does not need the dynamic allocation control function of VCI / VPI, and only needs to have the dynamic band allocation function based on the band management of each link. Further, the subscriber exchange LS only needs to have a signal cell conversion function, and does not need a cell exchange function. The relay exchange TS also needs to have a signaling terminal relay function, and does not need a cell relay switching function.

FIG. 6 is a schematic block diagram of an ATM network showing another embodiment of the present invention, and FIG. 7 is a specific block diagram thereof. In this embodiment, the signaling network is realized as a virtual channel network in the ATM cross connect network. The operation is the same as in the case of the ATM network of FIGS.

Although the transit exchange TS is connected to the cross-connect network as shown in FIG. 7, it is only connected to the signaling virtual channel network and is logically different from the cross-connect network to which ATM cells are transferred. Be separate. Therefore, as described above, the relay exchange TS needs the control signal cellizing / cell terminating function, but does not need the cell relay switching function.

In this embodiment, the VP in the cross-connect network was previously assigned by the VPI, but V
It may be assigned by both PI / VCI.

[0029]

As described in detail above, in the communication system according to the present invention, a relay exchange having no cell relay switching function is used in order to secure a bandwidth for each call by the relay exchange having a bandwidth management function. Dynamic bandwidth allocation is possible. In addition, signals relating to call processing are not exchanged between the transit exchange and the cross-connect system.

Furthermore, since ATM cells from the subscriber exchange can be transferred to the other subscriber exchange without passing through the transit exchange, the delay time can be shortened and the size and function of the transit exchange can be reduced, which is economical. A high communication system can be constructed.

[Brief description of drawings]

FIG. 1A shows an embodiment of a communication system according to the present invention.
It is a typical system configuration diagram of a TM network.

FIG. 2 is a block diagram of a more specific ATM network according to the present embodiment.

FIG. 3 is a schematic configuration diagram of a repeater exchange according to the present embodiment.

FIG. 4 is a schematic configuration diagram of a multiplexing device in the present embodiment.

5A is a diagram showing a flow of control signals in this embodiment, and FIG. 5B is a diagram showing a flow of ATM cells in a cross-connect network in this embodiment.

FIG. 6 is a schematic system configuration diagram of an ATM network showing another embodiment of the present invention.

FIG. 7 is a configuration diagram of a specific ATM network according to another embodiment.

[Explanation of symbols]

 1 Multiplexing device 2 Multiplexing device 3 Multiplexing device 4 Signaling network 5 Link 6 Link 10 Relay switch 11-13 Local switch 20 Relay switch 21-23 Local switch 30 Relay switch 31-33 Local switch 40 Bus 41 Buffer 42 Header translator 43 Address Filter 44 Buffer 101 Switch 102 Control Unit 103 Transmission Line Usage Status Table

Claims (7)

[Claims] 1. A cross-connect network comprising a plurality of channels, a control signal transmission network for transmitting a control signal including at least a channel designation signal and a band request signal, and a cross-connect network connected to the cross-connect network through one of the channels. In a communication system including a plurality of local switching nodes capable of communicating with each other, the control signal transmission network includes a plurality of relay switching nodes that transfer the control signals, and each of the relay switching nodes includes at least 1 Switch means for transferring the control signal between the local switching nodes via one other relay switching node; and a predetermined transmission path of the cross-connect network managed by the relay switching node, Band management means for allocating a band in accordance with the band request signal included in the control signal, Communication system, characterized in that. 2. The communication system according to claim 1, wherein the plurality of channels in the cross-connect network are preset virtual channels. 3. The bandwidth management means is a memory means for storing a bandwidth allocation status of the transmission path to be managed, and a transmission path to be managed is the total of the requested bandwidth and the bandwidth already used. 3. The communication system according to claim 1 or 2, further comprising: a memory control unit that registers the requested bandwidth in the memory unit when the bandwidth is equal to or less than the allocatable bandwidth. 4. The communication according to claim 1, wherein the cross-connect network is an ATM (asynchronous transfer mode) cross-connect network, and the control signal transmission network is a signaling network. system. 5. The communication system according to claim 4, wherein the signaling network comprises a virtual channel in the ATM cross connect network. 6. A cross-connect network capable of mutually connecting arbitrary local switching nodes, and a control signal including at least a required band and a destination transmitted from a certain local switching node via a plurality of relay switching nodes. In a communication method in a communication network comprising: a control signal transmission network for transferring the control signal, the control signal is transferred between the calling local switching node and the destination local switching node through the control signal transmission network, and based on the control signal. And secures the required bandwidth between the calling local exchange node and the destination local exchange node within a range defined for each of the relay exchange nodes, and the calling local exchange node through the bandwidth secured transmission path. A communication method characterized by performing data transmission with a destination local switching node. 7. The request band securing step reserves the request band by transferring the control signal from the call originating local switching node to the destination local switching node, and the call originating local from the destination local switching node. 7. The communication method according to claim 6, wherein the request band between the calling local switching node and the destination local switching node is registered by transferring a response signal to the control signal to a switching node.