JPH0946345A - Atm communication network - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain a high speed and flexible ATM(asynchronous transfer mode) communication network by previously grasping information including a free band in a connection passing route by a subscriber's exchange when there is no band changing request. SOLUTION: An ATM exchange 20 to be an originating side subscriber's exchange is provided with a route information collecting part 22 for collecting route information including the free information of a virtual path set up between the exchange 20 and an ATM exchange 40 to be a terminating side subscriber's exchange and a protocol controller 21 for supporting a protocol for adaptively controlling a flow between a user terminal 3 and an ATM communication network 1 in accordance with the route information. Since an extensible free band can be grasped by the subscriber's exchange, band change can quickly be executed and hardware and others for various protocols and a new protocol can be changed only by the subscriber's exchange, simplifying a repeating exchange.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention is used in an asynchronous transfer mode communication network (hereinafter referred to as an ATM communication network). The present invention is used for controlling a virtual path (hereinafter referred to as VP) band. In particular, it relates to a technique for shortening the time from when a bandwidth increase request is sent from the user terminal device until the bandwidth is actually increased.

[0002]

2. Description of the Related Art A VP which is a virtual transmission line on a physical transmission line
There is known an ATM communication network which is provided with and performs communication. The concept of this conventional ATM communication network is shown in FIG. Figure 15 is AT
It is a figure which shows the concept of M communication network. In FIG.
4 ₁ , 4 ₂ , 4 ₃ , 4 ₄ are ATM exchanges, 7 ₁ , 7 ₂ ,
7 ₃ is a relay transmission line which is a physical transmission line, and 3 ₁ and 3 ₂ are user terminal devices. Here, FRM (First Resource Ma)
nagement) An example of the protocol is shown. User terminal device 3 ₁
Alternatively, 3 ₂ sends a resource management cell (hereinafter referred to as an RM cell) to the ATM communication network to request a band change, for example, when file transfer or the like is desired. Here, it is assumed that the user requests a bandwidth increase of 10 Mb / s. ATM switches 4 ₁ , 4 ₂ ,
4 ₃ and 4 ₄ read the content of the RM cell, “10 Mb / s extension request”, and use the ATM switch 4 ₁ currently used.
~ 4 ₄ and relay transmission lines 7 _{1 to} 7 ₃ have a desired band, at the same time as securing that resource, the AT of the next stage
Transfer the RM cell to the M switch. Since the RM cell is identified by another bit in the header called the PTI (payload type identifier) number in the VPI (virtual path identifier) / VCI (virtual channel identifier) used by this user, this RM cell is used by this user. It is possible to automatically transfer existing routes.

[0003]

FIG. 16 is a diagram showing a timing chart of RM cell handling in each VCI. As shown here, each ATM switch 4 ₁ to _{4 4}
Then, it takes some time to access the empty information of the resource.

FIG. 17 is a diagram showing a time response to a user request. In this way at the time to increase the bandwidth, it takes the response time in order to go to check the sky bandwidth to each ATM exchange 4 _{1-4 4.} This is a delay for the request, which is a service problem. Furthermore, the actual network has a long distance and a large number of transit exchange stages. In this case, the response time is particularly problematic. Also,
Other protocols such as ABR (Available Bit Rate se)
rvices: IEEE Network.March / April 1995, pp49-56)
When trying to support other types, even high-speed transit exchanges needed those protocol processes.

That is, there are generally a plurality of types of RM cell protocols transmitted from the user terminal device 3 ₁ .
It is not fixed in one. Therefore, it is necessary to the function corresponding to the protocol each ATM switch ₄₁ to ₄ comprising respectively, it can not avoid complication on the hardware configuration.

The present invention has been made in view of such a background, and an object thereof is to provide an ATM communication network having high speed and flexibility. It is an object of the present invention to provide an ATM communication network that can simplify the hardware configuration of an ATM exchange. It is an object of the present invention to provide a high throughput ATM network with a reduced cell discard rate.

[0007]

The main feature of the present invention is that the subscriber exchange recognizes information including the empty band of the route through which the connection passes in advance when there is no band change request. , When a user requests a bandwidth change or the like, the protocol controller in the exchange that accommodates the subscriber permits or disallows it, and the controller also centrally controls other protocols. I am trying. Therefore, the portion corresponding to the protocol used by the user terminal device only needs to be provided in the subscriber exchange that directly accommodates the user terminal device, and the relay exchange and other ATM exchanges have functions corresponding to a plurality of types of protocols. There is no need to prepare.

That is, the present invention comprises a plurality of subscriber exchanges, a plurality of physical transmission lines that connect the plurality of subscriber exchanges to each other, and a relay exchange that is inserted into the plurality of physical transmission lines. A virtual path is established between the plurality of subscriber exchanges, and the subscriber exchange is an ATM communication network including means for supporting a protocol for adaptively performing flow control between the user and the network.

Here, a feature of the present invention is that the originating side subscriber exchange collects route information including vacant information of a virtual path set between the originating side subscriber exchange and the destination side subscriber exchange. And means for performing the flow control according to the route information.

The means for collecting the route information includes means for providing a cell for collecting the route information for each of the virtual paths, the means being provided in the originating-side subscriber exchange, the relay exchange and the subscriber. It is desirable that the exchange be provided with means for mounting the route information in the information area when the cell arrives and transmitting the route information according to the route information recorded in the destination area.

The destination-side subscriber exchange and the repeater exchange can also be provided with means for sending a cell carrying route information about the virtual path relating to the exchange to the originating-side subscriber exchange.

[0012] In this way, since the route information is sent from the required place without requiring any action from the originating side subscriber exchange, it is possible to reduce the load on the originating side subscriber exchange.

Alternatively, a center device is provided in the communication network, and means for sending a cell carrying the route information addressed to the subscriber exchange and the relay exchange is provided to the center exchange. Can also be configured to include means for reading and collecting route information from the arrived cell and means for notifying the subscriber exchange of the contents of the means for collecting.

The means for transmitting comprises a means for transmitting cells carrying route information including the congestion information when congestion occurs on the virtual path of the subscriber exchange or the transit exchange. You can also

As described above, by transmitting the cell on which the route information is mounted only when there is a change, unnecessary cell transmission / reception can be avoided.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a conceptual diagram of an ATM communication network of the present invention. Figure 2 shows A as the originating subscriber exchange.
3 is a block diagram of a main part of the TM exchange 20. FIG. Figure 3 is R
It is a block diagram of M cell. 4 and 5 ATM exchange as a subscriber exchange in transit exchange and the call-4 _1-4
FIG. _{3 is} a block diagram of a main part of ₃ . FIG. 6 is a block diagram of the main part of the center device 6.

According to the present invention, ATM exchanges 20 and 40 as subscriber exchanges and relay transmission lines 7 _{1 to} 7 as physical transmission lines connecting the ATM exchanges 20 and 40 to each other are provided.
_4, and a ATM switch ₄₁ to ₃ as a relay switch which is interposed in the trunk transmission line 7 _{1-7 4,} the virtual path is set between the ATM switch 20,40,4 _{1-4 3} , ATM switch 20 or 40 is an ATM communication network having a protocol controller 21 shown in FIG. 2 as a means for supporting a protocol in which the user terminal device 3 adaptively performs flow control with the ATM communication network 1.

Here, the feature of the present invention is that the virtual path established between the ATM switch 20, which is the originating subscriber switch, and the ATM switch 40, which is the destination subscriber switch, is set up. It is provided with a route information collecting unit 22 as a unit for collecting route information including vacant information, and a protocol controller 21 as a unit for performing the flow control according to the route information.

The route information collecting unit 22 is provided in the ATM exchange 20 which is the originating subscriber exchange, and the RM cell transmitting unit as a means for transmitting the RM cell for collecting the route information for each virtual path. includes a 23, the ATM switch 40,4 _{1-4 3} as a relay switch and call-subscriber exchange of, as shown in FIG. 4, equipped with route information on the information area when the cell arrives A route mounting unit 14 is provided as a means for transmitting according to the route information recorded in the destination area.

Further, ATM exchange 4 _{1-4 3,} 40 is a called side local exchange and the transit exchange, as shown in FIG. 5, the equipped with RM cell routing information about the virtual path according to the switch A route information issuing unit 15 may be provided as a means for sending to the calling-side subscriber exchange.

Alternatively, the center device 6 is provided in the communication network.
The ATM exchanges 4 ₁ to 4 ₃ and 40 are provided with a route information issuing unit 15 as a means for transmitting cells carrying the above-mentioned route information addressed to the center device 6, and arrive at the center device 6. A route information collecting unit 60 as a means for reading and collecting route information from a cell, and contents of the route information collecting unit 60 are ATs which are subscriber exchanges on the originating side.
It is also possible to provide a route information notification unit 61 as means for notifying the M switch 20.

Further, the route information issuing unit 15 determines the AT
BECN congestion in virtual paths of the M switch ₄₁ to _3, 40 equipped with route information including the congestion information when an error occurs (Backword Explicit Congestion Notifica
tion) may be provided with means for sending out each cell.

In order to make the explanation easy to understand, here, the calling side subscriber exchange and the receiving side subscriber exchange are expressed as if they have different configurations. However, in reality, the calling side subscriber exchange is used. It may be realized as an ATM exchange having a configuration in which each of the configurations of the subscriber exchanges on the receiving side and the receiving side is also provided.

[0024]

【Example】

(First Embodiment) A first embodiment of the present invention will be described with reference to FIG. As shown in FIG. 1, the user terminal device 3 issues a cell based on a band change request or other various protocols to the ATM communication network 1. The contents of this cell are immediately determined by the ATM switch 20 in which the subscriber is housed. AT
In the protocol controller 21 of the M switch 20, the V
It has a route performance table 24 that manages performance information of CI passing routes, and compares, for example, the requested bandwidth from the VCI with the contents of the route performance table, and permits transfer, bandwidth change, and the like.

FIG. 7 is a diagram showing a cyclic state of the RM cell according to the first embodiment of the present invention. R is the method of collecting route information
ATM switch 20 ₂ which is the subscriber switch originating from the M cell
ATM exchange 4 which is the destination subscriber exchange
Wrap at 0 ₂ . FIG. 3 is a diagram showing the structure of the RM cell, which is composed of a destination area H and a message area M. In the message area M, ATM exchanges 4 ₁ to 4 ₃ ,
Each time the vehicle passes 40, the usage rate, the empty band, the cell loss rate, and other route information are installed. AT in the destination area H
The route information is written by the M switchboard 20 ₂ .

[0026] In addition, without any processing the ATM exchange 4 ₁ to 4 _3, 40 in the RM cell, it is also possible to estimate the congestion in the round time of the RM cell.

(Second Embodiment) A second embodiment of the present invention will be described with reference to FIG. FIG. 8 is a diagram showing a cyclic state of the RM cell according to the second embodiment of the present invention. ATM which is each relay exchange
The exchanges 4 ₁ to 4 ₃ or the AT which is the destination subscriber exchange
The M exchanges 40 ₁ and 40 ₂ periodically voluntarily make RMs.
The route performance is reported by sending cells to the ATM switches 20 ₁ and 20 ₂ which are the originating subscriber switches.

(Third Embodiment) A third embodiment of the present invention will be described with reference to FIG. FIG. 9 is a diagram showing the overall configuration of the third embodiment of the present invention and the transfer status of RM cells. The center device 6 shown in FIG. 6 grasps the traffic conditions in the ATM communication network 1, and based on the congestion node and other information,
This is a method of providing information to ATM exchanges 20 ₁ and 20 ₂ which are subscriber exchanges.

The center device 6 includes an AT which is a repeater exchange.
A route information collecting unit 60 for collecting information from the M exchanges 4 ₁ to 4 ₃ is provided, and R from the ATM exchanges 4 ₁ to 4 ₃ is provided.
It receives M cells and collects route information. The obtained route information is newly written in the message area M of the RM header, and this is sent to the ATM switch 20 which is the calling subscriber switch.
Transfer to ₁ and 20 ₂ .

(Fourth Embodiment) The fourth embodiment of the present invention is shown in FIG.
This will be described with reference to FIG. FIG. 10 is a diagram showing a cell transmission situation of the fourth embodiment of the present invention. The present invention in the fourth embodiment, ATM switch 40 ₁ of the ATM exchange ₄₁ to the ₃ or the terminating local exchange as the transit exchange during congestion
And 40 ₂ send BECN cells, and based on the information, ATM switches 20 ₁ and 20 ₂ which are subscriber switches.
It is the one that takes action.

The timing of taking an action is different from the method of periodically transmitting RM cells shown in the second embodiment of the present invention. The basic configuration of the BECN cell is the same as the configuration of the RM cell shown in FIG.

In common with the first to fourth embodiments of the present invention,
An operation example in the subscriber exchange will be described with reference to FIGS. 11 and 12. FIG. 11 is a diagram showing the flow of RM cells in the FRM protocol. FIG. 12 is a diagram showing the state of band change in the FRM protocol. In FIG. 12, the horizontal axis shows time and the vertical axis shows band. In response to a bandwidth change request from the user terminal device 3 ₁ , an ATM that is a subscriber exchange
In the exchange 20, the route performance table 24 of the route to which the VC belongs belongs is indexed to see, for example, the usage rate. This usage rate is the link information and the like with the highest usage rate on the route. The protocol controller 21 estimates the remaining bandwidth and the like based on this usage rate, and returns the bandwidth change and the like to the user terminal device 3.

As shown in FIG. 11, the user terminal device 3 ₁
Indicates "10" to the ATM exchange 20 which is a subscriber exchange.
Mb / s to index the route performance table 24 of extension request .ATM exchanger 20 in the protocol controller 21 sends a request for ", quickly answer examines the root and its usage to the user terminal 3 ₁ Therefore, the time from “request” to “OK” can be shortened by using the present invention as shown in FIG.

FIG. 13 is a diagram showing the flow of RM cells in the ABR protocol. FIG. 14 is a diagram showing a situation of band change in the ABR protocol. In FIG. 14, the horizontal axis represents time and the vertical axis represents band. The example of the ABR protocol shown here adopts a method of gradually expanding the band for each band expansion request “Inc” from the user terminal device 3 ₁ . As shown in FIG. 13, A is issued in response to the bandwidth expansion request “Inc”.
TM switch 20 is indexed to route the performance table 24 in the protocol controller 21, it returns the RM cell as quickly answer examines the root and its usage to the user terminal 3 _1. Therefore, as shown in FIG. 14, each time the user terminal device 3 ₁ receives an RM cell, the band can be expanded stepwise. Further, the user terminal device 3 may receive a request for non-expansion or reduction from the ATM switching device 20 via the RM cell, but in that case, the user terminal device 3 reduces the bandwidth stepwise. In any case, the time until the ATM switch 20 receives the band expansion request "Inc" and returns the RM cell as a response thereto can be shortened by using the present invention.

[0035]

As described above, since the available bandwidth that can be expanded by the exchange in which the subscriber is accommodated is known, the bandwidth can be changed at high speed, and various protocols and new protocols can be changed. On the other hand, the hardware and other changes need only be made in the subscriber exchange, and the relay exchange can be simplified.

[Brief description of drawings]

FIG. 1 is a conceptual diagram of an ATM communication network of the present invention.

FIG. 2 is a block diagram of a main part of an ATM exchange as a calling side subscriber exchange.

FIG. 3 is a configuration diagram of an RM cell.

FIG. 4 is a block diagram of a main part of an ATM exchange as a relay exchange and a subscriber exchange on the receiving side.

FIG. 5 is a block diagram of a main part of an ATM exchange as a relay exchange and a subscriber exchange on the receiving side.

FIG. 6 is a block diagram of a main part of a center device.

FIG. 7 is a diagram showing a cyclic state of an RM cell according to the first embodiment of the present invention.

FIG. 8 is a diagram showing a cyclic state of an RM cell according to the second embodiment of the present invention.

FIG. 9 is a diagram showing the overall configuration of a third embodiment of the present invention and the transfer status of RM cells.

FIG. 10 is a diagram showing a cell transmission situation of the fourth embodiment of the present invention.

FIG. 11 is a diagram showing a flow of RM cells in the FRM protocol.

FIG. 12 is a diagram showing a situation of band change in the FRM protocol.

FIG. 13 is a diagram showing a flow of RM cells in the ABR protocol.

FIG. 14 is a diagram showing a situation of bandwidth change in the ABR protocol.

FIG. 15 is a diagram showing the concept of an ATM communication network.

FIG. 16 is a diagram showing a timing chart of RM cell handling in each VCI.

FIG. 17 is a diagram showing a time response to a user request.

[Explanation of symbols]

1 ATM network 3, 3 ₁ , 3 ₂ user terminal device 4 ₁ to 4 ₄ , 20, 20 ₁ , 20 ₂ , 40, 40 ₁ , 4
0 ₂ ATM switch 6 Center device 7 _{1 to} 7 ₄ , 7 ₁₁ , 7 ₁₂ 7, 7 ₄₁ , 7 ₄₂ Relay transmission line 14 Route information loading unit 15 Route information issuing unit 21 Protocol controller 22, 60 Route information collecting unit 23 RM cell Sending unit 24 Route performance table 61 Route information notifying unit H Destination area M Message area

Claims (5)

[Claims] 1. A plurality of subscriber exchanges, a plurality of physical transmission lines that connect the plurality of subscriber exchanges to each other, and a relay exchange that is inserted into the plurality of physical transmission lines. A virtual path is set up between the subscriber exchanges, and the subscriber exchange is the calling subscriber exchange in the ATM communication network equipped with means for supporting a protocol in which the user adaptively performs flow control with the network. Is provided with means for collecting route information including free information of a virtual path set with the destination-side subscriber exchange, and means for performing the flow control according to the route information. ATM
Communication network. 2. A means for collecting the route information includes a means provided in a subscriber exchange on the originating side and transmitting a cell for collecting the route information for each of the virtual paths, the relay exchange and the 2. The ATM communication network according to claim 1, wherein the subscriber exchange comprises means for mounting route information in its information area when the cell arrives and transmitting it according to the route information recorded in the destination area. 3. The terminating side subscriber exchange and the transit exchange are provided with means for sending a cell carrying route information about a virtual path relating to the exchange to the originating side subscriber exchange. The ATM communication network described. 4. A center device is provided in the communication network, and means for sending to the subscriber exchange and the relay exchange a cell carrying the route information addressed to the center device is provided in the center device. 2. The ATM communication network according to claim 1, further comprising means for reading and collecting route information from the arrived cell and means for notifying the subscriber exchange of the contents of the means for collecting. 5. The transmitting means comprises means for transmitting cells carrying route information including congestion information when congestion occurs in a virtual path of the subscriber exchange or the transit exchange, respectively. Item 3 or 4
The ATM communication network described.