JP3327315B2 - ATM communication network - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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, the present invention relates to a technique for reducing the time from when a bandwidth increase request is sent from a user terminal device to when 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 performs communication by providing a communication network. FIG. 15 shows the concept of this conventional ATM communication network. FIG.
1 is a diagram illustrating the concept of an M communication network. In FIG.
4 ₁ , 4 ₂ , 4 ₃ , 4 ₄ are ATM switches, 7 ₁ , 7 ₂ ,
7 ₃ trunk transmission line is a physical transmission path, 3 _1, 3 ₂ is a user terminal. Here, FRM (First Resource Ma
nagement) Here is an example of the protocol. User terminal device 3 ₁
Or 3 _2, when for example want to transfer files and other resources management cell to the ATM communication network (hereinafter, referred to as RM cells) sends, to request a change of bandwidth. Here, a description will be given on the assumption that the user requests a bandwidth increase of 10 Mb / s. Each ATM switch 4 ₁ , 4 ₂ ,
At 4 ₃ and 4 ₄ , the content of the RM cell “10 Mb / s extension request” is read, and the currently used ATM switch 4 ₁ is read.
If there is a desired band to 4 ₄ and the relay transmission line 7 _{1-7 3,} at the same time to ensure that resource, next AT
The RM cell is transferred to the M exchange. The RM cell is used by the user to identify the VPI (virtual path identifier) / VCI (virtual channel identifier) used by the user with another bit in a header called a PTI (payload type identifier) number. Route can be automatically forwarded.

[0003]

FIG. 16 is a diagram showing a timing chart of RM cell handling in each VCI. As shown here, each ATM exchange 4 ₁ to 4 ₄
In this case, some time is required to access the resource availability information and the like.

FIG. 17 shows 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 results in a delay for the request and a service problem. Further, the actual network has a long distance and the number of transit exchanges is large. In this case, there is a problem particularly in response time. Also,
Other protocols, such as ABR (Available Bit Rate se
rvices: IEEE Network.March / April 1995, see pp49-56)
When trying to support others, even high-speed transit exchanges needed to process those protocols.

Namely, the RM cell is sent from the user terminal 3 ₁ protocol, generally there are a plurality kinds,
It is not one thing. 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 has as its object to provide a high-speed and flexible ATM communication network. SUMMARY OF THE INVENTION It is an object of the present invention to provide an ATM communication network capable of simplifying a hardware configuration of an ATM exchange. SUMMARY OF THE INVENTION It is an object of the present invention to provide an ATM network with a reduced cell loss rate and a high throughput.

[0007]

The most important feature of the present invention is that, at the time when there is no bandwidth change request, information including the free bandwidth of the route through which the connection is made is previously grasped by the subscriber exchange. When a user requests a band change or the like, permission or non-permission is given by a protocol controller in the exchange in which the subscriber is accommodated, and other controllers are integrally controlled by the controller. And Therefore, the portion corresponding to the protocol used by the user terminal device need only be provided in the local exchange directly accommodating the user terminal device, and the transit 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 local exchanges, a plurality of physical transmission lines connecting the plurality of local exchanges, and a relay exchange interposed between the plurality of physical transmission lines, A virtual path is set up between the plurality of local exchanges, and the local exchange is an ATM communication network having means for supporting a protocol for a user to adaptively perform flow control with a network.

Here, a feature of the present invention is that the originating local exchange has means for collecting route information including free information of a virtual path set between the local exchange and the destination local 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, provided in the originating local exchange. It is desirable that the exchange has a means for mounting the route information in the information area when the cell arrives and transmitting the route information in accordance with the route information recorded in the destination area.

The destination local exchange and the transit exchange may include means for transmitting a cell carrying route information on a virtual path relating to the local exchange to the originating local exchange.

As described above, since the route information is sent from a necessary portion without requiring any action from the originating local exchange, the load on the originating local exchange can be reduced.

[0013] Alternatively, a center device is provided in the communication network, and the local exchange and the transit exchange are provided with means for transmitting a cell carrying the route information addressed to the center device. May be configured to include means for reading and collecting route information from the arriving cell, and means for notifying the subscriber exchange of the contents of the means for collecting.

The transmitting means includes means for transmitting, when congestion occurs in a virtual path relating to the subscriber exchange or the transit exchange, cells carrying route information including the congestion information, respectively. Can also.

As described above, by transmitting a cell carrying route information only when there is a change, unnecessary transmission / reception of cells can be avoided.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a conceptual diagram of an ATM communication network according to the present invention. FIG. 2 shows A as an originating local exchange.
FIG. 2 is a block diagram of a main part of the TM exchange 20. FIG.
It is a block diagram of an 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 FIG. FIG. 6 is a block diagram of a main part of the center device 6.

[0017] The present invention includes an ATM switch 20 and 40 as a subscriber exchange, a relay transmission line 7 _1-7 as a physical transmission path for connecting between the ATM exchanges 20 and 40 mutually
_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} The ATM exchange 20 or 40 is an ATM communication network provided with 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 ATM switch 20 as the originating local exchange is provided with a virtual path set between the ATM exchange 20 and the destination local exchange. It comprises a route information collecting unit 22 as means for collecting route information including free information, and a protocol controller 21 as means 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 a subscriber exchange on the originating side, and transmits an 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 And a route mounting unit 14 as means for sending out 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 section 15 may be provided as means for sending the route information to the originating local 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 a cell carrying the route information addressed to the center device 6. A route information collecting unit 60 as means for reading and collecting route information from a cell, and using the contents of the route information collecting unit 60 as an AT which is a local exchange on the originating side.
A route information notifying unit 61 as a means for notifying the M exchange 20 may be provided.

Further, the route information issuing unit 15 transmits the
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
Option) Each cell may be provided with a means for transmitting the cell.

For the sake of simplicity of explanation, here, it is assumed that the originating local exchange and the destination local exchange have different configurations, but actually, the originating local exchange is represented. It is preferable that the present invention is realized as an ATM exchange having a configuration including both the configurations of the local exchange and the destination local exchange.

[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 band change request and other cells based on various protocols to the ATM communication network 1. The contents of this cell are immediately determined by the ATM exchange 20 in which the subscriber is accommodated. AT
In the protocol controller 21 of the M exchange 20, the V
It has a route performance table 24 that manages the performance information of the CI passing route, compares the required bandwidth from the VCI, for example, with the contents of the route performance table, and permits transfer, band change, and the like.

FIG. 7 is a diagram showing a traveling state of the RM cell according to the first embodiment of the present invention. The route information collection method is R
The ATM switch 20 ₂ which is the subscriber exchange on the originating side is provided with the M cell.
ATM switch 4 which is transmitted from the receiving side and is the destination local exchange.
Wrap 0 _2. Figure 3 is a diagram showing a configuration of a RM cell is composed of a destination region H and a message area M, the message area M, ATM exchange 4 _{1-4 3,}
Each time it passes through 40, a usage rate, an empty band, a cell loss rate, and other route information are mounted. AT in destination area H
Via information has been written by the M exchange 20 _2.

The ATM switches 4 ₁ to 4 ₃ and 40 do not process RM cells at all, and it is possible to estimate congestion in the round time of RM cells.

(Second Embodiment) A second embodiment of the present invention will be described with reference to FIG. FIG. 8 is a diagram showing a traveling state of the RM cell according to the second embodiment of the present invention. ATM which is each transit exchange
A switching unit ₄₁ to ₃ or of the terminating local exchange AT
M switch 40 ₁ and 40 ₂ are periodically spontaneously RM
By sending to ATM switch 20 ₁ and 20 ₂ is a calling side local exchange cells, reports the route performance.

(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 traffic condition in the ATM communication network 1 is grasped by the center device 6 shown in FIG. 6, and based on the congestion node and other information,
To ATM switch 20 ₁ and 20 ₂ are subscriber exchange is a method of providing information.

The center device 6 has an AT which is a transit exchange
Route information collection unit 60 for collecting information from the M switch ₄₁ to ₃ is provided, R from the ATM exchange 4 _{1-4 3}
Receives M cells and collects route information. The obtained route information is newly written in the message area M of the RM hell, and this is written to the ATM exchange 20 which is the originating subscriber exchange.
Transferred to ₁ and 20 _2.

(Fourth Embodiment) FIG. 10 shows a fourth embodiment of the present invention.
This will be described with reference to FIG. FIG. 10 is a diagram showing a cell transmission status according to 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 from the sending BECN cell, ATM switch 20 ₁ and 20 ₂ are subscriber exchange based on the information
Is to perform the action.

The timing at which an action is performed is different from the method of periodically transmitting an RM cell 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 local exchange will be described with reference to FIGS. FIG. 11 is a diagram showing a flow of the RM cell in the FRM protocol. FIG. 12 is a diagram showing a state of band change in the FRM protocol. FIG. 12 shows time on the horizontal axis and band on the vertical axis. To request bandwidth changes from the user terminal 3 _1, ATM is a local exchange
In the exchange 20, the route performance table 24 of the route to which the VC belongs is indexed to check the usage rate, for example. This usage rate is the link information with the highest usage rate on the route and the like. The protocol controller 21 estimates the remaining bandwidth and the like based on the actual usage rate, and returns a change in the bandwidth and the like to the user terminal device 3.

As shown in FIG. 11, the user terminal device 3 ₁
Is "10" for the ATM switch 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, as shown in Fig. 12, the time from "request" to "OK" can be shortened by using the present invention.

FIG. 13 is a diagram showing the flow of the RM cell in the ABR protocol. FIG. 14 is a diagram showing a state of band change in the ABR protocol. FIG. 14 shows time on the horizontal axis and band on the vertical axis. Examples of ABR protocol shown here takes a way to extend the stepwise band to the band extension request every "Inc" from the user terminal 3 _1. As shown in FIG. 13, A corresponds to the bandwidth extension 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. Accordingly, as shown in FIG. 14, the user terminal 3 ₁ each time it receives the RM cell, it is possible to extend the bandwidth stepwise. In some cases, the user terminal device 3 may receive a non-expansion or reduction request from the ATM switch 20 via the RM cell. In this case, the user terminal device 3 reduces the bandwidth step by step. In any case, the time from when the ATM switch 20 receives the bandwidth extension request "Inc" and returns the RM cell as a response to the request can be shortened by using the present invention.

[0035]

As described above, since the available bandwidth which 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. However, the hardware and other changes need only be made to the subscriber exchange, and the transit exchange can be simplified.

[Brief description of the drawings]

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

FIG. 2 is a block diagram of a main part of an ATM exchange as an originating 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 transit exchange and a destination local exchange;

FIG. 5 is a block diagram of a main part of an ATM exchange as a transit exchange and a destination local exchange;

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

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

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

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

FIG. 10 is a diagram showing a cell transmission status according to a fourth embodiment of the present invention.

FIG. 11 is a diagram showing a flow of an RM cell 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 an RM cell in the ABR protocol.

FIG. 14 is a diagram showing a state of a band 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 ₄₁ to _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 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

 ──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Haruhisa Hasegawa 1-6-1, Uchisaiwaicho, Chiyoda-ku, Tokyo Nippon Telegraph and Telephone Corporation (56) References JP-A-7-231322 (JP, A) European publication 635958 (EP, A1)

Claims (4)

(57) [Claims] A plurality of subscriber exchanges, a plurality of physical transmission paths connecting the plurality of subscriber exchanges, and a relay exchange interposed between the plurality of physical transmission paths. A virtual path is set up between the local exchanges, the local exchange contains a plurality of users having different protocols, and has means for supporting a protocol in which the users adaptively perform flow control with a network. In the ATM communication network, the originating local exchange has a virtual path usage rate, an empty band, and a cell loss set up with the destination local exchange.
Means to collect route information, including rates ;
By referring to the route information stored in the table for the performance information of each route, the performance information of the routes assigned to each user, the different
Multiple protocols terminate between the user and the local exchange
And, ATM communication network, comprising the means for performing the flow control. Wherein means for collecting the route information is provided on the originating local exchange includes means for sending the cell for collecting the route information for each of the virtual path, the transit exchange comprises means for transmitting in accordance via information in the information area equipped with a route information recorded in the destination area when this cell arrives, the receiving-side
When the cell arrives, the local exchange of that
The subscriber exchange on the originating side by loading the route information in the
2. The ATM according to claim 1 , further comprising means for returning the packet to the ATM.
Communication network. 3. The destination local exchange and the transit exchange each transmit a cell carrying route information on a virtual path relating to the exchange to the originating local exchange.
2. The ATM communication network according to claim 1, further comprising: means for sending data. 4. The system according to claim 1, wherein said transmitting means comprises means for transmitting, when congestion occurs in a virtual path relating to said local exchange or said transit exchange, cells carrying route information including said congestion information. A described in item 3
TM communication network.