JPH08149135A - Atm exchange system - Google Patents

Abstract

PURPOSE: To allow the system to accommodate a high speed line and plural low speed lines in mixture and to attain ATM exchange with high efficiency on a cell basis. CONSTITUTION: Plural low speed lines DS1 are packed to be a high speed line rate and routing tag information is generated based on a VPI of a received cell independently of a high speed line OC3 21 and a low speed line DS1 11 at a high speed line rate. When virtual connection is sent from plural caller DS1T to plural called DS1R, in the unit packaging plural DS1, the caller DS1T converts a VCI into a value pointing out the called DS1R in an exchange 100 and to a value where no duplication takes place as to the virtual connection with respect to the called DS1R respectively and routing tag information pointing out the accommodated position of the corresponding called DS1R is generated based on the VPI of the received cell at a high speed line rate and the VCI is passed without any processing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to an ATM switching system,
More specifically, an ATM of a switching system that accommodates a high-speed line and a plurality of low-speed lines together and performs ATM exchange on a cell basis
Regarding the exchange method. ATM (Asynchronous Transfer Mo
de) is a B-ISD that realizes a variety of data communication from low-speed data to high-speed moving image data in a unified and economical manner.
This is a core technology of N, and in order to realize it, it is indispensable to provide an ATM switching system in which a high-speed line and a plurality of low-speed lines are mixedly accommodated and efficient ATM switching is performed on a cell basis.

[0002]

BACKGROUND ART FIG. 6 is a diagram for explaining a prior art, low-speed lines (1 called 11 _{0-11 63} DS1 in FIG.
544 Mbps) line termination unit {DS1 (0) to DS1
(63)}, 220 demultiplexing unit which performs multiplexing and demultiplexing of the line terminating unit 11 _{0-11 63,} line terminating unit of the high speed line 21 is referred to as OC3 (156 Mbps) (OC3), 23
Is a high-speed line (45 Mbps) line terminator (DS3) called DS3, and 25 ₁ and 25 ₃ are virtual identifiers (VI).
Label conversion unit (RC), 3 is an ATM switch (ASW) that performs self-routing of ATM cells, and 50 is an ATM switch.
A CPU that performs main control of the exchange and 6 is its control bus.

In an ATM network equipped with such a switch, a virtual path identifier (VPI) representing a transmission route and a virtual connection identifier (VCI) representing a virtual connection (VC) set on the VPI are used. Perform cell exchange. In order to do this, the ATM switch 3
The label conversion units 25 ₁ and 25 ₃ are placed in front of, and the routing information in the exchange (ATM switch 3) is obtained by looking up the label conversion table based on the VPI and VCI of the input cell. Further, in an ATM network in which VCs are switched by link-by-link, new VPI and VCI are obtained from the label converters 25 ₁ and 25 ₃ .

One cell which is a transmission unit is, for example, 53 octets.
The header part consists of 12 bits.
VPI area consisting of 16 bits and VCI area consisting of 16 bits
Is provided. Therefore, full use of VPI and VCI
Then theoretically 2 at the same time ²⁸Individual calls can be identified (exchanged)
It works. However, with this, the label conversion unit 25₁, 25
₃It requires a huge amount of memory, which is not realistic.

In reality, the number of VCs required to be simultaneously connected on a high-speed line is generally 4096 or more. In this case, the address sizes of the label conversion units 25 ₁ and 25 ₃ are 4096 or more, respectively. On the other hand, in a low-speed line, the number of VCs required to be simultaneously connected may be 384 or more in the case of, for example, a frame relay service, although it depends on the service type.

High-speed line (150M) and low-speed line (1.5
Comparing M), although the line speed ratio is 100 times, the ratio of simultaneously connected VC numbers is about 11 times at most.
The high-speed line is generally used for a communication service suitable for a high-speed VC (for example, image communication), and the low-speed line is generally used for a communication service suitable for a low-speed VC (for example, today's inter-computer communication). It can be said that the small ratio of the number of simultaneously connected VCs described above reflects this.

Therefore, as shown in FIG. 6, for example, 64 low speed lines DS1 (0) to DS are provided in the high speed lines OC3 and DS3.
Consider the realization of a realistic ATM switch in which 1 (63) is mixedly accommodated and ATM exchange is performed on a cell basis. In this case, a preferable configuration required for this type of ATM switch is that the configurations of parts having common functions have the same size and structure as much as possible. For this reason, when the low speed lines DS1 (0) to DS1 (63) are mixed and accommodated, the problem is where to arrange the label converting unit for the low speed lines and how to configure them.

As a first proposal, a label conversion unit 250 ₂ having the same size and structure as the existing label conversion units 25 ₁ and 25 ₃ is mounted at a position (after the demultiplexing unit 220) where the line rate is increased to the high speed. Can be considered. However, if the table space of the label converting unit 250 ₂ is set to “4096” which is suitable for a high speed line, for example, a table space for the demultiplexing unit 220 that bundles 64 low speed lines (for example, 384).
X64 = 24576 required) is insufficient. As a result, the required number of VCs cannot be secured in each of the low speed lines DS1 (0) to DS1 (63). In addition, the table space of the label conversion unit 250 ₂ is set to “24576” which is suitable for a low speed line, for example.
Then, the table space of the label conversion units 25 ₁ and 25 ₃ becomes unnecessarily large and the cost becomes high.

A second alternative is a low speed line DS1.
It is conceivable to mount the label conversion units 130 _{0 to} 130 ₆₃ of the same size and structure at the positions (0) to DS1 (63), respectively. However, in this case, the 64 label conversion units 130 _{0 to} 130 ₆₃ perform generation / addition of routing tag information and conversion of VPI and VCI, respectively.
The cost of the low-speed line becomes high. Moreover, since the routing tag information is generated and added and the header is converted in the low-speed line unit, the label conversion unit 25 at the high-speed line rate position is used.
0 ₂ is wasted. Therefore, it is conceivable to delete this label conversion unit 250 ₂ , but considering the commonality of control (synchronization of processing timing, etc.) at the position of the high-speed line rate, the label conversion unit 250 ₂ is necessary. As a result, the label conversion unit 250 ₂ in this case must be operated in vain to match the time.

[0010]

As described above, conventionally, no ATM switching system has been proposed for efficiently performing label conversion for low-speed lines and efficiently performing ATM switching. It is an object of the present invention to provide an ATM switching system in which a high-speed line and a plurality of low-speed lines are mixedly accommodated and an ATM exchange is efficiently performed on a cell basis.

[0011]

The above-mentioned problems can be solved by the structure shown in FIG. That is, the ATM exchange system of the present invention is
In an ATM switching system of an exchange which accommodates a high speed line and a plurality of low speed lines together and performs ATM exchange on a cell basis, the plurality of low speed lines are bundled and pulled up to a high speed line rate position, and at the high speed line rate position. The routing tag information used in the exchange is generated based on the virtual path identifier of the input cell without distinction between the high speed line and the low speed line.

[0012]

The operation of the present invention will be specifically described with reference to FIG. However, FIG. 1 does not limit the present invention. In the ATM switching system of the present invention, for example, the high-speed line unit 21
And performing ATM exchange cell basis by the ATM switch 3 a plurality of low-speed lines 11 ₀ to 11 ₆₃ while mixed housing. In this case, a plurality of low-speed lines 11 ₀ to 11 ₆₃ with pulling on the position of the high-speed line rate by bundling the demultiplexer 22, in the position of the high-speed line rate, each label conversion unit 25 _1, 25 ₂ Fast The routing tag information used in the exchange 100/200 is generated based on the virtual path identifier VPI of the input cell without distinction between the line and the low speed line.

According to the present invention, at the position of the high speed line rate, the routing tag information used in the switch is generated based on the virtual path identifier of the input cell without distinction between the high speed line and the low speed line. 25 ₁ , 25
₂ , size and structure can be common. Moreover, since the functions required of the label conversion units 25 ₁ and 25 ₂ are both to generate the routing tag information used in the exchange,
Its size and structure are not large.

Preferably, a plurality of switches in the exchange 100, for example
Low speed line 11₀~ 11₆₃Within a unit that bundles
Side low speed line 11_0T~ 11_63TTo multiple destination low-speed lines
11 _0R~ 11_63RSet a virtual connection for
In this case, for example, the originating low-speed line unit 11_0TLabel attached to
Converter 13₀Then, the virtual path identifier VPI is assigned to the exchange 10
For example, the receiving side low speed line section 11 within 0_63RA value that points to (for example,
VPI = 63R) and virtual connection identifier VC
I is the destination low-speed line unit 11_63RAlready set for
Value that does not cause duplicates for virtual connections (calls)
(For example, first convert to VCI = 0)
At the high line rate position, for example, the label conversion unit 25₂But
Corresponding based on virtual path identifier VPI = 63R of input cell
Destination side low-speed line section 11_63RRooty pointing to the housing position of
Generate tag information (for example, TAG = 63R),
And at least the virtual connection identifier VCI = 0
Is transparent. In addition, setting of the label converters 13 and 25
Is performed by the control unit 5 at the time of call setup.

As described above, according to the present invention, the connection path T in the exchange 100 is determined by the virtual path identifier VPI = 63R.
Determine AG = 63R and determine virtual connection identifier V
Since CI = 0 is transparent, the virtual connection identifier VCI = 0 can be used as an identifier of a virtual connection established between, for example, the terminals TE ₀₀ and TE _C0 connected to the LANs (1) and (2).

[0016] Preferably, spans between the two exchanges 100 and 200 connected through an ATM trunk line 300, the low-speed line 11 _0-11 of the terminating exchange 200 a slow network 11 _{0-11 63} originating exchange 100 _When a virtual connection is set for _63, for _example , in the _originating low-speed line unit _110T , the virtual path identifier VPI is a value _indicating, for example, the low-speed line unit _{1163R in the destination} exchange 200 (for example, VPI =
63R), and the virtual connection identifier VCI is a value (for example, a value that does not overlap with the virtual connection (call) already set for the _destination low-speed line unit 11 _63R .
At the beginning, each is converted to VCI = 0), and at the position of the high-speed line rate, for example, the label conversion unit 25 ₂ is based on the virtual path identifier VPI = 63R and the ATM trunk line 3
00 (that is, OC3 _{R in} this example) is generated and added with routing tag information (for example, TAG = OC3 _R ) and the virtual path identifier VPI = 63R and virtual connection identifier VCI = 0 are not transparent. ,
In response to this, the high-speed line unit 21 of the destination exchange 200 generates routing tag information (for example, TAG = 63R) _indicating the accommodation position of the corresponding destination low-speed line unit 11 _63R based on the virtual path identifier VPI = 63R of the input cell. It is given and at least the virtual connection identifier VCI = 0 is transparent.

As described above, according to the present invention, the virtual path identifier VPI = 63R finally determines the connection route TAG = 63R in the destination exchange 200, and the virtual connection identifier VCI = 0 is transparent. Therefore, the virtual connection identifier VCI = 0 can be used as an identifier of a virtual connection established between, for example, the terminals TE ₀₀ and TE _C0 connected to the LANs (1) and (4). In this case, by setting the respective unique VPI for each low-speed lines 11 ₀ to 11 ₆₃ of the exchange 100,200, LAN (1) ~
It is obvious that a virtual connection can be arbitrarily established between arbitrary terminals TE in (4).

Preferably, the exchange 100/200 is provided with a plurality of cell buffers having different qualities of service, and distributes the input cells to the corresponding cell buffers based on the quality of service selection information included in the routing tag information. Therefore, even a plurality of terminals TE connected to the same low-speed line unit 11 have different service qualities (for example, one service call has no cell discard and the other service call has cell discard due to congestion). Receive ATM exchange service.

Further, preferably, a virtual identifier VP reserved in advance by the system in the ATM trunk line 300.
When the I / VCI is present, the low speed line section 11 of the originating exchange 100 has a virtual identifier VPI / VC other than the reserved one.
At the same time as converting to I, the destination exchange 200 returns these to the prescribed virtual identifiers VPI / VCI. Therefore, even if the virtual identifier VPI / VCI reserved by the system is not used, the ATM that extends between the exchanges 100 and 200 can be used.
Exchange can be done effectively.

Preferably, the label converting units 25 ₁ and 25 ₂ having the same structure generate and add the routing tag information used in the exchange 100/200 based on the virtual path identifier VPI of the input cell and at least the same. A device that allows the virtual connection identifier VCI to pass through as it is is provided between the ATM switch 3, the high-speed line unit 21, and the position where the low-speed lines 11 _{0 to} 11 ₆₃ are bundled and raised to the high-speed line rate.

An ATM switch 100 / having such a configuration
The 200 is an excellent exchange because it is highly functionally and structurally common. Also, preferably, the originating low-speed line unit _110T
To 11 _63T is a label conversion unit 13 _{0-13 63} to impart a virtual path identifier VPI and virtual connection identifier VCI corresponding to each virtual connection to the input data respectively provided, and receiving-side low-speed line unit 11 _0R to 11 _63R Is provided with a data conversion unit for converting the data of the cell into the data of the corresponding communication channel based on the virtual connection identifier VCI of the input cell.

Therefore, such low-speed line units 11 ₀ to 1 1
1 ₆₃ can accommodate various types of communication networks.

[0023]

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Note that the same reference numerals indicate the same or corresponding parts throughout the drawings. FIG. 2 shows an ATM of the embodiment.
FIG. 1 is a diagram showing the structure of an exchange, in which 10 ₀ to 10 ₃ are ATMs of the same structure, each mounting a plurality of low-speed line termination units.
-DS1 shelf (ADS1SH), 11 _{0-11 15} are line terminating portion of the low-speed lines DS1 (1.544Mbps) {DS1 (0 ) ~DS1 (15)}, 12 are multi-line termination unit 11 _{0-11 15} DS1 common part (DS
1 COM), 14 is its multiplexing unit (MPX), 15 is also a demultiplexing unit (DMPX), 15 ₀ to _{15 15} are quality of service buffers (QOSBUF) for temporarily pooling received cells in a grade according to the quality of service, 20 Is a subscriber interface shelf (SIFSH) equipped with a plurality of high-speed line termination units.
f), 21 the line terminating portion of the high-speed line OC3 (156Mbps) (OC3), 22 is ATM-DS1 Shelf 1 ₀
ATM-DS1 interface unit which performs multiplexing and demultiplexing of _{~1 3 (ADSINF: ATM DS1 Shelf} Interface Grou
p), 22 ₁ is its multiplexing unit (MPX), 22 ₂ is the same demultiplexing unit (DMPX), and 23 is the high-speed line DS3 (45 Mb).
ps) line termination unit (DS3), 24 is SIFSH20
Common part (SIFCOM), 25 _{1 to} 25 ₃ are label conversion parts (RC), and 26 is a multiplexing part (MP) of SIFCOM 24.
X), 27 is also a separating unit (DMPX), and 3 is an ATM switch (AS) that performs self-routing of ATM cells.
W), 4 is a broadband signal processing control unit (BSGC: Broadband Signaling Controll) for performing signal analysis of ATM cells.
er), 4 ₁ is its multiplexing unit (MPX), 4 ₂ is also a demultiplexing unit (DMPX), 5 is a processor (BCPR: Broadband Call Processor) that performs main control of the ATM switch, and 6 is its control bus.

ATM from low speed line terminations 11 _{0 to} 11 ₁₅
Uplink cells toward the switch 3 are multiplexed by a simple time division multiplexing method. On the other hand, the cell of the downlink direction from the ATM switch 3 to the low-speed line terminating unit 11 _{0-11 15} downstream cell rates from SIFCOM24 (156Mbp
s). Quality of service buffer 15 ₀ ~
15 ₁₅ and the speed is converted to low speed (1.5 Mbps) by the DS1COM 12, and the low speed line termination unit 1
Sent from _{10 to} 11 ₁₅ .

SIFSH24 is OC3, DS3, ADS
Any line termination device such as INF can be installed at any position.
Each exchange is equipped with multiple common slots
Each time OC3, DS3, ADSINF, etc. according to the specifications of
Can accommodate any number and combination of line terminators
It It is also easy to add more. FIG. 3 shows the AT of the first embodiment.
FIG. 3 is a diagram for explaining the M exchange method, which is a duplicated diagram in the exchange 100.
A virtual connection was established between a number of low-speed line termination units 11.
The cell exchange operation in the case is shown. However, each low speed on the calling side
The line terminating unit is 11₀~ 11₂And each low speed on the receiving side
The line terminating unit is 11_A~ 11_C, Respectively. Each low speed
Line end 11₀~ 11₂, 11_A~ 11_CEach is external
It is connected to a frame relay service network (not shown),
The data channels CH on the network are represented by numbers 0 to 4 for each network.
You. Hereinafter, the originating low-speed line termination unit 11₀Data channel
CH0 and destination low-speed line termination unit 11 _AData channel C
Cell exchange when a virtual connection is established with H0
The replacement operation will be described. In this case, the label conversion units 13 and 2
Contents such as 5 are set in advance by the processor 5 when setting a call
Has been done.

The label converter 13 ₀ sets the cell data D corresponding to the channel CH0 of the frame relay service network to VP.
I = A _m and VCI = 0 are given. The cells are multiplexed,
It is input to the label conversion unit 25 ₂ of the SIFCOM 24. The label conversion unit 25 ₂ uses the routing tag information TAG = used in the exchange 100 based on the VPI = A _m of the input cell.
A and quality of service class QOS = m are generated, and these are added to the header part of the cell.

The upper bits of TAG = A are used for the route selection of the ATM switch, and the lower bits thereof are used for the route selection of the separation units 22 ₂ and 15. Further, the quality of service class QOS = m in this example is added in a form associated with the lower bits of the routing tag information TAG = A, and the QOS bit is used for selecting the quality of service buffers m and n provided in the separation unit 15. Used.

TAG = A, Q by the label conversion unit 25 _2.
The cell assigned with OS = m is input to the ATM switch 3. The ATM switch 3 looks at the upper bit of TAG = A and outputs the cell to the output terminals (A to C). These output terminals (A to C) are common output terminals for higher bits such as TAG = A, B, and C. Next, the separation unit 22 ₂ is TAG.
= Look at the lower bit of A and output the cell to the output terminals (A to C). The output terminals (A to C) are TAG = A, B,
This is an output terminal common to lower bits such as C.

The separating unit 15 distributes the cell to any one of the output terminals A, B, C, etc. by looking at the lower bit of TAG = A. At that time, the QOS bit is also referred to, and in this example, with QOS = m, the cell is stored on the side of the quality of service buffer m. At this point, the cells other than VCI = 0 in the cell header and the cell data D have been used and may be deleted. The low-speed line termination unit 11 _A on the receiving side
Sees VCI = 0 of the input cell and converts the portion of the cell data D into frame relay data of channel CH0.

Similarly, as shown in the figure, virtual connections of various routes are established at the same time. In this case, the route in the exchange 100 is determined only by the VPI, and the number of routes can be selected to be 4096, for example. That is,
A total of 4096 routes can be selected including the high-speed line units 21 and 23 and each low-speed line unit 11. On the other hand, paying attention to the low speed line terminating unit 11 _A to 11 _C of the called side can simultaneously set virtual connection (the call) of the low-speed line terminating unit 11 _A to 11 _C number of each VCI in. Therefore, if this VCI number is selected to be 384, for example, 64 × 384 = 24576 virtual connections (calls) can be simultaneously set for all low-speed line units 11 of the system. This is a sufficient fulfillment of real-world requirements. Moreover, the label converters 13 ₀ to 1
The table space of 3 ₁₅ may be 384 or more, and the table space of the label converting unit 25 ₂ may be 4096 or more. Of course, the number of VPIs and the number of VCIs can be arbitrarily determined.

FIG. 4 is a diagram for explaining the ATM switching system according to the second embodiment. This drawing shows the originating side exchange 100 and the destination exchange 200.
2 shows a cell exchange operation when a virtual connection is established between a plurality of low speed line termination units 11 and. However, the low-speed line termination units of the originating exchange 100 are _denoted by reference numerals 110 to 11 respectively.
_2, and the low-speed line terminating unit of the receiving-side exchange 200 respectively represent by reference numeral 11 _A to 11 _C. Similarly, each low-speed line terminating unit _{11 0 ~11 2, 11 A ~11} C is connected with the respective external frame relay service network (not shown), a data channel CH on net-per network 0 It is represented by the numbers from 4 to 4.
Hereinafter, the data channel CH of the originating low-speed line termination unit 11 ₀
0 and the data channel CH0 of the destination low-speed line termination unit 11 _A
The cell exchange operation when a virtual connection is established between the and will be described. In this case, the contents of the label converting units 13, 25, etc. are set in advance by the processor 5 at the time of setting a call.

In the originating exchange 100, the label converter 13 ₀ adds VPI = A _m and VCI = 0 to the cell data D corresponding to the channel CH0 of the frame relay service network. The cells are multiplexed and input to the label conversion unit 25 ₂ of the SIFCOM 24. The label conversion unit 25 ₂ generates the routing tag information TAG = X and the quality of service class QOS = m to be used in the exchange 100 based on the VPI = A _m of the input cell, and adds these to the header of the cell. This TAG = X indicates the QC3 connected to the exchange 200 on the receiving side.

The ATM switch 3 sees TAG = X and outputs the cell to the output terminal X. The cell is the originating exchange 100
Entering the label conversion unit 25 ₁ through the OC3, ATM trunks 300 and OC3 of the terminating exchange 200. The label conversion unit 25 ₂ generates routing tag information TAG = A and quality of service class QOS = m to be used in the exchange 200 based on VPI = A _m of the input cell, and adds these to the header of the cell. ATM switch 3 is TAG
The higher order bit of = A is viewed and the cell is output to the output terminals (A to C). The output terminals (A to C) are TAG = A, B,
This is an output terminal common to upper bits such as C. Next, the separation unit 22 ₂ sees the lower bit of TAG = A and outputs the cell to the output terminals (A to C). This output terminal (A
.About.C) are common output terminals for lower bits such as TAG = A, B, C.

The separating unit 15 distributes the cell to any one of the output terminals A, B, C, etc. by looking at the lower bit of TAG = A. At that time, the QOS bit is also referred to, and in this example, with QOS = m, the cell is stored on the side of the quality of service buffer m. And the low-speed line termination unit 1 on the receiving side
1 _A sees VCI = 0 of the input cell and converts the portion of the cell data D into frame relay data of channel CH0.

Similarly, as shown in the figure, virtual connections of various routes are simultaneously established. For example, in the label conversion unit 13 ₀ of the originating exchange 100, VPI = C _m , VCI =
The cell assigned 0 is input to the label conversion unit 25 ₃ via DS3, the trunk line, and the DS3 of the destination exchange 200 by TAG = Y and QOS = m. Furthermore, TAG = C and QOS = m due to VPI = C _m in the cell header part,
The cell is finally the channel CH of the low speed line terminating unit 11 _C.
0 (VCI = 0). Others are the same.

It is possible to set a unique VPI for each low speed line section 11 of the exchanges 100 and 200. By doing this, a virtual connection can be arbitrarily established between a total of 128 low-speed line units. At the same time, high-speed line 2
It is also possible to connect an external call input from 1 or 23 to an arbitrary incoming side low speed line unit 11 _R , and a call generated by an arbitrary calling side low speed line unit 11 _T to the high speed line units 21 and 23. It is also possible to connect to the outside via.

FIG. 5 is a diagram for explaining the ATM exchange system of the third embodiment. This figure shows the originating exchange 100 and the destination exchange 200.
And a virtual connection is established between a plurality of low-speed line termination units 11 and
It shows a case where cell switching is performed without using the reserved VCI because the CI exists. In this case, the label converters 13 _{0 to} 13 ₂ of the originating exchange 100 add VCI = a to e instead of VCI = 0 to 4 reserved on the trunk line. On the other hand, the label converters 25 ₁ and 25 ₃ of the destination exchange 200 which received this convert VCI = a to e of the input cells into VCI = 0 to 4, respectively. It should be noted that this method can be easily applied to a case where there is a reserved VPI in the trunk line in advance and therefore the reserved VPI cannot be used.

In the above embodiment, the low speed line terminating unit 11 is used.
The example of accommodating the frame relay service network is described above, but the present invention is not limited to this. For example, another ATM is used for the low-speed line termination unit 11.
It is also possible to accommodate a network. In this case, the label conversion unit 13 performs necessary label conversion of VPI and VCI of the input cell instead of adding VPI and VCI. Although the preferred embodiments of the present invention have been described above, it goes without saying that various changes in configuration and control can be made without departing from the spirit of the present invention.

[0039]

As described above, according to the present invention, at the position of the high speed line rate, the routing tag information used in the exchange is generated without distinction between the high speed line and the low speed line based on the virtual path identifier of the input cell. Therefore, the size and structure of each label conversion unit can be made common at the position of the high-speed line rate. Moreover, since all the functions required for these label conversion units are the generation of routing tag information used in the exchange, the size and structure thereof are not large. Therefore, according to the present invention, a high-speed line and a plurality of low-speed lines can be mixedly accommodated and efficient ATM exchange can be performed on a cell basis.

[Brief description of drawings]

FIG. 1 is a diagram illustrating the principle of the present invention.

FIG. 2 is a diagram showing a configuration of an ATM exchange according to an embodiment.

FIG. 3 is a diagram for explaining the ATM exchange system of the first embodiment.

FIG. 4 is a diagram for explaining an ATM exchange system of the second embodiment.

FIG. 5 is a diagram for explaining an ATM exchange system according to a third embodiment.

FIG. 6 is a diagram illustrating a conventional technique.

[Explanation of symbols]

100, 200 Switch 300 Trunk line 11 _{0 to} 11 ₆₃ Low speed line section 13 _{0 to} 13 ₆₃ Label conversion section 21 High speed line section 22 Demultiplexing section 25 ₁ , 25 ₂ Label conversion section 3 ATM switch 5 Control section 6 Control bus

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takaro Kato 3-9-18 Shin-Yokohama, Kohoku-ku, Yokohama-shi, Kanagawa Fujitsu Communication Systems Limited (72) Inventor Kazuo Takeoka 3 Shin-Yokohama, Kohoku-ku, Yokohama, Kanagawa 3-9-18, Fujitsu Communication Systems, Inc. (72) Inventor Oshima Wagun, 3-9-18 Shin-Yokohama, Kohoku Ward, Yokohama City, Kanagawa Prefecture

Claims (7)

[Claims] 1. An AT for an exchange that accommodates a high-speed line and a plurality of low-speed lines together and performs ATM exchange on a cell basis.
In the M switching system, the plurality of low speed lines are bundled and pulled up to the position of the high speed line rate, and the high speed line and the low speed line are distinguished in the position of the high speed line rate based on the virtual path identifier of the input cell in the switch. An ATM exchange method characterized by generating routing tag information to be used. 2. When a virtual connection is set to a plurality of destination low-speed lines from the plurality of low-speed lines on the originating side within a unit in which a plurality of low-speed lines are bundled, a virtual path identifier is set on the low-speed line unit on the originating side. Is converted into a value indicating the destination low-speed line section in the same exchange, and the virtual connection identifier is converted into a value that does not cause overlap in the virtual connection set for the destination low-speed line section. The ATM according to claim 1, wherein at the position, routing tag information indicating the accommodation position of the corresponding destination low-speed line section is generated and added based on the virtual path identifier of the input cell, and at least the virtual connection identifier is transparent. Exchange method. 3. When a virtual connection is set up between two exchanges connected via an ATM trunk line to a low speed line of a destination exchange by a low speed line of the originating exchange, in the low speed line of the originating side, The virtual path identifier is converted into a value that points to the low-speed line part in the destination exchange, and the virtual connection identifier is converted into a value that does not cause overlap in the virtual connection set for the destination low-speed line part. At the line rate position, routing tag information indicating the accommodating position of the ATM trunk line is generated and added based on the virtual path identifier, and the virtual path identifier and the virtual connection identifier are not passed through, respectively, and the receiving side exchange which receives this In the high-speed line part, routing tag information indicating the accommodation position of the corresponding destination low-speed line part is generated based on the virtual path identifier of the input cell. Imparting to, and at least a virtual connection identifier, characterized in that the plain claim 1
ATM exchange method. 4. The switch is provided with a plurality of cell buffers having different qualities of service, and the input cells are distributed to the corresponding cell buffers based on the service quality selection information included in the routing tag information. ATM exchange method. 5. When there is a virtual identifier reserved by the system in advance on the ATM trunk line, the low speed line part of the originating exchange converts it into a virtual identifier other than the reserved one, and the destination exchange specifies these. 4. The ATM exchange system according to claim 3, wherein the ATM identifier is returned to the virtual identifier. 6. An ATM label converting unit having the same structure, which generates and adds routing tag information used in an exchange based on a virtual path identifier of an input cell and passes at least the virtual connection identifier as it is. 2. The ATM switching system according to claim 1, further comprising: a switch, a high-speed line unit, and a position where a plurality of low-speed lines are bundled and raised to a high-speed line rate, respectively. 7. The low-speed line unit on the outgoing side includes a label conversion unit for giving a virtual path identifier and a virtual connection identifier corresponding to each virtual connection to input data, and the low-speed line unit on the incoming side includes a virtual connection of an input cell. 7. The ATM switching system according to claim 6, further comprising a data conversion unit which converts data of the cell into data of a corresponding communication channel based on the identifier.