JP3198086B2 - Circuit switching network - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an STM (Synchronous
Transfer Mode) Used for communication networks. The present invention uses TCP
−IP (Transmission Control Protocol-Internet Prot
ocol) A technology for transferring data having an address via an STM connection.

[0002]

2. Description of the Related Art The operation and problems of a conventional circuit switching network based on STM will be described with reference to FIGS. FIG.
FIG. 1 is a diagram showing a main part configuration of a conventional circuit switching network based on STM. FIG. 5 is a diagram showing a main part configuration of a conventional subscriber exchange. In an STM communication network, signals on a physical channel are multiplexed into time slots and circuit-switched, so the delay time during communication is extremely short, and an ATM (Asynchronous Transfer Mode) header using virtual paths and cells is used. There is no overhead.

For example, if there is a delay of 20 to 30 ms or more in telephone voice, there is a problem in quality, and an echo canceller is required. In general, it is better to have a small delay not only for telephone calls but also for two-way video meetings. In view of the above, STM is a transfer mode suitable for a digital telephone network.

As shown in FIG. 4, in a conventional circuit switching network based on STM, a user inputs a telephone number of a destination to a CCITT.
No. defined in the Recommendation The transmission in the STM mode by transmitting to the exchange through the common line signaling network allows the physical transmission to be independent of the E.7. 164 addresses (ITU
-T is mapped to an ISDN address standardized by -T for communication. That is, ST in the STM network
The MTM connection is established, and the user data is transferred to the E.M. 164 addresses and transferred to the destination exchange.

In such a conventional circuit switching network based on STM, switching is performed by exchanging time slots of information multiplexed by 8 bytes on a frame. This operation is realized by, for example, sequential write random read as shown in FIG. That is, the sequential counter CT
R writes data to the data buffer memory DBM at sequential addresses with a sequential address, and the address control memory ACM changes the reading order to perform time slot conversion.

[0006]

SUMMARY OF THE INVENTION Such a conventional ST
As described above, the circuit switching network based on M has the advantages that the delay time is extremely short and that there is no overhead as compared with ATM or the like. However, such a conventional circuit switching network based on STM requires that an STM connection be set in advance from a terminal of a calling user to a terminal of a called user, and data be transferred via the STM connection. is there.

FIG. 6 shows an image of a dedicated STM connection. For this reason, as shown in FIG. 6, there is a problem that the application can only be used as a dedicated data line between large-scale offices.

On the other hand, regarding data communication performed by the TCP-IP architecture, a TCP-IP address, which is an identification number of a terminal, is written in a header of a packet and sent to a communication network such as the Internet that supports the TCP-IP. Each router such as an exchange searches for the existence of the address and transfers the datagram without having to set up a connection between two terminals with which communication is desired.
As described above, a dedicated connection is not required, and data can be transferred by a very simple procedure. However, in this case, a delay time is longer than that of a circuit switching network based on STM, and overhead is required.

The inventors have considered constructing a new circuit switching network having both the advantages of the circuit switching network using the STM and the advantages of data communication using the TCP-IP address.

The present invention has been made in such a background, and can be provided only as a mere dedicated line by providing a relay network by STM based on a TCP-IP address used for data communication. Missing S
An object of the present invention is to provide a circuit switching network capable of dynamically providing a TM circuit. An object of the present invention is to provide a circuit switching network having a small delay time and a small overhead.

[0011]

SUMMARY OF THE INVENTION The present invention provides a TCP-IP
The packet having the header in which the address has been written is further added to the packet containing the terminal exchange which accommodates the terminal indicated by this TCP-IP address. The main feature is that the packet is transferred to a terminal as a desired destination via the STM network by adding a header in which a 164 address is written. At this time, the transit exchange checks the header of the arriving packet and reloads the packet in a predetermined time slot. As a result, the exchange that has received the packet determines the time slot in which the packet is to be loaded at that time without setting up a dedicated connection in the STM network in advance, so that the data communication performed by the above-described TCP-IP architecture can be performed. Data can be transferred by link-by-link with such simplicity.

That is, the present invention relates to a circuit switching network,
A plurality of subscriber exchanges accommodating one or more terminals, and a transit exchange for connecting the subscriber exchanges to each other, wherein the subscriber exchange and the transit exchange are connected via a STM network. It is. It is a feature of the present invention that the local exchange has a T
Means for receiving a packet having a header in which a CP-IP address is written, and an E.P.E. in the STM network corresponding to the TCP-IP address. 164 addresses and a TC obtained by referring to the table.
E. corresponding to the P-IP address Means for adding a header in which the E.164 address is written to the header, and referring to the added header, Means for transferring the packet in a time slot corresponding to 164 addresses.

[0013] The transit exchange switches the E.D. of the packet written in a time slot. Means for referring to the header in which the E.164 address has been written, and E.C. It is preferable to provide a means for switching to a time slot corresponding to 164 addresses.

It is preferable that the apparatus further comprises means for temporarily storing the packet when the time slot does not have a vacancy until the time slot has a vacancy.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a diagram showing a configuration of a circuit switching network according to an embodiment of the present invention. FIG. 2 is a block diagram showing a main part block configuration of the local exchange according to the embodiment of the present invention. FIG. 3 is a diagram showing a block configuration of a main part of the transit exchange according to the embodiment of the present invention.

The present invention relates to a circuit switching network, comprising a subscriber exchange LS accommodating a terminal TE and a transit exchange TS connecting the subscriber exchanges LS, as shown in FIG. The exchange LS and the transit exchange TS are ST
It is a circuit switching network connected via the M network 1. A feature of the present invention is that, as shown in FIG. 2, the subscriber exchange LS is a means for receiving a TCP / IP packet having a header in which a TCP-IP address coming from the terminal TE is written. Unit 2 and an E.M.T. in the STM network 1 corresponding to this TCP-IP address. Table 3 in which the T.164 address is recorded, and E.164 corresponding to the TCP-IP address obtained by referring to Table 3. The receiving unit 2 is a means for adding a header in which the 164 address is written to the header, and the E.164 is referred to by referring to the added header.
In the time slot corresponding to 164 addresses, the TCP
/ IP packet transfer means.

As shown in FIG. 3, the transit exchange TS transmits the packet written in the time slot to the E.P. The header reference unit 5 is a means for referring to the header in which the 164 address has been written, and the packet is written in the header again according to the reference result of the header reference unit 5. 1
And a relay section 6 which is a means for switching to a time slot corresponding to 64 addresses.

Further, when there is no empty time slot in the local exchange LS shown in FIG. 2 and the transit exchange TS shown in FIG. 3, the packet is temporarily stored until the empty time slot is generated. A burst buffer 7 serving as a storage unit is provided.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. The TCP / IP packet transferred from the terminal TE is transmitted to the E.P. 164 addresses are assigned. That is, in the STM network 1, TC
The E.E. of the local exchange LS in which the terminal TE serving as the destination of the P-IP address is accommodated. 164 addresses are assigned. At this time, the receiving unit 2 sets the E.D. address corresponding to the TCP-IP address. Reference is made to Table 3 to retrieve the 164 address. Table 3 contains E.E.R. corresponding to the TCP-IP address in advance. 164 addresses are recorded.

Thus, the TCP / IP packet is
Further, E. The header in which the 164 address is written is added and input to the transmission unit 4. The header copy unit 8 of the transmission unit 4 writes the E. coli written in the header of the input packet.
The 164 address is copied and transferred to the control circuit 9. The control circuit 9 controls the E. In accordance with the 164 addresses, data transfer is performed according to the procedure described with reference to FIG. At this time, the embodiment of the present invention includes the burst buffer 7 for temporarily storing packets when there is no free time slot. The delay circuit 10 compensates for the control delay of the control circuit 9 and places the packet in a desired time slot.

As shown in FIG. 3, the relay exchange TS copies a packet for each time slot by the data copying unit 11 and inputs the packet to the header reference unit 5. The header reference section 5 virtually reproduces the input packet, thereby resolving the E.C. The header in which the 164 address is written is searched. E. found The 164 address is transferred to the control circuit 9. The subsequent operation is the same as the operation of the transmitting unit 4 of the local exchange LS.

As described above, by the transit exchange TS,
E. FIG. Since the 164 address is read from the packet and the packet is reloaded into a predetermined time slot, the transit exchange TS receiving the packet does not need a dedicated line set in advance, and the time slot in which the packet is received at that time is loaded. Is determined each time, it is possible to transfer data by link-by-link as simply as data communication performed by the above-described TCP-IP architecture. Therefore, it is possible to hold the line only during the data transfer and release the line when the transfer is completed.

As a result, a link can be established at a high speed, network resources can be occupied only during the data transfer period, and the other periods can be released. Therefore, ATM
In the case of the data transfer by the comparative example, one cell has 53 bytes in ATM, and 5 bytes of them are overhead. However, this embodiment does not require this overhead. Also, since there is no problem of fluctuation and no cell loss, it is easy to assemble the packet on the receiving side.

[0024]

As described above, according to the present invention,
Based on the TCP-IP address used for data communication,
By providing a transit network by TM,
An STM line that could only be provided as a mere dedicated line can be dynamically provided. As a result, a circuit switching network with a small delay time and a small overhead can be realized.

[Brief description of the drawings]

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

FIG. 2 is a diagram showing a block configuration of a main part of the local exchange according to the embodiment of the present invention.

FIG. 3 is a diagram showing a main block configuration of a transit exchange according to the embodiment of the present invention.

FIG. 4 is a diagram showing a main configuration of a conventional circuit-switched network based on STM.

FIG. 5 is a diagram showing a main configuration of a conventional subscriber exchange.

FIG. 6 is a diagram showing an image of a dedicated STM connection.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 STM network 2 receiving unit 3 table 4 transmitting unit 5 header referencing unit 6 relay unit 7 burst buffer 8 header copying unit 9 control circuit 10 delay circuit 11 data copying unit ACM address control memory CTR sequential counter DBM data buffer memory LS subscriber exchange TS transit exchange

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-4-98918 (JP, A) Interface Vol. 18 No. 9 “Efficient ISDN Utilization Techniques (1 below)” (1992-9-1) pp. 213-229 [CSNW-1998-20040-009] (58) Fields investigated (Int. Cl. ⁷ , DB name) H04L 12/56 H04L 12/50

Claims (3)

(57) [Claims] A plurality of subscriber exchanges accommodating one or more terminals, and a transit exchange for connecting the subscriber exchanges to each other, wherein the subscriber exchange and the transit exchange comprise:
In a circuit-switched network connected via an STM (Synchronous Transfer Mode) network, the local exchange has a TCP-I signal coming from the terminal.
P (Transmission Control Protocol-Internet Protoco
l) means for receiving a packet having a header in which an address is written, and an E.E.C. in the STM network corresponding to this TCP-IP address. 164 addresses, and a TCP-I obtained by referring to the table.
E. address corresponding to the P address Means for adding a header in which the E.164 address is written to the header, and referring to the added header, Next specified by 164 address
Means for transferring the packet in an empty time slot going to a relay exchange or a subscriber exchange. 2. The transit exchange according to claim 1, wherein said E.D. Means for referring to the header in which the E.164 address has been written, and E.C. Next transit exchange specified by 164 address
2. The circuit switching network according to claim 1, further comprising means for switching to an empty time slot going to a subscriber exchange. 3. The circuit-switched network according to claim 1, further comprising means for temporarily storing the packet when the time slot has no free space until the time slot becomes free.