JPH02126746A - Network mutual connecting device - Google Patents

Abstract

PURPOSE:To attain the data communication between the mutual lines of different types of exchanging services by providing a mutual connecting device (ICU) connected to a LAN (local area network) and to exchange and connect the line exchanging service and the packet exchanging service of ISDN (digital unifying) network. CONSTITUTION:For an ICU 4, layer 1 processing parts 11 and 11' separate packet exchanging and line exchanging service lines 1 and 2 to a B channel and a D channel. WPU (wide area side processor) 5 and 5' search for a rooting table 51 and inform an LPU (LAN side processor) 6 of the destination address through a bus 9. The LPU 6 checks whether the packet exchanging or the destination address of ISDN exists. A WPU 5 respectively sets the data to the B channel of the line and an opposite subscriber number in the function of a layer 3 of a D channel and message information to show the packet exchanging or the line exchanging service and sends them to an ISDN network 7.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a network interconnection device, and more particularly to a network interconnection device for connecting a local area network (LAN) and a wide area network, an integrated services digital network (ISDN). This invention relates to an interconnection device equipped with a network side circuit switching function.

[Conventional technology]

Connect LANs to each other or further connect LANs to a wide area network.
There is a tendency to try to connect N (for example, "
Nikkei Electronics 11988.5-16 (published by Nikkei McGraw-Hill) pp. 140-146).

The above document describes an example in which a hierarchical LAN is configured by connecting a branch line LAN to a 100 MB/sec optical ring LAN (mainline LAN).

By the way, as the scale of the LAN increases, it becomes necessary to connect it to a wide area network. recently.

LAN and packet-switched networks (x, 2 according to CCITT recommendations)
Research is being conducted to connect it to the 5th application. The problem here is that while packet-switched networks have a physical layer, data link layer, and network layer for reliable communication, LANs have logical This means that data is being transferred without setting up a link. Therefore, the LANs of each company announced are as follows:
Many have a data link layer.

[Problem to be solved by the invention] In this way, recently, LAs that are capable of connecting to wide area networks have been developed.
N is proposed. However, circuit switching technologies such as packet switching and circuit switching have traditionally been provided as services provided by first-class line carriers. Packet-switched connections made in data exchange (DDX) networks and the like are known.

In recent years, as the introduction of digital technology into transmission lines has expanded from short distances to long distances, the application of digital technology to telephone exchanges has progressed, and digital telephone networks are being realized. In addition, data networks such as packet switching networks are the forerunners of digital communication networks as digital data switching networks, but in the future they will become digital telephone networks.

Digital integrated network including digital facsimile network (
ISDN). ISD
N has a B channel used for user information channels and circuit-switched, packet-switched, leased lines, and a D channel used for circuit-switched signaling channels and packet information channels. On the other hand, packet-level protocols are defined in CCITT Recommendations X and 25, and include connection control procedures that control call setup and release, and data transfer procedures that perform error control and flow control for data transmission and reception. It consists of The frame level protocol below the packet level corresponds to level 2 of CCITT Recommendation x,25, and the transmission control procedure is called a link access procedure (LAP). The communication mode of this LAP is balanced type (ABM) and bidirectional simultaneous transmission (LAP-B).
) and unbalanced type (ARM) bidirectional simultaneous transmission (LAP).
Two communication modes are defined.

Now, on the premise of constantly communicating large amounts of data,
If a user who has contracted for a packet switching service with a Type 1 network operator wants to communicate with other users who primarily make telephone calls using an ISDN line, the network side may not be able to connect directly via the ISDN network. Unless provided, mutual communication is not possible.

The purpose of the present invention is to solve such conventional problems and to
By simply adding a few processes while communicating with N, IS
An object of the present invention is to provide a network interconnection device that can utilize packet switching services and line switching services of a DN network, and can perform data communication between lines of different types of switching services as needed.

[Means to solve the problem]

In order to achieve the above object, the network interconnection device of the present invention connects a local area network (LAN) and an integrated digital network (ISDN network) as a wide area network, and uses circuit switching provided on the ISDN network side. In an interconnection device that relays communication between an ISDN network side terminal that uses both service and packet switching service and a terminal within the LAN, from the control (D) channel information of an incoming call from the ISDN network, Destination address information is determined from either the packet switching or circuit switching service requested by the signaling (B) channel of the incoming call, and the address information included in the data signal of the signaling (B) channel. A wide area network side processor to be taken out, a routing table that checks whether a corresponding address exists in the LAN connected to the wide area network side processor and to which the interconnection device is connected, and a bus If the processor on the wide area network side determines that the corresponding address does not exist within the LAN and is instructing packet switching or circuit switching different from that on the calling side on the ISDN network side, then a LAN side processor that receives the determination result and the data of the incoming call via the bus, and sends the data to the corresponding line on the wide area network side according to the same process as the routing process of the call originating from the LAN to the wide area network side; It is characterized by having the following.

[For production]

In the present invention, an interconnection device (hereinafter referred to as ICU) is installed which is connected to the LAN and which exchanges and connects service lines for both the circuit switching service and the packet switching service of the ISDN network. This ICU performs a service conversion and circuit switching function of converting communication data transmitted through the circuit switching service of the ISDN network into a packet switching service and transmitting it again to the ISDN network. By connecting ISDN network circuit switching service terminals accommodated in the same LAN's ICU and packet switching service terminals of the same network via the ICU, the ISD
While being used as an N terminal, it is possible to perform data communication between lines of different types of exchange services via the ICU as necessary.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram of an ICU (interconnection unit t) showing one embodiment of the present invention.

In Figure 1, 4 is an I that performs service conversion and circuit switching.
CU, 7 is the ISDN network that accommodates this ICU, 8 is the LAN that connects this ICU, 1 is the ISDN packet switching service (ISDN-P) line, 2 is the ISDN
Circuit switched service (ISDN-C) line, 3 is a connection line with LAN, 5 and 5' are ISDN wide area network (WAN) side processors (WPU), 6 is LAN side processor (LP
U), 9 corresponds to the bus to which the LPU and WPU are connected, 11 and 11' correspond to the layer 1 processing unit (physical layer processing unit) of the ISDN line, and 12 and 12' correspond to the layer 2 of the B channel of the ISDN line. LAPB (layer 2) processing unit (data link layer processing unit), 13 and 13' are LAPD (layer 2) processing units (data link layer processing unit) of the D channel of the ISDN line, 14 and 14' are B channel processing units Layer 3 processing function (network layer processing function), 1
5 and 15' are D channel layer 3 processing functions (network layer processing functions). In addition, WPU5,5'
The layer 3 processing function for B channel and D channel 14.
15 built-in terminals, and further LAN terminals (ES,...
, ) is provided. The LPU 6 also includes an address information table 61 for terminals within the WAN (DET, 2).

The ICU 4 uses a plurality of processors (PUs) in a distributed manner, and the layer 1 processing unit 11.11' terminates the user/network interface line, as well as the packet-switched/circuit-switched ISDN basic interface line (or - 2 (or 23) signaling channels (B channels) with a speed of 64 Kbit/s and 16 Kbit/s (or 64 Kbit/s
) into a control channel (D channel) with a speed of

Next, the LAPD layer 2 processing units 13 and 13' comply with the CCITT I series recommendations and the TTC (Telegraph and Telephone Technical Consultative Committee) standards for the separated D channel. 13' determines the D channel type and passes the information data to the layer 3 processing functions 15, 15'.

Based on this D channel message information, the layer 3 processing functions 15 and 15' determine whether the B channel call input from the wide area side to the ICU 4 uses ISDN packet switching or circuit switching service. ,W
The determination is made using the hardware or software within the PU (wide area processor) 5.

Furthermore, the B channel information separated by the layer 1 processing section 11.11' is transferred to the LAPB (layer 2) processing section 12.12.
' When reaching the layer 3 processing function 14, 14' in WPU5.5', the layer 3 processing function 14.1
4' is the ID indicating whether it is wide area communication or LAN side communication in the destination address information shown in the layer 3 function of the information, and the LA shared by the WPU 5 and the other WPU 5'.
The destination is obtained by comparing the contents of the address table 51 in N. This ID is included in the description of the network address, and for example, if layered description is used, it will identify whether it is a wide area side or a LAN side, which subnetwork on the LAN side, and which terminal in the subnetwork. are written to specify them hierarchically.

WPtJ5.5' searches the routing table 51 and, if the ID indicates the wide area side as a result of the comparison, sends the destination address to the LPU (LAN) via the bus 9.
side processor) 6.

The LPU 6 compares the information in the wide area address table 61 with the destination address and checks whether there is a destination address that corresponds to either ISDN packet switching or circuit switching. Connection services between ISDN circuit-switched or packet-switched networks are provided by first-class network carriers, so for the same type of switching services, this ICU
4 is not involved at all.

As a result of the above check, if there is a corresponding address, the LP
U6 issues a communication request to WPU 5.5' via bus 9 as if a call had occurred from within LAN 5 to the corresponding service line type of ISDN network 7.

WPU5 responds to a communication request from LPU6.

Data is set in the B channel of the line, and the other party's subscriber number, which is the other party's destination address information, and message information indicating packet switching or circuit switching service are set in the layer 3 function of the D channel, and the ISDN network 7 It operates to send to.

As a result, a switching function is realized by converting packet communication and circuit switching communication services by changing messages in the D channel, and further transferring B channel information between the packet switching service and the circuit switching service.

In the subsequent operation, the WPU 5 once transmits B channel data to the LPU 6 via the bus 9, and the LPU 6 then repeats the procedure in which the data is returned to the WPU 5 via the bus 9.

Figure 2 shows the LAN terminals (ES, C and ISD) in Figure 1.
FIG. 2 is a diagram showing the flow of signals within the ICU that are relayed to the N wide area network side terminal (DTE, 2).

In FIG. 2, 81.81' indicates terminals ES, ES, , 7 receiving packet switching services within LANa.
1.71' is a terminal DTE that exists on the ISDN wide area network side and receives circuit switching or packet switching services.

For example, when communicating by circuit switching data from a terminal 81 connected to the LAN 8 to a packet terminal 71 connected to the industrial SDN wide area network 7, the LPU 6 in the ICU 4 is the destination address information in the layer 3 function of the information. By looking at the ID, it is determined that this is a wide area communication, and by transferring this to the WPU 5, it is transmitted to the terminal 71 connected to the wide area network 7 via the packet switching service line 1. In this case, all terminals connected to the LAN 8 are packet terminals, and if the terminal connected to the destination ISDN wide area network 7 is the packet terminal 71, communication is carried out via the packet switching service line 1, and the circuit switching In the case of the terminal 71', communication is carried out via the circuit switched service line 2.

In addition, when communicating by circuit switching data from the terminal 71' connected to the wide area network 7 to the packet terminal 81' connected to the LAN 8, the I/O data is transmitted via the circuit switching service line 2.
WPU5' in ICu2 looks at the ID which is the destination address information in the layer 3 function of the information, which is sent to CU4,
It determines that this is a communication to LAN8 and sends it to L
By transferring to PU6, LA via connection line 3
It is transmitted to terminal 81' connected to N8. When these terminals communicate with each other in the opposite direction, it is done in exactly the same way.

In this way, circuit switching services and packet switching services can be exchanged between the LAN and the ISDN network. Of course, communication is possible even in the case of exchange services of the same type.

Although only two terminals are shown as terminals within the LANB, in reality, several dozen or more terminals are connected.

Further, although only the ISDN basic interface is described in FIGS. 1 and 2, connection and exchange of ISDN-secondary group interfaces (23B+D) can also be realized in the same way.

FIG. 3 is a system diagram of the entire data communication system using the present invention.

Here, ICU4 connected to LAN8 and this IC
A terminal 71 (
A terminal 71' (DTE, ) using the circuit switching service is shown in a state where the circuit is switched by the ICU 4. The ICU 4 of this embodiment is I
After performing the routing process for the circuit switching service and packet switching service of the SDN network, mutual mode conversion and circuit switching can be provided simultaneously.

When communicating through the route shown in FIG. 3, the packet switching service terminal 71 and the circuit switching service terminal 71' of the ISDN network 7 are connected via the ICU 4, and mutual communication becomes possible. Furthermore, the terminal (ES engineer, 2) in LANB and the terminal 71 in the ISDN network 7
．． Communication with 71' is also possible as shown in FIG.

As a result, each terminal that uses the packet switching service and circuit switching service of the ISDN network 7 can connect to this ICU 4.
are connected to each other via , and data communication is possible.

Therefore, mutual exchange of packet switching services and circuit switching services for which the ISDN network 7 does not provide services is performed by the ICU 4.
This becomes possible. In addition, IS of packet switching service
Although it is impossible for a DN terminal and an ISDN data terminal with only circuit switching services to directly communicate with each other via the ISDN network 7, this communication is realized via the ICU 4. However, the wide-area side terminals that wish to connect must of course be recognized by registering their addresses in the ICU 4, and the addresses and data description formats of these terminals themselves must be recognized by the ICU 4.
It is necessary to follow the rules stipulated by U4.

In this embodiment, since packet switching services and circuit switching services can be exchanged, for example, a user who has a contract for only circuit switching services with a first-class line carrier can
This function is effective when using an SDN line to perform data communication as needed while normally performing mainly telephone communication. As another example, a user who has a contract for a packet switching service with a Class 1 carrier on the premise of constantly communicating large amounts of data may use the above-mentioned ISDN service.
In the past, even if you wanted to communicate with a user, mutual communication was impossible because the network side did not provide direct connection via the ISDN network, but in this embodiment, mutual communication is easily possible via the ICU 4. can be realized.

〔Effect of the invention〕

As explained above, according to the present invention, by adding a small amount of processing while performing LAN communication, IS
Each terminal that uses the packet switching service and circuit switching service of the DN network can be connected to each other via the ICU and data communication can be performed, resulting in extremely high flexibility and improved services for subscribers. .

[Brief explanation of drawings]

Fig. 1 is a configuration diagram of an interconnection device that performs service conversion and line switching, showing an embodiment of the present invention, and Fig. 2 shows the flow of signals within the ICU relayed between a LAN terminal and an ISDN wide area terminal. The diagram shown in FIG. 3 is a system diagram of a data communication system using the present invention. 1: ISDN packet switching service line, 2: ISDN
Circuit exchange service line, 3: Connection line with LAN, 4
: Interconnect unit (ICU), 5.5': ISDN wide area processor (WPU), 6: LAN side processor (LPU), 7: ISDN network, 8: LAN, 9:
Bus, 11.11': Layer 1 processing unit of ISDN line, 12, 12': Layer 2 processing unit of LAPB, 1
3.13': LAPD layer 2 processing unit, 14,1
4. ': B channel layer 3 processing function in WPtJ, 15.15' D channel layer 3 in eWPtJ
Processing function, 51e LAN terminal address information table, 61: ISDN wide area side terminal address information table,
71.71': Wide area terminal, 81.81': L
AN side terminal. Patent applicant: Nippon Telegraph and Telephone Corporation Agent: Masatoshi Isomura

Claims (1)

[Claims] (1) An ISDN network side terminal that connects a local area network (LAN) and an integrated digital network (ISDN network) as a wide area network and uses both circuit switching services and packet switching services provided by the above ISDN network. In the interconnection device that relays communication between the terminals and terminals in the LAN, control of calls received from the ISDN network (
D) From the channel information, the signal of the incoming call (B) The service of either packet switching or circuit switching requested by the channel, and the address information contained in the data signal of the signal (B) channel. , a wide area network side processor for extracting destination address information, a routing table connected to the wide area network side processor and checking whether a corresponding address exists in a LAN to which the interconnection device is connected; The wide area network side is connected to the processor on the wide area network side via a bus, and the wide area network side indicates that the corresponding address does not exist in the LAN and is instructing packet exchange or circuit switching different from that of the originating side on the ISDN network side. If the processor makes a determination, it receives the determination result and the data of the incoming call via the bus, and transmits the data to the corresponding line on the wide area network according to the same process as the routing process for a call originating from within the LAN to the wide area network. A network interconnection device comprising: a LAN side processor that sends out a LAN side processor;