JPH0248838A - Communication control processing equipment - Google Patents

Abstract

PURPOSE:To realize an inter-line connector and a line terminator by one and the same communication control processing equipment by providing a line terminator function and a data terminal equipment function to the communication control processing equipment at the same time. CONSTITUTION:Upon the receipt of a call request from a packet terminal 306, the communication control processing equipment 304 execute the processing the X.25 data line terminator function provided for the private line connection when a called X.25 packet terminal 307 is connected to private lines 303a, 303b and the private lines 303a, b are usable. On the other hand, when the called X.25 packet terminal 307 is not connected to private lines 303a, 303b and the private lines 303a, b are not usable, and when the packet exchange network 302 is connected and the exchange network 302 is usable, the processing of the X.25 data terminal equipment function provided for the packet exchange network connection is executed. Thus, the same equipment 304 is used to connect the X.25 packet exchange network and to communicate with the packet terminal connected to the private lines.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a communication control processing device, and particularly to a data terminal device (hereinafter abbreviated as DTE).
nal equipment) function and data line terminal equipment (hereinafter abbreviated as DCE) (Data
C1rcuit Terminating Equ
The present invention relates to a communication control processing device that is capable of communicating with a plurality of terminals connected to a packet switching network, a private line, etc. by simultaneously installing ip+ment) functions and arbitrarily selecting and switching between them.

[Conventional technology]

All computers, input/output devices, etc. connected to a data transmission system are called DTE (data terminal equipment), and the transmission equipment in a data transmission system, that is, the equipment necessary to transmit signals, is called DCE (data line termination equipment). It is called. Therefore, in the components of the data transmission system, one DTE is connected to the data transmission line via the DCE, and the other I)TE is also connected to the same data transmission line via the DCE. The DCE performs mutual conversion between the signal interface conditions with the DTE (DTE/DCE interface) and the signal interface conditions on the transmission line side. For example, a modulator/demodulator (modem) or an in-home data line termination device is one type of DCE. The signal transmitted from the DTE to the DCE is a DC signal of several volts, but the DCE
converts this signal into a signal suitable for the transmission line. AC signals are often used on transmission paths other than short-distance transmission paths, and in this case, a modem is used as the DCE. In addition, if the transmission path is digital, DTE
Converts the output of the D S to a digital signal level suitable for the digital transmission path and performs synchronization.
U (D 1g1tal Service U
nlt) is used. Regarding these interface conditions, the CCITT (International Telegraph and Telephone Consultative Committee) has established functional, electrical, and physical standards as international standards (for DCE and DTE,
25).

Conventionally, when interconnecting local area networks (hereinafter abbreviated as LAN), when connecting LAN and other terminals, there are two methods: when connecting via a dedicated line, when connecting via a packet switching network. , and @ when connecting via wire switching networks, signals were converted using dedicated connection devices. In other words, since there was only one type of DCE, it was not possible to select an alternative relay route even if a failure or congestion occurred.

Therefore, for example, an inter-network connection device described in Japanese Patent Application Laid-Open No. 62-107555 was proposed, and since it became possible to connect using two types of relays, a packet switching network and a dedicated line, it was And it became advantageous on expansion changes. As shown in FIG.
Since there are two types of relay paths (400), either one can be selected and used as a relay path for each call or each packet. That is, the network connection device 1402a
, b are intra-LAN terminals 1406a, b.

When a call request from C is received, information such as whether there is a dedicated line connection to the LAN of the first destination and an address within the packet switching network is searched. If connected via dedicated line 1400,
Check whether the dedicated line is in a state where it is possible to make a call due to a line failure, the other party's station is busy, etc., and if it is possible to make a call, the dedicated line 1
400 to request the inter-network connection device 1402 on the destination side to set up a connection to the destination terminal. If the destination LAN is not connected to the dedicated line 1400, or if the call setup via the dedicated line fails, the call is checked to see if it is possible to make a call to the packet switching network 1401, and the call is sent to the packet switching network 1401. Sends a call request packet to the destination network connection device. In FIG. 14, 1404a, b, and 1405a are nodes within the LAN, and 1406a, b, and a are terminal devices accommodated in each node.

In this way, in the conventional system, two types of relay paths can be selected, but the inter-network connection devices 1401a, b and each node 1404a, b, 1405a are realized by separate communication control processing devices. .

[Problem to be solved by the invention]

As mentioned above, in conventional systems, it is necessary to configure the inter-network connection device for connecting to the X,25 packet switching network and the line termination device for connecting to the dedicated line on separate communication control processing devices. It was difficult to realize a network configuration at low cost.

For example, when transmitting a packet from terminal 1406a to terminal 1406b via dedicated line 1400, node 1
405a via the network connection device 1402a, the dedicated line 1400, and the network connection device 140.
2b to terminal 1 via the line terminal of node 1404b.
The call was received on 406b.

As described above, in the prior art, no consideration was given at all to a communication control processing device that simultaneously accommodates a connection to an X.25 packet switching network and a packet terminal connected to a dedicated line.

The purpose of the present invention is to solve such conventional problems, to enable connection with an X, 25 packet switching network and communication with a packet terminal connected to a dedicated line using the same communication control processing device, An object of the present invention is to provide a communication control processing device that can reduce costs.

[Means to solve the problem]

In order to achieve the above object, the communication control processing device of the present invention is a communication control processing device that is connected to a public data switching network and a dedicated line, and controls data transfer via the public data switching network and the dedicated line. A plurality of line connection control means are provided corresponding to each line, each having a built-in data link control program, and a DTE (data terminal) for controlling the line connection control means and for connecting to the public data exchange network. Built-in device program, DCE (line termination equipment) program for connecting to the above dedicated line, control program for controlling the private network, and conversion program for converting each protocol to other protocols. and a table storing network configuration information accessed by the processing means, and the processing means selects and executes the DTE program on the interface connected to the public data exchange network. , is characterized in that the above-mentioned DCE program is selected and executed on the interface connected to the above-mentioned dedicated line.Furthermore, when the above-mentioned processing means receives a call request from a terminal within the private network, ,
When communicating with the called terminal via one side of the public data switching network, if it is possible to connect to both the dedicated line and the public data switching network, use the dedicated line in a polarized manner, start the DCE program, and If the leased line is faulty or unconnectable, the public data switched network is used to start the DTE program, and if a call setup packet is received via the leased line or the public data switched network, the input line is Another feature is that a DCE program is started when the input line is a private line, and a DTE program is started when the input line is a public data exchange network.

[For production]

In the present invention, a communication control processing device accommodates a plurality of different relay paths such as a packet switching network and a leased line, and the device has a DCE function recommended in X.
It has both TE functions at the same time, and selects either the DTE function or DCE function of X, 25 based on the data communication network management information set at the start of operation or information obtained by executing communication control procedures. do. That is, when connecting to an X,25 packet terminal via a packet switching network or connecting to an X,25 packet terminal via a leased line, either the DTE or DCE function within the device is selected and By using the same communication control processing unit, it is possible to
, 25 communicates with packet terminals. Therefore, there is no need for an inter-network connection device as shown in FIG. 14, and multiple relay paths including packet switching networks and dedicated lines, as well as multiple terminals can be accommodated at the node location, reducing hardware costs. Switching between relay routes is also easy.

〔Example〕

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

FIG. 3 is a configuration diagram of a network to which the present invention is applied.

In FIG. 3, 304 and 305 are packet switches or communication control processing devices (CeF2) equipped with similar functions.
．． 5), and these are accommodated in the packet data communication network 301, which is a private network. Communication control processing device 305
is connected to another communication control processing device 304 via a communication line 303d within the private network 301, and the communication line 30
It is connected to the packet terminal 306 via 3e. on the other hand,
The communication control processing device 304 has a dedicated line 303a and a dedicated line 30.
Packet terminal 3°7b, 307 of X, 25 via 3b
c, and is also connected to the packet switching network 302 via the communication line 303c, and this packet switching network 3
X, 25 packet terminals 307a, 307 via 02
connected to b.

Here, in connection with the packet terminal 307b, the dedicated line 303a is a communication line that is always used, and the packet switching network 302 is prepared as a communication line that is used when the dedicated line 303a has a failure. Therefore, the communication control processing device 304
When transmitting a packet to the packet terminal 3゜7b, it first selects the dedicated line 303a, and
Packet switching network 302 is selected only when 3a is in failure. As is well known in the national long-distance dial system, privately installed R
When communicating between terminals in the packet switching network 301 and between terminals in the packet switching network 302, the destination is called with seven digits such as (966)9111.
When communicating outside the private network 301 or outside the packet switching network 302, a several-digit toll number (for example, 044 (966) 9111) is added to call the destination.

FIG. 2 shows the communication control processing device (304) in FIG.
It is a diagram showing the hardware configuration of.

202a, 202b, 202c, and 202d are line connection control units, respectively, which control the data links of the lines to be connected. That is, the line connection control unit 202 is provided for each line, and corresponds to dedicated lines 303a, 303b,
One corresponds to the line 303c connected to the packet switching network 302, and the other corresponds to the line 303d connected to the relay device in the private network. 203 is a buffer unit that stores packets, and 201 is a processor that performs network control, protocol conversion and communication control processing that converts CCITT Recommendation x, 25 procedures and network control procedures within a private network. Performs various controls between hardware within the device 304.

FIG. 1 shows a communication control processing device (
304) is a diagram showing the software configuration.

In FIG. 1, 107 is a data link control program, and each line connection control unit 202a, b shown in FIG.
, c, and d, respectively.

104 is a program that executes the DTE function of the CCITT Recommendation Next, 105 is a program that executes the DCE function of the protocols of CCITT Recommendation X, 25, and executes the connection procedure as a DCE connected to the leased line. Further, 106 is a network control program within the private network, which executes a connection procedure as a node connected to the private network 301. 103 is CCITT Recommendation X, which is a network control protocol in a private network, a packet switching network, and a leased line connection protocol.

This is a protocol conversion program that performs mutual protocol conversion with the X.25 procedure. Further, 101 manages network configuration information possessed by the communication control and processing device 304, and this configuration information is stored in the protocol conversion program 103.
to the private network control program 106, which are referenced by the programs 103 to 106. 102
is a program scheduler that schedules and manages the execution of each program from the protocol conversion program 103 to the data link control program 107. Note that network configuration information 101, program scheduler 102, and each program and program 103 to 107
is installed in processor 201 shown in FIG.

FIG. 4 is a format diagram of call request/incoming call packets used on packet switching networks and leased lines;
The figure is a format diagram of a call request packet used within a private network.

Packets for packet switching networks and leased lines and packets for private networks have different header configurations.

In Figure 4, 402 to 405 are CCITT recommendations x
, 25 is the header of the call request/incoming call packet. That is, 402 is a general format identifier, 403 is a logical channel group number, 404 is a logical channel number, and 405 is a packet type identifier. 407 is the called DTE address of the packet switching network 302, 408 is the calling DTE address, and the bit length of these addresses is the same as the field before them, that is, the DTE address length 4.
It is set to 06. 411 is the address of the called terminal set in the facility section, and 412 is the address of the calling terminal also set in the facility section. 410 is
This field is used to set the optional user facilities specified in CCITT Recommendation X and the facilities provided by the private network. Facility is DT
A service function provided by the network in response to a request from E,
Facilities include those required by the DTE for call handling,
There are two types: one that is requested at the time of user registration; Also, 4
09 is the facility length.

In FIG. 5, 503 is set with the identifier of the call request packet, 504 is the address within the called network of the private network 301,
In 505, a calling network address is set, and within the private network, the network address length is a fixed length. 502 is a packet header length, and indicates the lengths of 503 to 505. 5o8 is the address of the called terminal set in the facility section, and 509 is the address of the calling terminal also set in the facility section. 507 includes CCITT
Recommendation Further, 506 is a facility length.

Next, the address processing and call setting procedure in the communication control processing device 304 for each call will be described in detail.

FIG. 6 is a processing flowchart when the communication control processing bag [(304) receives a call request from a packet terminal in the private network.

That is, when the communication control processing device 304 receives a call request from the packet terminal 306 in the private network, when communicating with the called To, C.C.
It shows the process up to selecting ITT Recommendation X, Recommendation Edge TE function, or DCE function.

First, when the communication control processing device 304 receives a call request from the packet terminal 306 in the private network, it sends the call from the called address 508 (see FIG. 5) in the call request to the called X, 25 packet terminal 307. Obtain information on the presence or absence of a leased line connection and a packet switching network connection (step 601), then perform branch processing according to the presence or absence of a leased line connection to the called X, 25 packet terminal 307 (step 602), That is, it is determined whether the called terminal is connected to the dedicated lines 303a, 303b, and if it is connected, the process goes to step 603, and if it is not connected, the process goes to step 6.
Proceed to 05. When connected, the dedicated line 303a
, b is in a usable state (step 603), and if it is available, the processing of the CCITT recommendation X and recommendation blade CE functions provided for leased line connection is executed (step 604). At this time, the dedicated line connection DCE program 105 shown in FIG. 1 is activated.

On the other hand, if the called packet terminals X and 25 are not connected to the dedicated lines 303a and 303b in step 602, and if the dedicated lines 303a and b cannot be used due to line failure or the like in step 603, the packet switching network 302 If it is connected to the packet switching network 302, it is determined whether the packet switching network 302 is available for use (step 606). At times, the processing of the CCITT Recommendation If connection cannot be established via the packet switching network 302 in steps 605 and 606, the calling terminal is notified of call disconnection and notification of call failure (step 608).

FIG. 7 is a processing flowchart after starting the dedicated line connection DCE program in FIG. 6.

That is, when the communication control processing device 304 receives a call request from the packet terminal 306 in the private network, it sends the call to the called X, 25 packet terminal 307b or
c (step 604 in FIG. 6).

First, D in X, 25 packets (401 shown in Figure 4)
Processing for setting the TE address (step 701,
702), that is, the called DTE address 407 in the X,25 packet is assigned the packet (
Set the called network address 504 of 501) shown in FIG. 505 (step 70
2).

Next, the incoming packet is transmitted to the called x, 25 packet terminal (step 7Q3). That is, as shown in FIG. 13, which will be described later, a calling packet CN for calling the called packet terminal is sent out (step 703). Next, within a certain period of time, called X.

By receiving an incoming call acceptance packet from the X.25 packet terminal, it is determined that the call can be set up (step 7o4). Next, it notifies the calling packet terminal 306 in the private network that the connection is complete and that data transfer is possible (
Step 7o5). On the other hand, if the call cannot be set up in step 704, it is determined that the other party's terminal is busy, and the call is disconnected to the calling packet terminal without determining whether connection via the packet switching network 302 is possible. Notify me 1
The failure of the call is notified (step 706).

Figure 8 shows the DTE for connection to the packet switching network in Figure 6.
It is a detailed flowchart of program startup. That is, the communication #control processing device 304 is connected to the packet terminal 3 in the private network.
When a call request is received from 06, the process of executing the DTE function when communicating with the called x and 25 packet terminals 307a and 307b via the packet switching network is shown (step 607 in FIG. 6). Steps 801 to 8o3 are.

X shown in FIG. 4 when placing a call to a packet-switched network.

This process sets the DTE address in the 25 packet 401. That is, from the called address 505 of the packet 501 used in the private network shown in FIG. 5 and the address table (not shown, hereinafter referred to as address table) stored in the network configuration information 101 shown in FIG. , connected to the packet switching network shown in Figure 4
, 25 obtains the DTE address 407 of the packet terminal (step 801). Here, x, 25 packet terminal 3
The terminal address 307a is set according to the address system of the packet switching network, and the terminal address 307b is set according to the address system of the private network.6 In other words, as shown in FIG.
2, a system including the toll number of this exchange network, such as (966) 9111, is set, and the terminal address 307b is accommodated in the private network 301 via the dedicated line 303a. Therefore, the DTE address 408 of the communication control processing device 304 connected to the packet switching network (see FIG. ) from the address table (Step 8o2),
Set the called DTE address 407 and the calling DTE address 408 in the x, 25 packet (step 803
). Next, a calling packet is sent to the packet-switched network (step 804), i.e., this is a calling packet CR sent to the packet-switched network 302, as described below in FIG. .

The communication control processing device 304 determines that call setup is possible by receiving a connection completion packet from the packet switching network within a certain period of time (step 805). Notifies the packet terminal 306 that the connection is complete and that data transfer is possible (
Step 806). On the other hand, if it is determined in step 805 that the call cannot be set up, the calling packet terminal is notified of the call disconnection and is informed of the call failure (step 807).

FIG. 9 is a processing flowchart for selecting the X,25 DTE function or the DCE function when the communication control processing device 304 receives a call setup packet from the X,25 packet terminal via a leased line or packet switching network. be.

First, processing is branched depending on the input line of the received packet (step 901). In other words, if the input line is a leased line, CCITT Recommendation
, executes the processing of the 25DCE function (step 902).
. In addition, if the input line is a packet switching network, CCITT Recommendation X, 25DT provided for connection to the packet switching network
Processing of the E function is executed (step 903).

The process after starting the DCE program for leased line connection shown in step 902 is detailed in FIG. 10, and the process after starting the DTE program for packet switching network connection shown in step 903 is explained in detail in FIG. do.

FIG. 10 is a processing flowchart for executing the DCE function when the communication control processing device 304 receives a call request from an X, 25 packet terminal via a dedicated line.

First, the calling D in the X, 25 packet 401 shown in FIG.
Check whether the TE address 408 is omitted (step 1001), and if it is not omitted,
, 25, the calling DTE address 408 in the packet 501 is used in the private network as the calling network address 505 in the packet 501.
(step 1002). On the other hand, step 10
01, if the calling DTE address is omitted, the network address 5 in the private network of the communication control processing device 304 is
Step 1008 to obtain 05 from the address table.
) is set in the calling network address 505 of the packet 501 used in the private network (step 1009). Also, X
, 25, check whether the called DTE address 409 in the packet 401 is omitted (step 1003).
, if not omitted, the called DTE address 407 in the X,25 packet is used in the packet 5 used in the private network.
01 in the called network address 504 (Step 1
0o4). Next, a call is made to the packet terminal 306 in the private network (step 1005). Next, by receiving a connection completion packet from the packet terminal 306 in the private network within a certain period of time, it is determined that the call setup is possible (step 100
6). If call setting is possible, calling X, 25 packet terminal 3
A connection completion packet is sent to 07b and 307c to inform that data transfer is possible (step 1007).
. Meanwhile, in step 1003, the called DTE address 40
If step 9 is omitted and the call cannot be set up in step 1006, a disconnection instruction packet is sent to the calling X, 25 packet terminal to notify the call disconnection and cancel the failure of the first call. Notify (step 1010).

Figure 11 shows the DT for connection to the packet switching network in Figure 9.
It is a detailed flowchart of the E program startup process.

That is, the communication control processing device 304 connects the X, 25 packet terminal 307a via the packet switching network.

This is a process of executing the DTE function when an incoming call is received from 307b (step 903 in FIG. 9).

Steps 1101 to 1103 are processing for setting an intra-network address in the packet 501 used in the private network. That is, in order to obtain the network address 504 of the packet terminal 306 in the private network from the called address 411 in the X, 25 packet 401 shown in FIG. The called network address 50 in the packet 501 used in the private network is obtained from the table (step 1102), respectively.
4. Set in calling network address 505 (step 11
03). Then, a call is made to the packet terminal 106 within the private network (step 1104).

Next, by receiving a connection completion packet from the packet terminal in the private network within a certain period of time, it is determined that the call can be set up (Step 1105), and since it is determined that the call can be set up,
An incoming call acceptance packet is transmitted to the packet switching network (step 1106). On the other hand, if the call cannot be set up in step 1105, a recovery request packet is sent to the packet switching network and the call is disconnected (step 1107).

FIG. 12 is a sequence chart showing the call setting procedure when using a packet switching network, and FIG. 13 is a sequence chart showing the call setting procedure when using a leased line. 13, the same reference numerals as corresponding parts in the system configuration shown in FIG. 3 are given. 1st
2 and 13, 1201a, 1201b
, 1201c is a call request packet (CR) that requests a call from a calling terminal to a switching network or a communication control processing device that accommodates a called terminal, and 1202 is a network or processing device that accommodates this for a called terminal. 1203 is an incoming call packet (CN) for notifying the other party of an incoming call from the other party, and 1203 is an incoming call acceptance packet (CN) for informing the other party that the called terminal has accepted the incoming call packet.
A), 1204a, 1204b, and 1204c are connection completion packets (CC
). Note that lowercase letters appended to the same numbers, such as a, b, and c, indicate packets of the same type between the packet terminal in the private network and the communication control processing device 305, between the communication control processing devices 305 and 304, Communication control processing device 304
- Represents the distinction of packets on each interface between packet-switched networks. In Figures 12 and 13, if the call acceptance packet (CA) is not returned, the network or processing device determines that the call cannot be set up, and the calling terminal is sent a connection completion packet (CC). Notify call disconnection instead.

In this way, in this embodiment, (a) both the inter-network connection device and the line terminating device (DCE) can be provided in the communication control processing device, thereby making it possible to reduce hardware costs. (b) X, 25 packet terminals can be connected to the same communication control processing device and packet switching network or dedicated line as a relay route without changing the specifications of the connection protocol control unit of the X, 25 packet terminals for connection to the packet switching network. It becomes possible to interconnect with (c) If there are two types of relay paths, a packet switching network and a dedicated line, between the X, 25 packet terminal and the communication control processing unit, even if a line failure occurs in one relay path, the It is possible to communicate using the relay route.

〔Effect of the invention〕

As explained above, according to the present invention, since the communication control processing device is equipped with the DCE function and the DTE function at the same time, the same communication control processing device can realize the inter-network connection device and the line termination device. As a result, it is possible to reduce hardware costs. In addition, the communication control processing device accommodates multiple relay paths at the same time, and all of these relay paths use the same protocol according to CCITT Recommendations Relay routes can be easily obtained.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of the software configuration of a communication control processing device showing one embodiment of the present invention, FIG. 2 is a block diagram of the hardware configuration of the communication control processing device showing one embodiment of the present invention, and FIG. 4 is a block diagram of a communication system to which the present invention can be applied, FIG. 4 is a diagram of a packet format used by a communication control processing device when setting up a call on a packet switching network and a leased line, and FIG. 5 is a diagram of a packet format used when setting up a call within a private network. The packet format diagrams, FIGS. 6, 7, and 8 are processing flowcharts when the communication control processing device makes a call to an X, 25 packet terminal, and FIGS. 9, 10, and 8 respectively. Figures 11 and 11 are processing flowcharts when the communication control processing device receives calls from X and 25 packet terminals, respectively;
FIG. 12 is a sequence chart of a call setting procedure when the communication control processing device uses a packet switching network as a relay path;
FIG. 13 is a sequence chart of a call setting procedure when a communication control processing device uses a dedicated line as a relay path, and FIG. 14 is a connection state diagram of a conventional inter-network connection device. 101: Network configuration information, 102 Niprogram scheduler, 103: Protocol conversion program, 10
4: DTE program for packet switching network connection, 105:
DCE program for dedicated line connection, 106: Private network network control program, 107: Data link control program, 201: Processor, 202: Line connection control unit, 203: Buffer, 301: Private network, 302: Packet switching network, 303 : Relay path, 304, 305: Communication control processing device, 306: Packet terminal accommodated in private network, 307: X, 25 packet terminal, 401: X, 25 packet, 501: Packet within private network, 1201: Call origination Request packet, 1202: Incoming call packet, 1203: Incoming call acceptance packet, 1204: Connection completion packet. Figure Figure Figure Figure Figure

Claims (1)

[Scope of Claims] 1. A communication control processing device that is connected to a public data switching network and a dedicated line and controls data transfer via the public data switching network and the dedicated line, provided corresponding to each line. , a plurality of line connection control means each containing a data link control program, a DTE (data terminal equipment) program for controlling the line connection control means and for connecting to the public data exchange network, and a data terminal equipment (DTE) program for connecting to the private line. A processing means incorporating a DCE (line terminating equipment) program for connection, a control program for controlling the network within the private network, and a conversion program for converting each protocol to another protocol; the processing means selects and executes the DTE program on the interface connected to the public data exchange network, and the processing means selects and executes the DTE program on the interface connected to the private line; Here, a communication control processing device is characterized in that it selects and executes the above DCE program. 2. When the processing means receives a call request from a terminal within the private network, when communicating with the called terminal via either the leased line or the public data exchange network, the processing means shall communicate with the called terminal via either the leased line or the public data exchange network. When it is possible to connect to both networks, the dedicated line is used preferentially to start the DCE program, and when the dedicated line is faulty or cannot be connected, the public data exchange network is used to start the DCE program.
When the program is started and a call setup packet is received via a leased line or public data switching network, if the input line is a leased line, the DCE program is started;
2. The communication control processing device according to claim 1, wherein a DTE program is activated when the input line is a public data exchange network.