JPS6351619B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a packet terminal testing method, and particularly to a method in which an additional device is installed between the terminal and the circuit switching network to perform a protocol test on the packet terminal.

In a circuit-switched network, data is transferred by setting communication routes between ingress and egress lines using selection signals.
Immediate transmission and reception is possible with only a delay in propagation time.
In contrast, in a packet-switched network, a message is divided into packets (blocks), the destination and other control information necessary for forwarding the message are added to each block, and the message is forwarded block by block via a storage switch. The packet assembly time for each exchange cannot be ignored, and the transmission delay time varies greatly depending on the number of relay exchanges.

Conventional methods for testing the protocols (communication protocols) of packet terminals connected to such packet switching networks and used for high-level transmission control (HDLC) procedures include (1) installing a test device in the same location as the packet terminal; (2) Installing a testing device in a location different from the packet terminal, setting up a transmission line between the two, and conducting the test through that transmission line. There is a method.

Protocols are also hierarchical due to differences in their control functions, with electrical and physical level protocols determining values such as voltage and current at the lowest level, and then frame level, packet level, hostle level, etc. Furthermore, there are various protocols such as user level. Here, it is assumed that it is sufficient to be able to test protocols at the frame level or higher, rather than finely controlling voltage, current values, etc.

Among the conventional testing methods mentioned above, (1) the method of installing in the same location requires the packet terminal and the testing machine to be installed in close proximity, so it may be necessary to move one or both of them; If this is not possible, it becomes a constraint. In addition, in the (2) method of installing in different locations, for example, in tests before a packet terminal joins the packet network, or in tests to analyze the cause of a failure that occurs during operation after joining the network, Since it is impossible to distinguish whether the failure is a failure or a failure on the terminal side, it is necessary to set up a dedicated transmission line just for terminal testing.

Furthermore, as another test method, there is a method (3) in which the packet terminal is housed in the packet network and the test is performed by connecting the terminal and the test equipment via the packet network. Because of the intervention, in the same way as method (2) above,
Isolating the fault is difficult, requiring a lot of time to analyze the cause, or requiring a dedicated line to directly connect the terminal and test equipment.

The purpose of the present invention is to eliminate these conventional drawbacks by making it possible to perform the same tests as when using a dedicated line without using a dedicated line for terminals that are intended to be connected to a packet switching network. The object of the present invention is to provide a packet terminal testing method that can isolate protocol abnormalities when connected via a packet network.

In order to achieve the above object, the packet terminal testing method of the present invention is a method for testing the protocol of a terminal connected to a packet switching network, in which the terminal under test is connected to a testing machine via a circuit switching network, and An additional device is inserted between the above-mentioned terminal and the circuit-switched network, and between the above-mentioned test device and the circuit-switched network, and the additional devices (a) perform connection control procedures specified by the circuit-switched service interface. Set up a communication path between the above additional devices via a circuit switched network, (b)
Next, set up a communication path between the above terminal, the test machine, and each additional device to complete the communication path between the above terminal and the test machine, and (c) directly transmit the sending and receiving frames through the communication path. It is characterized by conducting protocol tests at or above level.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a connection diagram of a packet terminal testing system showing an embodiment of the present invention.

In FIG. 1, 1 is a packet terminal (terminal under test), 2 is a test machine, 31, 32 are additional devices, 41,
42 is a line termination device, 5 is a circuit switching network, and 6 is a communication path within the circuit switching network.

As mentioned above, if a test is performed by connecting the terminal 1 and the test device 2 via the packet network while the terminal under test 1 is accommodated in the packet network, the delay time of the transmission frame will be extremely large, and the timing conditions etc. Therefore, in the present invention, the packet terminal 1 is connected to a circuit switching network 5 with a small transmission delay time, and the protocol test is performed by connecting the packet terminal 1 to the test device 2 via the circuit switching network 5.

Normally, when connecting a terminal to the circuit switching network 5, the circuit termination devices 41, 4 equipped with a modem (modem)
However, in the present invention, as shown in FIG. 1, additional devices 31 and 32 are further installed between the line termination devices 41 and 42 and the terminal 1 or the test device 2.

When communicating between terminals connected via the circuit-switched network 5, first lift the handset and dial to call the other party, following the connection control procedure specified by the interface of the circuit-switched service. However, in the test method of the present invention, these operations are performed by the additional device 3.
Perform between 1 and 32.

The additional devices 31 and 32 have the following functions. That is, (a) in accordance with the connection control procedure specified by the circuit switching service interface;
(b) A function to set up and then release the communication path between the additional devices 31 and 32 via the circuit switching network 5; (b) a function to set up and then release the connection between the packet terminal 1 and the test device 2; , and (c) After the communication path between the packet terminal 1 and the test device 2 is set up, it is a function that allows transmitted and received frames to pass through.

FIG. 2 is a block diagram of the additional device shown in FIG. 1.

In FIG. 2, reference numeral 11 denotes a line connection control unit in the interface of the line switching service, for example, based on the synchronous X series interface;
12 is a transmitting circuit, 13 is a receiving circuit, and 14 is a terminal connection control unit between the packet terminal 1 or the test device 2 based on the connection line of the synchronous X series interface and its operation in the interface of the packet switching service. , T ₁ , T ₂ are CCITT
Transmitter specified in Recommendation X24, R ₁ and R ₂ are also receivers, C ₁ and C ₂ are also control lines, I ₁ and I ₂
similarly indicate the indication lines.

3 and 4 are diagrams showing each operation sequence of the line connection control section of the terminal side additional device and the line connection control section of the testing machine side additional device in FIG. 2,
FIG. 5 is an operational state transition diagram of the terminal connection control section of each additional device shown in FIG.

Taking as an example a case where a test is requested from the packet terminal 1 side, explanation will be given with reference to FIGS. 2 to 5.

(1) First, a communication path 6 is set up in the line switching network 5 between the line connection control unit 11 of the additional device 31 and the line connection control unit 11 of the additional device 32. The operation of the line connection control section 11 of the additional device 31 at this time is as follows:
As shown in T ₂ and C ₂ (signals flowing from the additional device 31 to the circuit switching network 5 on the transmission line T ₂ and control line C ₂ ) in FIG.
Turn T ₂ from “1” to “0” and C ₂ from off to on, and after the synchronization character “SYN”,
Sends a partner device selection signal and waits for connection. R ₂ , I ₂ (from the circuit switching network 5 to the additional device 31 in FIG. 3)
In the ready state, as shown in the signal flowing on the reception line R ₂ and the induction line I ₂
R ₂ is "1" and I ₂ is off, but by making a call request, the synchronization character "SYN" indicating that it is possible to send a selection signal to R ₂ is continuously received, and furthermore, when the connection is completed, I ₂ is turned off. It turns on from

On the other hand, the operation of the line connection control unit ₁₁ of the additional device _{32 on} the testing machine 2 side is as shown in FIG. As shown in Figure ₂ ), in the ready state, R ₂ is "1" and I ₂ is off, but due to an incoming call from the terminal side, the synchronization character "SYN" from the exchange is intercepted. A bell signal "BEL" is received by _R2 . As a result, T ₂ , C ₂ (transmission line T ₂ , control line C ₂
As shown in (the signal flowing above), confirm the reception of the incoming call by turning _C2 from off to on.
After that, the connection is completed when _I2 changes from off to on.

For more detailed operation, please refer to "Circuit Switched Service Interface" or CCITT Recommendation.
As stated in X.21.

Finally, communication path 6 is established between additional devices 31 and 32.
When the setting is completed and communication becomes possible, the additional devices 31 and 32 can determine that communication is now possible by monitoring the _I2 line. Additionally, the operator can be notified of the on state of the _I2 line by displaying a lamp.

(2) The additional devices are connected to each other, and the additional devices 31,
When the _I2 wire of 32 is turned on, the additional device 31,3
The _I1 line is turned on under the control of the terminal connection control section 14 in 2. This is the DCE ready state in Figure 5a.

The display method of the state transition diagram in Figure 5a is as shown in Figure 5b: the state name is in the upper half of the circle, the signal on _T1 is in the upper left of the lower half, and the signal on _R1 is in the lower left. , the signal on C ₁ is shown in the upper right, and the signal on I ₁ is shown in the lower right, respectively, in an on/off state (ON, OFF) and an unrelated state (-). DET on the arrow line
is the packet terminal 1 or the test device 2, and
DCE indicates additional devices 31 and 32, respectively;
This indicates that they are the cause of transition.

As mentioned above, I ₁ by DCE (additional equipment)
is turned on and the state changes from DCE Not Ready to Ready, packet terminal 1
And when testing machine 2 turns on the _C1 wire, the _C1 wire,
Since the C ₂ line, I ₁ line, and I ₂ line are all turned on, the transmitting circuit 12 and receiving circuit 13 of the additional devices 31 and 32 are turned on. As a result, the transmitting circuit 12 sends information to the circuit switching network 5 side.
The receiving circuit 13 shifts to a state in which information from the line switching network 5 is passed through. In FIG. 5a, the state has shifted from the DCE ready state to the communicable state.

(3) Next, as a through line is set up between the packet terminal 1 and the test device 2 via the circuit switching network 5 in accordance with (1) and (2) above, the connection between the packet terminal 1 and the test device 2 is Any information can be sent and received, and the protocol of the packet terminal 1 can be tested. Fifth
In Figure a, the state has shifted from the communicable state to the data transfer state, and data (D) is transferred onto T ₁ and R ₁ .

(4) When the test is finished and it is necessary to disconnect the line, the packet terminal 1 or test device 2
Turn off the _C1 line and move from the data transfer state shown in Figure 5a to the DCE ready state. additional device 31,
The terminal connection control unit 14 of 32 monitors _C1 and notifies the operator if it turns off. The operator activates the line connection control section 11 to disconnect the communication path, complete the test, and return from the DCE ready state to the DCE not ready state.

In addition, in the data transfer state of FIG. 5a,
When the additional devices 31 and 32 turn off _I1 , the DCE not ready state is entered.

In this embodiment, it is assumed that the line connection control units 11 of the additional devices 31 and 32 operate based on the synchronous X series interface among the line switching service interfaces, and the terminal connection control unit 14 operates based on the packet switching service interface. Although the operation is based on the connection line and operation of the synchronous X series interface in the service interface, other interfaces and terminals for connecting the line connection control unit 11 with the line switching network 5 are used. By using the connection control unit as a connection interface with the line termination device 41 included in the terminal 1 connected to the additional device, protocol tests of various terminals can be performed.

In addition, when accommodating a packet network from the beginning, for example, in screening when a terminal joins,
If a protocol error occurs in the terminal, it may have an adverse effect on the packet network, but in the present invention, the protocol test of the terminal is first performed via the circuit switched network, and after confirming that there is no error, the packet network is The above concerns are completely eliminated. Furthermore, when testing the protocol of a terminal via a circuit-switched network, the test can be performed in exactly the same way as using a leased line, allowing the use of remote test equipment and the ability to test terminals accommodated in a packet network. It is economical because there is no need to set up a dedicated line for testing between test machines.

As explained above, according to the present invention, by installing an additional device between the terminal and the line-switched network, when a leased line is used for a terminal that is intended to be accommodated in a packet-switched network, It is possible to perform the exact same protocol test as before, and then connect via a packet network to easily isolate protocol abnormalities.

[Brief explanation of drawings]

Figure 1 is a connection diagram of a packet terminal testing system showing an embodiment of the present invention, Figure 2 is a configuration diagram of the additional equipment in Figure 1, and Figures 3 and 4 are the terminal side additional equipment in Figure 2. and the operation sequence chart of the line connection control section in the additional equipment on the testing machine side.
FIG. 3 is an operation state transition diagram of a terminal connection control unit in each additional device shown in the figure. 1: Packet terminal, 2: Test machine, 31, 32:
Additional device, 41, 42: Line termination device, 5: Circuit switching network, 6: Communication path of circuit switching network, 11: Line connection control unit, 12: Transmission circuit, 13: Receiving circuit, 1
4: Terminal connection control section, T ₁ , T ₂ : Transmission line, R ₁ ,
R ₂ : Reception line, C ₁ , C ₂ : Control line, I ₁ , I ₂ :
Induction line.

Claims (1)

[Claims] 1 In a method of testing the protocol of a terminal connected to a packet-switched network, the terminal is connected to a test equipment via a circuit-switched network, and additional equipment is installed between the terminal and the test equipment and the circuit-switched network. (a) Set up a communication path between the additional devices via the circuit switching network in accordance with the connection control procedure specified by the interface of the circuit switching service, and (b) (c) Set up a communication path between the above terminal, the test machine, and each additional device to complete the communication path between the above terminal and the test machine, and (c) directly transmit the sending and receiving frames through the communication path to transmit the frames.
A packet terminal test method that is characterized by performing protocol tests at or above level.