Error detection/correction and fault detection/recovery – Pulse or data error handling – Transmission facility testing
Reexamination Certificate
2000-07-18
2004-06-15
Tu, Christine T. (Department: 2133)
Error detection/correction and fault detection/recovery
Pulse or data error handling
Transmission facility testing
C714S004110, C370S249000
Reexamination Certificate
active
06751761
ABSTRACT:
TECHNICAL FIELD
The present invention generally relates to network test methods, network testing apparatuses, and recording media, and, more particularly, to a network test method, a network testing apparatus, and a recording medium, by which a test can be carried out in a system having a plurality of nodes (network connecting devices such as personal computers and workstations) connected to a computer network such as a LAN (Local Area Network) or WAN (Wide Area Network).
BACKGROUND ART
The following is a description of examples of the prior art.
FIG. 1
shows the structure of a system, and
FIG. 2
shows the 7-layer model for OSI.
Conventionally, systems having a plurality of nodes (network connecting devices for personal computers, workstations, and the like) connected to a computer network have been well known.
A LAN is applied to the system shown in FIG.
1
. In this system, a router
2
is connected to a main line LAN
1
, and a hub
3
-
1
is connected to the router
2
. A branch line LAN
4
is connected to the hub
3
-
1
, and another hub
3
-
2
is connected to the branch line LAN
4
.
A large number of nodes
5
-
1
,
5
-
2
,
5
-
3
, . . . are connected to the hub
3
-
1
. Though not shown, a large number of nodes are also connected to the hub
3
-
2
connected to the branch line LAN
4
. In this system, the nodes are used for communication through the LAN lines.
Each of the nodes has the functions of the OSI (Open Systems Interconnection) reference model. The OSI reference model is the standard model of network protocols concerning open systems interconnection.
The functions of the OSI reference model can be represented by the 7-layer model L
0
for OSI shown in FIG.
2
. The 7-layer model L
0
for OSI comprises an application layer L
1
, a presentation layer L
2
, a session layer L
3
, a transport layer L
4
, a network layer L
5
, a datalink layer L
6
, and a physical layer L
7
.
The application layer L
1
is a layer for performing necessary communication in an operation by a user through application. The presentation layer L
2
is a layer for conversion into data format presentable for the application layer L
1
. The session layer L
3
is a layer for providing a function of orderly application interaction.
The transport layer L
4
is a layer for establishing and releasing transport connection, multiplexing data, performing flow control and retransmission control, and the like. The network layer L
5
has functions of performing path control, establishing and releasing network connection, multiplexing data, performing flow control, and dividing and combining packets. The datalink layer L
6
detects an error in a bit string and restores the bit string to ensure accurate data transfer. The physical layer L
7
controls an electric and mechanical interface so as to carry out bit serial transmission or parallel transmission on a physical medium such as a communication line.
In
FIG. 2
, “LLC” stands for logical link control, “MAC” stands for media access control, and “MAU” stands for media attachment unit.
Conventionally, to test a LAN circuit in a system (a computer network), the network connecting devices (the nodes) transmit and receive data so as to check their normality.
Also, the test targets the nodes themselves, and a test is not converted on the entire network including the network transmission paths.
Accordingly, with the conventional test method, there have been the following problems.
(1) As described above, in a conventional computer network test, each network connecting device (such as a node) serves as a testing device to transmit and receive data, thereby confirming normality of the network. Accordingly, only the connecting devices are tested, and a total network test on the entire network including the transmission paths is not properly carried out.
(2) As the LANs are widely used, there are many different types of networks to be tested. To test these networks and ensure normality, a conventional connector loopback test, such as a physical-layer loopback or node loopback, is not adequate.
(3) In the conventional computer network test, the test itself is carried out through a program. However, the layer structure of the network is not taken into account in the conventional test. For instance, when normality is confirmed on the physical layer, the network control program is not activated, or which layer a communication error between applications comes from cannot be detected. To solve this problem, it is necessary to change the fundamentals of the network test.
Therefore, the objects of the present invention are to solve the above problems in the prior art, and to enable a computer to perform a test on each layer in a network by a special-purpose testing device, so that the connection of the network and nodes are entirely secured.
DISCLOSURE THE INVENTION
To achieve the above objects of the present invention, the present invention provides a method of testing a network for normality with a testing device in which a testing program is installed. This testing program includes two independent programs, a transmission program and a reception program, and a loopback test is performed between the transmission program and the reception program, thereby confirming normality of the network.
In the above method, the transmission program and the reception program each have a testing interface in each of a logical link control layer, a network layer, a transport layer, and an application layer, and transmission and reception of test data during the loopback test are performed through the testing interfaces.
The transmission program transmits test data from the application layer, the transport layer, and the network layer, while the reception program receives the test data on the application layer, the transport layer, and the network layer, thereby determining normality of the application layer, the transport layer, and the network layer of the network.
In accordance with the present invention, when testing a network for normality by a testing device in which a testing program is installed, a loopback test is performed between a transmission program and a reception program, which are independent of each other. Based on the result of the loopback test, normality of the network is determined.
In this manner, a test on each layer of the network can be performed by the special-purpose device. Thus, stable connection between the network and nodes can be ensured.
In accordance with the present invention, the transmission program and the reception program transmit and receive test data through the respective interfaces of the logical link control layer, the network layer, the transport layer, and the application layer.
In this manner, a test can be performed on each layer of the network by the special-purpose device, and connection between the network and nodes can be ensured. Also, the cause of a network error and which layer the network error comes from can be detected. Thus, a setting error that cannot be detected in each layer through a conventional program can be easily solved.
REFERENCES:
patent: 5511163 (1996-04-01), Lerche et al.
patent: 5778189 (1998-07-01), Kimura et al.
patent: 5838518 (1998-11-01), Frater
patent: 5862362 (1999-01-01), Somasegar et al.
patent: 5951645 (1999-09-01), Goto
patent: 63-301648 (1988-12-01), None
patent: 4-56445 (1992-02-01), None
patent: 6-96040 (1994-04-01), None
patent: 9-265462 (1997-10-01), None
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