1. Field of the Invention
The present invention relates to a system for obtaining communication statuses of calls passing through communication devices on a data communication network employing a logical multiplexing method in real time per a communication device.
2. Description of the Related Art
Needs for data communication network, as well as Internet, have a yearly increased. There is no particular prescription of a transmission path for a data communication network, and thus the network can be formed not only for wired communication, but for wireless or mobile communication.
In this condition, there is a great demand for easily analyzing faults and obtaining a communication status or a traffic of user data in a data communication device employing a logical multiplexing method structured with Local Area Network (LAN)--Wide Area Network (WAN)--LAN.
In here, a logical multiplexing method is defined as a method for multi-specifying a plurality of addresses by writing a destination address on a predetermined format and transmitting it via a transmission path.
A person who constructs and operates a network requires means for knowing not only physical condition of transmission lines but communication statuses of end users.
The person who operates a network further requires to continuously know whether or not data transmission between end users is performed as usual, as possible without deteriorating its communication performance for communication paths.
In a connection oriented communication on a data communication network employing a logical multiplexing method, it is possible to obtain only about call establishment status in a communication device. However, it is not possible to obtain the call communication status whether or not user data transmission is actually facilitated in an upper layer in real time.
Therefore, it has be performed to obtain the communication status by collecting and analyzing communication data with the use of a line tracing function, which may accumulate the communication data in the communication device.
In a connection-less communication, there is no means for obtaining a status of the communication path itself in a communication device, and therefore there is no way to know whether or not real data transmission is performed in normal. To cope with the above-described problem, the communication status as a counter measure for faults has been obtained by the function of collecting and analyzing the communication data of a device for analyzing data, such as an analyzer, connected to the network.
However, the conventional function for obtaining the data communication status has been used with the following limited condition or range.
In the line tracing function, the data communication status is obtained by recording all user frames per a line and querying information of the recorded frames to analyze. It is required for building this function in a communication device to have bulk memory capacity to record all frames and write data in the storage at a high speed.
It has been also required that a technical engineer who has a best knowledge of each data communication protocol and a frame structure should analyze data outputted by querying the communication data sequence.
It is not preferable to use this analyzing function because its cost is too expensive. Further it is not simple to connect this analyzer to other devices in the network. Additionally, all passing frames are indicated in detail and information analysis becomes difficult. That causes a requirement of an advanced analysis skill.
As described above, when employing the conventional means, such as the line tracing function as a means for obtaining communication status on a data communication network of a logic multiplexing type, it is required to have much memory capacity in a communication device. Because of that, it causes a problem not to immediately analyze the information.
When an analyzer is employed to cut and divide the communication for analyzing the faults, it takes too long time to cut communications for the faults. There is another problem that the analyzer is too expensive, and therefore, it costs too much to connect the analyzer to the network.