Multiplex communications – Fault recovery
Reexamination Certificate
1998-06-04
2001-04-10
Kizou, Hassan (Department: 2662)
Multiplex communications
Fault recovery
C370S311000, C713S300000, C713S310000, C713S320000, C714S002000, C455S013400, C710S046000
Reexamination Certificate
active
06215764
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to computer network systems, and more particularly to a method and apparatus for detecting the link status of a network device in a computer network system.
BACKGROUND OF THE INVENTION
The past few years have been an exciting and challenging time of the information age and information channels will form the most important links in the most current message-based enterprises of the future. The computer network systems have become a major part of this evolution. The development of computer network systems goes further by providing message-based communication schemes.
Nowadays, as long as a computer system is powered on, users can use any function which was already installed in the computer system at any time. However, if a user has a time period without using the computer system, the system is still being with power on unless the system is powered off. This consumes system power and conflicts with environment protection. In order to save energy, it is therefore preferable that the computer system can automatically detect the current status of whole system utilization so that it can determine whether some of system components should be powered off. As a result, it greatly saves the electrical power. Moreover, if a new job to be performed is found, the system can be fully powered on automatically, and quickly enters its working state.
For a computer in a network system, if the network is disconnected, data can not be transferred through the network. Therefore, the network communication performance can be greatly improved if the data transfer of a computer is determined first by referring to the current link status of its network system.
Polling is one of conventional methods of communicating important timely message for a computer network system. Software polling is a traditional way to query the link status of a physical layer chip (PHY) for a network device. In the design of this approach, a management frame (as defined in the IEEE 802.3u standard) is transmitted to the MII (Media Independent Interface) management interface for asking a PHY the link status information. The software must fill the management frame by bit by bit. It is thus not efficient. Alternatively, automatically polling through the hardware can be an efficient way to accomplish the same functionality and reduce the loading of software.
Another traditional way to query the link status of a network device is to poll a status register inside the PHY when its polling function is enabled and the polling to the status register stops only when the polling function is disabled. The MII is thus occupied and not available to other jobs. As a result, it defers reading other registers.
From the foregoing discussions of prior arts, it can be seen that the disadvantages as pointed out earlier make the conventional approach inappropriate for a computer system to detect the status about its communications links. There exists a strong need for having a more efficient method and apparatus for a computer system to automatically detect the network link status (link on or link loss) about its communication links so that the computer system can operate in a proper mode accordingly and achieve the power saving features.
SUMMARY OF THE INVENTION
This invention has been made to overcome the above mentioned drawbacks and inefficiencies in a network system. The primary object of the present invention is to provide a new method and apparatus for automatically detecting the link status for a network device.
In accomplishing that object, it is another object of the invention to provide an automatic link status detection mechanism as characterized above to allow a computer system to operate intelligently in a proper mode. The possible operation modes include a normal operation mode if the link state is on, or a suspend mode if the link state is down. If a network on the system is disconnected and the system enters a suspend mode, the system can select the “wake up” conditions to resume itself from the suspend mode to a normal operation mode.
Another object of the invention is to provide a method to wake up a computer system. For a network, the current state is either in a “connect” or a “disconnect” state. Typically, when the current state for a network is in a “connect” state, receiving a special packet may wake up the computer system. While the original state for a network is in a “disconnect” state (or “link loss”), the resumed network connection may also wake up a computer system according to the present invention.
It is a further object of the present invention to provide a link status detection method in which “preamble” of the MII management frame is improved. In this MII management frame, it is to assure that an exact polling cycle is complete when a polling cycle is issued to a PHY.
Briefly, the invention discloses a method and apparatus for automatically detecting the link status of a network device to provide the most current information for saving energy and best utilization. Accordingly, the computer systems can adjust their operating conditions with a reliable low power. Additionally, it eliminates the inconvenience of having to power the system on and off frequently by a system user.
The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from a careful reading of a detailed description provided herein below, with appropriate reference to the accompanying drawings.
REFERENCES:
patent: 5504910 (1996-04-01), Wisor
patent: 6011799 (2000-01-01), Kerstein
patent: 6026494 (2000-02-01), Foster
patent: 6055641 (2000-04-01), Konaka
Chao Yen-Jiuan
Hsieh Hui-Chen
Wey Yih-Sheng
Kizou Hassan
Silicon Integrated Systems Corp.
Stevens Roberta
LandOfFree
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