摘要 |
A reliable and simple means to awaken sleeping computers is to maintain the network interface subsystem at full power, and to filter detected packets so that when desired packets are detected, full power is restored to the entire computer. An interface to connect a computer to a network is provided, where, the computer has a high power state and a low power state, and the computer is capable of normal operation when in the high power state, and the computer is substantially inactivated when in the low power state. A packet is received from the network. The packet is filtered by computing a hash function using at least one byte selected from the packet. A transition is initiated, responsive to a result of filtering the packet, to transition the computer from the low power state to the high power state. A mask may be used to select the at least one byte. Several bytes may be selected by the mask. A first register may be used to hold the mask. A second register may be used to hold a desired result of the hash function calculation. A result of the hash function calculation is compared with a contents of the second register to determine whether or not the result of the hash function calculation matches the contents of the second register. A perfect filtering or a second hash function filtering may be combined by AND or NOT logical operations, in making the decision whether or not to awaken the computer.
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