Understanding remote wake-up
The ability to remotely wake computers is an important development in computer management. The feature has evolved from a simple remote power-on capability to a complex system able to interact with many devices and OS power states.
Early implementations required the system to have a standby power supply. The system could be started from a power off state by sending a "Magic Packet*." The adapter responds to a "Magic Packet" that has its own MAC address by toggling a signal connected to the computer power control circuitry. The power control circuitry, in response, activates power resulting in the computer booting the OS.
The ability to power on the computer allowed network administrators to complete off-hours maintenance at remote locations without sending a technician. This early implementation did not require an OS that was aware of remote wake-up.
APM provided BIOS-based power control. Newer computers feature Advanced Configuration and Power Interface (ACPI), which extends the APM concept to allow the OS to selectively control power by individual components.
ACPI supports many power states. Each state represents a different level of power, from fully powered up to completely powered down, with partial levels of power in each intermediate state. Here is a summary of the power states:
- S0 - On and fully operational.
- S1 - System is in low power mode (sleep mode). The CPU clock is stopped, but RAM is powered on and being refreshed.
- S3 - Suspend to RAM (standby mode). Most components are shutdown except RAM.
- S4 - Suspend to disk (hibernate mode). The memory contents are swapped to the disk drive, and then reloaded into RAM when the system is awakened.
- S5 - Power off.
ACPI aware operating systems, such as Microsoft Windows 98*, Windows Me*, Windows 2000*, Windows XP*, and Windows Vista*, support remote wake-up from standby or hibernate mode.
Wake-up packets are typically sent by network management programs, though simple programs can be used for this purpose (available on the Internet at no charge).
You will need to configure specific BIOS settings to enable remote wake-up on your system.
- In both APM and ACPI computers, settings for Wake on LAN (WOL), generally display under the Power Control area, and are titled "Wake on LAN" and/or "Wake on PME." To allow remote wake-up, enable the setting that corresponds to your adapter connection.
- Systems using an ACPI aware OS (such as Windows* XP), can power up the system from a power off state, by enabling ACPI specific settings such as "Wake on LAN from S5."
- Many ACPI computers can be configured to work in APM mode. Check your BIOS settings to verify your operating mode.
Multi-port Ethernet adapters
Wake on LAN is supported on port A only on most multi-port adapters. See the software release notes (readme.txt) for a list of adapters that support Wake on LAN on port A only.
10-Gigabit Ethernet adapters
Wake on LAN is not supported on Intel® Ethernet 10-gigabit adapters.
Operating system settings
The Magic Packet format is not the only packet type that can initiate the remote wake feature. For other packet types, see operating system settings below.
Non ACPI-capable Microsoft Windows* products
Microsoft Windows NT* and Windows 95* are not ACPI-capable. Some settings are not available in these operating systems. See the "Other operating systems" section below.
ACPI-capable Microsoft Windows* products
Microsoft Windows 98, Windows Me, Windows 2000, Windows XP, Windows Vista, and later versions of Windows are ACPI-capable. In some ACPI-capable computers, the BIOS has a setting that allows you to wake from an S5 state, but the majority of these operating systems only support remote wake from standby.
Other operating systems
In operating systems that do not support remote wake-up technology, you can still use the "Magic Packet" method of remotely powering up a computer.
- Power on the computer
- Invoke the Intel® Boot Agent configuration utility by entering CTRL-S when the Boot Agent prompt displays on the screen.
- Enable the Legacy OS Wakeup Support. The adapter can then respond to a Magic Packet wake up event.