Remote Wake up Basics for Intel® Ethernet Products
What is 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 to a complex system able to interact with many devices and operating system (OS) power states.
Early implementations required the system to have a standby power supply. The system could start from a powered off state by sending a Magic Packet*. By toggling a signal connected to the computer power control circuitry, the adapter responds to a Magic Packet that has its own MAC address. The power control circuitry, in response, activates power resulting in the computer starting 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 didn't 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 stops, but RAM powers on and refreshes.
- S3 - Suspend to RAM (standby mode). Most components shut down except RAM.
- S4 - Suspend to disk (hibernate mode). The memory contents swap to the disk drive, and then reload into RAM when the system wakes.
- S5 - Power off.
ACPI-aware operating systems support remote wake-up from standby or hibernate mode.
Network management programs typically send wake-up packets, though you can use simple programs for this purpose (available on the Internet at no charge).
BIOS settings
You 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.
- Are titled Wake on LAN or Wake on PME.
- Systems using an ACPI-aware OS (such as Windows* XP) can power up the system from a power off state. You can power up the system by enabling ACPI-specific settings such as Wake-on-LAN from S5.
- You can configure many ACPI computers to work in APM mode. Check your BIOS settings to verify your operating mode.
Multiport Ethernet adapters
Wake-on-LAN is supported on port A only on most multiport 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 isn't supported on Intel® Ethernet 10-gigabit adapters.
Operating system settings
The Magic Packet format isn't the only packet type that can initiate the remote wake feature. For other packet types, see operating system settings below.
| Note | For the most up-to-date settings information, refer to the Ethernet User Guide. |
ACPI-capable Windows* products
Recent Windows versions are ACPI capable. In some ACPI-capable computers, the BIOS has a setting that allows you to wake from an S5 state. However, most of these operating systems only support remote wake from standby.
| Enable wake from shutdown by Magic Packet |
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| Enable wake from standby |
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| Note | The Legacy OS Wakeup Support parameter wasn't available in early versions of the Intel Boot Agent. To update your Intel Boot Agent to the latest version, download PREBOOT.EXE and follow the included instructions. If you need more information on how to enable Wake-on-LAN, go to the Upgrade, Enable, or Disable Flash with the Intel® Ethernet Flash Firmware Utility page. |