Sleep Proxy Service
Encyclopedia
Apple's Bonjour Sleep Proxy service is an open source
component of zero configuration networking, designed to assist in reducing power consumption
of networked
electronic devices. A device acting as a sleep proxy server will respond to Multicast DNS queries for another, compatible device which has gone into low power mode
. The low-power-mode device remains asleep while the Sleep Proxy Server responds to any Multicast DNS queries.
When the sleep proxy server sees a query which requires the low-power-mode device to wake up, the Sleep Proxy Server sends a special wake-up-packet ("magic packet") to the low-power-mode device. Finally, communication parameters are updated via Multicast DNS and normal communications proceed.
Apple Inc. describes the service as Bonjour Sleep Proxy in their support documents. The service supports the Wake on Demand feature, first offered in Mac OS X Snow Leopard.
requests on behalf of the low-power-mode device:
"When a Sleep Proxy sees an IPv4 ARP or IPv6 ND Request for one of the sleeping device's addresses, it answers on behalf of the sleeping device, without waking it up, giving its own MAC address as the current (temporary) owner of that address."
This may appear confusing to network administrator
s who are not expecting the behaviour of changing MAC addresses.
, the wake-up-packet is sent via Wireless Multimedia Extensions
(WMM).. This was not possible in previous implementations of Wake on LAN (WoL). The wireless hardware must be updated enough to include WMM support.. Apple provides instructions for checking compatibility with this feature for Macintosh computers.
-supported services, while the host computer sleeps. Some examples of supported services are:
has a page describing steps for troubleshooting Sleep Proxy Service.
can be seen with Bonjour Browser.
Open source
The term open source describes practices in production and development that promote access to the end product's source materials. Some consider open source a philosophy, others consider it a pragmatic methodology...
component of zero configuration networking, designed to assist in reducing power consumption
Power management
Power management is a feature of some electrical appliances, especially copiers, computers and computer peripherals such as monitors and printers, that turns off the power or switches the system to a low-power state when inactive. In computing this is known as PC power management and is built...
of networked
Computer network
A computer network, often simply referred to as a network, is a collection of hardware components and computers interconnected by communication channels that allow sharing of resources and information....
electronic devices. A device acting as a sleep proxy server will respond to Multicast DNS queries for another, compatible device which has gone into low power mode
Sleep mode
Sleep mode refers to a low power mode for electronic devices such as computers, televisions, and remote controlled devices. These modes save significant electrical consumption compared to leaving a device fully on and idle, but allow the user to avoid having to reset programming codes or wait for a...
. The low-power-mode device remains asleep while the Sleep Proxy Server responds to any Multicast DNS queries.
When the sleep proxy server sees a query which requires the low-power-mode device to wake up, the Sleep Proxy Server sends a special wake-up-packet ("magic packet") to the low-power-mode device. Finally, communication parameters are updated via Multicast DNS and normal communications proceed.
Apple Inc. describes the service as Bonjour Sleep Proxy in their support documents. The service supports the Wake on Demand feature, first offered in Mac OS X Snow Leopard.
Address resolution protocol
The sleep proxy service responds to address resolution protocolAddress Resolution Protocol
Address Resolution Protocol is a telecommunications protocol used for resolution of network layer addresses into link layer addresses, a critical function in multiple-access networks. ARP was defined by RFC 826 in 1982. It is Internet Standard STD 37...
requests on behalf of the low-power-mode device:
"When a Sleep Proxy sees an IPv4 ARP or IPv6 ND Request for one of the sleeping device's addresses, it answers on behalf of the sleeping device, without waking it up, giving its own MAC address as the current (temporary) owner of that address."
This may appear confusing to network administrator
Network administrator
A network administrator, network analyst or network engineer is a person responsible for the maintenance of computer hardware and software that comprises a computer network...
s who are not expecting the behaviour of changing MAC addresses.
Wireless magic packet
In case the low-power-mode device is communicating via Wi-FiWi-Fi
Wi-Fi or Wifi, is a mechanism for wirelessly connecting electronic devices. A device enabled with Wi-Fi, such as a personal computer, video game console, smartphone, or digital audio player, can connect to the Internet via a wireless network access point. An access point has a range of about 20...
, the wake-up-packet is sent via Wireless Multimedia Extensions
Wireless Multimedia Extensions
Wireless Multimedia Extensions , also known as Wi-Fi Multimedia , is a Wi-Fi Alliance interoperability certification, based on the IEEE 802.11e standard. It provides basic Quality of service features to IEEE 802.11 networks. WMM prioritizes traffic according to four Access Categories - voice,...
(WMM).. This was not possible in previous implementations of Wake on LAN (WoL). The wireless hardware must be updated enough to include WMM support.. Apple provides instructions for checking compatibility with this feature for Macintosh computers.
Supported services and examples
The sleep proxy service is able to advertise any BonjourBonjour (software)
In computing, Bonjour is Apple Inc.'s trade name for its implementation of Zeroconf, a group of technologies that includes service discovery, address assignment, and name resolution...
-supported services, while the host computer sleeps. Some examples of supported services are:
- File sharingFile sharingFile sharing is the practice of distributing or providing access to digitally stored information, such as computer programs, multimedia , documents, or electronic books. It may be implemented through a variety of ways...
: a host supporting the sleep proxy service, which offers file services, may go to sleep as needed. When someone needs to access shared files, the host will wake up automatically. - iTunes library sharingDigital Audio Access ProtocolThe Digital Audio Access Protocol is the proprietary protocol introduced by Apple in its iTunes software to share media across a local network....
: the computer hosting the iTunesITunesiTunes is a media player computer program, used for playing, downloading, and organizing digital music and video files on desktop computers. It can also manage contents on iPod, iPhone, iPod Touch and iPad....
library may go to sleep, and will automatically wake when someone wishes to browse the iTunes library from a different PC. - Printer sharing: a printer may be connected and shared from a computer supporting sleep proxy service. The computer can go to sleep when not in use, but will wake when needed to service a print job being sent from a different computer.
- SSHSecure ShellSecure Shell is a network protocol for secure data communication, remote shell services or command execution and other secure network services between two networked computers that it connects via a secure channel over an insecure network: a server and a client...
: a computer offering SSH access may go to sleep, and awaken via the sleep proxy service when an SSH login is initiated. On DarwinDarwin (operating system)Darwin is an open source POSIX-compliant computer operating system released by Apple Inc. in 2000. It is composed of code developed by Apple, as well as code derived from NeXTSTEP, BSD, and other free software projects....
or MacintoshMacintoshThe Macintosh , or Mac, is a series of several lines of personal computers designed, developed, and marketed by Apple Inc. The first Macintosh was introduced by Apple's then-chairman Steve Jobs on January 24, 1984; it was the first commercially successful personal computer to feature a mouse and a...
computers, the host can be put back to sleep using the command line instruction: pmsetPmsetIn computing, pmset is a command line utility to manipulate power management settings under the Darwin and Mac OS X operating systems. It can assign sleep settings, schedule sleep and wake times, and display power information.- History :...
sleepnow. - Desktop sharingDesktop sharingDesktop sharing is a common name for technologies and products that allow remote access and remote collaboration on a person's computer desktop through a graphical Terminal emulator.The most common two scenarios for desktop sharing are:* Remote log-in...
: similar to above examples.
Troubleshooting
Stuart CheshireStuart Cheshire
Stuart Cheshire is the author of Bolo, a networked tank game, originally written for the BBC Micro and later ported to the Apple Macintosh....
has a page describing steps for troubleshooting Sleep Proxy Service.
Implementations
Implementations on a local area networkLocal area network
A local area network is a computer network that interconnects computers in a limited area such as a home, school, computer laboratory, or office building...
can be seen with Bonjour Browser.
- Apple AirPortAirPortAirPort and AirPort Extreme are local area wireless networking products from Apple Inc. based on the IEEE 802.11 standard ....
Express with firmware version 7.4.1 or 7.4.2 - Apple AirPortAirPortAirPort and AirPort Extreme are local area wireless networking products from Apple Inc. based on the IEEE 802.11 standard ....
Extreme with firmware version 7.4.1 or 7.4.2 - Legacy AppleTVs (confirmed for version 3.0.2)
- Second Generation AppleTVs (confirmed for version iOS 4.3)
- Apple Time CapsuleTime Capsule (Apple)The Time Capsule is a wireless network-attached storage device combined with a wireless residential gateway router made by Apple Inc. It is described as a "Backup Appliance", designed to work in tandem with the Time Machine backup utility, introduced in Mac OS X 10.5 "Leopard".The device includes a...
- Computers running Mac OS X Snow Leopard act as a Bonjour sleep proxy server when Internet sharing is enabled.
External links
, see Mosaics tab for figures, see Mosaics tab for figures, see Mosaics tab for figures- Fscklog.com: Snow Leopard und 2009er Macs: Wake on WLAN (German, Deutsch)
- Macrumors.com: A Closer Look at Snow Leopard's Wake on Demand Feature
- opensource.apple.com: Open-source mDNS implementation including the sleep proxy service
- UC San Diego: SleepServer: A Software-Only Approach for Reducing the Energy Consumption of PCs within Enterprise Environments 22 June 2010. UsenixUSENIX-External links:* *...
2010. - Microsoft Research: Sleepless In Seattle No Longer 22 June 2010. UsenixUSENIX-External links:* *...
2010.