NTP pool
Encyclopedia
The NTP pool is a dynamic collection of networked computer
s that volunteer to provide highly accurate time
via the Network Time Protocol
to clients worldwide. The machines that are "in the pool" are part of the pool.ntp.org domain
as well as of several subdomain
s divided by geographical zone
and are distributed to NTP clients via round robin DNS
. Work is being done to make the geographic zone selection unnecessary, via customized authoritative DNS servers that utilize geolocation software
.
As of June 2011, the pool consists of about 2180 active time servers. Because of the decentralization
of this project accurate statistics on the number of clients cannot be obtained, but according to the project's website the pool provides time to between five and 15 million systems. Because of client growth the project is in perpetual need of more servers.
There is always a desire for more time servers, as the more time servers are in the pool, the lower the resource demand on each member. Joining the pool requires at least a broadband
connection to the Internet, a static IP address
, and accurate time from another source (for example from another NTP server, from a DCF77
receiver, WWVB
receiver or a GPS receiver).
This project was started by Adrian von Bidder in January 2003 after a discussion on comp.protocols.time.ntp about abuse of the public stratum 1 servers. The system has been maintained and developed by Ask Bjørn Hansen
since July 2005.
Computer
A computer is a programmable machine designed to sequentially and automatically carry out a sequence of arithmetic or logical operations. The particular sequence of operations can be changed readily, allowing the computer to solve more than one kind of problem...
s that volunteer to provide highly accurate time
Time
Time is a part of the measuring system used to sequence events, to compare the durations of events and the intervals between them, and to quantify rates of change such as the motions of objects....
via the Network Time Protocol
Network Time Protocol
The Network Time Protocol is a protocol and software implementation for synchronizing the clocks of computer systems over packet-switched, variable-latency data networks. Originally designed by David L...
to clients worldwide. The machines that are "in the pool" are part of the pool.ntp.org domain
Domain name system
The Domain Name System is a hierarchical distributed naming system for computers, services, or any resource connected to the Internet or a private network. It associates various information with domain names assigned to each of the participating entities...
as well as of several subdomain
Subdomain
In the Domain Name System hierarchy, a subdomain is a domain that is part of a larger domain.- Overview :The Domain Name System has a tree structure or hierarchy, with each node on the tree being a domain name. A subdomain is a domain that is part of a larger domain, the only domain that is not...
s divided by geographical zone
Geographical zone
The five main latitude regions of the Earth's surface comprise geographical zones, divided by the major circles of latitude. The differences between them relate to climate, and the behaviour of the Sun...
and are distributed to NTP clients via round robin DNS
Round robin DNS
Round robin DNSis a technique of load distribution, load balancing, or fault-tolerance provisioning multiple, redundant Internet Protocol service hosts, e.g., Web servers, FTP servers, by managing the Domain Name System's responses to address requests from client computers according to an...
. Work is being done to make the geographic zone selection unnecessary, via customized authoritative DNS servers that utilize geolocation software
Geolocation software
In computing, geolocation software is used to deduce the geolocation of another party. For example, on the Internet, one geolocation approach is to identify the subject party's IP address, then determine what country , organization, or user the IP address has been assigned to, and finally,...
.
As of June 2011, the pool consists of about 2180 active time servers. Because of the decentralization
Decentralization
__FORCETOC__Decentralization or decentralisation is the process of dispersing decision-making governance closer to the people and/or citizens. It includes the dispersal of administration or governance in sectors or areas like engineering, management science, political science, political economy,...
of this project accurate statistics on the number of clients cannot be obtained, but according to the project's website the pool provides time to between five and 15 million systems. Because of client growth the project is in perpetual need of more servers.
There is always a desire for more time servers, as the more time servers are in the pool, the lower the resource demand on each member. Joining the pool requires at least a broadband
Broadband
The term broadband refers to a telecommunications signal or device of greater bandwidth, in some sense, than another standard or usual signal or device . Different criteria for "broad" have been applied in different contexts and at different times...
connection to the Internet, a static IP address
IP address
An Internet Protocol address is a numerical label assigned to each device participating in a computer network that uses the Internet Protocol for communication. An IP address serves two principal functions: host or network interface identification and location addressing...
, and accurate time from another source (for example from another NTP server, from a DCF77
DCF77
DCF77 is a longwave time signal and standard-frequency radio station. Its primary and backup transmitter are located in Mainflingen, about 25 km south-east of Frankfurt am Main, Germany. It is operated by Media Broadcast GmbH , on behalf of the Physikalisch-Technische Bundesanstalt, Germany's...
receiver, WWVB
WWVB
WWVB is a NIST time signal radio station near Fort Collins, Colorado, co-located with WWV. WWVB is the station that radio-controlled clocks in most of North America use to synchronize themselves. The signal transmitted from WWVB is a continuous 60 kHz carrier wave, derived from a set of atomic...
receiver or a GPS receiver).
This project was started by Adrian von Bidder in January 2003 after a discussion on comp.protocols.time.ntp about abuse of the public stratum 1 servers. The system has been maintained and developed by Ask Bjørn Hansen
Ask Bjørn Hansen
Ask Bjørn Hansen, aka Ask Bjoern Hansen, born June 9, 1977, is a programmer best known in the Perl community. He is known for maintaining , the NTP pool as well as developing Qpsmtpd. He is a member emeritus of the Apache Software Foundation....
since July 2005.