LINUX MAGAZINES » Richard N Williams

Networking Secrets – Synchronization

Richard N Williams — Mon, 05 Jul 2010 08:09:10 +0000

An efficient and error free operation is the goal of any administrator that is setting up a computer network. Ensuring the smooth running and passing of data without errors or loss of connections is a prerequisite for any decent functioning network system.

There are some fundamental things that can be carried out to minimise risk of encountering problems further down the line. A decent network server is a must, as is an efficient router but there is one piece of technology often overlooked in computer networking – the network time server.

The importance of correct computer network time only becomes apparent when something goes wrong. When an error does occur (and without adequate time synchronization it is a matter of when not if) it can be next to impossible to pin down what caused in and where. Just imagine all the error logs on the different machines all with timestamps telling a different time, finding out where and when the error occurred can be near impossible – and that’s before you can even get round to fixing it.

Fortunately most network administrators appreciate the value of synchronization and most ensure the network receives a time signal from across the Internet. However, many administrators are unaware of the vulnerabilities this may cause throughout the network.

By using an online time server, a UDP port (123) needs be kept open which can be an open gate to malicious programs and users. Furthermore, there is no authentication of the online time server so the signal could be hijacked or just be inaccurate.

A dedicated network time server running the protocol NTP (Network Time Protocol) will operate externally to the network and receive the time from an atomic clock source directly (through radio or GPS) making NTP servers, secure, accurate and reliable.

Richard N Williams is a technical author and specialist in atomic clocks, telecommunications, NTP and network time synchronisation helping to develop dedicated NTP clocks. Please visit us for more information about an NTP server or other NTP time server solutions.

Author: Richard N Williams
Article Source: EzineArticles.com
Latest trends in mobile phone

The World in Synchronisation

Richard N Williams — Fri, 02 Jul 2010 00:31:03 +0000

Time synchronisation plays an ever more important role in the modern world with more and more technologies reliant on accurate and reliable time.

Time synchronisation is not just important but can also be crucial in the safe running of systems such as air traffic control that simply couldn’t function without accurate synchronisation. Think of the catastrophes that could happen in the air of aircraft were out of synchronisation with each other?

In global commerce too accurate and reliable time synchronisation is highly important. When the world’s stock markets open in the morning and traders from across the world buy stock on their computers. As stock fluctuates second by second if machines are out of synchronisation it could cost millions.

But synchronisation is also imperative in modern computer networking; it keeps systems secure and enables proper control and debugging of systems. Even if a computer network is not involved in any time sensitive transactions a lack of synchronisation can leave it vulnerable to malicious attacks and can also be susceptible to data loss.

Accurate synchronisation is possible in computer networking thanks to two developments: UTC and NTP.

UTC is a timescale -coordinated universal time, it is based on GMT but is controlled by an array of atomic clocks making it accurate to within a few nanoseconds.

NTP is a software protocol – Network Time Protocol, designed to accurately synchronise computer networks to a single time source. Both of these implementations come together in a single device which is relied upon the world over to synchronise computer networks – the NTP server.

An NTP time server or network time server is a device that receives the time from an atomic clock, UTC source and distributes it across a network. Because the time source is continually checked by the time server and is from an atomic clock it makes the network accurate to within a few milliseconds of UTC providing synchronisation on a global scale.

Author: Richard N Williams
Article Source: EzineArticles.com
Latest trends in mobile phone

A Guide to Synchronising a Network With NTP

Richard N Williams — Wed, 30 Jun 2010 23:09:00 +0000

Network Time Protocol (NTP) is a TCP/IP protocol developed when the internet was in its infancy. It was developed by David Mills of the University of Delaware who was trying to synchronise computers across a network with a degree of precision.

NTP is a UNIX based protocol but it has been ported to operate just as effectively on PCs and a version has been included with operating systems since Windows 2000 (including Windows 7, Vista and XP).

NTP, and the daemon (application) that controls it, is not just a method of passing the time around. Any system running the NTP daemon can act as a client by querying the reference time from other servers or it can make its own time available for other devices to use which in effect turns it into a time server itself. It can also act as a peer by collaborating with other peers to find the most stable and accurate time source to use.

One of the most flexible aspects of NTP is its hierarchical nature. NTP divides devices into strata, each stratum level is defined by its proximity to the reference clock (atomic clock). The atomic clock itself is a stratum 0 device, the closest device to it (often a dedicated NTP time server) is a stratum 1 device whilst other devices that connect to that become stratum 2. NTP can maintain accuracy to within 16 stratum levels.

Any network that needs to be synchronised, has to first identify and locate a time source for NTP to distribute. Internet sources of time are available but thee are often taken from stratum 2 devices that operate through the firewall. The only way NTP can peer the time is if the TCP/IP port is left open to allow the traffic through. This could lead to security issues as malicious users can take advantage of this firewall hole.

Dedicated NTP time servers find a source of time via GPS or radio signals and so don’t leave a network vulnerable to attack. By attaching a NTP time server to a router and entire network of hundreds and even thousands of devices can be synchronised thanks to NTP’s hierarchical structure.

Author: Richard N Williams
Article Source: EzineArticles.com
Buy electrical pressure cooker