What is the difference between internal and external synchronisation

The most important one is that in a distributed system, the different nodes maintain their own time using local clocks and their time values may not be same for the different nodes.

The various clocks in the system even if set to a common time value at an instant, drift apart due to unavoidable reasons. Hence some kind of continuous mechanism for synchronization is needed so that they can coordinate and work together to achieve the objectives of the distributed system. Two types of synchronization are possible- external synchronization and internal synchronization.

In a real time scenario, it is important for the system to be synchronous with each other and with a common external reference time. This is called external synchronization. But in certain systems, it is only necessary for the nodes in the system to be synchronized with each other. This is called internal synchronization. In many applications, the relative ordering of events is more important than actual physical time.

Here event ordering is done without clock time values. Hence, depending on the area and type of application, clock synchronization techniques used differs. In certain real time applications, the system requires to be both internally and externally synchronized.

But this algorithm fails in situations where the time server fails. Like Article. Last Updated : 15 Jan, Distributed System is a collection of computers connected via the high speed communication network.

In the distributed system, the hardware and software components communicate and coordinate their actions by message passing. Each node in distributed systems can share their resources with other nodes. So, there is need of proper allocation of resources to preserve the state of resources and help coordinate between the several processes. To resolve such conflicts, synchronization is used. Synchronization in distributed systems is achieved via clocks.

The physical clocks are used to adjust the time of nodes. You can also search for this author in PubMed Google Scholar. Reprints and Permissions. Integrating External and Internal Clock Synchronization. Real-Time Systems 12, — Download citation. Issue Date : March Anyone you share the following link with will be able to read this content:. Sorry, a shareable link is not currently available for this article.

Provided by the Springer Nature SharedIt content-sharing initiative. Skip to main content. Search SpringerLink Search. Abstract We address the problem of how to integrate fault-tolerant external and internal clock synchronization.

References Cristian, F. Google Scholar Cristian, F. Google Scholar Fetzer, C. View author publications. Rights and permissions Reprints and Permissions.