Internal Clock Synchronization Mechanism in Distributed System clock synchronization computer time

Internal Clock Synchronization Mechanism in Distributed System clock synchronization computer time

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In a distributed system, internal clock synchronization is crucial to ensure that all nodes maintain a consistent and accurate sense of time. Since each computer in a distributed system has its own internal clock, slight differences (clock drift) occur due to hardware variations and environmental factors. Clock synchronization mechanisms help minimize these differences and keep all clocks in sync.

Types of Clock Synchronization in Distributed Systems

Clock synchronization is broadly classified into two types:

1. External Synchronization: Synchronizes clocks with an external time source (e.g., NTP, GPS).
2. Internal Synchronization: Ensures that the clocks of all nodes in a system stay within a certain bound of each other.

Internal Clock Synchronization Mechanisms

Several algorithms help maintain internal synchronization:

1. Cristian’s Algorithm

• A process requests time from a time server.
• The server responds with the current time.
• The process adjusts its clock considering the message transmission delay.

2. Berkeley’s Algorithm

• A master node polls all nodes in the system for their time.
• It computes an average time and instructs each node to adjust its clock.
• Suitable for systems without access to an external time source.

3. Happened-Before Relation (Lamport Timestamps)

• Used in logical synchronization.
• Ensures that causally related events follow a consistent order.

4. Vector Clocks

• Extends Lamport’s timestamps.
• Each process maintains a vector of counters to track causal relationships.

5. Network Time Protocol (NTP)

• Used in large-scale distributed systems.
• Synchronizes system clocks using a hierarchy of time sources.

Conclusion

Internal clock synchronization ensures consistency in event ordering, data consistency, and fault tolerance in distributed systems. Algorithms like Berkeley’s and Cristian’s help maintain accurate synchronization, while logical clocks like Lamport and Vector Clocks help maintain event ordering.

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