Internal Clock Synchronization Mechanism in Distributed System clock synchronization computer time

Internal Clock Synchronization Mechanism in Distributed System clock synchronization computer time

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.

Would you like a detailed explanation of any specific algorithm?

In a Distributed System, different nodes (computers) work together but do not share a common physical clock. To coordinate operations correctly, clock synchronization is critical.

Here’s a comprehensive explanation of the Internal Clock Synchronization Mechanism in distributed systems:

What is Clock Synchronization in Distributed Systems?

In distributed systems, each computer has its own internal clock. However, these clocks can drift apart over time due to:

• Hardware differences

• Network latency

• System load

So, we need clock synchronization protocols to keep their logical or physical time in sync.

Two Types of Synchronization

Here, we’ll focus on Internal Clock Synchronization.

Internal Clock Synchronization Mechanisms

1. Cristian’s Algorithm

• A node contacts a time server and estimates its current time by:

  • Sending a request

  • Measuring round-trip time (RTT)

  • Adjusting its clock based on server time minus half of RTT

Formula:

2. Berkeley’s Algorithm

• A master node polls all nodes for their times.

• It computes an average time (ignoring outliers).

• It then tells each node how to adjust its clock (positive or negative).

Suitable for internal synchronization (no need for an external reference).

3. Network Time Protocol (NTP) – Also supports Internal Sync

• Though mainly used for external sync, NTP also allows distributed nodes to sync with each other.

• Uses a hierarchical structure of time servers (stratum levels).

• Very accurate (to the millisecond level).

4. Lamport Timestamps (Logical Clock)

• Does not rely on actual time but maintains event ordering.

• Each process maintains a counter and:

  • Increments its counter for each event

  • Sends it along with messages

  • Updates its clock to max(local, received)+1

Ensures causal ordering rather than exact time.

5. Vector Clocks

• More advanced than Lamport clocks

• Maintains a vector of counters, one for each process

• Tracks causal relationships more accurately

Why Internal Clock Synchronization is Important?

• Event Ordering: Ensure that operations across nodes are performed in the correct sequence

• Coordination: For distributed databases, mutual exclusion, etc.

• Debugging & Monitoring: Consistent timestamps help in logs and system analysis

Summary Table

Would you like a diagram, code implementation, or examples from real distributed systems like Cassandra or Hadoop?

Internal Clock Synchronization Mechanism in Distributed System clock synchronization computer time

Clock Synchronization in Distributed Systems

Comparative Study of Clock Synchronization Algorithms in …