Distributed Models
Last updated
Three layers of abstraction used to describe and reason about distributed systems: physical (hardware), architectural (components + patterns + middleware), and fundamental (non-functional properties such as reliability, security, performance).
Synchronous: known bounds on execution time, message delay, and clock drift.
Asynchronous: no bounds on any of the above — much weaker but matches the open Internet.
Real systems are usually partially synchronous: bounds exist but are unknown or hold only eventually.
A physical model considers: underlying hardware elements
An architectural model considers:
Architectural elements - components of the system that interact with each other.
Architectural paterns
Associated middleware solutions
Fundemental models define: The non functional aspects such as:
Reliability
Security
Performance
Two simple models of distributed system interaction are:
Synchronous system model - assumes known bounds on:
The time to execute
Message transmission delay
Local clock drift rate
Asynchronous system model - assumes no bound on:
Process execution speed
Message transmission delays
Clock drift rates
Last updated