Asynchronous Byzantine Agreement in Incomplete Networks: Understanding the Basics
If you`re interested in the world of distributed systems, you must have come across the term “Byzantine Agreement.” It is a fundamental problem in the domain of Distributed Computing, where a set of processes try to reach agreement on a value or a decision, even in the presence of malicious or faulty processes. Byzantine Agreement has been extensively studied in the context of complete networks, where every process can communicate with every other process. However, in real-world scenarios, it`s not always possible for every process to communicate with every other process. We call such networks incomplete networks. In this article, we will understand the concept of asynchronous Byzantine Agreement in incomplete networks.
What is Asynchronous Byzantine Agreement?
In an asynchronous system, there is no bound on the time taken for a process to send or receive a message. In other words, the system has no timing assumptions. Asynchronous Byzantine Agreement is a problem where a set of processes try to agree on a value or a decision despite the absence of any timing assumptions.
What is an Incomplete Network?
In a distributed system with n processes, we say that the network is complete if every process can communicate with every other process. An incomplete network is a network where some processes cannot exchange messages directly. In other words, there are some pairs of processes that cannot communicate directly with each other.
The Byzantine Agreement Problem in Incomplete Networks
Let`s consider a scenario where we have an incomplete network of processes, and some of these processes are malicious or faulty. The goal of the remaining processes is to achieve Byzantine Agreement, i.e., agree on a common value, even in the presence of malicious or faulty processes. In an incomplete network, the processes that cannot communicate directly with each other may have different views on the current state of the system.
Synchronous Byzantine Agreement is a well-studied problem in the presence of malicious or faulty processes but in a complete network. In an incomplete network, the problem becomes more challenging and requires new techniques and algorithms to solve.
Asynchronous Byzantine Agreement in Incomplete Networks
The problem of Byzantine Agreement in an incomplete and asynchronous network is still an active area of research. Several solutions have been proposed based on different assumptions and techniques.
One approach is to use a communication graph to model the network, where edges represent direct communication links between processes. The communication graph is augmented with additional edges to ensure that all processes can reach each other indirectly. Then, a Byzantine Agreement protocol is run on the augmented graph.
Another approach is to use a gossip-based algorithm, where processes exchange messages randomly with each other. The protocol ensures that the messages exchanged propagate to all processes in the network, eventually leading to Byzantine Agreement.
Conclusion
Byzantine Agreement is a fundamental problem in Distributed Computing, where a set of processes try to agree on a value or a decision, even in the presence of malicious or faulty processes. Incomplete networks, where not all processes can communicate directly with each other, pose a new challenge in the domain. Several techniques and algorithms have been proposed to solve the problem of asynchronous Byzantine Agreement in incomplete networks, and it`s still an active area of research.