What is a known limitation of the PBFT-Based consensus mechanism?

The PBFT (Practical Byzantine Fault Tolerance) consensus mechanism provides a robust way of ensuring agreement among distributed nodes in a blockchain network. One of its primary characteristics is that all validators are known and connected to one another, often maintaining constant communication with each other to reach consensus. This structure is critical for the algorithm's design, as it relies on a limited and predefined number of validators to validate transactions and block proposals.

Being known implies that validators can be trusted based on their identity, which enhances security but also limits the scalability of the network. PBFT performs well with a small, known number of validators, but as the number of validators increases or nodes become less reliable, the efficiency of the consensus process can degrade. Validator connectivity is crucial because PBFT requires frequent communication among them to ensure all nodes agree on the state of the ledger before processing transactions, which can create bottlenecks.

While other consensus mechanisms, such as those based on proof of work, allow for greater anonymity and potentially larger networks, PBFT's design is inherently reliant on the known identities and connectivity of its validators, which is why this characteristic is recognized as a limitation in broader applications.