Mysticeti: A Low-Latency DAG-Based Byzantine Consensus Protocol

แนวคิดหลัก

Mysticeti is a family of DAG-based Byzantine consensus protocols that achieve low latency and high resource efficiency by avoiding explicit certification of blocks and proposing a novel commit rule that allows every block to be committed without delays.

บทคัดย่อ

The Mysticeti protocols aim to push the latency boundaries of state machine replication in DAG-based blockchains. Mysticeti-C is a low-latency consensus protocol that commits multiple blocks per round, while Mysticeti-FPC extends Mysticeti-C with a fast path for transactions that do not require consensus.
Mysticeti-C avoids the need for explicit block certification by interpreting the structure of the DAG to reach decisions. It identifies two key patterns - the skip pattern and the certificate pattern - to implicitly certify blocks without additional protocol messages. Mysticeti-C also treats every block as a first-class block that can be proposed and decided directly, allowing it to commit the majority of blocks in just 3 message delays, which is the lower bound for Byzantine consensus.
Mysticeti-FPC integrates the fast path for consensusless transactions directly into the DAG structure, eliminating the need for additional protocol messages and individual transaction signatures. This design choice frees up network and CPU resources that can be used for executing transactions instead of generating and verifying certificates.
The Mysticeti protocols are designed to be robust against crash failures, the most common failure mode in blockchains. They can tolerate crash failures with minimal performance degradation, in contrast to traditional BFT consensus protocols that are designed to handle both crash and Byzantine faults.
The authors implement and evaluate both Mysticeti-C and Mysticeti-FPC, demonstrating their superior performance compared to certified DAG-based designs in both consensus and consensusless modes. They also report on the experiences and performance benefits of integrating Mysticeti-C into a production blockchain, resulting in a 4x latency reduction.

สถิติ

Mysticeti-C achieves WAN latency of 0.5s for consensus commit while maintaining a throughput of over 100k TPS.
Integrating Mysticeti-C into a production blockchain resulted in a 4x latency reduction.

คำพูด

"Mysticeti-C is the first DAG-based consensus protocol that decides the majority of the blocks in 3 message delays."
"Mysticeti-FPC integrates the fast path for consensusless transactions directly into the DAG structure, eliminating the need for additional protocol messages and individual transaction signatures."

ข้อมูลเชิงลึกที่สำคัญจาก

Mysticeti: Reaching the Limits of Latency with Uncertified DAGs

by Kushal Babel... ที่ arxiv.org 05-01-2024

https://arxiv.org/pdf/2310.14821.pdf

สอบถามเพิ่มเติม

How can the Mysticeti protocols be extended to support more complex transaction types beyond simple asset transfers?

The Mysticeti protocols can be extended to support more complex transaction types by introducing additional validation mechanisms and rules specific to the new transaction types. For example, for transactions involving smart contracts or more intricate logic, validators can implement custom validation checks to ensure the correctness and integrity of the transactions. This may involve additional verification steps, such as checking the execution of smart contract code or validating the inputs and outputs of the transactions based on specific business rules.
Furthermore, the protocols can be enhanced to include specialized consensus mechanisms tailored to the requirements of the complex transaction types. For instance, for transactions that involve conditional logic or multi-step processes, the consensus algorithm can be modified to accommodate these complexities and ensure that all validators reach an agreement on the validity of such transactions.
Additionally, the introduction of specific transaction types may require modifications to the block structure and validation process within the protocols. Validators can adapt the block format to include additional fields or metadata specific to the new transaction types, allowing for more detailed information to be included in the blocks and facilitating the validation of complex transactions.
Overall, by customizing the validation process, consensus mechanisms, and block structure, the Mysticeti protocols can be extended to effectively support a wide range of complex transaction types beyond simple asset transfers.

What are the potential trade-offs between the number of proposer slots per round and the robustness of the Mysticeti-C protocol under different network conditions?

The number of proposer slots per round in the Mysticeti-C protocol can impact the latency, throughput, and robustness of the protocol under varying network conditions. Here are some potential trade-offs to consider:

Latency vs. Robustness: Increasing the number of proposer slots per round can improve the protocol's latency by allowing for more concurrent block proposals. However, this may also introduce more complexity and potential points of failure, impacting the robustness of the protocol, especially in the presence of network delays or Byzantine faults.

Throughput vs. Consistency: A higher number of proposer slots can increase the protocol's throughput by enabling more transactions to be processed in parallel. However, this may also lead to a higher likelihood of conflicts or inconsistencies between blocks proposed by different validators, affecting the overall consistency of the blockchain.

Network Congestion: In scenarios of high network congestion or limited bandwidth, a larger number of proposer slots per round may exacerbate communication overhead and increase the risk of message delays or packet loss. This can impact the protocol's ability to reach agreements efficiently and reliably.

Validator Churn: The number of proposer slots can also influence the protocol's resilience to validator churn. A higher number of slots may make it more challenging to manage changes in the validator set or handle crash recoveries effectively, potentially affecting the overall stability and continuity of the consensus process.

In summary, the choice of the number of proposer slots per round in the Mysticeti-C protocol involves balancing considerations of latency, throughput, consistency, network conditions, and validator churn to ensure optimal performance and robustness under different network scenarios.

How can the Mysticeti protocols be adapted to work in a permissionless setting with dynamic validator sets?

Adapting the Mysticeti protocols to operate in a permissionless setting with dynamic validator sets requires several key modifications and considerations:

Validator Onboarding: In a permissionless setting, new validators can join the network at any time. The protocols need to incorporate mechanisms for onboarding new validators securely, verifying their identities, and ensuring they meet the necessary requirements to participate in the consensus process.

Validator Reputation: To maintain the integrity of the network, reputation systems can be implemented to track the performance and behavior of validators. Validators with a history of malicious actions or poor performance can be penalized or removed from the network, promoting accountability and trustworthiness.

Decentralized Governance: Permissionless settings often involve decentralized governance models where validators collectively make decisions about protocol upgrades, parameter changes, and network rules. Implementing governance mechanisms, such as voting mechanisms or decentralized autonomous organizations (DAOs), can enable validators to participate in decision-making processes democratically.

Dynamic Consensus Algorithms: The protocols should be designed to adapt to changes in the validator set dynamically. Consensus algorithms that can adjust the participation of validators based on their reputation, performance, or stake can help maintain the security and efficiency of the network in the presence of dynamic validator sets.

Incentive Mechanisms: In permissionless settings, incentive mechanisms play a crucial role in motivating validators to act honestly and contribute to the network's security and performance. Designing robust incentive structures, such as block rewards, transaction fees, or slashing conditions, can encourage validators to behave in the best interest of the network.

By incorporating these adaptations and considerations, the Mysticeti protocols can be effectively tailored to operate in permissionless environments with dynamic validator sets, ensuring the security, scalability, and decentralization of the blockchain network.