DAG - Directed Acyclic Graph

DAG stands for "Directed Acyclic Graph"

Due to the single-chain structure of traditional blockchain projects, speed of transactions is low. DAG will bring the blockchain technology to an asynchronous era. The following are some features:

1. The throughput is huge and far exceeds DPoS.

2. The structure is complex and error-prone. When the transaction volume is large, due to the complex structure of the chain, the historical consensus is likely inconsistent, or the system cannot serialize the transaction. Resulting in some transaction never being confirmed. Some projects have to rely on various centralized organizations to ensure the stable operation of the project, creating centralization issues.

3. No transaction fees. On the surface, seems like an advantage, but is actually a drawback. Without the fee, the attacker can send a large number of costless transactions to occupy the resources. Most DAGs without fees also have shortcomings in data structures and consensus issues. No fees means no need to mine, and no be inflation. But, expect a lack of interests from the people who maintain the normal operation of the system.

4. The ecological construction is difficult. Based on the above, misusing the system is possible without fees, and without profit to incentivize people to maintain the system. This system will not function.

Here are some of its differences with a traditional blockchain system:

1. Unit: Blockchain units are blocks, but DAG units are a single transactions

2. Topology: a Blockchain is, like its name implies, a chain of blocks, while a DAG is a network of nodes that can perform transactions independently from one another

3. Granularity: Blockchain units are a combination of many transactions from multiple users, compared to DAG units, which are relevant to a single transaction

Ambr's main considerations are scalability, decentralization, and security, and is the first to use DAG to promote interoperability. Ambr introduces a DAG structure based on a multi-chain account structure to isolate the units and accounts of participants in the network. At the same time, the verification chain, using the Casper protocol, is added to solve the inherent uncertainty in the DAG system (transaction confirmation, node synchronization, order, and etc.). These improvements allow the system to support smart contracts, drastically increasing the overall functionality.