The Ledgerium Blockchain is a peer-to-peer decentralized network run by authorized systems, so it is a form of Proof of Authority blockchain. Ledgerium Node is essentially a server with a unique identity on the network. The peer node might be an organisation in a consortium of banks. Each organisation runs one or more blockchain node to host a local copy of the ledger.
The Ledgerium Blockchain network contains a distributed, cryptographically secure ledger that maintains the history of immutable transactions on the network. Each peer node stores a global state of the ledger locally. The Ledgerium protocol defines the rules of the endorsement process. In the process, every peer can independently verify the transaction history without any external authority. Peer, however, can't write transactions on the blockchain.
Block Producer has a critical role to play on the Ledgerium Blockchain. It produces or adds blocks to the blockchain. Block Producer executes 'sending' XLG across accounts or instant smart contract transactions or private transactions. Block producer maintains the pool of transactions, in which it gathers transactions from various DApps, combines them in a block and publishes it on the blockchain. There is a proposal process for becoming a Block Producer from a peer.
To make any changes to the consortium, existing block producers make proposals that all other block producers in the Ledgerium network need to vote on.
In the case scenario of a new peer node wanting to become a block producer, an existing block producer creates a proposal to invite the account. Other block producers then vote Yes or No on the proposal. If the proposal is approved, the Ledgerium Protocol accepts the new peer as a new block producer and adds it to the consortium.
A similar proposal process is required to remove an existing block producer from the Ledgerium Blockchain consortium.
Every block producer will get its turn to produce block as per the IBFT consensus mechanism described Consensus
The Ledgerium Foundation also defines a
voting policy for the network when they initiated it and it is N2 where n stands for a number of block producers in the consortium. The voting policy determines the basic rules for all proposal voting on the network. The voting policy includes the percentage of votes required to pass the proposal, and the duration before the vote expires.
For more details, you can refer to Governance.
The block producer that is selected to propose the next block is called proposer. The consensus facilitates two algorithms to select proposer.
The Ledgerium Foundation adopted the round-robin algorithm in which each proposer is selected deterministically and in the round-robin fashion. Block Producer that gets a chance to be a proposer will depend upon the number of producers participating in the consortium. The Ledgerium Blockchain has
21 Block Producers in the consortium. One proposer is producing block
every 5 seconds and the role of the proposer moves on to the next producer in the sequence. For more Read Consensus
Denial-of-service attacks occur when an attacker sends a flood of internet traffic to an IP address to prevent IP address server from connecting to the internet. An attacker scans the network, tries to learn the IP address of various Block producers nodes and disconnects them from communication by flooding them with traffic.
One recommended way to mitigate these risks is for block producer to carefully structure their network topology in a so-called
sentry node architecture. Block Producer should only connect to full-nodes they trust because they operate them themselves or are run by other block producers they know socially. A block producer will typically run in a data centre. Most data centres provide direct links to the networks of major cloud providers. The block producer can use those links to connect to sentry nodes in the cloud. This shifts the burden of denial-of-service from the producer's node directly to its sentry nodes and may require new sentry nodes be spun up or activated to mitigate attacks on existing ones.
Sentry nodes can be quickly spun-up or change their IP addresses. Because the links to the sentry nodes are in private IP space, an internet-based attacked cannot disturb them directly. This will ensure producer block proposals and votes always make it to the rest of the network.
It is expected that good operating procedures on that part of producers will completely mitigate these threats.