CBSA Blockchain Scalability & Performance 1 — Questions and Answers
Question 1: What is the primary purpose of a Layer 2 scaling solution in blockchain?
- To replace the main blockchain with a faster alternative chain
- To process transactions off the main chain while inheriting its security (Correct answer)
- To increase the block size limit of the main chain
- To reduce the number of validator nodes in the network
Correct answer: To process transactions off the main chain while inheriting its security
Layer 2 solutions process transactions off the main blockchain (Layer 1) while leveraging its security and settlement guarantees.
Question 2: Which scaling technique divides a blockchain network into smaller groups of nodes, each responsible for processing a subset of transactions?
- Sidechains
- Plasma chains
- Sharding (Correct answer)
- State channels
Correct answer: Sharding
Sharding splits the network into parallel partitions called shards, each handling a portion of the transaction load to increase overall throughput.
Question 3: What is a 'state channel' in the context of blockchain scaling?
- A dedicated server for handling high-value transactions
- An off-chain communication channel where participants exchange signed transactions privately and settle on-chain only at the end (Correct answer)
- A special smart contract pattern for batching token transfers
- A cryptographic bridge between two different blockchains
Correct answer: An off-chain communication channel where participants exchange signed transactions privately and settle on-chain only at the end
State channels allow participants to conduct many transactions off-chain and only broadcast the final settled state to the main blockchain.
Question 4: Bitcoin's Lightning Network is an example of which Layer 2 scaling category?
- Plasma framework
- ZK-Rollup
- Payment/State channel network (Correct answer)
- Sidechain
Correct answer: Payment/State channel network
The Lightning Network is a payment channel network built on Bitcoin, enabling fast and cheap off-chain transactions settled bilaterally.
Question 5: Which metric is most commonly used to measure and compare blockchain transaction throughput?
- Block reward rate (BRR)
- Transactions per second (TPS) (Correct answer)
- Node synchronization time (NST)
- Hash difficulty target
Correct answer: Transactions per second (TPS)
Transactions per second (TPS) directly measures how many transactions a network can confirm per second, making it the standard throughput benchmark.
Question 6: What is an 'Optimistic Rollup' in Layer 2 blockchain scaling?
- A rollup that assumes all transactions are invalid until cryptographically proven otherwise
- A Layer 2 solution that batches off-chain transactions and assumes their validity, relying on fraud proofs during a challenge window (Correct answer)
- A consensus mechanism designed for faster block production on Layer 1
- A sharding approach that optimistically pre-assigns validators to shards
Correct answer: A Layer 2 solution that batches off-chain transactions and assumes their validity, relying on fraud proofs during a challenge window
Optimistic Rollups assume transactions are valid by default and allow a challenge period during which verifiers can submit fraud proofs to dispute invalid state transitions.
Question 7: What does the 'blockchain trilemma' (as described by Vitalik Buterin) refer to?
- The three types of consensus: Proof of Work, Proof of Stake, and Delegated Proof of Stake
- The inherent difficulty of simultaneously achieving decentralization, security, and scalability in a blockchain (Correct answer)
- The three architectural layers: data, network, and consensus
- The challenge of integrating blockchain with three categories of legacy enterprise systems
Correct answer: The inherent difficulty of simultaneously achieving decentralization, security, and scalability in a blockchain
The blockchain trilemma states that achieving decentralization, security, and scalability all at once is extremely difficult, and improving one typically comes at the expense of another.
