Network Communication and Protocol Layers BDC Practice Questions (Page 6)

Questions 26–30

1. 26expert · hard

   A blockchain network is under an eclipse attack where an attacker controls all of a victim node's connections. The victim node is accepting blocks from the attacker but not from the honest network. Which detection mechanism is most effective?

   • AIncrease the block size to make the attack more expensive
   • BDisable all inbound connections to prevent attackers from connecting
   • CUse a longer timeout for peer connections
   • DMonitor the diversity of peer IP addresses and compare block hashes with external sources
   Reveal Solution Discussion Select an answer first
2. 27foundation · easy

   What is the primary purpose of the peer-to-peer messaging protocol in a blockchain network?

   • ATo enable nodes to share the same view of transactions and blocks without a central authority
   • BTo provide a secure channel for nodes to send private messages to each other
   • CTo allow nodes to vote on which transactions should be included in the next block
   • DTo synchronize the clocks of all nodes in the network
   Reveal Solution Discussion Select an answer first
4. 28application · medium

   A developer is designing a blockchain for IoT devices with limited bandwidth. They need to reduce redundant data transmission while ensuring all nodes eventually receive every transaction. Which approach should they use?

   • AGossip protocol with deduplication and bloom filters
   • BOnly propagate transactions to a random subset of nodes and rely on them to forward
   • CCentralized hub that stores all transactions and nodes poll for updates
   • DFlooding every transaction to every node without any filtering
   Reveal Solution Discussion Select an answer first
5. 29application · medium

   A blockchain network is experiencing slow block propagation because nodes are only connecting to a small set of well-known peers. The developer wants to improve network resilience and decentralization. What should they implement?

   • AReduce the maximum number of peer connections
   • BDisable peer discovery and rely on manual configuration
   • CImplement a DHT-based peer discovery mechanism
   • DUse a single centralized peer list server
   Reveal Solution Discussion Select an answer first
6. 30foundation · easy

   In a blockchain network, how do nodes typically exchange transaction and block data?

   • ANodes only exchange data when a new block is mined, and only with the miner of that block.
   • BNodes use a publish-subscribe system where only authorized subscribers receive transaction data.
   • CNodes broadcast data to all directly connected peers, who then relay it to their peers until it reaches the entire network.
   • DEach node sends data to a central server, which then redistributes it to all other nodes.
   Reveal Solution Discussion Select an answer first