Network Communication and Protocol Layers BDC Practice Questions (Page 8)

Questions 36–40

1. 36foundation · easy

   In a Sybil attack on a blockchain network, what does the attacker do?

   • AExploits a software bug to crash a node
   • BIntercepts and modifies messages between two honest nodes
   • COverwhelms a node with excessive traffic to cause denial of service
   • DCreates many fake identities to gain disproportionate influence over the network
   Reveal Solution Discussion Select an answer first
2. 37application · medium

   A blockchain platform is being designed to support multiple decentralized applications (dApps) with different business logic. The developers want to isolate the application logic from the core blockchain protocol. Which layer should they use?

   • ANetwork layer that handles peer-to-peer communication.
   • BConsensus layer that validates blocks.
   • CApplication layer that hosts smart contracts and dApp interfaces.
   • DData layer that stores blockchain state.
   Reveal Solution Discussion Select an answer first
4. 38expert · hard

   A blockchain developer is troubleshooting a node that receives transactions but never sees them included in a block. The node is fully synced and connected to many peers. Which layer is most likely misconfigured?

   • AThe consensus layer, because the node may not be participating in block proposal or validation correctly
   • BThe P2P layer, because the node may not be connected to miners
   • CThe application layer, because the node may not be broadcasting transactions
   • DThe transport layer, because the node may not be sending transactions to miners
   Reveal Solution Discussion Select an answer first
5. 39expert · hard

   A blockchain network is experiencing frequent orphaned blocks due to slow propagation. The developer must reduce orphan rates without increasing bandwidth usage significantly. Which solution is most effective?

   • AImplement compact block relay and increase the block interval
   • BReduce the number of peer connections to minimize overhead
   • CIncrease the block size to include more transactions
   • DUse a centralized block broadcaster to ensure all nodes receive blocks instantly
   Reveal Solution Discussion Select an answer first
6. 40application · medium

   A blockchain network is experiencing delayed block propagation due to some nodes not forwarding blocks promptly. The developer suspects malicious nodes are intentionally delaying propagation. Which mechanism can help detect and mitigate this behavior?

   • AUse a fixed set of trusted nodes for all propagation
   • BIncrease the block size to accommodate more transactions
   • CDisable block forwarding and rely on transaction propagation only
   • DMonitor peer latency and reputation scores, and disconnect peers that consistently delay propagation
   Reveal Solution Discussion Select an answer first