Network Communication and Protocol Layers BDC Practice Questions (Page 9)

Questions 41–45

1. 41foundation · easy

   In a blockchain's layered protocol stack, which layer is responsible for defining the rules for creating and validating blocks?

   • ANetwork layer
   • BApplication layer
   • CConsensus layer
   • DBlockchain layer
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2. 42application · medium

   A blockchain network is facing a Sybil attack where an attacker creates thousands of fake nodes to dominate the peer discovery process. Which mechanism is most effective in mitigating this attack?

   • AProof-of-work or proof-of-stake requirements for node identity
   • BEncrypting all peer-to-peer communication
   • CUsing a centralized node registry
   • DIncreasing the timeout for peer connections
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4. 43expert · hard

   A developer is designing a blockchain protocol that must support both high-throughput transaction processing and secure P2P communication. They are considering using a gossip protocol for propagation and a BFT consensus. Which layer should handle the gossip protocol?

   • AThe transport layer, because gossip ensures reliable delivery
   • BThe P2P layer, because gossip is a mechanism for message dissemination among peers
   • CThe application layer, because gossip validates transactions
   • DThe consensus layer, because gossip determines the order of transactions
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5. 44application · medium

   A developer is troubleshooting a blockchain node that can establish TCP connections to peers but fails to synchronize the latest blocks. The node's clock is correct and the network is reachable. Which protocol layer is most likely causing the issue?

   • AThe physical layer, because the network cable is faulty
   • BThe network layer, because IP routing is misconfigured
   • CThe transport layer, because TCP is not suitable for blockchain data transfer
   • DThe application layer, because the node may be running an incompatible consensus or block validation rule
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6. 45foundation · easy

   In a peer-to-peer blockchain network, what is the typical first step for a new node to join the network?

   • AIt broadcasts a message to the entire internet asking for peers to connect.
   • BIt connects to a central registry server to obtain a list of all active nodes.
   • CIt waits for an existing node to send it an invitation to join.
   • DIt uses a discovery mechanism such as DNS seeds or hardcoded peers to find initial peer addresses.
   Reveal Solution Discussion Select an answer first