Network Communication and Protocol Layers BDC Practice Questions (Page 7)

Questions 31–35

1. 31application · medium

   A blockchain developer is setting up a node behind a NAT that cannot accept inbound connections. What is the best way to ensure the node can still participate in the network?

   • ADisable all network activity and use a local-only node
   • BOnly make outbound connections and rely on other nodes to initiate
   • CUse a VPN to connect to a single remote node
   • DUse UPnP or manual port forwarding to allow inbound connections
   Reveal Solution Discussion Select an answer first
2. 32application · medium

   A blockchain network uses a gossip protocol for transaction propagation. A node receives a transaction it has never seen before. What should the node do to ensure reliable propagation while preventing infinite loops?

   • AForward the transaction only to a randomly selected subset of peers without tracking.
   • BStore the transaction locally and wait for a block to include it before forwarding.
   • CEncrypt the transaction and send it only to the network's supernodes.
   • DBroadcast the transaction to all connected peers and mark it as seen to avoid re-broadcasting.
   Reveal Solution Discussion Select an answer first
4. 33expert · hard

   A blockchain developer is designing a permissioned network for a financial consortium. They must balance the need for strong Sybil resistance against the requirement for low-latency transaction finality. Which approach best meets both constraints?

   • AUse a public proof-of-stake network with a large validator set
   • BUse a permissioned network with identity-based authentication and a practical Byzantine fault tolerance (PBFT) consensus
   • CUse a public proof-of-work network to ensure Sybil resistance and accept higher latency
   • DUse a centralized server to validate all transactions and broadcast results
   Reveal Solution Discussion Select an answer first
5. 34expert · hard

   A blockchain network is experiencing frequent orphaned blocks due to slow propagation. The team is considering two options: (1) increasing the block size to reduce the number of blocks, or (2) implementing a compact block relay protocol. Which option is more effective at reducing orphaned blocks?

   • AIncrease the block size to reduce the number of blocks.
   • BBoth are equally effective.
   • CNeither will affect orphaned blocks.
   • DImplement a compact block relay protocol that sends only the block header and missing transactions.
   Reveal Solution Discussion Select an answer first
6. 35foundation · easy

   When a node receives a new transaction, what does it typically do before forwarding it to its peers?

   • AIt immediately forwards it to all peers to minimize latency.
   • BIt sends the transaction only to the miner with the highest hash rate.
   • CIt validates the transaction's signature and format, then forwards it if valid.
   • DIt waits for a block containing the transaction before forwarding it.
   Reveal Solution Discussion Select an answer first