Protocol Layering Concepts and TCP/IP Layering ICSSCADA Practice Questions (Page 4)

Questions 16–20

1. 16application · medium

   A control network uses a mix of legacy serial RTUs and modern Ethernet-based PLCs. An engineer is designing a gateway to translate between the two. The engineer needs to ensure that the gateway can route IP packets between different subnets while also handling the conversion of application-layer protocols. Which TCP/IP model layers must the gateway actively process to accomplish both tasks?

   • ANetwork layer and application layer
   • BNetwork layer and transport layer
   • CTransport layer and data-link layer
   • DApplication layer and physical layer
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2. 17application · easy

   A network administrator is documenting the data flow for a DNP3 message sent over a serial-to-Ethernet converter. The administrator needs to identify the PDU at each layer. Which sequence correctly lists the PDUs from the application layer down to the physical layer?

   • AData, frame, packet, segment, bit
   • BData, segment, frame, packet, bit
   • CData, packet, segment, frame, bit
   • DData, segment, packet, frame, bit
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4. 18application · medium

   A cybersecurity analyst is reviewing network documentation for a power utility. The analyst notices that the documentation uses the TCP/IP model, but the analyst is more familiar with the OSI model. The analyst needs to map a firewall rule that filters based on port numbers. In the TCP/IP model, which layer handles port-based filtering?

   • ANetwork access layer
   • BTransport layer
   • CInternet layer
   • DApplication layer
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5. 19application · medium

   An engineer is configuring a new historian server to receive data from multiple PLCs over a TCP/IP network. The engineer wants to ensure that data is delivered reliably and in order, and that the application can identify which PLC sent each message. Which combination of protocol-layer interactions is required?

   • AUDP at the transport layer provides reliable delivery, and the application layer uses MAC addresses to identify PLCs.
   • BIP at the network layer provides addressing to identify each PLC, and TCP at the transport layer provides reliable, ordered delivery.
   • CEthernet at the data-link layer provides reliable delivery, and IP at the network layer provides ordering.
   • DTCP at the transport layer provides reliable, ordered delivery, and the application layer uses port numbers to identify the source PLC.
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6. 20application · medium

   A trainer is explaining the differences between the OSI and TCP/IP models to a group of ICS technicians. The trainer wants to emphasize that the TCP/IP model was designed around real-world protocols. Which statement best highlights a key difference between the two models?

   • AThe OSI model is used only for wireless networks, while the TCP/IP model is used only for wired networks.
   • BThe TCP/IP model defines protocols for every layer, while the OSI model does not define any protocols.
   • CThe OSI model was developed as a theoretical framework, while the TCP/IP model was built around existing protocols like TCP and IP.
   • DThe TCP/IP model has seven layers, while the OSI model has four layers.
   Reveal Solution Discussion Select an answer first