Protocol Layering Concepts and TCP/IP Layering ICSSCADA Practice Questions (Page 6)

Questions 26–30

1. 26expert · medium

   A security appliance is placed inline between two switches in an ICS network. The appliance is configured to inspect Modbus TCP traffic for malicious function codes. The appliance receives a frame, strips the Ethernet header, then inspects the IP header, then the TCP header, and finally the Modbus payload. Which process is the appliance performing?

   • ADe-encapsulation
   • BFragmentation
   • CEncapsulation
   • DReassembly
   Reveal Solution Discussion Select an answer first
2. 27expert · medium

   An ICS network uses a mix of devices that support both IPv4 and IPv6. A security appliance is configured to filter traffic based on IP addresses. The appliance is currently configured to inspect only IPv4 packets. The engineer needs to ensure that IPv6 traffic is also inspected. Which TCP/IP model layer is responsible for handling both IPv4 and IPv6, and what must the engineer do?

   • ANetwork layer; configure the appliance to inspect both IPv4 and IPv6 packets.
   • BApplication layer; configure the appliance to inspect both HTTP and Modbus traffic.
   • CData-link layer; configure the appliance to inspect both Ethernet and Wi-Fi frames.
   • DTransport layer; configure the appliance to inspect both TCP and UDP segments.
   Reveal Solution Discussion Select an answer first
4. 28foundation · easy

   In a layered protocol stack, how do protocols at different layers interact to provide end-to-end communication?

   • AEach layer works independently without any interaction with other layers
   • BProtocols at each layer communicate directly with the same layer on the remote host without using lower layers
   • COnly the Application layer and Physical layer interact directly
   • DEach layer provides services to the layer above and uses services from the layer below
   Reveal Solution Discussion Select an answer first
5. 29application · medium

   A network analyst is troubleshooting a slow link between a historian server and a remote RTU. The analyst captures packets at the RTU's network interface and sees that the RTU is receiving large TCP segments that are being fragmented into smaller IP packets. Which PDU name correctly describes the data unit that the RTU's network interface card (NIC) processes and forwards to the IP layer?

   • ADatagram
   • BPacket
   • CSegment
   • DFrame
   Reveal Solution Discussion Select an answer first
6. 30application · easy

   A network engineer is setting up a new segment for a substation LAN. The engineer needs to ensure that devices on the same Ethernet switch can communicate using IP addresses. Which OSI layer is primarily responsible for moving frames between devices on the same LAN segment?

   • ANetwork layer
   • BPhysical layer
   • CData link layer
   • DTransport layer
   Reveal Solution Discussion Select an answer first