Internet RFCs and STDs ICSSCADA Practice Questions (Page 6)

Questions 26–30

1. 26expert · hard

   An engineer is reviewing the RFC status of a protocol used in a nuclear plant's safety system. The protocol is defined by an RFC that is currently a Draft Standard. The plant's safety requirements mandate the use of 'mature and stable' protocols. What should the engineer recommend?

   • AUse the protocol because it is already an RFC.
   • BUse the protocol but document the risks.
   • CUse the protocol because Draft Standard is mature enough.
   • DUse the protocol only if it becomes an Internet Standard.
   Reveal Solution Discussion Select an answer first
2. 27expert · hard

   A manufacturing plant uses a mix of legacy and modern devices. The legacy devices use a proprietary protocol that is not RFC-defined, while the modern devices use standard TCP/IP. The plant is expanding and needs to integrate the legacy devices with the new network. What is the most effective approach?

   • AUse a protocol converter or gateway to translate between the proprietary protocol and TCP/IP.
   • BReplace all legacy devices with modern IP-enabled devices.
   • CDisable the legacy devices and use only the modern devices.
   • DRun the legacy protocol over UDP to reduce overhead.
   Reveal Solution Discussion Select an answer first
4. 28application · medium

   A control systems engineer is configuring a new remote terminal unit (RTU) that communicates with a master station over a cellular link. The RTU supports both TCP and UDP for its SCADA protocol. The link is subject to intermittent packet loss, and the application does not have built-in retransmission. Which RFC-defined protocol should the engineer choose to ensure reliable data delivery?

   • AICMP (RFC 792)
   • BUDP (RFC 768)
   • CTCP (RFC 9293)
   • DIGMP (RFC 2236)
   Reveal Solution Discussion Select an answer first
5. 29application · medium

   A security analyst is documenting the network protocols used in a water treatment facility. The analyst finds that the facility uses a protocol that is defined by multiple RFCs, and the latest RFC obsoletes an earlier one. The analyst wants to reference the current authoritative specification. What should the analyst do?

   • AReference the RFC that has the most citations in vendor documentation.
   • BReference the earliest RFC that originally defined the protocol.
   • CReference the most recent RFC that obsoletes the earlier ones.
   • DReference the RFC with the highest STD number.
   Reveal Solution Discussion Select an answer first
6. 30expert · hard

   An ICS engineer is designing a network for a water treatment plant. The plant has a mix of legacy serial RTUs and modern IP-enabled PLCs. The engineer needs to ensure that all devices can communicate reliably with the central SCADA system. The network team insists on using UDP for all traffic to reduce overhead. Which approach should the engineer take?

   • AUse TCP for traffic that requires reliability, and UDP for time-sensitive or broadcast traffic.
   • BUse UDP for all traffic, as it is faster and simpler.
   • CUse a proprietary protocol that bypasses the TCP/IP stack.
   • DUse only TCP for all traffic to ensure reliability.
   Reveal Solution Discussion Select an answer first