CISSP Communication and Network Security Practice Question
This CISSP practice question tests your understanding of communication and network security. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
Which TWO of the following are valid reasons to implement network segmentation?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
To isolate sensitive data and systems from the rest of the network.
Network segmentation isolates sensitive data and systems by creating separate broadcast domains or VLANs, restricting unauthorized access and lateral movement. This is a core security principle for protecting critical assets, as it limits the attack surface and enforces access controls between segments.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✓
To isolate sensitive data and systems from the rest of the network.
Why this is correct
Limits exposure of critical assets.
Related concept
Read the scenario before looking for a memorised answer.
✗
To eliminate single points of failure.
Why it's wrong here
Redundancy, not segmentation, addresses SPOF.
✓
To contain broadcast traffic and improve performance.
Why this is correct
Reduces broadcast domains.
Related concept
Read the scenario before looking for a memorised answer.
✗
To reduce network latency.
Why it's wrong here
Segmentation may increase latency due to inter-VLAN routing.
✗
To simplify routing tables.
Why it's wrong here
Segmentation often adds complexity.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates confuse network segmentation with performance optimization techniques like load balancing or redundancy, leading them to incorrectly select options that address latency or fault tolerance rather than the primary security and broadcast containment benefits.
Detailed technical explanation
How to think about this question
Network segmentation is commonly implemented using VLANs (IEEE 802.1Q) to create separate Layer 2 broadcast domains, with inter-VLAN routing performed by a router or Layer 3 switch. In a real-world scenario, a PCI DSS-compliant environment segments the cardholder data environment (CDE) from the corporate network, using ACLs or firewalls to enforce strict traffic filtering between segments, which also reduces broadcast traffic and improves performance by limiting the scope of ARP requests and STP topology changes.
KKey Concepts to Remember
Read the scenario before looking for a memorised answer.
Find the constraint that changes the correct option.
Eliminate answers that are true in general but not in this case.
TExam Day Tips
→Watch for words such as best, first, most likely and least administrative effort.
→Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A SOC analyst notices unusual lateral movement in the network at 2 AM. The IR playbook dictates: identify and contain (isolate the affected machine), then eradicate (remove the malware), then recover (restore from backup), then document. Skipping containment before eradication risks the attacker regaining access. Questions like this test the sequence and rationale of incident response phases.
Related glossary terms
Concepts from this question explained
These glossary pages explain the core terms tested in this CISSP question in full detail.
Communication and Network Security — This question tests Communication and Network Security — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: To isolate sensitive data and systems from the rest of the network. — Network segmentation isolates sensitive data and systems by creating separate broadcast domains or VLANs, restricting unauthorized access and lateral movement. This is a core security principle for protecting critical assets, as it limits the attack surface and enforces access controls between segments.
What should I do if I get this CISSP question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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Question Discussion
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