The correct answer is to increase the buffer-to-buffer credit count to 300 on the ISL interfaces. This resolves the timeout errors because the current 16 credits are insufficient to cover the 2 ms round-trip time at 16 Gbps, causing credit starvation where the sending switch must pause transmission while waiting for buffer credits to be returned. For a 100 km link, the standard buffer credit calculation over distance timeout formula requires roughly one credit per km at 16 Gbps, so 200 credits is the bare minimum for full throughput, but increasing to 300 provides a safety margin against bursty traffic and ensures no timeout errors during backup jobs. On the Cisco DCCOR 350-601 exam, this scenario tests your understanding of Fibre Channel flow control and the buffer credit equation (BB_Credits = (Distance in km × 2) × (Speed in Gbps / 2)), with a common trap being to confuse this with FCIP or NPIV—neither of which addresses physical distance latency. Remember the mnemonic: “One credit per km per Gbps, double for safety.”
350-601 Storage Network Practice Question
This 350-601 practice question tests your understanding of storage network. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. 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.
A large enterprise data center has a disaster recovery site 100 km away. The SAN uses two MDS 9700 series switches at each site, connected via a dedicated dark fiber. Each link operates at 16 Gbps with a round-trip time of 2 ms. Recently, backup jobs to the remote storage array have been failing with timeout errors. The backup server is local to Site A, but the backup target is in Site B. The link utilization never exceeds 40%, and no errors are reported on the interfaces. The engineer suspects the issue is related to buffer credits. The current buffer credit count on the ISL is 16. The engineer calculates that for 16 Gbps over 100 km (2 ms RTT), they need at least 200 credits to maintain full throughput. Which action is most appropriate to resolve the issue?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "least"
Why it matters: You want the option with minimum overhead, fewest steps, or lowest impact — not the most feature-rich or comprehensive answer.
Clue: "never"
Why it matters: Absolute qualifier. True only if the statement has zero exceptions — be cautious of options that seem obvious but break down in edge cases.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Increase the buffer-to-buffer credit count to 300 on the ISL interfaces.
Increasing buffer credits resolves the timeout issue due to credit starvation. Option D is correct. Option A is wrong because the links are physically direct; FCIP is not needed. Option B is wrong because NPIV is not related to buffer credits. Option C is wrong because reducing speed lowers performance.
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.
✗
Enable NPIV on the ISL ports to allow multiple logins.
Why it's wrong here
NPIV is for end devices, not for ISL buffer credit issues.
✓
Increase the buffer-to-buffer credit count to 300 on the ISL interfaces.
Why this is correct
More credits allow more frames in flight, avoiding timeout and maintaining throughput.
Clue confirmation
The clue words "least", "never" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
✗
Configure the ISL to operate at 8 Gbps to reduce the buffer credit requirement.
Why it's wrong here
Halving speed would halve the needed credits, but it also halves available bandwidth.
✗
Implement FCIP over the existing dark fiber to offload buffer credit management.
Why it's wrong here
FCIP would introduce TCP overhead and does not solve the buffer credit issue.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Many certification questions include familiar terms but test a specific constraint. Read the exact wording before choosing an answer that is generally true but wrong for this case.
Detailed technical explanation
How to think about this question
This question should be treated as a scenario, not a definition check. Identify the problem, the constraint and the best action. Then compare each option against those facts.
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.
Use explanations to understand the rule behind the answer.
TExam Day Tips
→Underline the problem statement mentally.
→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 practitioner preparing for the 350-601 exam encounters this exact type of scenario on the job. The correct answer here is not the most general option — it is the best answer for the specific constraint described. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Real exam questions reward reading the full scenario before eliminating options, because the constraint defines which answer fits.
What to study next
Got this wrong? Here's your next step.
Identify which 350-601 exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
Storage Network — This question tests Storage Network — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Increase the buffer-to-buffer credit count to 300 on the ISL interfaces. — Increasing buffer credits resolves the timeout issue due to credit starvation. Option D is correct. Option A is wrong because the links are physically direct; FCIP is not needed. Option B is wrong because NPIV is not related to buffer credits. Option C is wrong because reducing speed lowers performance.
What should I do if I get this 350-601 question wrong?
Identify which 350-601 exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
Are there clue words in this question I should notice?
Yes — watch for: "least", "never". You want the option with minimum overhead, fewest steps, or lowest impact — not the most feature-rich or comprehensive answer.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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