Quick Answer
The answer is unlimited, but limited by platform resources. According to RFC 5880, no maximum number of BFD sessions per interface is specified, meaning the protocol itself imposes no hard cap; instead, the limit is determined entirely by the router’s available CPU, memory, and hardware forwarding capacity. On the Cisco CCNP ENARSI 300-410 exam, this concept tests your understanding that BFD is a lightweight, session-oriented protocol designed for scalability, and the common trap is assuming a fixed limit like 32 or 64 sessions per interface. Remember that while Cisco routers can support many BFD sessions on a single interface, each session consumes timers and state information, so the actual ceiling depends on the platform’s resource budget. Memory tip: “BFD has no built-in fence—only your platform’s resources make the final sense.”
This 300-410 practice question tests your understanding of bidirectional forwarding detection (bfd). 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.
According to RFC 5880, what is the maximum number of BFD sessions that can be supported by a single interface on a Cisco router?
1 session per interface
Why wrong: Multiple BFD sessions can exist on the same interface, one per neighbor.
256 sessions per interface
Why wrong: This is a platform-specific limit, not an RFC-defined limit.
Unlimited, but limited by platform resources
Correct. RFC 5880 does not define a maximum; it is implementation-specific.
16 sessions per interface
Why wrong: This is not an RFC-defined limit.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
Unlimited, but limited by platform resources
RFC 5880 does not specify a maximum number of BFD sessions per interface; it is platform-dependent. Cisco routers can support multiple BFD sessions per interface, limited only by hardware resources.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
For each option: why learners choose it and why it is or isn't the right answer here.
1 session per interface
Why it's wrong here
Multiple BFD sessions can exist on the same interface, one per neighbor.
256 sessions per interface
Why it's wrong here
This is a platform-specific limit, not an RFC-defined limit.
Unlimited, but limited by platform resources
Why this is correct
Correct. RFC 5880 does not define a maximum; it is implementation-specific.
Related concept
Read the scenario before looking for a memorised answer.
16 sessions per interface
Why it's wrong here
This is not an RFC-defined limit.
Common exam traps
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
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.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
A practitioner preparing for the 300-410 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
Identify which 300-410 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.
Bidirectional Forwarding Detection (BFD) — study guide chapter
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FAQ
Bidirectional Forwarding Detection (BFD) — This question tests Bidirectional Forwarding Detection (BFD) — Read the scenario before looking for a memorised answer..
The correct answer is: Unlimited, but limited by platform resources — RFC 5880 does not specify a maximum number of BFD sessions per interface; it is platform-dependent. Cisco routers can support multiple BFD sessions per interface, limited only by hardware resources.
Identify which 300-410 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.
Read the scenario before looking for a memorised answer.
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Last reviewed: Jun 18, 2026
This 300-410 practice question is part of Courseiva's free Cisco certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the 300-410 exam.
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