easyMultiple Choice
350-401 The default STP hello timer value in seconds? Practice Question
What is the default STP hello timer value in seconds?
⚠ Common exam trap
Cisco often tests the distinction between the hello timer (2 seconds), forward delay (15 seconds), and max age (20 seconds), and candidates frequently confuse the hello timer with the forward delay or max age values.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
2 seconds
The default STP hello timer is 2 seconds, as defined by IEEE 802.1D. This timer controls how often a root bridge sends configuration BPDUs to maintain the spanning-tree topology. The hello timer value is used in conjunction with the forward delay and max age timers to ensure loop-free convergence.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
1 second
Why it's wrong here
1 second is the minimum configurable hello timer value, not the default. The IEEE 802.1D default hello is 2 seconds; while a 1-second hello would double BPDU frequency and can speed up failure detection in theory, it also doubles control-plane overhead, so it is not used as the standard default.
- ✓
2 seconds
Why this is correct
2 seconds is the correct default hello timer as defined by IEEE 802.1D for classic Spanning Tree Protocol. The root bridge sends a configuration BPDU every 2 seconds, and non-root bridges forward these BPDUs outward to maintain a stable, loop-free topology. This 2-second default is also used in Rapid Spanning Tree Protocol (RSTP) and Multiple Spanning Tree Protocol (MSTP).
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5 seconds
Why it's wrong here
5 seconds is not a default STP timer value; the IEEE 802.1D standard specifies only three default timers: hello (2 seconds), forward delay (15 seconds), and max age (20 seconds). A 5-second value could be a manual tuning choice, but it has no standard role and would fall between the hello and forward delay timelines, offering no operational advantage for default configurations.
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10 seconds
Why it's wrong here
10 seconds is not the default hello timer; it represents the upper boundary of the configurable hello interval range (1–10 seconds) in Cisco's STP implementation. The default hello is 2 seconds, and setting it to 10 seconds would cause configuration BPDUs to be sent only every 10 seconds, significantly delaying propagation of topology changes and slowing convergence.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This 350-401 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 350-401 exam.