easyMultiple Choice
300-410 Practice Question: Which BGP message type is sent when a fatal error…
Which BGP message type is sent when a fatal error is detected, causing the BGP session to close?
⚠ Common exam trap
The trap is confusing KEEPALIVE with NOTIFICATION — candidates may think KEEPALIVE closes the session when it fails, but KEEPALIVE only maintains the session; NOTIFICATION is the explicit error message that triggers closure.
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
✓
NOTIFICATION
The BGP NOTIFICATION message is sent when a fatal error is detected, such as a hold timer expiration, a malformed attribute, or a configuration mismatch. Upon sending or receiving a NOTIFICATION, the BGP session is immediately closed. This is defined in RFC 4271.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
OPEN
Why it's wrong here
OPEN negotiates session parameters at peer establishment and carries no error-handling function; a fatal error triggers a NOTIFICATION message instead. OPEN is correct only when initiating a BGP peering, exchanging version, hold time, router ID and capabilities before any routes flow.
- ✗
UPDATE
Why it's wrong here
UPDATE advertises and withdraws reachability information, so it cannot signal session teardown; a fatal error is reported via NOTIFICATION, which closes the session. UPDATE would be the right message when propagating new prefixes or withdrawing unreachable routes between established peers.
- ✓
NOTIFICATION
Why this is correct
NOTIFICATION carries the error code and subcode identifying the fatal condition, then the session tears down immediately. It is the only BGP message type designed to report errors and terminate the peering, satisfying the stem's requirement that the session closes on detection of a fatal error.
- ✗
KEEPALIVE
Why it's wrong here
KEEPALIVE merely confirms the peer is reachable within the hold time and carries no error codes; NOTIFICATION is the message that reports a fatal error and closes the session. KEEPALIVE is correct when maintaining an idle but established peering between UPDATE transmissions.
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JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official Cisco exam blueprint
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.