CLCOR Protocols And Endpoints Practice Question
When a SIP phone initiates a call, which message does the CUCM send to acknowledge the initial INVITE?
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
✓
100 Trying
A '100 Trying' message is the standard response to indicate that the INVITE has been received and is being processed.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
401 Unauthorized
Why it's wrong here
401 is a challenge for credentials.
- ✓
100 Trying
Why this is correct
100 Trying is the provisional response.
- ✗
180 Ringing
Why it's wrong here
180 Ringing is sent when the destination is alerted.
- ✗
200 OK
Why it's wrong here
200 OK indicates the call is established.
About these practice questions
One of 263 original CLCOR practice questions on Courseiva, each with a full explanation and wrong-answer analysis — not exam dumps or protected exam content. Learn why practice questions differ from exam dumps →
JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed August 2026 · checked against the official Cisco exam blueprint
This CLCOR 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 CLCOR exam.