350-501 Networking Practice Question
In IS-IS, what is the purpose of the System ID portion of the NET address?
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
✓
It identifies the router within the area
The NET (Network Entity Title) consists of AFI, Area ID, System ID, and SEL. The System ID uniquely identifies a router within an area.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
It identifies the router within the area
Why this is correct
Correct; System ID is unique per router in the area.
- ✗
It identifies the area to which the router belongs
Why it's wrong here
The Area ID identifies the area.
- ✗
It indicates the routing protocol version
Why it's wrong here
There is no version field.
- ✗
It specifies the ISO layer (SEL) for routing
Why it's wrong here
SEL is the last byte, always 0 for a router.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This 350-501 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 350-501 exam.