350-501 Architecture Practice Question
A service provider is designing a core network with IS-IS as the IGP. To support MPLS traffic engineering, which IS-IS extensions are required?
⚠ Common exam trap
Cisco often tests the distinction between wide metrics (which are a prerequisite for TE extensions) and the TE extensions themselves, leading candidates to mistakenly select wide metrics as the answer when the question specifically asks for the extensions that enable MPLS TE.
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
✓
IS-IS TE extensions (RFC 5305)
IS-IS TE extensions (RFC 5305) are required to carry MPLS Traffic Engineering information, such as link bandwidth, administrative groups, and TE metric, in Type-Length-Value (TLV) fields within IS-IS Link State PDUs. These extensions enable the IGP to flood TE attributes that MPLS TE uses for constraint-based path computation, such as with RSVP-TE or Segment Routing.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
IS-IS multi-topology (MT)
Why it's wrong here
MT is for separate topologies, not directly for TE.
- ✓
IS-IS TE extensions (RFC 5305)
Why this is correct
TE extensions advertise link bandwidth, admin-group, etc.
- ✗
IS-IS wide metrics
Why it's wrong here
Wide metrics allow larger cost values but do not carry TE attributes.
- ✗
IS-IS L1/L2 routing
Why it's wrong here
L1/L2 routing is standard IS-IS behavior, not specific to TE.
Visual reference
Go deeper
Related to this question
About these practice questions
This 350-501 question is part of Courseiva's 971-question bank — original exam-style content with full explanations and wrong-answer analysis, never real exam questions or exam dumps. Learn why practice questions differ from exam dumps →
JA
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.