JNCIP-ENT EVPN Practice Question
You are analyzing BGP EVPN updates and observe an Extended Community attached to a Type-2 route containing a sequence number. What is the primary function of this MAC Mobility Extended Community?
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 facilitates loop-free MAC movement tracking by incrementing sequence numbers when a host changes attachment PEs.
The MAC Mobility Extended Community carries a sequence number used to resolve MAC moves. If a host moves from one PE to another, the new PE advertises the MAC with an incremented sequence number, causing all other PEs to update their tables to point to the new location.
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 signals the EVPN split-horizon label for BUM traffic.
Why it's wrong here
Split-horizon uses the ESI label extended community, not the MAC mobility community.
- ✓
It facilitates loop-free MAC movement tracking by incrementing sequence numbers when a host changes attachment PEs.
Why this is correct
MAC mobility sequence numbers ensure that the network correctly updates MAC locations and prevents blackholing during rapid MAC moves.
- ✗
It determines the Designated Forwarder for multi-homed Ethernet segments.
Why it's wrong here
Designated Forwarder selection is handled by Type-4 routes and segment parameters, not MAC mobility communities.
- ✗
It defines the VXLAN Network Identifier (VNI) mapping for data-plane decapsulation.
Why it's wrong here
VNI mapping is carried via route targets or tunnel encapsulations, not MAC mobility communities.
Visual reference
Quick reference
Access Control Model Comparison
| Model | Acronym | Who Controls Access? | Best For |
|---|---|---|---|
| Discretionary Access Control | DAC | Resource owner | Small teams, file shares |
| Mandatory Access Control | MAC | System / security labels | Classified govt / military |
| Role-Based Access Control | RBAC | Administrator (via roles) | Enterprise environments |
| Attribute-Based Access Control | ABAC | Policy engine (user + resource attributes) | Fine-grained, dynamic policies |
| Rule-Based Access Control | RuBAC | System rules / ACLs | Firewall rules, network ACLs |
About these practice questions
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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 Juniper Networks exam blueprint
This JNCIP-ENT practice question is part of Courseiva's free Juniper Networks 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 JNCIP-ENT exam.