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JNCIS-ENT · domain

Layer 2 Switching And VLANs

This domain covers Layer 2 forwarding on Juniper EX Series switches running Junos OS: VLAN creation and membership, access and trunk port configuration, native VLAN and tagged/untagged frame handling, and the MAC address table. Questions are scenario-based, asking you to pick the correct configuration steps or interpret operational command output when troubleshooting connectivity.

20 questions8 easy6 medium6 hard

Focused practice

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What this domain covers

What to know about Layer 2 Switching And VLANs

Be able to create a VLAN, assign a physical interface as an access port, and configure a trunk with correct tagged and native VLAN handling on EX Series switches. The single most important thing: match interface mode and VLAN membership so frames are forwarded in the intended VLAN.

Creating VLANs with 'set vlans' and assigning them to physical interfaces

Configuring access ports with 'interface-mode access' and 'vlan members'

Trunk ports with 'interface-mode trunk', 'vlan members', and native-vlan-id

Reading 'show ethernet-switching table' and 'show bridge mac-table' output

Why learners struggle

Why Layer 2 Switching And VLANs questions are commonly missed

Common Networking Hardware questions are often missed because learners confuse device functions and port types. The exam tests specific hardware features like PoE and managed switching that are easy to mix up.

  • ·Router vs switch — routing vs switching function
  • ·PoE vs PoE+ — power budget differences
  • ·Managed vs unmanaged — configuration capability
  • ·Access point vs router — wireless vs routing
  • ·Patch panel vs switch — termination vs active
  • ·Cat5e vs Cat6 — speed and frequency limits

Watch out for

Common Layer 2 Switching And VLANs exam traps

  • ▸Forgetting to set the interface mode to access before adding the VLAN membership, so the port stays in the default mode.
  • ▸Assuming a trunk carries untagged traffic without configuring native-vlan-id, causing untagged frames to be dropped or mishandled.
  • ▸Confusing 'show ethernet-switching table' with 'show bridge mac-table' and misreading which VLAN or interface a MAC was learned on.

Question index

All Layer 2 Switching And VLANs questions (20)

Click any question to see the full explanation, or start a practice session above.

1

An enterprise network design requires implementing private VLANs (PVLANs) on an EX Series switch. Which THREE components or port types are characteristic of a private VLAN architecture? (Choose three.)

Hard
2

You are reviewing the configuration of an EX Series switch and notice that interface ge-0/0/15 is configured with 'interface-mode access' but has no explicit 'vlan members' statement defined. Which VLAN does the interface default to?

Medium
3

An administrator needs to view the MAC address learning table on an EX Series switch to verify which switchport a specific server is connected to. Which operational command should be used?

Easy
4

You are configuring a Private VLAN (PVLAN) on an EX Series switch to isolate hosts within a DMZ segment while allowing them to reach a shared gateway. Which TWO statements correctly describe the behavior of PVLAN port types in this scenario? (Choose two.)

Medium
5

When configuring Private VLANs (PVLANs) on Juniper EX Series switches, which TWO types of ports are defined within the architecture? (Choose two.)

Hard
6

An administrator configures a new VLAN ID 300 on an EX Series switch but forgets to assign any interfaces to it. What is the operational status of this VLAN?

Easy
7

An enterprise network uses private VLANs. A server connected to an isolated port needs to send traffic out of the primary VLAN. Which statement accurately describes how traffic forwarding operates for an isolated port in Junos?

Hard
8

An administrator runs 'show vlans' and notices that a particular VLAN has the status 'Active' but no interfaces listed under it. What does this indicate?

Easy
9

An operator executes the command 'show bridge mac-table' on an EX Series switch running Junos OS. Which information is displayed in the output of this command?

Easy
10

An engineer is deploying Private VLANs on an EX Series switch and needs to verify proper operational status and traffic isolation. Which THREE tasks or verification checks should be performed? (Choose three.)

Hard
11

An administrator needs to delete an entire VLAN configuration named 'guest' along with its VLAN ID and associated properties. Which configuration command should be executed?

Easy
12

Which THREE parameters are typically verified when troubleshooting a missing MAC address entry in the bridge table of a Juniper switch? (Choose three.)

Medium
13

You are troubleshooting a Layer 2 connectivity problem where a trunk port is dropping tagged traffic for VLAN 50. Which TWO configuration checks should be performed? (Choose two.)

Medium
14

An administrator is configuring VLANs on a Junos EX Series switch. Which TWO tasks must be performed to successfully assign a physical interface as an access port for a newly created VLAN? (Choose two.)

Easy
15

An administrator is configuring a new EX Series switch running Junos OS and needs to assign an access port to VLAN finance. Which configuration hierarchy is used to assign an interface to a specific VLAN?

Easy
16

You are troubleshooting a connectivity issue between an EX4300 switch access port and an end-host. The port is configured as an access port for VLAN 100, but the host cannot communicate. You run 'show ethernet-switching interface ge-0/0/1' and notice the port status is down/down. Which underlying reason most likely explains this state?

Medium
17

An engineer is configuring a trunk port on an EX Series switch and needs to ensure that untagged and priority-tagged frames are handled correctly. Which TWO configuration actions are required? (Choose two.)

Medium
18

An EX4300 switch is configured with a trunk port that carries VLAN 10 and VLAN 20. The trunk is connected to a third-party switch that uses a native VLAN of 1 for untagged traffic. You notice that untagged frames from the third-party switch are being dropped on the EX4300. Which configuration change resolves this issue?

Hard
19

An administrator needs to create a VLAN named 'voice' with a VLAN ID of 50 on a Junos EX Series switch. Which configuration path achieves this?

Easy
20

An administrator is configuring Selective QinQ on an EX Series switch using VLAN translation. Which THREE components are required to successfully rewrite inner and outer VLAN tags? (Choose three.)

Hard

Frequently asked questions

What does the Layer 2 Switching And VLANs domain cover on the JNCIS-ENT exam?
Be able to create a VLAN, assign a physical interface as an access port, and configure a trunk with correct tagged and native VLAN handling on EX Series switches. The single most important thing: match interface mode and VLAN membership so frames are forwarded in the intended VLAN.
How many questions are in this domain?
This page lists all 20 Layer 2 Switching And VLANs questions in the JNCIS-ENT question bank. The actual exam draws from this domain proportionally to its weighting in the official exam blueprint.
What is the best way to practise this domain?
Start with a short focused session (10 questions) to identify gaps, then work through explanations. Repeat with a longer session once the weak areas feel solid.
Can I practise only Layer 2 Switching And VLANs questions?
Yes — the session launcher on this page filters questions to this domain only. Choose any session length for inline explanations and scoring.
Juniper Networks Enterprise Routing and Switching, Specialist (JNCIS-ENT, JN0-352) (JNCIS-ENT) Layer 2 Switching And VLANs Practice Questions