How should I use these Layer 2 Switching And VLANs practice questions?

Read each scenario carefully and choose your answer before revealing the explanation. Then check why your choice was right or wrong. Repeat until the reasoning feels automatic.

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Yes — use the session launcher on this page to start a 10-, 20-, 30- or 50-question session drawn entirely from the Layer 2 Switching And VLANs domain.

JNCIS-ENT · topic practice

Layer 2 Switching And VLANs practice questions

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.

Courseiva uses original exam-style practice questions designed for learning and revision. The goal is to understand the concepts, recognise exam patterns, and improve through explanations — not memorise copied exam dumps.

Editorial oversight:Johnson Ajibi· MSc IT Security, IEEE Senior Member

20 questionsDomain: Layer 2 Switching And VLANs

Practice 10 questions Browse domain →

What the exam tests

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.

Practice set

Layer 2 Switching And VLANs questions

20 questions · select your answer, then reveal the explanation

Question 1mediummultiple choice

Layer 2 Switching And VLANs practice questions

What to know about Layer 2 Switching And VLANs

Why Layer 2 Switching And VLANs questions are commonly missed

Common Layer 2 Switching And VLANs exam traps

Layer 2 Switching And VLANs questions

You are configuring Q-in-Q tunneling on an enterprise EX4600 switch. The customer-facing edge port must encapsulate incoming customer frames with an outer VLAN tag of 200. Which port mode should be configured on the customer-facing interface?

While reviewing the MAC address table on an EX Series switch using 'show ethernet-switching table', you notice a specific MAC address has a 'Flags' field showing 'L'. What does the 'L' flag indicate?

An engineer must configure an EX Series switch trunk port to allow all VLANs while explicitly blocking VLAN 50. Which Junos configuration statement accomplishes this behavior?

On an EX Series switch, you have configured private VLANs (PVLANs) where community VLAN ports need to communicate with a designated promiscuous port, but not with ports in other community VLANs. Which hierarchical configuration is mandatory to bind the primary VLAN and secondary VLANs together?

An engineer configures Selective QinQ on an EX Series switch. Incoming customer frames tagged with VLAN 10 must be mapped to outer VLAN 500, while frames tagged with VLAN 20 must be mapped to outer VLAN 600. Which configuration component is required to achieve this granular mapping?

An administrator wants to verify the configured access VLAN and port mode on interface ge-0/0/2. Which operational command should be used?

You are configuring a trunk port on an EX Series switch and need to specify that untagged frames received on this port should be placed into VLAN 10. Which command accomplishes this?

You are configuring multiple VLANs on an EX Series switch and wish to set the aging time for learned MAC addresses to 600 seconds. Where is this parameter configured?

An administrator needs to delete a MAC address entry from the ethernet-switching table on an EX Series switch due to a stuck entry. Which operational command is used?

An administrator configures an interface as a trunk port on an EX Series switch, but forgets to specify any VLAN members. By default, how does Junos handle VLAN membership on a newly configured trunk port?

An enterprise network requires QinQ tunneling where the outer tag EtherType must be explicitly set to 0x88a8 (802.1ad) instead of the standard 0x8100. Where is the custom outer TPID configured on a Junos EX Series switch?

You need to limit the number of dynamic MAC addresses learned on access interface ge-0/0/5 to a maximum of 10 to prevent MAC flooding attacks. Which configuration accomplishes this?

An administrator notices that MAC address flapping is occurring between two ports on an EX Series switch due to an unauthorized bridge loop. Which Junos feature can be enabled to automatically detect and action on MAC address movement anomalies?

An administrator wants to check the total number of active VLANs currently configured on a Junos EX Series switch. Which operational command should be used?

An engineer is deploying Selective QinQ where customer inner VLAN tags must be preserved while the outer tag is swapped or added based on ingress port rules. Which Junos statement enables tag preservation?

You are configuring an access port on an EX Series switch and want to ensure that if a MAC address is learned on the port, it persists even after a switch reboot or aging timer expiration. Which configuration attribute achieves this?

An EX Series switch is configured with a private VLAN primary VLAN 10 and secondary isolated VLAN 20. An administrator wants to verify the active private VLAN port associations and mappings. Which operational command displays this information?

An administrator needs to remove VLAN 20 from a trunk port that currently allows all VLANs. Which configuration command correctly prunes VLAN 20?

You are troubleshooting an issue where devices on VLAN 10 cannot communicate across switches because frames are dropping. You suspect a native VLAN mismatch on the interconnecting trunk link. Which operational command helps identify the native VLAN configuration on all trunk ports?

You are configuring voice and data VLANs on an EX Series access port. You want the IP phone to process tagged voice traffic for VLAN 50 and pass untagged data traffic from a connected PC into access VLAN 10. Which configuration achieves this?

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