150-130 · Question #108
What are two uses for port-based VLANs? (Choose two.)
The correct answer is A. Create separate broadcast domains inside a single Layer 2 network. D. Separate user traffic into different logical network segments based on department. See the full explanation below for the reasoning.
Question
What are two uses for port-based VLANs? (Choose two.)
Options
- ACreate separate broadcast domains inside a single Layer 2 network.
- BSegregate traffic at Layer 3.
- CEliminate the need for routers between different subnets.
- DSeparate user traffic into different logical network segments based on department.
How the community answered
(58 responses)- A83% (48)
- B12% (7)
- C5% (3)
Community Discussion
8
Toby R.Jun 27, 2026A and D are your answers here. Port-based VLANs create separate broadcast domains within a single Layer 2 switch (that is exactly what they do at a fundamental level), and the classic real-world use case is separating users by department into different logical segments, like putting HR on one VLAN and Engineering on another. B is wrong because VLANs work at Layer 2, not Layer 3, and C is the opposite of true since you still need a router or Layer 3 switch to move traffic between VLANs.
Goran A.Jun 29, 2026Solid on B and C, and if you want to see that broadcast-domain isolation principle taken to its logical extreme, pull up VSANs on a Cisco MDS or Virtual Fabrics on a Brocade DCX, same segmentation idea inside a Fibre Channel fabric, separate name server per VSAN, separate FSPF topology, and you still need IVR to route traffic between them, same lesson Toby is describing, just a different alphabet.
Viktor S.Jun 27, 2026A and D, obvious once you remember VLANs are Layer 2, not Layer 3.
Toby R.Jun 29, 2026Right, though the exam also wants you to know that inter-VLAN routing still needs a Layer 3 device, so knowing VLANs are Layer 2 is only half the battle if the question is asking how hosts on different VLANs actually communicate.
Goran A.Jun 27, 2026I have been doing port segmentation on Brocade ICX stacks for years and C is absolutely one of the right picks here, alongside A. The whole point of throwing ports into separate VLANs is that traffic stays inside its own broadcast domain and you do not need a router hop to get from one end of the building to the other when both devices live in the same VLAN. That is literally the inter-VLAN routing problem that VLANs solve at Layer 2, you put the devices in the same segment and the router becomes unnecessary for that traffic path. Anyone who has watched a switchshow and seen how the fabric handles intra-VLAN frames knows they never leave the switch, no routing decision is made, that is the definition of eliminating the router requirement. D is too vague and B is just wrong because VLANs are a Layer 2 construct, so my answer is A and C, full stop.
Viktor S.Jun 29, 2026Goran, you have the intra-VLAN behavior right but you have the benefit backwards, because putting devices into separate VLANs is exactly what creates the requirement for a router between them, not what removes it. D covers the actual payoff of segmentation, which is containing broadcast traffic to smaller domains, and that is the reason the question pairs it with A.
Yusuf A.Jun 16, 2026B has to be one, VLANs literally segment traffic at Layer 3 boundaries.
Viktor S.Jun 17, 2026Yusuf, VLANs segment traffic at Layer 2, not Layer 3, so that reasoning collapses before it starts. A and D are correct because VLANs create separate broadcast domains at the data link layer, and a router or Layer 3 switch is still needed to move traffic between them.