Server Fault is a question and answer site for system and network administrators. It's 100% free, no registration required.

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

Would you say Virtual LAN (VLAN) is superior to a traditional hardware switch? What are the pros and cons of using either of these technologies?

share|improve this question

migrated from Sep 27 '10 at 21:08

This question came from our site for computer enthusiasts and power users.

In what way do you want to know if one is superior to the other? Are cars superior to wheels? Are houses superior to bricks? Are hands superior to fingers? One is is part of the other, there is no "vs." here, as it isn't like you can say "switches suck, I'm gonna go and buy a couple of VLANs instead and not have any switches". I'm not sure if this is your homework question quoted verbatim or if you're just really bad at paraphrasing, but this makes little sense as it stands. – RobM Sep 27 '10 at 21:26
Sorry for my English. I know that a hardware switch will be needed what I mean was is it better to use all hardware switches or just create a VLAN and why. I'm trying to make a nice network here. I just wanted to make sure there wasn't a major disadvantage to a VLAN that I was missing. – 에이바 Sep 30 '10 at 1:00
up vote 10 down vote accepted

The main benefit of VLANs are flexibility, you're no longer restricted to one subnet per switch. This can have real benefits when replacing switches with larger models, as it allows you to have more than one subnet on a single switch, which saves both hardware and time required to renumber everything to a single subnet. In the case of our datacenter switch, we have six subnets on that thing (a Cisco 6509), and we were able to add a 7th (a firewall DMZ) with only some changes to the Cisco IOS config file in the switch.

share|improve this answer
Additionally some of these "switches" are so feature-rich that they actually become simple routers and can route between VLANed subnets. – Mark Wagner Sep 27 '10 at 22:12
There's also some downsides. VLANs (especially with trunks between switches, quite common as it were) have some interesting gotchas from a security POV. If you're relying on VLAns to segregate "hostile" networks, bear in mind that even an access port can act as a trunk, if you send .1q packets at it (in-so-far as it will then send packets on in the "wrong" VLAN). – Vatine Sep 28 '10 at 6:13

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.