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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?

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migrated from superuser.com Sep 27 '10 at 21:08

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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

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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.

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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

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