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

I already have a network for 4 kind of purpose (Local Network, VoIP, Accounting Depart, Sales Depart). All of them on same network (

I'm planning to separate these networks and i have decided use VLAN. I will use dd-wrt loaded Linksys WRT54GL for this purpose.

Can I use present dummy switches with multiple VLANs or do i have to separate all departments with cables and switches ? This option very hard for me because voip phones beside of computers and connected to same switches.

I would appreciate any suggestions.

Regards, ibrahim

share|improve this question

the only way of mixing "blind" switches with dot1q switches is by cascading "simple switches" out from a port set in access mode with only one vlan - this way each branch of the network coming out of the dot1q enabled switch will act as a single network

share|improve this answer

i had both taged trunk going across 'dummy switch' and working fine and failing to pass thru. i guess it has something to do with 'simple switches' not being able to pass slightly longer frames [ containing vlan tag ].

so.. just try passing trunk via cheap switch, see if it works and let us know.

share|improve this answer
you can pass vlan trunks across dummy switches but you still need a vlan aware switch or network drivers at the end to split it out – JamesRyan Aug 27 '09 at 15:09
@EK - well not exactly. i had dummy switches that refused to pass tagged frames. – pQd Aug 27 '09 at 16:01

Dumb switches can't do anything with VLAN tagged packets...except remove the tagging, as mentioned previous posts.
What is your goal in doing this? If you are trying to use VLAN tagging with priority tagging to separate your VOIP traffic from network traffic, you really need to get some smart switches. Otherwise, don't go through the hassle of setting up VLANs, it will increase complexity of your network with little gain... My .02

share|improve this answer
my network is not so big and i do not want to spend money to extra switch costs. I want to use my exist structure. Separate networks with cabling is too hard work for me. Only one cable goes to rooms and distribute network with switches and all staff has voip phone on desk. – Anonymous Sep 9 '09 at 14:23

Your Answer


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