VLan help

leigh_boy · 3 Jul 2015 at 10:01

hi guys im in a bit of a pickle here, im heading over to our china office next month and they are moving to a new office that only has enough network ports for either pc'c or ip phones, the issue is china telecom want something silly like 10k £ and 6K in line rental to install 30 pstn lines (current setup) and run cables all round the building so we scratched that off, so we are going to install voip phone system, but we will have to use the lan jacks on the phones to pass through to the computers.

now that i have planted that concept, I will need to Vlan the phones from the pc's

so it will look a bit like this

server-----switch -----phone--------pc
-------------------- vlan20 ------ vlan 1

can this be done?
i would have thought so just dependent on the hardware.
I then need QOS so that phones get priority in the switch using hp 2920's
oh and then i need the server to deliver dhcp to both vlans

help!?

lude1962 · 3 Jul 2015 at 10:08

I'm no expert but doesnt the voip system ie cisco separate the phones from your normal lan

as its Friday I'll add some more non expert thoughts, you want 2 vlans to each switch port, ie vlan1 for phones, vlan2 for pc's, that sounds complicated and seems to defeat the object of having vlans.

when you say switch do you mean switch or router ?

dhcp side is the easy bit just a matter of setting up the correct scopes

leigh_boy · 3 Jul 2015 at 11:59

ok so with IP phones it is good practice to separate them from the rest of the network so that QOS can be setup for the best performance, with cisco phones they use dhcp 150 and this will tell the phone what vlan to go on and the pc port on the phone will then trunk the other vlan for the pc, not complicated

when i say switch i mean switch the diagram is not perfect lol but basically the phone system is on 1 vlan and everything else is on another and the router will r in this case cisco ASA will route the phone vlan to the gateway for any voip calls although most likely will go out over PRI on a tagged port

Illusion · 9 Jul 2015 at 10:10

This is absolutely doable with enterprise level IP phones, I would imagine it makes more sense to have the computers untagged into one vlan and the phones tagged to another as decent VoIP phones will be able to support vlan tagging. This will depend on what sort of comfig options the phones offer you though. Other than this its just a case of passing the vlans to relevant devices to do DHCP and qos/shaping.

@lude1962 passing two vlans over a port is not complicated and doesn't defeat the point of vlans what so ever...!

Leigh boy I'd be happy to help you out with this if needs be I have extensive experience with this type of setup and HP switching. Email available in trust if you have any questions.