Link to home
Start Free TrialLog in
Avatar of SpiderPig
SpiderPigFlag for United States of America

asked on

Segmenting VoiP from LAN on the network level

Hello all,
I have a customer with a very simple network, 2 WAN connections going into a Sonicwall TZ-210, then one switch on a 192.168.1.0 network with single CAT5e drops on each office. They are using RingCentral phones/ service. I would like to segment the VoIP from the LAN and basically have the phones go out to the world from the X2 WAN which is bunch of T1 and everything else will go out from X1 - fiber connection.

How would I go about achieving this? If I get a good HP switch that can do a layer 2-3 VLANs, will that solve my problem in being limited by office drops? Any ideas/ documentation on this?
Avatar of Korbus
Korbus

You could put all your LAN traffic on one subnet, say 10.0.0.X, and put all your VOIP traffic on another subnet, say 10.0.1.X.
Your sonicwall should be able to easily route any traffic coming from a 10.0.1.X address out your, X2 connection.

This way, you can put BOTH sub-nets on a single cable, assuming the phones are the ones with two plugs- one to the router, one to the PC (it acts like a tiny hub).  No special switch is needed either.
Avatar of SpiderPig

ASKER

Problem is I dont want to go around and change phones to a static IP, if I keep the Sonicwall as the DHCP server, it wouldnt know how to assign IPs to the different devices right? Unless I use vLANs like a layer 3 vLAN which is not on the port level.
I don't think you will be able to broadcast a different DHCP scope to two devices on the same network cable.  Then again, I suppose you could punch in all the phones MAC addresses, to assign a specific address in the DHCP server (assuming your DHCP server has that capability), but this wont be much different that just assigning them a static IP.

I don't see how a VLAN would help with this at all, though I'm not really sure what you mean by a layer 3 VLAN, layer 3 is the IP layer, right?  As far as I was aware, each VLAN would need to be on it's own cable or more specifically, it's own port on the VLAN capable switch (layer 2).   In other words, each port/cable can be assigned only to a single VLAN.

I suppose a VLAN capable switch AT the user's DESK, to take the single incoming cable, an make two vlans out of it, would work the way you want.  But that will get expensive real fast, and probably wont provide any bandwidth/traffic benefit.

I think you will either need to use a second cable to each desk, or manually assign the phone addresses (static or by MAC&DHCP).
It depends on your network gear and your DHCP server.  Most enterprise level gear and software will have no problem doing what you ask.  but simple mom and pop level gear and software, not so much.   A managed switch like a layer 3 HP should allow for you to configure a DHCP listener on the vlan interface.  The DHCP server needs to be aware of the subnet associated with the VLAN.  If yours does then that is all you need to do.   However depending on the number of phones and computers, it may just be more efficient to just hard code different gateways.
A managed switch like a layer 3 HP should allow for you to configure a DHCP listener on the vlan interface.

When you say vlan interface, you mean a particular port on the switch, assigned to than VLAN, right?  

If so, note the OP has only one cable (and so, port on the switch) to connect BOTH the phone and PC.  How would the switch know which VLAN to put each device on?  And, how would 2 VLANS on the same cable, be any different from just 2 sub-nets on the same cable?

If not, I'm interested in what you meant, could you please clarify.
And thats what I originally wanted to know :) I guess thats where layer 3 VLAN comes in handy no?

And yes, I was thinking of getting this one:
http://www8.hp.com/us/en/products/networking-switches/product-detail.html?oid=5354564#!tab=features

My sonicwall is capable of running multiple DHCPs assigned to different networks and zones. One thing I cannot fix is single connection shared by both phone and PC...
ASKER CERTIFIED SOLUTION
Avatar of Korbus
Korbus

Link to home
membership
This solution is only available to members.
To access this solution, you must be a member of Experts Exchange.
Start Free Trial
SOLUTION
Link to home
membership
This solution is only available to members.
To access this solution, you must be a member of Experts Exchange.
Start Free Trial
So in essence if I have two devices which will connect to the same switch port, I cannot use tag the port as a specific VLAN as it will effect the other device connected to that port? So we are back to square zero, unless we consider creating another zone on the firewall and then assign that DHCP to that zone and then either config MAC addresses or just manually configure a different IP on the phones. Correct?
Afraid so.
Thank you guys, and sorry for the delay.