Before I go into the benefits of VLANs, I think I should quickly explain what a VLAN is:
What is a VLAN?
A Virtual Local Area Network (VLAN) is a way to segment your network virtually without having a need for physical separation (i.e. multiple switches and Ethernet cables). The VLAN allows for segmenting at the port level down to even the packet level with VLAN tagging.
Why should I VLAN my network?
- Redundancy & Fail-over: If you are planning or needing to have two or more DHCP servers running on one network you will need VLANs. Common if you want to have two Internet connections going through two separate routers.
- Voice Quality: If you want to prioritize the voice traffic on your network over other traffic (data or video).
- Security: If you want to protect your voice traffic on your network from internal users or viruses.
How do I configure my IP phones for the Voice VLAN?
Each phone is a little different and will require Administrative credentials to accomplish. The best way to set this up is to:
- Default the phone to factory settings
- Setup the phone on the proper VLAN.
- After getting the phone up on the network, follow the specific phone guides to re-provision the phone onto our network.
Note: We will not overwrite the VLAN setting on the phone.
Drawing and Explanation
In the diagram below we have outlined an office with 3 desk phones and a conference room.
For VLANs the router is not doing anything special, unless you have a carrier network that supports QoS tagging. Then it could, if the router supports it tag all voice VLANs for higher priority, but this is still rare in carrier networks.
The switch is really doing the bulk of the work. There are 2 VLANs setup here. Voice is dark red and Data is represented by the light red line. This setup only required 5 ports on the switch. 1 is Data VLAN Only (Printer), 1 is Voice VLAN Only (conference) and 3 are setup for both voice and data since the same physical cable is handling a phone and a computers traffic.