Voice and Data using two ports

One solution is to run a second LAN drop to each cubicle. This is the simplest solution from the networking perspective: ccna voice

Voice VLAN – Auxiliary VLAN – Two Ports

One port is dedicated to carrying Data traffic, the other is dedicated to carrying Voice traffic. They are distinguished on the Switch using a simple access port in two different VLANs (the Data VLAN and the Voice VLAN):

Configurationshow runshow vlan brief

Switch(config)# vlan 22

Switch(config-vlan)# name DATA

Switch(config)# vlan 33

Switch(config-vlan)# name VOICE

Switch(config)# interface ethernet0/0

Switch(config-if)# switchport mode access

Switch(config-if)# switchport access vlan 22

Switch(config)# interface ethernet0/1

Switch(config-if)# switchport mode access

Switch(config-if)# switchport access vlan 33

Most modern office buildings now include multiple ports at each cubicle in order to account for multiple devices that need to be connected to the corporate network. Unfortunately, this wasn’t always an option for office’s which were not recently built.

Voice and Data using one port

A lot of older office build outs, which already only have one LAN drop at each cubicle, simply cannot afford the additional cost or delays to pay another technician to crawl through all the ceilings and walls to run another LAN drop to each cubicle. Which means the cubicles are limited to a single LAN drop per employee.

VOIP phone manufacturers were able to foresee this problem, and created another solution built right into the VOIP phones themselves.

The majority of VOIP phones come with two Ethernet ports: One meant to face the wall jack (and subsequently, the corporate LAN), the other meant to face a PC:

Voice VLAN – Auxiliary VLAN – Back of VOIP Phone

Using these two ports, the PC can be connected to the phone, and the phone can subsequently be connected to the single wall jack. This allows both devices to share a single wall jack.

Voice VLAN – Auxiliary VLAN – One Port for two VLANs

The key is how to configure the switch, as now the single port will be receiving both Voice and Data traffic. We’ve already determined that Voice and Data traffic must be confined to distinct VLANs, but now both types of traffic are arriving on a single port.

There are two solutions: One solution is to configure the port as a Trunk port. The other is to make use of the Auxiliary VLAN (or Voice VLAN) feature. Both solutions are discussed and compared below.

Voice and Data using a Trunk port and the Native VLAN

Traditionally, if you want to carry traffic for multiple VLANs on a single port, you would configure a Trunk port.

This would allow traffic for multiple VLANs to traverse the single link. But typically traffic on trunk ports require tagging to distinguish which bits belong to one VLAN and which bits belong to another VLAN.

VOIP phones have the capacity to send and understand 802.1q VLAN tags, and can therefore be configured to send a VLAN tag for all the Voice traffic.

PC’s, as we’ve already discussed, only send untagged traffic. As such, the switch must have a way to associate the received untagged traffic on the trunk port to a particular VLAN. This is the exact purpose of the Native VLAN.

Therefore, in order to properly configure a single port to accommodate both a Voice and Data VLAN, you must first configure the interface as a Trunk port, then configure the Data VLAN as the Native VLAN: