Voice VLAN Overview
In a LAN, voice devices, such as IP phones, VoIP endpoints, and voice systems are placed into the same VLAN. This VLAN is referred as the voice VLAN. If the voice devices are in different voice VLANs, IP (L3) routers are needed to provide communication.
This section contains the following topics:
The following are typical voice deployment scenarios:
- UC3xx/UC5xx hosted: All Cisco phones and VoIP endpoints support this deployment model. For this model, the UC3xx/UC5xx, Cisco phones and VoIP endpoints reside in the same voice VLAN. The default voice VLAN of UC3xx/UC5xx is default to VLAN 100.
- Third party IP PBX-hosted: Cisco SBTG CP3xx, CP5xx phones and SPA8xxx endpoints support this deployment model. In this model, the VLAN used by the phones is determined by the network configuration. There may or may not be separate voice and data VLANs. The phones and VoIP endpoints register with an on-premise IP PBX.
- IP Centrex/ITSP hosted: Cisco CP3xx, CP5xx phones and SPA8xxx endpoints support this deployment model. For this model, the VLAN used by the phones is determined by the network configuration. There may or may not be separate voice and data VLANs. The phones and VoIP endpoints register with an off-premise SIP proxy in “the cloud”.
From a VLAN perspective, the above models operate in both VLAN-aware and VLAN-unaware environments. In the VLAN-aware environment, the voice VLAN is one of the many VLANs configured in an installation. In the VLAN-unaware scenario, it is equivalent to the VLAN aware environment where the devices operate with the default VLAN being the only existing VLAN and also being the voice VLAN.
The switch always operates as a VLAN aware switch.
The switch supports a single voice VLAN. The voice VLAN is defaulted to VLAN 1. A different voice VLAN can be manually configured. It can also be dynamically learned when Auto Voice VLAN is enabled.
Ports can be manually added to the voice VLAN by using basic VLAN configuration as described in the Configuring VLAN Interface Setting section, and by manually applying voice related Smartport macro to the ports. Alternatively, they can be added dynamically if the switch is in Telephony OUI mode, or has Auto Smartports enabled.