Dell POWERCONNECT 6200 SERIES Configuration Manual

Also see for POWERCONNECT 6200 SERIES: Getting started guide Getting started guide

Contents

Switching Configuration 37Voice VLANVoice VLAN enables switch ports to carry voice traffic with a defined priority in order to enable theseparation of voice and data traffic coming onto the port. A primary benefit of using Voice VLAN is toensure that the sound quality of an IP phone is safeguarded from deteriorating when the data traffic on theport is high.The inherent isolation provided by VLANs ensures that inter-VLAN traffic is under management controland that network attached clients cannot initiate a direct attack on voice components. QoS based on IEEE802.1P class of service (CoS) uses classification and scheduling to send network traffic from the switch in apredictable manner. The system uses the source MAC address of the traffic traveling through the port toidentify the IP phone data flow.IP Phones will use this VLAN. They will obtain their VLAN ID via CDP, DHCP or LLDP-MED. The voicetraffic is sent to the switch tagged. The setup protocols (CDP, DHCP, etc.) are not tagged.Using Voice VLANWhen an IP phone is connected to the switch, the voice traffic from the phone and the data traffic from thenetwork could potentially deteriorate the voice quality. You can overcome this in multiple ways usingdifferent options in Voice VLAN.You can configure the switch to support Voice VLAN on a port that is connecting the VOIP phone. Both ofthe following methods segregate the voice traffic and the data traffic in order to provide better service to thevoice traffic.• When a VLAN is associated with the Voice VLAN port, then the VLAN ID information is passed ontothe VOIP phone using the LLDP-MED mechanism. By this method, the voice data coming from theVOIP phone is tagged with the exchanged VLAN ID, thus regular data arriving on the switch is giventhe default PVID of the port, and the voice traffic is received on a pre-defined VLAN. As a result, bothkinds of traffic are segregated in order to provide better service to the voice traffic.