Which Four Steps Are Needed To Configure A Voice Vlan On A Switch Port? (Choose Four).

Which four steps are needed to configure a voice VLAN on a switch port? (Choose four).

• As the IEEE 802.1Q trunk the configuration of the interface.
• On the switch, the port allocates the Voice VLAN.
• On an interface the activation of the spanning-tree port fast.
• Addition of a voice VLAN.
• Make sure voice traffic is reliable and labeled even with the priority value CoS.
• With secondary interfaces, the configuration of a switch port interface.
• In the access, mode configures the port.
• To a switch, the port allocates the data VLAN.

Answer: For the addition of IP phone some o the commands need to be added on the port which are:

• SW3(config-vlan) # vlan 150
• SW3(config-vlan) # name voice
• SW3(config-vlan) # int fa0/20
• SW3(config-if) # switchport mode access
• SW3(config-if) # mls qos trust cos
• SW3(config-if) # switchport access vlan 150.

What do you know about Voice VLAN?

A voice VLAN is designed for the user voice data streams.it works by ensuring that the voice quality is perfect by improving the transmission of the streams. When it is moving along with another kind of traffic. During the transmission of it with other traffic the voice has the advantage because it will prioritize as compared to others.

Working of the Voice VLAN:

For the priority, the voices streams need to be identified first. The identification of the voice data streams happens in two ways: The first one is MAC address-based mode that can determine the origin MAC addresses received frames, other is VLAN-based mode which finds the VLAN tags of the received frames.

MAC address-based mode:

In this mode, the switch works by determining whether the data streams are voice data or not on the base of the origin MAC address of the data frames which enter the interface. The switch performs the processing after the frames sent by the PC and IP phone which is: if the MAC address of the source is the same as the OUI configured on the switch. the voice VLAN tag add along with frames, and their priority increased. If the address does not match with OUI, then the PVID VLAN tag is attached with the frames and it will not send with its priority.

VLAN-based mode:

In this mode, the switch finds if the packets are the voice packet on the base of the VLAN ID that enters the interface.at first, the IP phone sends the packets to the switch. After the switch received the frames, it can add the voice VLAN information in the related field and send them back.

For the packets that contain the voice VLAN information, the IP sends them along with tags again, if they are the same as the configured voice VLAN on the switch, then the switch sends the priority of frames. This way helps the switch to ensure that when the network congestion happens the priority transmission of the voice packets happens.

PROS of the Voice VLAN:

The advantage of the voice VLAN is described below:

• It can make sure that the device VoIP does not need to withstand directly the broadcast of the VLAN data.
• In some cases, it can make the configuration easy and simple.
• It can also prioritize various voice services.