A network engineer is setting up a new VoIP network for a customer. The current network is segmented only for computers and servers. No additional…

To integrate a VoIP system into an existing network without using additional switchports, the engineer must configure the switches to allow both a computer and a VoIP phone to share a single physical port. This is accomplished by creating a dedicated Voice VLAN (Virtual LAN) to logically separate the voice traffic from the data traffic. This separation is crucial for applying Quality of Service (QoS) policies to prioritize the delay-sensitive voice packets.

To carry traffic from both the data VLAN and the new voice VLAN over a single physical link to the switch, the IEEE 802.1Q protocol must be enabled. This protocol allows Ethernet frames to be "tagged" with a VLAN ID, enabling a single switchport to handle traffic for multiple VLANs simultaneously.

A. Change network translation definitions: Network Address Translation (NAT) is used at the network edge to translate private to public IPs, not for internal LAN segmentation.

C. Implement a routing protocol: A routing protocol is used for communication between different networks (routers), not for configuring VLANs on a local switch.

E. Reconfigure the DNS: DNS is for name resolution. While VoIP systems use DNS, reconfiguring it is not a primary step for creating the required network segmentation.

F. Place devices in the perimeter network: The perimeter network (DMZ) is a security zone for public-facing servers, which is an inappropriate and insecure location for internal user phones.

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1. Cisco Systems

Inc.

"Configuring Voice VLAN

" System Management Configuration Guide

Cisco IOS XE Gibraltar 16.12.x (Catalyst 9300 Switches). This guide details the standard industry practice: "The voice VLAN feature is for use on switch access ports. The feature enables access ports to carry IP voice traffic from an IP phone... You can configure an access port to send Cisco Discovery Protocol (CDP) packets that instruct an attached IP phone to send voice traffic to the switch in one of three ways... on the voice VLAN

which is tagged with a Layer 2 CoS priority value." This directly supports the need for a voice VLAN (D) and the underlying use of VLAN tagging (802.1Q) (B).

2. IEEE Std 802.1Q-2018

"IEEE Standard for Local and metropolitan area networks—Bridges and Bridged Networks

" IEEE Standards Association. Clause 9

"VLAN-aware Bridge components

" defines the frame format and procedures for VLAN tagging. This standard is the foundation that allows a single physical port to multiplex traffic from different VLANs

which is essential for a shared voice/data port.

3. Michigan Technological University

"Enterprise Network Administration (SAT3310) - VLANs

" Courseware. The section on Voice VLANs states: "A common scenario is to have an IP phone and a PC on a user's desk... The switch port is configured as an access port in the data VLAN

but it is also configured with a voice VLAN... The phone then tags its own voice traffic with the 802.1Q voice VLAN ID." This academic source confirms that setting up a voice VLAN (D) and using 802.1Q tagging (B) are the correct procedures for this scenario.