LevelOne GEL-5261, User Manual

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VoIP Traffic Configuration
This chapter covers the following topics:
◆ Global Settings – Enables VOIP globally, sets the Voice VLAN, and the aging
time for attached ports.
◆
Telephony OUI List – Configures the list of phones to be treated as VOIP devices
based on the specified Organization Unit Identifier (OUI).
◆ Port Settings – Configures the way in which a port is added to the Voice VLAN,
the filtering of non-VoIP packets, the method of detecting VoIP traffic, and the
priority assigned to voice traffic.
Overview
When IP telephony is deployed in an enterprise network, it is recommended to
isolate the Voice over IP (VoIP) network traffic from other data traffic. Traffic
isolation can provide higher voice quality by preventing excessive packet delays,
packet loss, and jitter. This is best achieved by assigning all VoIP traffic to a single
Voice VLAN.
The use of a Voice VLAN has several advantages. It provides security by isolating the
VoIP traffic from other data traffic. End-to-end QoS policies and high priority can be
applied to VoIP VLAN traffic across the network, guaranteeing the bandwidth it
needs. VLAN isolation also protects against disruptive broadcast and multicast
traffic that can seriously affect voice quality.
The switch allows you to specify a Voice VLAN for the network and set a CoS priority
for the VoIP traffic. The VoIP traffic can be detected on switch ports by using the
source MAC address of packets, or by using LLDP (IEEE 802.1AB) to discover
connected VoIP devices. When VoIP traffic is detected on a configured port, the
switch automatically assigns the port as a tagged member the Voice VLAN.
Alternatively, switch ports can be manually configured.