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18-3
Catalyst 2950 and Catalyst 2955 Switch Software Configuration Guide
OL-10101-02
Chapter 18 Configuring Voice VLAN
Configuring Voice VLAN
Voice VLAN Configuration Guidelines
These are the voice VLAN configuration guidelines:
• You should configure voice VLAN on switch access ports.
• The voice VLAN should be present and active on the switch for the IP phone to correctly
communicate on the voice VLAN. Use the show vlan privileged EXEC command to see if the
VLAN is present (listed in the display). If the VLAN is not listed, see
Chapter 16, “Configuring
VLANs” for information on how to create the VLAN.
• The Port Fast feature is automatically enabled when voice VLAN is configured. When you disable
voice VLAN, the Port Fast feature is not automatically disabled.
• When you enable port security on an interface that is also configured with a voice VLAN, you must
set the maximum allowed secure addresses on the port to at least two plus the maximum number of
secure addresses allowed on the access VLAN. When the port is connected to a Cisco IP phone, the
IP phone requires up to two MAC addresses. The address of the IP phone is learned on the voice
VLAN, and it might or might not be learned on the access VLAN. Connecting a PC to the IP phone
requires additional MAC addresses.
• If any type of port security is enabled on the access VLAN, dynamic port security is automatically
enabled on the voice VLAN.
• You cannot configure port security on a per-VLAN basis.
• You cannot configure static secure or sticky secure MAC addresses on a voice VLAN.
• Voice VLAN ports can also be these port types:
–
Dynamic access port. See the “Configuring Dynamic Access Ports on VMPS Clients” section
on page 16-26 for more information.
–
Secure port. See the “Configuring Port Security” section on page 21-6 for more information.
–
IEEE 802.1x authenticated port. See the “Using IEEE 802.1x Authentication with Voice VLAN
Ports” section on page 9-10 for more information.
Note If you enable IEEE 802.1x on an access port on which a voice VLAN is configured and
to which a Cisco IP Phone is connected, the Cisco IP Phone loses connectivity to the
switch for up to 30 seconds.
–
Protected port. See the “Configuring Protected Ports” section on page 21-4 for more
information.
Configuring a Port to Connect to a Cisco 7960 IP Phone
Because a Cisco 7960 IP Phone also supports a connection to a PC or other device, a port connecting the
switch to a Cisco
7960 IP Phone can carry mixed traffic.
You can configure the port to carry voice traffic in one of these ways:
• Configuring Ports to Carry Voice Traffic in IEEE 802.1Q Frames, page 18-4
• Configuring Ports to Carry Voice Traffic in IEEE 802.1p Priority-Tagged Frames, page 18-4
You can configure the IP phone to carry data traffic in one of these ways:
• Overriding the CoS Priority of Incoming Data Frames, page 18-5