Cisco Catalyst 3550 User Manual

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Catalyst 3550 Multilayer Switch Command Reference
OL-8566-01
Chapter 2 Catalyst 3550 Switch Cisco IOS Commands
switchport voice vlan
switchport voice vlan
Use the switchport voice vlan interface configuration command to configure voice VLAN on the port.
Use the no form of this command to return to the default setting.
switchport voice vlan {vlan-id | dot1p | none | untagged}
no switchport voice vlan
Syntax Description
Defaults The switch default is not to automatically configure the telephone (none).
The telephone default is not to tag frames.
Command Modes Interface configuration
Command History
Usage Guidelines You should configure voice VLAN on access ports.
Before you enable voice VLAN, we recommend you enable quality of service (QoS) on the switch by
entering the mls qos global configuration command and configure the port trust state to trust by entering
the mls qos trust cos interface configuration command.
When you enable port security on an interface that is also configured with a voice VLAN, set the
maximum allowed secure addresses on the port to two. When the port is connected to a Cisco IP phone,
the IP phone requires one MAC address. The Cisco IP phone address is learned on the voice VLAN, but
is not learned on the access VLAN. If you connect a single PC to the Cisco IP phone, no additional MAC
addresses are required. If you connect more than one PC to the Cisco IP phone, you must configure
enough secure addresses to allow one for each PC and one for the Cisco IP phone.
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 static secure MAC addresses on the voice 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.
vlan-id VLAN used for voice traffic. The range is 1 to 4094.
dot1p The telephone uses priority tagging and uses VLAN 0 (the native VLAN). By default,
the Cisco IP phone forwards the voice traffic with an IEEE 802.1p priority of 5.
none The telephone is not instructed through the CLI about the voice VLAN. The telephone
uses the configuration from the telephone key pad.
untagged The telephone does not tag frames and uses VLAN 4095. The default for the telephone
is untagged.
Release Modification
12.1(9)EA1 This command was introduced.

Cisco Catalyst 3550 Specifications

General

Category	Switch
QoS	Yes
Form Factor	Rack-mountable
Manageable	Yes
RAM	64 MB
Model	Catalyst 3550
Uplink Ports	2 x GBIC (Gigabit Interface Converter) or SFP (Small Form-factor Pluggable)
Layer Support	Layer 3
VLAN Support	Yes
MAC Address Table Size	12000 entries
Routing Protocol	EIGRP
Features	QoS
Operating Temperature	32 to 113°F (0 to 45°C)
Operating Humidity	10 - 95% (non-condensing)
Ports	24 or 48 10/100 ports