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The following are the prerequisites for voice VLANs:
Note |
Trunk ports can carry any number of voice VLANs, similar to regular VLANs. The configuration of voice VLANs is not supported on trunk ports. |
You cannot configure static secure MAC addresses in the voice VLAN.
Information About Voice VLAN
The voice VLAN feature enables access ports to carry IP voice traffic from an IP phone. When the switch is connected to a Cisco 7960 IP Phone, the phone sends voice traffic with Layer 3 IP precedence and Layer 2 class of service (CoS) values, which are both set to 5 by default. Because the sound quality of an IP phone call can deteriorate if the data is unevenly sent, the switch supports quality of service (QoS) based on IEEE 802.1p CoS. QoS uses classification and scheduling to send network traffic from the switch in a predictable manner.
The Cisco 7960 IP Phone is a configurable device, and you can configure it to forward traffic with an IEEE 802.1p priority. You can configure the switch to trust or override the traffic priority assigned by a Cisco IP Phone.
This network configuration is one way to connect a Cisco 7960 IP Phone.
The Cisco IP Phone contains an integrated three-port 10/100 switch. The ports provide dedicated connections to these devices:
You can configure an access port with an attached Cisco IP Phone to use one VLAN for voice traffic and another VLAN for data traffic from a device attached to the phone. You can configure access ports on the switch to send Cisco Discovery Protocol (CDP) packets that instruct an attached phone to send voice traffic to the switch in any of these ways:
Note |
In all configurations, the voice traffic carries a Layer 3 IP precedence value (the default is 5 for voice traffic and 3 for voice control traffic). |
The switch can also process tagged data traffic (traffic in IEEE 802.1Q or IEEE 802.1p frame types) from the device attached to the access port on the Cisco IP Phone. You can configure Layer 2 access ports on the switch to send CDP packets that instruct the attached phone to configure the phone access port in one of these modes:
Note |
Untagged traffic from the device attached to the Cisco IP Phone passes through the phone unchanged, regardless of the trust state of the access port on the phone. |
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 phone loses connectivity to the switch for up to 30 seconds. |
How to Configure Voice VLAN
You can configure a port connected to the Cisco IP Phone to send CDP packets to the phone to configure the way in which the phone sends voice traffic. The phone can carry voice traffic in IEEE 802.1Q frames for a specified voice VLAN with a Layer 2 CoS value. It can use IEEE 802.1p priority tagging to give voice traffic a higher priority and forward all voice traffic through the native (access) VLAN. The Cisco IP Phone can also send untagged voice traffic or use its own configuration to send voice traffic in the access VLAN. In all configurations, the voice traffic carries a Layer 3 IP precedence value (the default is 5).
3. trust device cisco-phone
4.
switchport voice vlan {
vlan-id |
dot1p |
none |
untagged}
6. Use one of the following:
You can connect a PC or other data device to a Cisco IP Phone port. To process tagged data traffic (in IEEE 802.1Q or IEEE 802.1p frames), you can configure the switch to send CDP packets to instruct the phone how to send data packets from the device attached to the access port on the Cisco IP Phone. The PC can generate packets with an assigned CoS value. You can configure the phone to not change (trust) or to override (not trust) the priority of frames arriving on the phone port from connected devices.
Follow these steps to set the priority of data traffic received from the non-voice port on the Cisco IP Phone:
To display voice VLAN configuration for an interface, use the show interfaces interface-id switchport privileged EXEC command.
After configuring voice VLANs, you can configure the following:
Related Topic | Document Title |
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For complete syntax and usage information for the commands used in this chapter. |
|
Additional configuration commands and procedures. |
LAN Switching Configuration Guide, Cisco IOS XE Release 3SE (Catalyst 3650 Switches) |
Platform-independent configuration information |
Identity Based Networking Services Configuration Guide, Cisco IOS XE Release 3SE (Catalyst 3650 Switches) |
Description | Link |
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To help you research and resolve system error messages in this release, use the Error Message Decoder tool. |
https://www.cisco.com/cgi-bin/Support/Errordecoder/index.cgi |
Standard/RFC | Title |
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RFC 1573 |
Evolution of the Interfaces Group of MIB-II |
RFC 1757 |
Remote Network Monitoring Management |
RFC 2021 |
SNMPv2 Management Information Base for the Transmission Control Protocol using SMIv2 |
MIB | MIBs Link |
---|---|
All supported MIBs for this release. |
To locate and download MIBs for selected platforms, Cisco IOS releases, and feature sets, use Cisco MIB Locator found at the following URL: |
Description | Link |
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Release |
Modification |
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Cisco IOS XE 3.3SE |
This feature was introduced. |