Voice VLANs are VLANs configured specially for voice traffic. By adding the ports connected with voice devices to voice VLANs, you can have voice traffic transmitted within voice VLANs and perform QoS-related configuration for voice traffic as required, thus ensuring the transmission priority of voice traffic and voice quality.

How an IP Phone Works

IP phones can convert analog voice signals into digital signals to enable them to be transmitted in IP-based networks. Used in conjunction with other voice devices, IP phones can offer large-capacity and low-cost voice communication solutions. As network devices, IP phones need IP addresses to operate properly in a network. Normally, an IP telephone automatically acquires an IP address from a DHCP server in its network.

When an IP phone applies for an IP address from a DHCP server, the IP phone can also apply for the following extensive information from the DHCP server through the Option184 field:

l IP address of the network call processor (NCP)

l IP address of the secondary NCP server

l Voice VLAN configuration

l Failover call routing

The following contents just describe the IP address acquiring process of IP phones in general. Different IP phones may work differently. Refer to the IP Phones User Manual for details.

Following describes the way an IP phone acquires an IP address.

Figure 1-1 Network diagram for IP phones

As shown in Figure 1-1, the IP phone needs to work in conjunction with the DHCP server and the NCP to establish a path for voice data transmission. An IP phone goes through the following three phases to become capable of transmitting voice data.

1) After the IP phone is powered on, it sends an untagged DHCP request message containing four special requests in the Option 184 field besides the request for an IP address. The message is broadcast in the default VLAN of the receiving port. After receiving the DHCP request message, DHCP Server1, which resides in the default VLAN of the port receiving the message, responds as follows:

l If DHCP Server1 does not support Option 184, it returns the IP address assigned to the IP phone but ignores the other four special requests in the Option 184 field. Without information about voice VLAN, the IP phone can only send untagged packets in the default VLAN of the port the IP phone is connected to. In this case, you need to manually configure the default VLAN of the port as a voice VLAN.

In cases where an IP phone obtains an IP address from a DHCP server that does not support Option 184, the IP phone directly communicates through the gateway after it obtains an IP address. It does not go through step 2 and step 3 described below.

l If DHCP Server1 supports Option 184, it returns the IP address assigned to the IP phone, the IP address of the NCP, the voice VLAN ID, and so on.

2) On acquiring the voice VLAN ID from DHCP Server1, the IP phone ignores the IP address assigned by DHCP Server1 and sends a new DHCP request message carrying the voice VLAN tag to the voice VLAN. After receiving the DHCP request, DHCP Server2 residing in the voice VLAN assigns a new IP address to the IP phone and sends a tagged response message to the IP phone. After the IP phone receives the tagged response message, it sends voice data packets tagged with the voice VLAN tag. In this case, the port on the device connecting to the IP phone must be configured to allow packets tagged with the voice VLAN tag to pass.

3) After the IP phone acquires the IP address assigned by DHCP Server2, the IP phone establishes a connection to the NCP specified by DHCP Server1 and downloads corresponding software. After that, the IP phone can communicate properly.

l An untagged packet carries no VLAN tag.

l A tagged packet carries the tag of a VLAN.

How the Device Identifies Voice Traffic

The device determines whether a received packet is a voice packet by checking its source MAC address. Packets with their source MAC addresses complying with the configured OUI (organizationally unique identifier) addresses are treated as voice packets. Ports receiving packets of this type will be added to the voice VLAN automatically for transmitting voice data.

You can configure OUI addresses for voice packets or specify to use the default OUI addresses.

An OUI address is a globally unique identifier assigned to a vendor by IEEE. You can determine which vendor a device belongs to according to the OUI address which forms the first 24 bits of a MAC address. The WX3000 supports OUI address mask configuration. You can adjust the matching depth of MAC address by setting different OUI address masks.

The following table lists the five default OUI addresses on the device.

Table 1-1 Default OUI addresses preset on the device

Number	OUI address	Vendor
1	0003-6b00-0000	Cisco phones
2	000f-e200-0000	H3C Aolynk phones
3	00d0-1e00-0000	Pingtel phones
4	00e0-7500-0000	Polycom phones
5	00e0-bb00-0000	3Com phones

Configuring Operation Mode for Voice VLAN

A voice VLAN can operate in two modes: automatic and manual. You can configure the operation mode for the voice VLAN according to data traffic passing through a port.

Processing mode of untagged packets sent by IP voice devices

l Automatic mode. A WX3000 device automatically adds a port connecting an IP voice device to the voice VLAN by learning the source MAC address in the untagged packet sent by the IP voice device when it is powered on. The voice VLAN uses the aging mechanism to maintain the number of ports in the voice VLAN. When the aging timer expires, the ports whose OUI addresses are not updated (that is, no voice traffic passes) will be removed from the voice VLAN. In automatic mode, ports can not be added to or removed from a voice VLAN manually.

l Manual mode: In this mode, you need to add a port to a voice VLAN or remove a port from a voice VLAN manually.

Processing mode of tagged packets sent by IP voice devices

Tagged packets from IP voice devices are forwarded based on their tagged VLAN IDs, whether the automatic or manual mode is used.

l If the voice traffic transmitted by an IP voice device carries VLAN tags, and 802.1x authentication and guest VLAN is enabled on the port which the IP voice device is connected to, assign different VLAN IDs for the voice VLAN, the default VLAN of the port, and the 802.1x guest VLAN to ensure the effective operation of these functions.

l If the voice traffic transmitted by an IP voice device carries no VLAN tag, the default VLAN of the port which the IP voice device is connected to must be configured as the voice VLAN. In this case, the 802.1x authentication is unavailable.

Support for Voice VLAN on Various Ports

Voice VLAN packets can be forwarded by access ports, trunk ports, and hybrid ports. You can enable a trunk or hybrid port belonging to other VLANs to forward voice and service packets simultaneously by enabling the voice VLAN.

The support for different types of voice traffic (that is, tagged traffic and untagged traffic) varies with port mode and port type, as listed in Table 1-2.

Table 1-2 Matching relationship between port types and voice traffic types

Port voice VLAN mode	Voice traffic type	Port type	Supported or not
Automatic mode	Tagged voice traffic	Access	Not supported
		Trunk	Supported Make sure the default VLAN of the port exists and is not a voice VLAN. And the access port permits the traffic of the default VLAN.
		Hybrid	Supported Make sure the default VLAN of the port exists and is not a voice VLAN. The default VLAN must be in the list of the tagged VLANs whose traffic is permitted by the access port.
	Untagged voice traffic	Access	Not supported, because the default VLAN of the port must be a voice VLAN and the access port is in the voice VLAN. This can be done by adding the port to the voice VLAN manually.
		Trunk
		Hybrid
Manual mode	Tagged voice traffic	Access	Not supported
		Trunk	Supported Make sure the default VLAN of the port exists and is not a voice VLAN. And the access port permits the traffic of the default VLAN.
		Hybrid	Supported Make sure the default VLAN of the port exists and is in the list of the tagged VLANs whose traffic is permitted by the access port.
	Untagged voice traffic	Access	Supported Make sure the default VLAN of the port is a voice VLAN.
		Trunk	Supported Make sure the default VLAN of the port is a voice VLAN and the port permits the traffic of the VLAN.
		Hybrid	Supported Make sure the default VLAN of the port is a voice VLAN and is in the list of untagged VLANs whose traffic is permitted by the port.

Security Mode of Voice VLAN

On the WX3000 devices, a voice VLAN can operate in the security mode. Voice VLANs operating in this mode only permit voice data, enabling you to perform voice traffic-specific priority configuration. With the security mode disabled, both voice data and service data can be transmitted in a voice VLAN.

Voice VLAN Configuration

Configuration Prerequisites

l Create the corresponding VLAN before configuring a voice VLAN.

l VLAN 1 (the default VLAN) cannot be configured as a voice VLAN.

Configuring a Voice VLAN to Operate in Automatic Mode

Follow these steps to configure a voice VLAN to operate in automatic mode:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Set an OUI address that can be identified by the voice VLAN	voice vlan mac-address oui mask oui-mask [ description text ]	Optional By default, the device determines the voice traffic according to the default OUI address.
Enable the voice VLAN security mode	voice vlan security enable	Optional By default, the voice VLAN security mode is enabled.
Set the aging time for the voice VLAN	voice vlan aging minutes	Optional The default aging time is 1,440 minutes.
Enable the voice VLAN function globally	voice vlan vlan-id enable	Required
Enter Ethernet port view	interface interface-type interface-number	Required
Enable the voice VLAN function on a port	voice vlan enable	Required By default, voice VLAN is disabled.
Enable the voice VLAN legacy function on the port	voice vlan legacy	Optional By default, voice VLAN legacy is disabled.
Set the voice VLAN operation mode on a port to automatic.	voice vlan mode auto	Optional The default voice VLAN operation mode on a port is automatic.

l For a voice VLAN operating in automatic mode, it does not support the adding of an Access port, and thus a voice VLAN cannot function when configuring with the VLAN VPN function.

l For a voice VLAN operating in automatic mode, it only supports that the Hybrid port to process the tagged voice traffic. However, the protocol VLAN feature requires the Hybrid port to remove tags from the packets, see VLAN in H3C WX3000 Series Unified Switches Switching Engine Configuration Guide for details. Therefore, a VLAN cannot be configured as a voice VLAN and a protocol VLAN simultaneously.

l For a port operating in automatic mode, a default VLAN cannot be configured as a voice VLAN; otherwise the system prompts you for unsuccessful configuration.

When the voice VLAN is working normally, if the device restarts, in order to make the established voice connections work normally, the system does not need to be triggered by the voice traffic to add the port in automatic mode to the local devices of the voice VLAN but does so immediately after the restart.

Configuring a Voice VLAN to Operate in Manual Mode

Follow these steps to configure a voice VLAN to operate in manual mode:

To do…			Use the command…	Remarks
Enter system view			system-view	—
Set an OUI address that can be identified by the voice VLAN			voice vlan mac-address oui mask oui-mask [ description text ]	Optional Without this address, the default OUI address is used.
Enable the voice VLAN security mode			voice vlan security enable	Optional By default, the voice VLAN security mode is enabled.
Set the aging time for a voice VLAN			voice vlan aging minutes	Optional The default aging time is 1,440 minutes.
Enable the voice VLAN function globally			voice vlan vlan-id enable	Required
Enter port view			interface interface-type interface-number	Required
Enable voice VLAN on a port			voice vlan enable	Required By default, voice VLAN is disabled on a port.
Enable the voice VLAN legacy function on the port			voice vlan legacy	Optional By default, voice VLAN legacy is disabled.
Set voice VLAN operation mode on a port to manual			undo voice vlan mode auto	Required The default voice VLAN operation mode on a port is automatic.
Quit to system view			quit	—
Add a port in manual mode to the voice VLAN	Access port	Enter VLAN view	vlan vlan-id	Required By default, all the ports belong to VLAN 1.
	Access port	Add the port to the VLAN	port interface-list
	Trunk or Hybrid port	Enter port view	interface interface-type interface-num
		Add the port to the VLAN	port trunk permit vlan vlan-id port hybrid vlan vlan-id { tagged \| untagged }
		Configure the voice VLAN to be the default VLAN of the port	port trunk pvid vlan vlan-id port hybrid pvid vlan vlan-id	Optional Refer to Table 1-2 to determine whether or not this operation is needed.

l The voice VLAN function can be enabled for only one VLAN at one time.

l If the Link Aggregation Control Protocol (LACP) is enabled on a port, voice VLAN feature cannot be enabled on it.

l Voice VLAN function can be enabled only for the static VLAN. A dynamic VLAN cannot be configured as a voice VLAN.

l When ACL number applied to a port reaches to its threshold, voice VLAN cannot be enabled on this port. You can use the display voice vlan error-info command to locate such ports.

l When a voice VLAN operates in security mode, the device in it permits only the packets whose source addresses are the identified voice OUI addresses. Packets whose source addresses cannot be identified, including certain authentication packets (such as 802.1x authentication packets), will be dropped. Therefore, you are suggested not to transmit both voice data and service data in a voice VLAN. If you have to do so, make sure that the voice VLAN does not operate in security mode.

l The voice VLAN legacy feature realizes the communication between the WX3000 series devices and other vendor's voice devices by automatically adding the voice VLAN tag to the voice data coming from other vendors’ voice device. The voice vlan legacy command can be executed before voice VLAN is enabled globally and on a port, but it takes effect only after voice VLAN is enabled globally and on the port.

To add a Trunk port or a Hybrid port to the voice VLAN, refer to Basic Port Configurations in H3C WX3000 Series Unified Switches Switching Engines Command Reference for the related command.

Displaying and Maintaining Voice VLAN

To do…	Use the command…	Remarks
Display the information about ports on which voice VLAN configuration fails	display voice vlan error-info	You can execute the display command in any view.
Display the voice VLAN configuration status	display voice vlan status
Display the currently valid OUI addresses	display voice vlan oui
Display the ports operating in the current voice VLAN	display vlan vlan-id

Voice VLAN Configuration Example

Voice VLAN Configuration Example (Automatic Mode)

Network requirements

Create a voice VLAN and configure it to operate in automatic mode to enable the port to which an IP phone is connected to join or exit the voice VLAN automatically and voice traffic to be transmitted within the voice VLAN, as shown in Figure 1-2.

l Create VLAN 2 and configure it as a voice VLAN, with the aging time being 100 minutes.

l The IP phone sends tagged packets. It is connected to GigabitEthernet 1/0/1, a hybrid port, with VLAN 6 being its default VLAN. Set this port to operate in automatic mode.

l You need to add a user-defined OUI address 0011-2200-000, with the mask being ffff-ff00-0000 and the description string being “test”.

Figure 1-2 Network diagram for voice VLAN configuration (automatic mode)

Configuration procedure

# Create VLAN 2 and VLAN 6.

<DeviceA> system-view

[DeviceA] vlan 2

[DeviceA-vlan2] quit

[DeviceA] vlan 6

[DeviceA-vlan6] quit

# Set the aging time for the voice VLAN.

[DeviceA] voice vlan aging 100

# Add a user-defined OUI address 0011-2200-000 and set the description string to “test”.

[DeviceA] voice vlan mac-address 0011-2200-0000 mask ffff-ff00-0000 description test

# Enable the voice VLAN function globally.

[DeviceA] voice vlan 2 enable

# Configure the vocie VLAN to operate in automatic mode on GigabitEthernet 1/0/1. This operation is optional. By default, a voice VLAN operates in automatic mode on a port.

[DeviceA] interface GigabitEthernet 1/0/1

[DeviceA-GigabitEthernet1/0/1] voice vlan mode auto

# Configure GigabitEthernet 1/0/1 as a hybrid port.

[DeviceA-GigabitEthernet1/0/1] port link-type hybrid

# Configure VLAN 6 as the default VLAN of GigabitEthernet 1/0/1, and configure GigabitEthernet 1/0/1 to permit packets with the tag of VLAN 6.

[DeviceA-GigabitEthernet1/0/1] port hybrid pvid vlan 6

[DeviceA-GigabitEthernet1/0/1] port hybrid vlan 6 tagged

# Enable the voice VLAN function on GigabitEthernet 1/0/1.

[DeviceA-GigabitEthernet1/0/1] voice vlan enable

Voice VLAN Configuration Example (Manual Mode)

Network requirements

Create a voice VLAN and configure it to operate in manual mode. Add the port to which an IP phone is connected to the voice VLAN to enable voice traffic to be transmitted within the voice VLAN, as shown in Figure 1-3.

l Create VLAN 2 and configure it as a voice VLAN. Set the voice VLAN to operate in security mode

l The IP phone sends untagged packets. It is connected to GigabitEthernet 1/0/1, a hybrid port. Set this port to operate in manual mode.

l You need to add a user-defined OUI address 0011-2200-000, with the mask being ffff-ff00-0000 and the description string being “test”.

Figure 1-3 Network diagram for voice VLAN configuration (manual mode)

Configuration procedure

# Enable the security mode for the voice VLAN so that the ports in the voice VLAN permit valid voice packets only. This operation is optional. The security mode is enabled by default.

<DeviceA> system-view

[DeviceA] voice vlan security enable

# Add a user-defined OUI address 0011-2200-000 and set the description string to “test”.

[DeviceA] voice vlan mac-address 0011-2200-0000 mask ffff-ff00-0000 description test

# Create VLAN 2 and configure it as a voice VLAN.

[DeviceA] vlan 2

[DeviceA-vlan2] quit

[DeviceA] voice vlan 2 enable

# Configure GigabitEthernet 1/0/1 to operate in manual mode.

[DeviceA] interface GigabitEthernet 1/0/1

[DeviceA-GigabitEthernet1/0/1] undo voice vlan mode auto

# Configure GigabitEthernet 1/0/1 as a hybrid port.

[DeviceA-GigabitEthernet1/0/1] port link-type hybrid

# Configure the voice VLAN as the default VLAN of GigabitEthernet 1/0/1, and add the voice VLAN to the list of untagged VLANs whose traffic is permitted by the port.

[DeviceA-GigabitEthernet1/0/1] port hybrid pvid vlan 2

[DeviceA-GigabitEthernet1/0/1] port hybrid vlan 2 untagged

# Enable the voice VLAN function on GigabitEthernet 1/0/1.

[DeviceA-GigabitEthernet1/0/1] voice vlan enable

Verification

# Display the OUI addresses, the corresponding OUI address masks and the corresponding description strings that the system supports.

<DeviceA> display voice vlan oui

Oui Address Mask Description

0003-6b00-0000 ffff-ff00-0000 Cisco phone

000f-e200-0000 ffff-ff00-0000 H3C Aolynk phone

0011-2200-0000 ffff-ff00-0000 test

00d0-1e00-0000 ffff-ff00-0000 Pingtel phone

00e0-7500-0000 ffff-ff00-0000 Polycom phone

00e0-bb00-0000 ffff-ff00-0000 3Com phone

# Display the status of the current voice VLAN.

<DeviceA> display voice vlan status

Voice Vlan status: ENABLE

Voice Vlan ID: 2

Voice Vlan security mode: Security

Voice Vlan aging time: 1440 minutes

Current voice vlan enabled port mode:

PORT MODE

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GigabitEthernet1/0/1 MANUAL

H3C WX3000 Series Unified Switches Switching Engine Configuration Guide-6W103

Voice VLAN Overview

Processing mode of untagged packets sent by IP voice devices

Processing mode of tagged packets sent by IP voice devices

Voice VLAN Configuration

Network requirements

Configuration procedure

Voice VLAN Configuration Example (Manual Mode)

Network requirements

Configuration procedure

Verification

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