H3C Technologies H3C S5560 Series Switches - Manual (Page 208)

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Step Command Remarks
3. Configure QoS priority
settings for incoming voice
VLAN packets.
• Configure the port to trust and
retain the QoS priority settings:
a. Use the 802.1p priority in
incoming packets for priority
mapping:
qos trust dot1p
b. Configure the port to trust and
retain the QoS priority
settings:
voice-vlan qos trust
• Configure the port to modify the
CoS and DSCP values:
voice-vlan qos cos-value
dscp-value
By default, a port modifies the
CoS and DSCP values for voice
VLAN packets to 6 and 46,
respectively.
If you execute the voice-vlan
qos and voice-vlan qos trust
commands multiple times, the
most recent configuration takes
effect.
For more information about the
qos trust dot1p command, see
ACL and QoS Command
Reference.
Configuring a port to operate in automatic voice VLAN
assignment mode
Configuration restrictions and guidelines
When you configure a port to operate in automatic voice VLAN assignment mode, follow these
restrictions and guidelines:
• Do not configure a VLAN as both a voice VLAN and a protocol-based VLAN. A voice VLAN in
automatic mode on a hybrid port processes only tagged incoming voice traffic. A protocol-based
VLAN on a hybrid port processes only untagged incoming packets. For more information about
protocol-based VLANs, see "Configuring protocol-based VLANs."
• H3C recommends not using the automatic voice VLAN assignment mode together with MSTP. In
MSTP mode, if a port is blocked in the MSTI of the target voice VLAN, the port drops the received
packets instead of delivering them to the CPU. As a result, the receiving port will not be dynamically
assigned to the voice VLAN.
• H3C recommends not using the automatic voice VLAN assignment mode together with PVST. In
PVST mode, if the target voice VLAN is not permitted on a port, the port is placed in blocked state.
The received packets are dropped instead of being delivered to the CPU. As a result, the receiving
port will not be dynamically assigned to the voice VLAN.
• H3C recommends not configuring both dynamic MAC-based VLAN assignment and automatic
voice VLAN assignment mode on a port. If you have to configure both of them on a port, configure
dynamic MAC-based VLAN assignment first. If you configure them in a reverse order, conflict will
occur. When you remove one of the configurations, the operation of the other is affected.
Configuration procedure
To configure a port to operate in automatic voice VLAN assignment mode:
Step Command Remarks
1. Enter system view. system-view N/A