H3C Technologies H3C WX5500E Series Access Controllers - Manual (Page 152)

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Table 47 Required configurations on ports of different link types for them to support tagged voice traffic
Port link type Voice VLAN assignment mode
supported for tagged voice traffic Configuration requirements
Access N/A N/A
Trunk Automatic and manual
In automatic mode, the PVID of the port cannot be
the voice VLAN.
In manual mode, the PVID of the port cannot be the
voice VLAN. Configure the port to permit packets
from the voice VLAN to pass through.
Hybrid Automatic and manual
In automatic mode, the PVID of the port cannot be
the voice VLAN.
In manual mode, the PVID of the port cannot be the
voice VLAN. Configure the port to permit packets
from the voice VLAN to pass through tagged.
Table 48 Required configurations on ports of different link types for them to support tagged voice traffic
Port link type Voice VLAN assignment mode
supported for untagged voice traffic Configuration requirements
Access Manual Configure the PVID of the port as the voice VLAN.
Trunk Manual
Configure the PVID of the port as the voice VLAN
and configure the port to permit packets from the
voice VLAN to pass through.
Hybrid Manual
Configure the PVID of the port as the voice VLAN
and configure the port to permit packets from the
voice VLAN to pass through untagged.
Security mode and normal mode of voice VLANs
Depending on their inbound packet filtering mechanisms, voice VLAN-enabled ports operate in one of
the following modes:
• Normal mode—In this mode, both voice packets and non-voice packets are allowed to pass
through a voice VLAN-enabled inbound port. When receiving a voice packet, the port forwards it
without checking its source MAC address against the OUI addresses configured for the device. If
the default VLAN of the port is the voice VLAN and the port operates in manual VLAN assignment
mode, the port forwards all received untagged packets in the voice VLAN. In normal mode, the
voice VLANs are vulnerable to traffic attacks. Vicious users can forge a large amount of voice
packets and send them to voice VLAN-enabled ports to consume the voice VLAN bandwidth,
affecting normal voice communication.
• Security mode—In this mode, only voice packets whose source MAC addresses comply with the
recognizable OUI addresses can pass through the voice VLAN-enabled inbound port, but all other
packets are dropped.
In a safe network, you can configure the voice VLANs to operate in normal mode. This reduces the
consumption of system resources due to source MAC addresses checking.
H3C recommends you not transmit both voice packets and non-voice packets in a voice VLAN. If you
have to, first make sure the voice VLAN security mode is disabled.