Recommended Voice Vlan Configuration Procedure - HP 1920 Gigabit Ethernet Switch Series User Manual

the PVID 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 untagged 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, reducing the
consumption of system resources due to source MAC addresses checking.
HP recommends not transmitting both voice packets and non-voice packets in a voice VLAN. If you have
to, first make sure that the voice VLAN security mode is disabled.
Table 48 How a voice VLAN-enable port processes packets in security/normal mode
Voice VLAN operating mode
Security mode
Normal mode
Recommended voice VLAN configuration
procedure
Before configuring the voice VLAN, you must create the VLAN and configure the link type of each port
to be assigned to the VLAN. Because VLAN 1 is the system-default VLAN, you do not need to create it;
however, you cannot configure it as the voice VLAN. For information about port link types, see
"Managing
Packet type
Untagged packets
Packets carrying the voice VLAN tag
Packets carrying other tags
Untagged packets
Packets carrying the voice VLAN tag
Packets carrying other tags
ports."
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Packet processing mode
If the source MAC address of a
packet matches an OUI address
configured for the device, it is
forwarded in the voice VLAN;
otherwise, it is dropped.
If the packet is a voice packet does
not carry the voice VLAN tag or
PVID tag, the packet is dropped.
Otherwise, the packet is
forwarded or dropped depending
on whether the port allows packets
of these VLANs to pass through.
The port does not check the source
MAC addresses of inbound
packets. All types of packets can
be transmitted in the voice VLAN.
Forwarded or dropped depending
on whether the port allows packets
of these VLANs to pass through