3Com Baseline 2928 PWR Plus User Manual page 183

When untagged packets are received from an IP phone:
In automatic mode, the system matches the source MAC addresses in the untagged packets sent
by the IP phone upon its power-on against the OUI list. If a match is found, the system
automatically assigns the receiving port to a voice VLAN, issues ACL rules and configures the
packet precedence. You can configure an aging timer for the voice VLAN. The system will remove
the port from the voice VLAN when the aging timer expires if no voice packet is received on the port
during the aging timer. Assigning ports to and removing ports from a voice VLAN are automatically
performed.
In manual mode, you need to assign the port to a voice VLAN manually. Then, the system matches
the source MAC addresses in the packets against the OUI addresses. If a match is found, the
system issues ACL rules and configures the packet precedence. In this mode, assigning ports to
and removing ports from a voice VLAN are performed manually.
In both modes, tagged packets are forwarded according to their tags.
The following table lists the relationships between the voice assignment VLAN mode, the voice traffic
type of an IP phone, and the port link type.
Table 1-2 Co-relation
Voice
VLAN Voice
assignmen traffic type
t mode
Tagged
voice traffic
Automatic
mode
Untagged
voice traffic
Tagged
voice traffic
Manual
mode
Untagged
voice traffic
Access
Supported, but you
must ensure that the
default VLAN of the
port has been created
Not supported and is not the voice
VLAN and the traffic
of the default VLAN
can pass through the
port.
Not supported Not supported
Supported, but you
must ensure that the
default VLAN of the
port has been created
Not supported and is not the voice
VLAN and the traffic
of the default VLAN
can pass through the
port.
Supported, but you
must configure the
Supported, but
default VLAN of the
you must
port as the voice
configure the
VLAN and configure
default VLAN of
the port to allow the
the port as the
traffic of the voice
voice VLAN.
VLAN to pass
through.
1-2
Port link type
Trunk
Supported, but you must
ensure that the default
VLAN of the port has been
created and is not the
voice VLAN and the traffic
of the default VLAN can
pass through the port
tagged.
Not supported
Supported, but you must
ensure that the default
VLAN of the port has been
created and is not the
voice VLAN and the traffic
of the voice VLAN can
pass through the port
tagged.
Supported, but you must
configure the default
VLAN of the port as the
voice VLAN and configure
the port to allow the traffic
of the voice VLAN to pass
through untagged.
Hybrid