Vlan Tagging - Dell PowerConnect 8024 User Configuration Manual

VLAN membership rules that apply to a port are based on the switchport
mode configured for the port. Table 22-2 shows the behavior of the three
switchport modes.
Table 22-2. Switchport Mode Behavior
Mode VLAN Membership
Access One VLAN
Trunk All VLANs that exist
in the system
General As many as desired
When a port is in General mode, all VLAN features are configurable. When
ingress filtering is on, the frame is dropped if the port is not a member of the
VLAN identified by the VLAN ID in the tag. If ingress filtering is off, all
tagged frames are forwarded. The port decides whether to forward or drop the
frame when the port receives the frame.

VLAN Tagging

PowerConnect 8000-series and 8100-series switches support IEEE 802.1Q
tagging. Ethernet frames on a tagged VLAN have a 4-byte VLAN tag in the
header. VLAN tagging is required when a VLAN spans multiple switches,
which is why trunk ports transmit and receive only tagged frames.
Tagging may be required when a single port supports multiple devices that are
members of different VLANs. For example, a single port might be connected
to an IP phone, a PC, and a printer (the PC and printer are connected via
ports on the IP phone). IP phones are typically configured to use a tagged
VLAN for voice traffic, while the PC and printers typically use the untagged
VLAN.
Trunk ports can receive tagged and untagged traffic. Untagged traffic is
tagged internally with the native VLAN. Native VLAN traffic received
untagged is transmitted untagged on a trunk port.
By default, trunk ports are members of all existing VLANs and will
automatically participate in any newly created VLANs. The administrator can
restrict the VLAN membership of a trunk port.
Frames Frames Sent
Accepted
Untagged Untagged
Tagged Tagged
Tagged or Tagged or
Untagged Untagged
Ingress
Filtering
Always On
Always On
On or Off
Configuring VLANs
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