Dell PowerEdge FX2/FX2s - Manual (Page 97)

interface level to filter traffic. When you enable tagging, a tag header is added to the frame after the
destination and source MAC addresses. The information that is preserved as the frame moves through the
network. The below figure shows the structure of a frame with a tag header. The VLAN ID is inserted in
the tag header.
Figure 15. Tagged Frame Format
The tag header contains some key information used by Dell Networking OS:
• The VLAN protocol identifier identifies the frame as tagged according to the IEEE 802.1Q
specifications (2 bytes).
• Tag control information (TCI) includes the VLAN ID (2 bytes total). The VLAN ID can have 4,096 values,
but two are reserved.
NOTE: The insertion of the tag header into the Ethernet frame increases the size of the frame to
more than the 1518 bytes specified in the IEEE 802.3 standard. Some devices that are not compliant
with IEEE 802.3 may not support the larger frame size.
Information contained in the tag header allows the system to prioritize traffic and to forward information
to ports associated with a specific VLAN ID. Tagged interfaces can belong to multiple VLANs, while
untagged interfaces can belong only to one VLAN.
Configuring VLAN Membership
By default, all Aggregator ports are member of all (4094) VLANs, including the default untagged VLAN 1.
You can use the CLI or CMC interface to reconfigure VLANs only on server-facing interfaces (1–8) so that
an interface has membership only in specified VLANs.
To assign an Aggregator interface in Layer 2 mode to a specified group of VLANs, use the vlan tagged
and vlan untagged commands. To view which interfaces are tagged or untagged and to which VLAN
they belong, use the show vlan command (Displaying VLAN Membership).
To reconfigure an interface as a member of only specified tagged VLANs, enter the vlan tagged
command in INTERFACE mode:
Command Syntax Command Mode Purpose
vlan tagged {vlan-id } INTERFACE Add the interface as a tagged member of one or
more VLANs, where:
vlan-id specifies a tagged VLAN number. Range:
2-4094
To reconfigure an interface as a member of only specified untagged VLANs, enter the vlan untagged
command in INTERFACE mode:
Interfaces 97