IEEE 802.1Q Virtual LANs (VLANs) provide the capability to overlay the physical network with
multiple virtual networks. VLANs allow you to isolate network traffic between virtual networks and
reduce the size of administrative and broadcast domains.

A VLAN contains end stations that have a common set of requirements that are independent of
physical location. You can group end stations in a VLAN even if they are not physically located in the
same LAN segment. VLANs are typically associated with IP subnetworks and all the end stations in
a particular IP subnet belong to the same VLAN. Traffic between VLANs must be routed. VLAN
membership is configurable on a per interface basis.

The VLAN used for carrying FCoE traffic needs to be explicitly designated as the FCoE VLAN. FCoE
VLANs are configured through the CEE CLI (see

“Configuring a VLAN interface to forward FCoE

traffic”

on page 49).

NOTE

Currently only one VLAN can be configured as the FCoE VLAN.

Ingress VLAN filtering

A frame arriving at Brocade FCoE hardware is either associated with a specific port or with a VLAN,
based on whether the frame is tagged or untagged:

•

Admit tagged frames only—The port the frame came in on is assigned to a single VLAN or to
multiple VLANs depending on the VLAN ID in the frame’s VLAN tag. This is called trunk mode.

•

Admit untagged frames only—These frames are assigned the port VLAN ID (PVID) assigned to
the port the frame came in on. This is called access mode.