Brocade Network OS Administrator’s Guide v4.1.1 - Manual (Page 355)

Configuring 802.1Q VLANs
● 802.1Q VLAN overview.................................................................................................355
● Configuring and managing 802.1Q VLANs................................................................... 357
● Private VLANs...............................................................................................................364
802.1Q VLAN overview
NOTE
This chapter addresses the use of standard Virtual LANs (VLANs) as defined by IEEE 802.1Q. Those
VLANs have VLAN IDs that range from 1 through 4096. To support multitenancy by means of classified
VLANs, the ID range has been extended through 8191. For details on this feature, refer to
Configuring
Virtual Fabrics on page 375.
IEEE 802.1Q 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 Network OS CLI (refer to
Configuring an interface port as a Layer 2
switch port on page 360 for details).
NOTE
Currently only one VLAN can be configured as the FCoE VLAN at a time.
Ingress VLAN filtering
A frame arriving at Brocade VDX hardware is either associated with a specific port or with a VLAN,
based on whether the frame is tagged or untagged. The association rules are as follows:
• 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.
• Admit VLAN tagged and untagged frames — All tagged and untagged frames are processed as
follows:
‐ All untagged frames are classified into native VLANs.
‐ If the tengigabitethernet interface port is configured as an fcoeport and is in access mode,
untagged Layer 2 or priority-tagged frames are forwarded by the egress port as untagged
frames, unless you enable priority-tagging on the tengigabitethernet interface. By default,
priority-tagging is disabled.
Network OS Administrator’s Guide 355
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