xStack
®
DGS-3400 Series Layer 2 Gigabit Ethernet Managed Switch CLI Manual
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35
IEEE
802.1Q
VLAN
C
OMMANDS
Along with normal VLAN configurations, this Switch now incorporate Double VLANs. Better known as Q-IN-Q VLANs,
Double VLANs allow network providers to expand their VLAN configurations to place VLANs within a larger inclusive
VLAN, which adds a new layer to the VLAN configuration. This basically lets large ISP's create L2 Virtual Private
Networks and also create transparent LANs for their customers, which will connect two or more customer LAN points
without over complicating configurations on the client's side. Not only will over-complication be avoided, but now the
administrator has over 4000 VLANs in which over 4000 VLANs can be placed, therefore greatly expanding the VLAN
network.
Implementation of this feature adds a VLAN frame to an existing VLAN frame for the ISP VLAN recognition and
classification. To ensure devices notice this added VLAN frame, an Ethernet encapsulation, here known as a tpid, is also
added to the frame. The device recognizes this tpid and therefore checks the VLAN tagged packet to see if a provider
VLAN tag has been added. If so, the packet is then routed through this provider VLAN, which contains smaller VLANs
with similar configurations to ensure speedy and guaranteed routing destination of the packet.
The IEEE 802.1Q VLAN commands in the Command Line Interface (CLI) are listed (along with the appropriate
parameters) in the following table.