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Configuring VLANs
Changing the Default VLAN Assignment for a Port
Initially all switch ports are assigned to VLAN 1, which is also their configured default VLAN. When
additional VLANs are created on the switch, ports are assigned to the VLANs so that traffic from devices
connected to these ports is bridged within the VLAN domain.
To assign a switch port to a new default VLAN, use the
ple, the following command assigns port 5 on slot 2 to VLAN 955:
-> vlan 955 members port 2/5 untagged
When the vlan members command is used, the port's default VLAN assignment is changed to the speci-
fied VLAN. The previous default VLAN assignment for the port (for example, VLAN 1, VLAN 10 or
VLAN 200) is dropped.
The vlan members command is also used to change the default VLAN assignment for an aggregate of
ports. The link aggregate control number is specified instead of a slot and port. For example, the
following command assigns link aggregate 10 to VLAN 755:
-> vlan 755 members linkagg 10 untagged
For more information about configuring an aggregate of ports, see
Aggregation".
Use the no form of the vlan members command to remove a default VPA. When this is done, VLAN 1 is
restored as the default VLAN for the port.
-> no vlan 955 members port 2/5
Using 802.1Q Tagging
Another method for assigning ports to VLANs involves configuring a switch port or link aggregate to
process 802.1Q-tagged frames that contain a specific VLAN ID designation. This method, referred to as
802.1Q tagging (or trunking), allows a single network link to carry traffic for multiple VLANs.
The OmniSwitch implements the IEEE 802.1Q standard for sending frames through the network tagged
with VLAN identification. This section details procedures for configuring and monitoring 802.1Q tagging
on a single switch port or link aggregate group.
"Tagged" refers to four bytes of reserved space in the header of the packet. The four bytes of "tagging" are
broken down as follows: the first two bytes indicate whether the packet is an 802.1Q packet, and the next
two bytes carry the VLAN identification (VID) and priority.
When packets ingress the switch, they are classified into a VLAN based on their 802.1Q tag information.
•
If the packet contains an 802.1Q tag, the VLAN ID in the tag must match either the default VLAN ID
for the port or a VLAN ID for which the port is tagged. If there is no match, the packet is dropped.
•
If the packet is not tagged at all, the packet is placed into the default VLAN to which the port that
received the packet is assigned.
The following diagram illustrates a simple network by using tagged and untagged traffic:
OmniSwitch AOS Release 7 Network Configuration Guide
vlan members untagged
Chapter 6, "Configuring Static Link
March 2011
Assigning Ports to VLANs
command. For exam-
page 4-7
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