Cheetah Gigabit Adapter
11
Using VLANs
The Cheetah Gigabit Adapter supports the IEEE 802.1Q VLAN
standard and can be configured to participate in a network
with other devices that use VLANs.
An IEEE 802.1Q VLAN is a group of ports that can be located
anywhere in the network, but communicate as though they
belong to the same physical segment. VLANs help to simplify
network management by allowing you to move devices to a
new VLAN without having to change any connections. VLANs
can be easily organized to reflect departmental groups (such
as Marketing or R&D) or usage groups (such as e-mail or
video conferencing).
VLANs provide greater network efficiency by reducing
broadcast traffic, but also allow you to make network changes
without having to update IP addresses or IP subnets. VLANs
inherently provide a high level of network security, since traffic
must pass through a router or a Layer 3 switch to reach a
different VLAN.
Usually VLANs are configured within IEEE 802.1Q VLAN-
enabled switches in the network where ports are assigned to
specific VLAN IDs. The Cheetah Gigabit Adapter allows up to
16 VLAN IDs to be configured directly within the card, so a
network server can share its resources with up to 16 VLANs
through just one switch link. This avoids the expense of having
multiple adapters in a server, and significantly reduces the
latency between clients and the server.
Note: The VLAN IDs configured within the adapter card must match those
in the IEEE 802.1Q-compliant switches throughout the network.
Also, the adapter must be attached to a switch port that permits
overlapping VLANs.
Traffic Priority
The Cheetah Gigabit Adapter supports the IEEE 802.1p
Quality of Service standard. Each VLAN is assigned a priority
level in the VLAN ID table. Defining priority levels in the adapter
card allows it to work with other network devices to deliver
higher priority packets first.
Note that the IEEE 802.1p standard must be supported by the
other devices in the network. Refer to the documentation of
your network devices for configuration options on handling
frames with priority tags.
VLAN Table Maintenance
The Cheetah Gigabit Adapter’s VLAN configuration features a
16-entry VLAN ID table. Just click on the “Insert” button to add
an entry to the table. Each entry requires a VLAN ID number in
the range of 0 to 4095 and a user priority level of 0 (lowest) to
7 (highest). The “Modify” and “Delete” buttons can be used to
edit or remove entries from the table.