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VLAN Configuration
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NXA-ENET24 - Software Management Guide
VLAN Configuration
Overview - IEEE 802.1Q VLANs
In large networks, routers are used to isolate broadcast traffic for each subnet into separate domains. This
switch provides a similar service at Layer 2 by using VLANs to organize any group of network nodes into
separate broadcast domains. VLANs confine broadcast traffic to the originating group, and can eliminate
broadcast storms in large networks. This also provides a more secure and cleaner network environment.
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 physical connections. VLANs can be easily organized to reflect departmental groups
(such as Marketing or R&D), usage groups (such as e-mail), or multicast groups (used for multimedia
applications such as MAX).
VLANs provide greater network efficiency by reducing broadcast traffic, and 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 configured Layer 3 link to reach a different VLAN.
This switch supports the following VLAN features:
Up to 255 VLANs based on the IEEE 802.1Q standard
Distributed VLAN learning across multiple switches using explicit or implicit tagging and GVRP
protocol
Port overlapping, allowing a port to participate in multiple VLANs
End stations can belong to multiple VLANs
Passing traffic between VLAN-aware and VLAN-unaware devices
Priority tagging
Assigning Ports to VLANs
Before enabling VLANs for the switch, you must first assign each port to the VLAN group(s) in which it will
participate. By default all ports are assigned to VLAN 1 as untagged ports.
Add a port as a tagged port if you want it to carry traffic for one or more VLANs, and any intermediate
network devices or the host at the other end of the connection supports VLANs. Then assign ports on the other
VLAN-aware network devices along the path that will carry this traffic to the same VLAN(s), either manually
or dynamically using GVRP. However, if you want a port on this switch to participate in one or more VLANs,
but none of the intermediate network devices nor the host at the other end of the connection supports VLANs,
then you should add this port to the VLAN as an untagged port.
VLAN-tagged frames can pass through VLAN-aware or VLAN-unaware network interconnection devices, but
the VLAN tags should be stripped off before passing it on to any end-node host that does not support VLAN
tagging (FIG. 127).
FIG. 127 Assigning Ports to VLANs
VA
VA: VLAN Aware
VU: VLAN Unaware
VA
tagged frames
VA VUVA
tagged
frames
untagged
frames