Filter
Top Products
EDS-518A Series User’s Manual Featured Functions
3-35
y VLANs provide extra security: Devices within each VLAN can only communicate with
other devices on the same VLAN. If a device on VLAN Marketing needs to communicate
with devices on VLAN Finance, the traffic must pass through a routing device or Layer 3
switch.
y VLANs help control traffic: With traditional networks, congestion can be caused by
broadcast traffic that is directed to all network devices, regardless of whether or not they need
it. VLANs increase the efficiency of your network because each VLAN can be set up to
contain only those devices that need to communicate with each other.
VLANs and MOXA EtherDevice Switch
Your EDS-518A provides support for VLANs using IEEE Std 802.1Q-1998. This standard allows
traffic from multiple VLANs to be carried across one physical link. The IEEE Std 802.1Q-1998
standard allows each port on your EDS-518A to be placed in:
y Any one VLAN defined on the EDS-518A.
y Several VLANs at the same time using 802.1Q tagging.
The standard requires that you define the 802.1Q VLAN ID for each VLAN on your EDS-518A
before the switch can use it to forward traffic:
Managing a VLAN
A new or initialized EDS-518A contains a single VLAN—the Default VLAN. This VLAN has the
following definition:
y VLAN Name—Management VLAN
y 802.1Q VLAN ID—1 (if tagging is required)
All the ports are initially placed on this VLAN, and it is the only VLAN that allows you to access
the management software of the EDS-518A over the network.
Communication Between VLANs
If devices connected to a VLAN need to communicate to devices on a different VLAN, a router or
Layer 3 switching device with connections to both VLANs needs to be installed. Communication
between VLANs can only take place if they are all connected to a routing or Layer 3 switching
device.
VLANs: Tagged and Untagged Membership
EDS-518A supports 802.1Q VLAN tagging, a system that allows traffic for multiple VLANs to be
carried on a single physical (backbone, trunk) link. When setting up VLANs you need to
understand when to use untagged and tagged membership of VLANs. Simply put, if a port is on a
single VLAN it can be an untagged member, but if the port needs to be a member of multiple
VLANs, tagged membership must be defined.
A typical host (e.g., clients) will be untagged members of one VLAN, defined as “Access Port” in
EDS-518A, while inter-switch connections will be tagged members of all VLANs, defined as
“Trunk Port” in EDS-518A.
The IEEE Std 802.1Q-1998 defines how VLANs operate within an open packet-switched network.
An 802.1Q compliant packet carries additional information that allows a switch to determine
which VLAN the port belongs. If a frame is carrying the additional information, it is known as a
tagged frame.
To carry multiple VLANs across a single physical (backbone, trunk) link, each packet must be
tagged with a VLAN identifier so that the switches can identify which packets belong to which
VLAN. To communicate between VLANs, a router must be used.
MOXA EDS-518A supports two types of VLAN port settings: