IE-SW-VL08M Series User’s Manual
Featured Functions
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Managing a VLAN
A new or initialized switch 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 IE-SW-VL08M 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
The IE-SW-VL08M 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
the switch, while inter-switch connections will be tagged members of all VLANs, defined as “Trunk
Port” in the IE-SW-VL08M.
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.
The IE-SW-VL08M supports two types of VLAN port settings:
y
Access Port:
The port connects to a single device that is not tagged. The user must define the
default port PVID that determines to which VLAN the device belongs. Once the ingress packet of
this Access Port egresses to another Trunk Port (the port needs all packets to carry tag
information), the IE-SW-VL08M will insert this PVID into this packet to help the next 802.1Q
VLAN switch recognize it.
y
Trunk Port:
The port connects to a LAN that consists of untagged devices/tagged devices and/or
switches and hubs. In general, the traffic of the Trunk Port must have a Tag. Users can also assign
PVID to a Trunk Port. The untagged packet on the Trunk Port will be assigned the port default
PVID as its VID.
The following section illustrates how to use these ports to set up different applications.
