Configuring the ECN330-switch
274 1553-KDU 137 365 Uen D 2006-06-16
Figure 107 VLAN Compliant and VLAN Non-compliant Devices
VLAN Classification – When the ECN330-switch receives a frame, it classifies
the frame in one of two ways. If the frame is untagged, the ECN330-switch
assigns the frame to an associated VLAN (based on the default VLAN ID of the
receiving port). But if the frame is tagged, the ECN330-switch uses the tagged
VLAN ID to identify the port broadcast domain of the frame.
Port Overlapping – Port overlapping can be used to allow access to commonly
shared network resources among different VLAN groups, such as file servers or
printers. Note that if VLANs are implemented that do not overlap, but still need
to communicate, they can be connected by enabling routing on the ECN330-
switch.
Untagged VLANs – Untagged (or static) VLANs are typically used to reduce
broadcast traffic and to increase security. A group of network users assigned to
a VLAN form a broadcast domain that is separate from other VLANs configured
on the ECN330-switch. Packets are forwarded only between ports that are
designated for the same VLAN. Untagged VLANs can be used to manually
isolate user groups or subnets. However, use IEEE 802.3 tagged VLANs with
GVRP whenever possible to fully automate VLAN registration.
Automatic VLAN Registration – GVRP (GARP VLAN Registration Protocol)
defines a system whereby the ECN330-switch can automatically learn the
VLANs to which each end station should be assigned. If an end station (or its
network adapter) supports the IEEE 802.1Q VLAN protocol, it can be configured
to broadcast a message to the network indicating the VLAN groups it wants to
join. When the ECN330-switch receives these messages, it will automatically
place the receiving port in the specified VLANs, and then forward the message
to all other ports. When the message arrives at another switch that supports
VC
VC: VLAN Compliant
VN: VLAN Non-compliant
VC
tagged frames
VC VNVC
tagged
frames
untagged
frames
To Next Page
Loading...
