Rockwell Automation Publication 1783-UM001B-EN-P - May 2010 45
Switch Management        Chapter 4
• Remove Selected - Click to remove the selected MAC ID from the 
authorized list.
• Learned MAC Addresses - This table lists the MAC IDs detected on the 
network by the 1783-EMS switch. The port number and MAC ID are 
shown for each device detected on the network. This list is built 
automatically by the 1783-EMS switch. 
• Authorized MAC Addresses - This list indicates which MAC IDs are 
allowed on the network. You must create this list. Whenever a new device 
comes online, this list is checked to determine if the device is authorized. If 
the device is not authorized, an input is sent the controller. (See
Appendix D
 for the I/O table of the 1783-EMS switch.)
VLAN Setup 
Used when network bandwidth becomes critical, VLAN is used to eliminate 
traffic caused by multicast and broadcast Ethernet traffic. With this feature, we 
can partition the switch ports into different private virtual networks.
For each received packet, the switch resolves the destination address and 
determines the appropriate port. The VLAN configuration is then checked to see 
if the destination address is configured to receive traffic from the source port.
For example, if a FLEX I/O module is connected to port 2 on the 1783-EMS08T 
switch, the I/O module is communicating with a ControlLogix module on
port 3. We want the ControlLogix module on port 3 to receive traffic from the 
FLEX I/O module on port 2. VLAN can be used to prevent other devices on the 
network from receiving packets from the FLEX I/O module. 
Our VLAN configuration would look as shown in the figure. The Egress port 
(source port 2) transmits to the Ingress port (destination port) 3.