Overlapped VLANs to the rescue
Overlapped VLANs in Contemporary Controls’ EISX_M, EICP_M, and EISB_M switches will allow one device to be shared among multiple VLANs—simultaneously isolating traffic between the VLANs. Normally, a router is needed when communicating between VLANs; however, overlapped VLANs allow a specific device to be shared in multiple VLANs without the need of a router.
Contemporary Controls’ R&D manager, Bennet Levine, says overlapped VLANs are very useful for the company’s customers who are interconnecting office and factory networks. “In the long run, overlapped VLANs save customers much aggravation. Why? Overlapped VLANs can be employed to keep problems that often occur in the office environment from affecting the factory,” explains Levine. He added that these office problems may not even be noticed immediately. “For example, if you are sitting at your desk and it takes one or two seconds longer to bring up a Web page from the Internet
VLAN is a feature that allows the switch to isolate traffic between groups of ports so the user can control which devices communicate with each other. VLANs enhance network performance because traffic originating in a VLAN will go nowhere else.
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— Richard Phelps, senior editor, Control Engineering