Contemporary Controls adds features to Ethernet switches

Contemporary Controls reports it’s added a variety of new features to its managed Ethernet switches to enhance their performance in industrial networks, such as EtherNet/IP. These features includes IGMP snooping, rate limiting, port security, and quality of service (QoS) enhancements, which is also known as Diffserv, IEEE 802.1p and TOS.

IGMP snooping is the ability of a switch to learn IP Multicast group membership. The purpose is to restrict multicast transmissions to only those ports that have requested them. Bennet Levine, Contemporary’s R&D manager, says IGMP snooping is significant in large EtherNet/IP networks. “EtherNet/IP devices use multicast messages for their real-time data,” he says. “However, on a switch that doesn’t support IGMP snooping, these multicast messages will be handled like broadcast messages, and potentially overwhelm some devices. Those devices may be unable to perform their normal activities when they receive a large amount of unwanted multicast traffic.”

Meanwhile, rate limiting can be used to restrict certain devices (or groups of devices connected to a port on the switch) from consuming too much network bandwidth. “Rate limiting also allows broadcast storm protection,” adds Levine.

In addition, when port security is enabled, the Ethernet switch will only pass traffic sent by specific devices. The MAC addresses of the devices, which can communicate through the switch, can be entered via the console port or web page. This feature can be enabled on a port-by-port basis. “This feature is beneficial if extra security is required on specific ports of the switch,” says Levine. “For example, if you wanted to only allow specific computers on the office network to be able to communicate with the factory network, you could enable port security on the switch port which connects to the office network.”

Finally, Levine reports that QoS enhancements allow specific ports or specific messages to have a higher priority when communicating through the company’s managed switch.

These features were scheduled to be available on Contemporary’s EICP_M, EISX_M and EISB_M products by the end of July 2005. For existing owners of these products, a software update will be made available. To obtain a software update or more information, send an e-mail to blevine@ccontrols.com or visit the company Web site .

—Jim Montague, news editor, Control Engineering, jmontague@reedbusiness.com

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