CMC Provides 64 Users for Testing

By Eric Griffith

July 28, 2003

The EmulationEngine product line -- which lets networkers mimic the addition of up to 64 wireless users at a time for testing purposes --has added support for 802.11g.

Communication Machinery Corporation (CMC) of Santa Barbara, Calif., has expanded the capabilities of its EmulationEngine Wi-Fi network testing product by adding a new version that supports user scalability testing under 802.11g networks. Other versions of the product support 802.11a or 11b networks only. 11g support is only found in the new dual-band version for 802.11a/g/b. It won't run the three types simultaneously, only one at a time.

The EmulationEngine hardware is the size of a standard access point with dual dipole antenna on the back. Dave Swan, the vice president of sales and marketing at CMC, describes the product's emulation simply as being "seen as 64 laptops with 802.11 NICs." The company calls each of these faux users -- each seen as if with a full MAC address, IP address, etc. -- as a virtual station, or vSTA.

Swan sees three types of end-users that would want or need to do emulation testing: developers and network engineers that design products, deployment users such as system integrators, and the enterprise support side, such as IT managers and the like.

"They all want to make sure things work with normal user loading," says Swan.

This WLAN stress tester is controlled by connecting it to a PC via Ethernet. The interface is access by running a Telnet session or via a Web browser. The generation of the vSTA "users" is all done at the radio level. The EmulationEngine can do internal tests, by asking the vSTAs to send iterated pings, or externally --when coupled with a traffic generator such as NetIQ's Chariot , IP data traffic can be to forwarded to the vSTAs, so the access point and switches on the WLAN will see 64 streams of generated traffic.

"Tools have developed over time with Ethernet, but when you add 802.11, using radio is less deterministic," says Swan. "You want to test not just one user and scale up, you want to test full user loading at a radio level to be sure the access point can handle it. We've seen inherent problems with products right out of the shrink-wrap. If they'd use the EmulationEngine, they'd have caught the problems."

The EmulationEngine products are based on Atheros chipsets. The individual 11a or 11b versions are $4,600 each, while the dual-band 802.11a/g/b is $6,500. The single-band version can be user upgraded at a later time with a kit costing $2,900. For testing with more than 64 virtual users, customers will have to purchase multiple EmulationEngines -- but getting the 11a and the 11b individual versions together would let you test both types of connection.

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