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Wireless Network Head-to-Head: Cisco Vs. Meru: Page 3 of 15

After performing side-by-side comparisons and analyzing packet traces, we came away suspecting that Meru's secret may leave a bitter aftertaste, especially if a neighboring business is running a Meru system on the same channel as your non-Meru system. Cisco was unambiguous in claiming that Meru is violating 802.11 standards by artificially manipulating the NAV (network allocation vector) value in certain duration fields (see "Duration, Duration, Duration" below). Meru denies these allegations, claiming its products are "100 percent standards-compliant." Based on our understanding of 802.11's virtual carrier sense architecture and the role that duration field values play in managing contention, we find Cisco's charges credible, but we'll reserve final judgment until other industry experts weigh in on this controversial issue.

It's worth noting that this is not simply an issue of RF interference between 802.11 systems. This is an issue of the degree to which one vendor can extend 802.11 standards to prioritize the wireless traffic of its system in a manner such that it diminishes the performance of adjacent systems. Despite claims by Cisco, it isn't clear whether Meru is violating 802.11 standards, but the company's continuing insistence that it "can only go so far" in explaining how it prioritizes traffic leaves it vulnerable to speculation, especially when suspicious protocol behavior is experienced.

Leaving aside the issue of standards compliance, we're still reluctant to offer an enthusiastic recommendation for Meru at this time. Yes, the system outperformed Cisco on our test bed, but we encountered numerous bugs and support problems along the way. Despite repeated requests, we also experienced problems getting Meru to connect us with customers that had large scale installations. We did speak with a very satisfied customer at a small liberal arts college in New York, but Meru was unable to arrange for an interview with any larger customers in time to meet our article deadline. In addition, while Meru may in fact have some creative and effective way to deliver QoS over WLANs, its architecture run counter to industry norms.

Three Strikes?

We've tested hundreds of wireless products over the years and, from the start, our experience with Meru was problematic. To evaluate its architecture and performance, Meru insisted that we test its products in an open-air environment, a challenge given the prevalence of wireless networks at our Syracuse University labs. Interference may be real-world, but you can't do competitive performance testing without controlling for that variable. To accommodate Meru, we conducted initial testing between midnight and 6 a.m., after working with the university IT staff to disable all production WLAN services that might have corrupted our results.