MANHASSET, N.Y. — Reacting to the explosive growth of Wi-Fi networks and voice-over-Internet Protocol telephony, Meru Networks Inc. is offering an enterprise wireless-LAN solution that emphasizes dynamic, over-the-air quality of service.
Meru uses advanced algorithms that sidestep collisions and contention issues as the number of network users rises, and claims it can increase active calls and supported users by a factor of five, while also making call handoffs transparent.
"Wireless LANs have had slow growth in the enterprise; voice will change that," said Ujjal Kohli, chief executive officer at Meru Networks, a Sunnyvale, Calif., startup founded in February 2002. "While voice-over-WLAN is a small market to date, we feel there's a huge interest in it now."
Extrapolating figures from In-Stat/MDR that showed voice-over-IP growing at 60 percent in 2002, Kohli said he expects the number of IP phones to surpass regular switched lines this year. These forecasts, and the continued growth of WLANs, the convergence of cellular and Wi-Fi phones, and the wireless capabilities of laptops and PDAs all factor into Meru's strategic emphasis on voice-over-WLAN, Kohli said.
Effective wireless voice requires advanced quality of service (QoS) for the enterprise, however — in particular, an ability to scale rapidly and with minimum effort, Kohli said. With the IEEE 802.11e task group ironing out a QoS scheme for WLANs at the media-access control (MAC) layer, Kohli said Meru's solutions will be compatible with that group's specifications, which he believes will nonetheless be insufficient to meet real-world needs. "It will be fine for home/Soho users, but it won't be scalable for the enterprise — though it will punch up our performance," he said.
Instead, Meru has developed its own MAC technology, which works in conjunction with a centralized controller running algorithms that implement a deterministic time-division multiplex (TDM) round-robin scheme on top of the best-effort carrier-sense, multiple-access, collision-avoidance (CSMA/CA) technology used by Ethernet-based 802.11 Wi-Fi networks.
Implementing TDM over CSMA/CA required the development of advanced algorithms that control every access point in the network to eliminate contention, collisions and interference — even while operating on the same channels. But the results speak for themselves, Kohli said.
Meru's Air Traffic Control architecture "brings predictability through scheduling — on top of content management — to reduce jitter and latencies, to the extent that we can support up to 100 users on any given access point," he said. "Up to 30 of those can be voice calls."
That's five times the user density and voice-handling capability of the base 802.11b network, though proprietary schemes do somewhat better, Kohli added. "However, those proprietary schemes require software additions to the client," he said. "Ours doesn't."
The company's Over-the-Air QoS scheme offers fine-grained QoS per application, user and flow in both the up- and downlink between the client and the access points. While some plans, such as one announced recently by Airflow Networks, split the voice and data between channels, Meru's approach allows a single channel to carry both.
Meru's system comprises a $595 access point based on a radio and baseband from RF Micro Devices Inc., the company's own MAC and an $8,000 central controller that interfaces to the enterprise backbone and the network's already installed switches, such as Cisco Systems' Catalyst line. The controller also implements what Kohli calls the basic requirements of centralized security enforcement and ready deployment and management.
"Those are core functions that many [companies] — such as Aruba, Airespace, Nortel and Proxim — perform well, but they lack the QoS, density and transparent mobility," said Kohli.
Meru's system is now shipping.
