Wireless LAN switch start-up Aruba Networks this week went public, and its initial stock price surged by nearly 30% in the first day of trading on the Nasdaq exchange.

Aruba’s public debut sets it apart from other WLAN switch start-ups, many of which folded, such as Vivato, or were snapped up by much larger companies, such as Cisco’s $600 million acquisition of Airespace. Besides Aruba, the best-known independent survivors are Trapeze Networks, Meru Networks and Colubris Networks, along with a flock of smaller vendors such as Bluesocket, Extricom and Xirrus -- all of which remain private companies.

Aruba offered 8 million shares on Tuesday, priced at $11 per share, through an underwriting syndicate of Goldman Sachs and Lehman Brothers. With a Nasdaq ticker symbol “ARUN,” the stock opened at $14 and ended the session at $14.15. According to some published accounts, the $11 price was just above the range of $8 to $10 that observers had expected.

As of Wednesday morning, the price had increased to just more than $15.50, and by midday was hovering around $15.

The money will be welcome, because Aruba hasn’t been making any. In the six months ending January 31, the company reported revenue of $51 million and a net loss of $11.7 million. For the same period a year earlier, revenues were $28 million and the company’s net loss was $9 million.

Industry watchers have hopes for the market, however. Some estimates project the global WLAN market will rise from about $1.5 billion today to between $3 billion and $4 billion in the next four years.

About five years ago, Aruba and its rivals introduced the WLAN switch, which is an Ethernet switch with software to handle the specific challenges and requirements of wireless authentication, security, roaming and management. The companion access points typically were simplified nodes with little more than an 802.11 radio and an Ethernet connection back to the switch. Most early networks of this type were overlays -- access points linked with WLAN switches that passed Ethernet traffic onto the enterprise wired infrastructure.

But that model is changing as chipmakers create new switch silicon that can handle both wired and wireless traffic in unified switches. Aruba has been adding products and shifting its focus away from being a WLAN switch vendor focused on connectivity to what CEO Dominic Orr calls “mobile access control,” which focuses on functions and features in the upper layers of the network stack.