This year marks a watershed for the Interop trade show in Las Vegas, as the granddaddy of enterprise networking events adds a software show and a security conference.

The added attractions are recent acquisitions of TechWeb Networks, a division of United Business Media, which presents Interop. But the changes reflect more than just business decisions, according to TechWeb and some industry observers and regular showgoers. Though networking is still important, it seems there's just not as much to say about the topic by itself.

Interop began in the late 1980s as a gathering of network equipment makers who wanted to find out whether their products could talk to each other. Under the Networld+Interop name, it grew huge in the late 1990s as enterprises embraced Ethernet, and as Cisco Systems, Nortel Networks, 3Com and Cabletron vied to build their networks. There were about 61,000 visitors to the Las Vegas show in 2001. But the event shrunk after the technology crash early in this decade, dropping one of two U.S. gatherings, losing the Networld part of its name and eventually moving out of the cavernous Las Vegas Convention Center.

Next week, the Software 2008 show and the CSI SX security conference will be held alongside Interop at the smaller Mandalay Bay Convention Center. CMP sees the two events as natural extensions of Interop, according to Lenny Heymann, the show's general manager. Enterprises need interoperability across all aspects of IT, he said.

"It's really very difficult to separate segments of the industry," Heymann said. Network administrators increasingly deal with application performance and security mechanisms, for example. And networking vendors themselves have branched out, he noted. Cisco has been a prime example, adding firewall and other security functions as well as application acceleration to its lineup over the past few years. Its biggest rival in core routing, Juniper Networks, is also a significant security player today.

Interop acquired Software 2008 last year, intending to locate it with its existing show, Heymann said. CSI SX is a long-running conference of the Computer Security Institute that now has a new home, he said. It doesn't include an exhibition, but there has been a growing section of the Interop show floor devoted to security products for several years, Heymann said.

Overall, TechWeb expects 25 percent more exhibitors compared to last year, and is looking for an increase in attendance from last year's 18,000 to as much as 20,000. The show has also brought back its second U.S. gathering, in New York in September, in addition to non-U.S. dates.