Reflecting on two decades of tech development and trying to identify 20 of the most influential players is tough, but we skimmed the cream with the help of longtime industry watchers. The result: a list of technologists, savvy business leaders and forward-looking IT executives who made a difference.

NETWORK INFRASTRUCTURE

Len Bosack and Sandy Lerner: Cross-campus Internet workers.
They might not have invented the router, as is often believed (see Q&A), but the two Stanford University employees built one heck of a company to exploit it.

The two recognized the multiprotocol router's commercial potential and founded Cisco in late 1984; when they left in 1990 (Lerner was forced out, and Bosack left of his own volition immediately thereafter), the company had grown from an unknown, four-employee start-up to a 250-person, publicly traded industry trend-setter with a market cap of $224 million. Today Cisco remains the router leader, as well as a dominant player in the access, switch, security, storage, VoIP and wireless markets. That market cap? It had grown to more than $120 billion as of late last month.

Desh Deshpande: Framed the future.
Deshpande launched a data-services revolution in 1991, when he founded switch maker Cascade Communications and propelled the concept of frame relay into the industry's consciousness. Cascade quickly became a dominant network vendor, growing from a one-person start-up to a $500 million company with 900 employees that Ascend Communications acquired in 1997 for $3.7 billion. Thanks in large part to Deshpande's efforts, frame relay has proven to be one of the most successful data services ever, the longtime de facto data communications standard for enterprise networks. After selling Cascade, Deshpande co-founded Sycamore Networks in 1998. Ever the entrepreneur and always the revolutionary, Deshpande this time brought the concept of intelligent optical switching to the foreground.

Bob Metcalfe: Talk about a legacy.
As a young engineer at Xerox PARC in 1973, Metcalfe invented Ethernet. Little did anyone know the technology, meant to connect local computers, would become synonymous with networking. There's no end in sight for Ethernet's dominance. Now operating at gigabit-plus speeds, it's a choice for even local, metropolitan and wide-area networks. Since his early days at PARC and then 3Com, which he founded in 1979, Metcalfe has been one of the industry's preeminent visionaries. He continues in that role today, helping develop upstart technology companies for Polaris Venture Partners.

Ray Noorda: LAN man.
Noorda took over the helm of struggling Novell in 1982 and in the process of resurrecting the company created the market for network operating systems. His insistence that engineers figure out a way to turn a bunch of disparate PCs into a networked entity turned Novell into the go-to LAN software vendor for years. Noorda's insight - that getting LAN technology entrenched in corporate America would require teams of highly trained and certified individuals - spawned reseller and certification programs still widely imitated today.