Cisco certifications, such as Cisco Certified Internetwork Expert and Cisco Certified Network Professional, have become sought-after credentials for most network professionals. They also are required levels of competency that many CIOs and other IT executives look for when hiring staff.

Some say the slew of Cisco certifications has become an alphabet soup of titles, and others add that no piece of paper outweighs experience and intelligence.

This year marks the 10th anniversary of Cisco's certification and education program, which started with the CCIE examination. More than 500,000 Cisco certifications have been issued since the program was started - that's about one Cisco-certified professional for every four of the approximately 2 million Cisco routers installed.

Cisco is very different than it was 10 years ago, and that has caused the company's training and certification organization to evolve as well. What started as a test of users' knowledge of WAN routers and protocols now includes switching, security, wireless, telephony and storage.

"One part of how we approach our programs is to look at the demand," says Don Field, senior manager of core technologies for Cisco's Internet learning solutions group. He says that as Cisco adds technologies to its portfolio, new certifications evolve from user and channel partner demand. And while Cisco's certification offerings grow, some programs get scaled back. For example, Cisco's SNA IP certification was phased out several years ago after most corporations migrated off SNA networks, Field says.

CCIE is the highest level of Cisco certification.It represents "the upper echelon of networking experts worldwide," Cisco's Web site says.

"Six years ago, we first introduced stepping-stone certifications to validate skills along the way to reaching the ultimate objective of being a CCIE," Field says. These include the CCNP and Cisco Certified Network Associate (CCNA) certifications. Each of these levels also has two to four subsets, such as specializations in routing and switching, security and voice.

Also available are four paths for certification: design, installation and support, security, and service provider specialization. Many of these specialized certifications are aimed at channel partners, integrators and resellers of specific products, and Cisco requires them to obtain various levels of channel partner support and status.