1. entry-level: Network+ and i-Net+ (CompTIA) 2. mid-level: level 1 Linux certs (Sair/GNU, LPI, Linux+ - CompTIA) Sun Solaris System Administrator entry-level Microsoft: MCSA entry-level Novell: CNA 3. senior-level: Level 2 & 3 Linux Certs (Sair/GNU, LPI, Red Hat RHCE) senior-level Microsoft: MCSE senior-level Novell: CNE, MCNE Sun Solaris Network Administrator
Beyond that, you could look into more advanced security or protocol analysis certifications, all of which could help to advance a senior network administrator to a higher career position.
As to your other question about the history of network specialists, since I don't honestly recognize that designation as a meaningful or specific certification per se, I can only say that as soon as networks became broadly available in the early to mid 1980s, IT professionals began to specialize in those topics. The first certifications in this area about which I'm aware date back to 1986 (Novell, 3Com, and Sytek) but none of them has ever been called "Network Specialist"--at least, not to my knowledge.
Good luck & hope this information helps,
This was first published in October 2002