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VoIP careers: Switching from old-school telephony

VoIP careers require those IT pros familiar with traditional PBX systems to brush up on IP telephony basics.

Among many other things, network convergence has come to mean the overlay of voice and data networks, where both types of service share an infrastructure and many kinds of capabilities. It's a testament to the power of data networking that digital voice is often regarded as one service among many -- albeit one with rather more time and signal-quality sensitivity than many other IP-based services. There's plenty of career advice and information available for digital networking professionals who want to learn about voice, but what about telephony mavens who have to step up to digital networking and Voice over IP (VoIP)? That's what you'll find covered here.

When it comes to networking careers, even old-school telephony professionals aren't completely out of the loop. They just need to make a change from circuit-switching to packet-switching, and much of what they otherwise know about networking will translate into the digital world to some degree or another. Actually, those who work on the infrastructure side of the telephony equation made this changeover many years ago, because all communications at the central office level and higher are now completely digital and have been that way since the migration to SONET began in the 1970s.

What, then, must those who've worked around private branch exchange (PBX) and other complex telephony systems learn in order to put their knowledge to work on VoIP networks? A solid understanding of TCP/IP networking protocols is absolutely essential, including a good working knowledge of core protocols such as IP, ICMP, UDP, TCP and various real-time telephony protocols based on H.323 SIP, and so on. It's also important to understand how digital voice communications work at a reasonably detailed level because the measurement and meaning of latency, jitter, packet loss, echo cancellation and so forth are key to establishing, monitoring and maintaining the quality of service (QoS) necessary to deliver acceptable voice communications and fidelity. This introduces a whole slew of other interesting topics related to managing network traffic and QoS, including advanced switch technologies such as MPLS, service-level management (SLM), service-level agreements (SLAs), and service-oriented architectures (SOAs) for networking.

Although one could spend a lifetime learning all these subjects in depth, resources to learn about them are readily available. A series of reading lists at will help guide professionals and includes pointers to academic (mostly graduate level) reading lists and the best books available. Calculated pursuit of some IT certification credentials may also help professionals prepare for such a change of career focus. These would include some or all of the following:

  • CompTIA Network+, for those in need of basic networking literacy.
  • National Association of Communications Systems Engineers (NACSE) has a whole series of certifications aimed at telecom professionals, from associate through multiple technician levels.
  • Cisco offers numerous certifications that include coverage of digital telephony or that concentrate entirely in this area. The coveted Cisco Certified Internetwork Engineer (CCIE) credential has a voice track, and the company also offers the Cisco Certified Voice Professional (CCVP) credential for those interested in this area. Cisco also has seven specialist credentials in -- among others -- the areas of voice, IP telephony and Unity systems.
  • Lucent Technologies offers a Voice over IP Specialist credential as part of its Certified Technical Expert (LCTE) program, with other focus areas on remote access and DSL also available. Likewise, both Avaya and Nortel also offer certifications that include or focus on VoIP topics.
  • The Telecommunications Industry Association (TIA) offers relevant credentials as well. Its Certified in Convergent Network Technologies (CCNT) requires professionals to pass six online exams on networking topics, including one exam on VoIP. Its Convergence Technologies Professional (CTP) certification covers modern telephony across the board, including VoIP and convergence of computers and communications.

Of these various offerings, the most useful for those seeking basic skills and competency will be the Network+ and the TIA CCNT and CTP credentials. All are vendor neutral and stress mastery of basic skills, terms, technologies, and knowledge. The NACSE exams are more demanding and orient themselves more at professional technicians or communications engineers. The vendor-sponsored credentials from, among others, Cisco, Lucent, Avaya and Nortel will be of greatest use to those who are interested in, or who work around, platforms from those companies.

But with some attention to the underlying subject matter, especially the networking protocols and services that make VoIP work, and the skills and knowledge necessary to understand, measure, optimize and manage them, interested professionals can find their way into this field. There's strong demand for qualified VoIP people, and those with a telephony background already have a leg-up into this field. A little study, some elbow grease, and perhaps a certification or two should see you nicely on your way.

Ed Tittel
About the author:
Ed Tittel is a freelance writer who specializes in information security, IT certification, and markup languages. He created the Exam Cram series, has contributed to more than 130 computer books, and writes regularly for several TechTarget Web sites. Email Ed at

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