Making the Switch to VoIP

Voice over Internet Protocol (VoIP) is the transport of voice-coded information embedded in an IP packet, typically using Ethernet as the data network physical transport medium. This is opposed to transmission over copper analog circuits using private branch exchange (PBX) switching technology. This technology has many benefits for the user to consider: reduction of long-term maintenance and st...

By James L. Seibert, P.E., RCDD, Telecommunications Team Leader, Brinjac Engineering, Inc., Harrisburg, Pa. December 1, 2004

Voice over Internet Protocol (VoIP) is the transport of voice-coded information embedded in an IP packet, typically using Ethernet as the data network physical transport medium. This is opposed to transmission over copper analog circuits using private branch exchange (PBX) switching technology.

This technology has many benefits for the user to consider: reduction of long-term maintenance and staff costs; flexibility and ease of use; migration to PC/computer technology allowing seamless integration of the voice and data services to a ubiquitous and converged system; and reduction of physical space associated with traditional PBX systems.

Different flavors

VoIP packets can be transmitted using a number of technologies and types of equipment:

IP-PBX-pure VoIP end-to-end solutions. “Pure” VoIP uses the data network for transport from an IP phone through the switched data network to the end-point IP phone. Typically, these systems use centralized call switching and processing that are connected into the core of the IP-centric data network. Call setup and teardown is accomplished in centralized servers connected to the network. Call switching is not distributed in this environment.

IP-PBX-VoIP transport utilizing analog phones. This is similar to pure VoIP, but analog technology is used to connect an analog phone instrument to the IP-PBX switch—switched locally through the IP-PBX switch—and connect the voice channel to the end-point analog phone instrument. VoIP packets are used for transmission between the IP-PBX switches but not to the phone instruments. This type of system will also support IP phones, using a virtual port on its IP-PBX switch. This system provides distributed call switching.

IP-enabled PBX. This solution uses traditional digital PBXs, with the addition of Ethernet “trunk” cards to enable connectivity to the data network for transport of VoIP packets, usually over private wide area networks (WAN).

Challenges

Deciding whether to implement VoIP requires that certain questions be answered, among them:

  • Is your current network “ready” for VoIP?

  • Can your WAN support the additional bandwidth of VoIP packets?

  • Can your cabling infrastructure and telecom closets support VoIP transmission and equipment?

  • Do the current telecom closets have normal/emergency power circuits built into them, backed up by a standby generator or uninterruptible power supply?

  • Will the IP-PBX integrate with your current public address systems?

The future

The current trend is toward IP-centric systems. IP-PBX technology will continue to improve, with high quality equipment already here and in use. Within 10 years, most traditional PBXs will likely go away and the majority of systems will be IP-PBX-based. Now is the time to start thinking about upgrading.

VoIP Advantages

Reduced maintenance and staff costs

Flexibility and ease of use

Less space required

Seamless integration of voice and data services to a converged system