Introduction
It’s safe to say Internet Protocol (IP) telephony has arrived as a feasible communications technology for business. And for good reason. Now that the telecom industry has had time to refine it and more organizations are deploying it, IP telephony is delivering on its claims of reducing calling costs, simplifying administration, and providing greater communications flexibility with software applications taking the place of traditional hardware systems. IT chiefs and corporate level decision-makers also are looking more closely at IP telephony as voice quality continues to improve, and as organizations that use IP continue to consistently reach the “Five 9’s” level of reliability with 99.999% system uptimes.
But perhaps the most compelling argument for implementing IP telephony is that Private Branch Exchange (PBX) telephone systems — the systems the business world has used the last 30+ years to generate calls — are expected to be near extinction by year-end 2008. Gartner, Synergy, Forrester and other industry analysts made that prediction as early as 2003, and their collective forecast is coming true as a number of PBX manufacturers announce plans to cease development and support of their PBX products. IP telephony, after all, is forcing their hand. Compared to IP’s standards-based software approach and ability to converge voice on a data network, traditional proprietary PBX systems are more difficult to integrate with an organization’s business applications and business rules, and have increasingly become more expensive to maintain or update. Therefore for many businesses, making the move to IP telephony and networked voice and data communications will be inevitable within the next few years. Yet because no two businesses or their IP projects are the same, doing your homework on IP PBX solutions, voice over IP and communications standards such as SIP remains key as IP telephony becomes an accepted technology for business.
IP Telephony, VoIP, and Unified Communications Explained
Since arriving on the communications landscape, IP telephony has become referred to in many circles as voice over IP, or VoIP. (More on that in a couple paragraphs.) Technology-wise, the term VoIP is widely used to describe the processes for managing transmissions of voice information utilizing the Internet Protocol standard. Rather than transmitting voice signals using traditional circuit-committed protocols of the Public Switched Telephone Network — think of the PSTN as a local and long distance phone service provider — VoIP sends voice, fax and video communications traffic over the Internet in digital format via discrete data packets.
Also by leveraging the Internet to deliver phone calls and faxes over shared voice/data network lines, VoIP enables organizations to avoid toll charges associated with the PSTN. This “toll bypass” can result in significant savings for long distance calls and telecom services, and is one of VoIP’s most touted advantages.
Along with reducing communications costs, analysts also envision businesses migrating to VoIP to improve operational efficiency by converging what historically have been separate voice and data networks. Accordingly, most VoIP providers have increased network reliability (along with efficiency), and now ensure Quality of Service (QoS) in their packet routers to dependably deliver voice and fax as well as video data packets to end-users. QoS further helps ensure that these VoIP-based voice packets receive priority delivery over an IP network. And while QoS minimizes or even eliminates the call latency that saddled early VoIP implementations, Quality of Service should not be confused with the voice quality of an IP-driven call.
Voice quality instead is gauged by:
- Delay, or the amount of time it takes a voice packet to be created, sent across the network, and converted back into sound;
- Echo, which results from the delay in voice packet networks and becomes more noticeable as delay increases (echo occurs throughout most voice networks today); and
- Jitter, which occurs when voice packets arrive at an interval greater than they’re sent.
Back to the terms IP telephony and VoIP being used interchangeably, there is indeed a distinction between the two: Whereas VoIP encompasses the process of voice communications traveling as data packets over the Internet, IP telephony more closely aligns with the premise-based phone system that actually initiates an IP call. This new-generation system is known as an IP PBX.
