The dirty secret of VoIP is that while it enables calls that don't cost much, it eats bandwidth that can cost a lot.
Despite technicians' best efforts to compress voice signal size using algorithms you need a Ph.D. in math just to read, voice signals remain large. For your business to carry VoIP effectively and reliably, you need the appropriate computing firepower and a big-enough pipeline to handle VoIP call volume into, out of and around your network .
Depending on your network and needs , you may be able to get by with a relatively low-bandwidth connection - but grow beyond a certain point and it may be time to upgrade to a DS3 connection .
Bandwidth is the amount of data that computers can transmit through a wire or wireless channel each second. A single voice conversation requires a bandwidth of 64 kilobits per second for good call quality, so 64 kbps is the basis for discussing transmission speeds.
64 kbps is called digital signal zero, or DS0, and is not considered to be a high-speed line nowadays; the minimum for high-speed transmission is about 24 times faster than DS0, and is called DS1. This is the maximum speed of most home-based DSL Internet service through telecom carriers, and more familiar as a "T1" line (for instance, your laptop probably has a T1 jack in its side—it's slightly wider than a phone jack). A dedicated T1 line is always on, transmitting and receiving the equivalent of 24 voice conversations from the Internet provider's servers.
But as a business's bandwidth requirements increase, the next step up is DS3, which is 672 times faster than DS0 and thus transmits 672 voice conversations (or the equivalent in other data) at once. Today's primary DS3 users are high-traffic Web sites, medium to large Web-hosting companies, medical centers, call centers, universities and government offices.
DS3 lines, also called T3 lines, are not cheap. Their high capacity makes them sought-after as the backbone of today's Internet. Also, DS3 lines are more complex than T1 - technically, they run 28 T1 lines alongside one another, and that takes extra equipment and software to work properly.
One broker quotes DS3 service starting at $2,000/month and up , although prices are dropping as ever-more users need DS3 and competition in this market rises.
Major telecom providers typically offer a range of services and speeds, including DS3; for example, Verizon Business publishes a chart showing the speeds and business applications of various bandwidth sizes.
Businesses should consider a dedicated T1 connection as the minimum to support VoIP and other data traffic—but when that starts to feel cramped, upgrading to a DS3 line (or a fraction of one) should solve a company's bandwidth problems for awhile.
Can I share the cost of DS3 service?
Yes. Businesses that don't need constant DS3-level bandwidth should consider a "burstable" connection, which involves sharing DS3 access with another company or companies through the DS3 provider. This gives access to extremely high transmission rates for much less than the cost of a full DS3 set-up, because the companies sharing the burstable connection don't usually combine to use all the bandwidth at the same time.
Are all DS3 providers created equal?
No, and those shopping for a business DS3 connection should focus on quality of service rather than price. In exchange for a low price, some providers may oversubscribe DS3 connections—without telling you, of course—threatening delivery of DS3 speeds during peak periods. Review the service level agreement (SLA) with a provider before signing anything.
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