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  • How Much Bandwidth do I need for VOIP?
Technology Articles > Software > Communications > How Much Bandwidth do I need for VOIP?

Voice over Internet Protocol (VoIP) phones rely on your Internet connection to send and receive voice conversations. Because of this, you’ll need a relatively speedy Internet connection in order for your call quality to remain steady and reliable. This become more of a concern when outfitting an entire office with VoIP phones. In many cases, upgrading your phones to VoIP means that you’ll also need to upgrade your broadband Internet connection. Use the following guide to determine how much bandwidth you’ll need and whether you need to upgrade your service or seek out a new Internet service provider (ISP).

VoIP Codecs

When shopping for VoIP phone systems, the first thing you need to find out to determine your broadband needs is the VoIP codec used by the communications system you’ll be installing. Each codec typically is listed alongside its bandwidth requirements per channel. Each phone conversation uses two channels: one for outgoing VoIP (upload) and one for incoming VoIP (download). To figure the bandwidth requirements for each line, take the bandwidth per codec and multiply it by two. For example, for G.711 codecs, the bandwidth is 64 kbps per channel, so each line will use about 128 kbps per phone line.

Number of Phone Lines

Although you won’t feasibly be using each and every phone line simultaneously, unless you’re operating a call center, you should have enough bandwidth to accommodate multiple calls at once. For example, if you are connecting 50 phone lines in your office, you’ll obviously need much more than 128 kbps for the entire system. Consider how often each of your phones will be used when factoring in your bandwidth needs. A reasonable estimate is to apportion about 80 kbps per phone line.

Balancing VoIP and Internet Usage

VoIP phone lines use the same Internet connection as your regular Internet access. This is important if you’ll be using your office’s Internet connection to access the web, mail attachments, access network attached storage devices or communicate with satellite offices. As a general rule of thumb, at least 50% of your bandwidth should be set aside for VoIP. This will avoid tying up your Internet usage with phone calls and slowing productivity for those working on the web. Similarly, you don’t want heavy Internet usage to degrade the call quality for your VoIP lines.

Common Bandwidths

Your bandwidth will vary depending on your office’s usage and your ISPs quality of service, but in general, you can expect about 128 kbps from an ISDN line and 1 to 6 Mbps for cable lines. ADSL and other WAN technologies can get bandwidth speeds up to several Mbps, but again, the level of service you receive from your ISP will vary depending on your price point. Dial-up modems, which get a mere 56 kbps are never suitable for VoIP.

When beginning your preliminary research for a VoIP system, use these guidelines to price out your bandwidth needs and factor in your bandwidth costs into your overall cost of ownership for your VoIP phone system. When you’re ready to make a decision, contact a VoIP vendor and have them assess your connection speeds and needs specific to your business.