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Does Bandwidth Affect VoIP?


Basically, voice over internet protocol (VoIP) works by taking analogue voice signals and converting them into digital signals, sending them as data via your broadband. Because VoIP uses your broadband, the bandwidth of your broadband can affect your VoIP.


VoIP can be a highly efficient and cost effective way of operating your business phone system, but it does require a minimum bandwidth to work well.



What is Bandwidth?


Bandwidth is the maximum amount of data that you can transfer across your internet connection over a given period of time.


It does not refer to the speed of data transfer, but rather the capacity of the network’s communications, even though you measure this in bandwidth speed.


The standard way of measuring bandwidth is in of bits per second (bps), in either thousands of bits (kbps) or millions (mbps).


If you decide to use VoIP as your telephone system, you need to be sure you have the bandwidth to handle it.



How Does VoIP Use Bandwidth?


The way VoIP uses bandwidth is through a series of codecs, which compress and decompress voice data.


A codec decodes a digital data stream or signal.


But your phone system will be competing with other elements in your business setup for bandwidth, such as emails, file transfers and web-based office systems.


Therefore, you should first determine the functional bandwidth you will require before installing your VoIP system.



How Much Bandwidth Does Your Phone System Need?


If you’re using VoIP, you want your voice calls to be of a good quality. The higher bandwidth speed you have, the more data you can send over your broadband connection.

You have two types of bandwidth:


  • Upload bandwidth, and
  • Download bandwidth.


Upload is the amount of data you can send to the internet, and download is the rate of data transferred from the internet to your computer.


How much bandwidth you VoIP system requires depends on how many calls you wish to make concurrently. This is the number of people making or receiving calls at the same time as each other.


For example, with only two phone lines, you could get by on an upload bandwidth of only 1 mbps. But if you had 11 phone lines, you might need a minimum of 10 mbps.


Generally, upload bandwidth rates are slower than download rates, so it makes sense to match the speed your VoIP needs with your upload bandwidth.


It’s about understanding what speed your internet service provider can sustain, and working from that basis.


It’s worth considering adding in your own safety margin when calculating the bandwidth you’ll require for your VoIP, rather than going by the absolute minimum.




What is Your Functional Bandwidth?


Functional bandwidth is the actual bandwidth you’re getting, not simply the bandwidth your internet service provider will confirm you’ve signed up for.


This is important, since your functional bandwidth will determine the actual bandwidth your VoIP system will use.


You can test your bandwidth with a throughput test, but you should do this by connecting directly to your router using an ethernet connection, rather than via Wi-Fi (which you should turn off when testing).



How Do You Optimise Bandwidth for VoIP?


The bandwidth you require will also depend on the type of VoIP system you choose and the type of connections you have set up to support it.


For example, a small office system can run on a single, shared ADSL connection, or two slower ADSL connections.


But larger numbers of users will require more bandwidth, and here a FTTC connection will be better for delivering this.


Once you are wanting a VoIP system that supports upwards of 60 users, you’re best option is a leased line.


Is VoIP Quality Important?


Call quality is really the key metric for measuring the success of your VoIP system, and it can have a big impact on how you conduct your business.


VoIP has a range of very useful system features, including call handling and flexible numbering, but the quality of your calls is core to your service.


Because of this, you should always opt for a trusted VoIP service provider, with the kind of adaptability and expertise to maximise the quality of your system.


It matters, for example, that you have a good router, which will prioritise your VoIP traffic over other types of internet traffic.


A good VoIP provider will also be able to identify other potential issues affecting call quality, which may not be bandwidth-related.


It’s important to be able to accurately identify the source and solutions for any VoIP quality issues.



Get in Touch


For more details about VoIP, and what you’ll need to get your service up and running, please call us on 03300881182, email, or fill in our contact form and we’ll be back in touch as soon as possible.