When considering a VoIP telephone system, the physical manner in which the new system will be installed within the network is an important consideration. You may either create separate networks for data communications and voice communications or combine the two onto a single network. It may seem simple and less costly to just have one network: one cable, one network switch port… but in reality, it might not work out that way. Voice traffic is sensitive as it operates in real time and any delay in delivering a voice packet will cause call quality issues such as jitter. These delays may be caused by poorly designed and managed networks or by an internet connection that is periodically saturated with data transfers that crush the voice packets.
In a single network environment, the cabling must conform to standards and you will require managed switches that allow the configuration of VLANs that will virtually segment the network and allow the proper management of the data and voice packets. This ensures that the voice traffic is protected and that call quality is maintained. Post- installation network management is important as inadvertent network modifications put the telephone services at risk if an error is made and of course with a single network, a single point of failure puts both data and telephone services at risk.
With separate data/voice networks, the installation and management process is simplified and the voice quality assured. Furthermore, in the event of an issue, passing the buck between network and telephone support technicians does not occur. In the same vein, having a dedicated Internet connection for voice traffic offers similar benefits when carrying VoIP traffic to outside of the corporate network to the datacenter where the hosted telephone system resides or when using SIP lines with an on-premise system.