Unless you are highly experienced with VoIP services (in which case you don’t need to be reading this!), you will most likely sign up your customer with a commercial VoIP provider, and follow their setup guidelines.
Setting up a VoIP system differs from VoIP provider to VoIP provider, but there are some specific things that are common to all VoIP setups:
1. Check if the Internet connection can handle VoIP. Note that VoIP traffic is two-way and so the uplink Internet path matters just as much as the downlink path. This is frequently overlooked. The customer may believe that he or she has a gold-plated 500 Mb/s Internet service, but this refers to the downlink (i.e., Internet to office); frequently the uplink is only 25 or 40 Mb/s.
While a VoIP call doesn’t require much bandwidth, it does require consistent and unblocked access in both directions. With a 25 Mb/s uplink, one person that decides to upload a video to their Facebook page could easily cause every voice call to stall or drop. Both directions of traffic matter!
2. Ensure that the LAN is set up to allow you to put the phones on a separate Virtual Local Area Network. If the customer has a setup with a “dumb” (i.e., unmanaged) switch - or, just as bad, a VLAN capable switch in the wiring closet feeding a forest of cheap switches at the employee stations! - then VoIP QoS may become quite difficult, or even impossible. To enforce proper QoS, VoIP traffic needs to be segregated from data traffic.
3. Research the handsets that the customer wants to use: in particular, their DHCP requirements and how VLAN tags can be applied to them. Certain handsets require DHCP options to be specified so that they can work. Setting up VLAN tagging is different for every handset. Also, ensure that if workstations are going to be daisy-chained through the handsets, then the handsets support Gigabit Ethernet - far too many of the older handsets only support Fast Ethernet.
4. Allow lots of time to set up and configure the VoIP system. If a third-party VoIP service provider is installing the system, try to be on site at the time the system goes in, to sort out network issues. And remember - Uplevel is here to help! We’ve helped partners figure out all kinds of VoIP problems, from call quality issues to the entire LAN coming down because somebody looped a handset across multiple switches (yes, this happens more often than you think …)