By now you’ve surely heard about VoIP, and you know that it allows for less costly, more feature-rich business calling. You may also have heard about SIP, which often gets mentioned in the same breath as VoIP. But chances are, you probably don’t truly understand the relationship between VoIP and SIP.
SIP stands for Session Initiation Protocol (News - Alert), and it is the magic that makes VoIP possible. SIP trunking is the way to connect the Internet to the traditional public switched telephone network (PSTN), which is necessary to talk with anyone not using a VoIP phone. All VoIP phone systems basically use SIP trunking, except for over-the-top providers such as Skype (News - Alert) that only work between Skype clients (unless you pay for Skype Out, at which time you’ve bought yourself a SIP trunk for your Skype calls so you can call regular phone lines).
SIP trunking helps VoIP replace traditional phone lines, and that’s part of why VoIP has grown so popular. VoIP saves businesses lots of money because instead of needing to use a dedicated phone line for each call, businesses that use VoIP only need to piggyback off their Internet connections.
Further, VoIP brings all the benefits that you would expect from digital calling—a plethora of features that come standard, unlike traditional phone lines. This list of features always includes voicemail, but it also includes things like call forwarding, ringing to multiple phones simultaneously, and interactive voice response built in to the system.
Since the SIP protocol has an IETF standard for multimedia initiations, it also becomes the means to deliver video over the Internet as well. This allows VoIP to not just replace traditional phone calls, but also offer features such as chat, presence and video calling. This is what is now call “unified communications.”
There are some caveats to VoIP, however.
First, a bad local Internet connection can reduce call quality unlike traditional calling. This isn’t a huge problem, but it does demand that a business has reliable Internet—something it probably already needs since cloud services and the evolution of business now are thoroughly Internet-based anyway.
Second, businesses need to make sure they buy into a reputable VoIP provider, since the local Internet connection is only half of the battle; the provider also must have good backbone connections so the call has enough bandwidth later on in its journey through the Internet. Most reputable VoIP providers ensure they have the necessary backend connectivity, but since it is possible to offer a VoIP service without a good network backbone, businesses still should make sure they choose a good provider.
That, in a nutshell, is the relationship between VoIP and SIP.
Edited by Rory J. Thompson