Session Initiation Protocol (SIP) is a digital way to make and receive phone calls and other forms of cloud-based communication over an Internet Protocol (IP) network.

Communications platforms like virtual phone systems, unified communications, and contact center software use SIP to talk to one another over the internet. Organizations and consumers alike use SIP to create, manage, and terminate calls (or sessions).

SIP Trunking is one way to place voice calls and send digital communications over the internet.

SIP trunking services allow us to make Voice over Internet Protocol (VoIP) calls, send SMS/MMS messages, place 911/emergency calls, and use other SIP-based real-time communications.

The primary benefits of SIP trunks compared to Primary Rate Interface (PRI) are cost savings, cloud flexibility, and scale. Because SIP trunks are elastic, businesses can scale SIP services up and down to meet demand easily.

In addition, cloud-based voice like SIP removes the need for fixed overhead costs and on-premise equipment. The infrastructure costs for SIP trunking are also lower because SIP eliminates the need for primary rate interfaces (PRIs), which requires enterprises to buy lines in bundles of 23. PRI customers who need 10 lines have to buy a bundle of 23, leaving 13 unused. SIP trunking, however, can be purchased in whatever number of units a business requires.

SIP trunking allows businesses to converge networks because it’s an application, not a service. Just as copper lines transmit signals instead of creating them, SIP allows any endpoint to communicate with another, as long as the two endpoints both agree to use SIP. That means a single-location company can converge its networks, roles, and equipment into one system that meets all of its communication needs.

Speed, agility, and leanness are guiding principles for companies that need to stay competitive today. To support those principles, businesses need technology, like SIP trunking, that supports them. The benefits of SIP trunking include:

• Unlimited call capacity: SIP trunking gives you unlimited, simultaneous call capacity so you can get concurrent calls to and from a single number. 
• Flexibility: Because phone numbers associated with SIP services are virtual, you don’t need to be tied to your physical location, except where regulations require this. This lets you use DID numbers and SIP trunks for a two-way voice service from your office in New York City, even though you don’t actually have an office in New York City.
• Scalability: SIP trunks bring flexibility and control to your business phone system, especially for larger enterprises. In these scenarios, your dedicated data circuits serve as the backbone for seamless communication.
• Cost savings: Traditional analog circuits are costly because they have to be designed, configured, maintained, and upgraded. SIP trunking provides the same call quality as traditional line, but since it runs over the Internet, it doesn’t require the same level of design and configuration. Plus, the maintenance and upgrades to the network would be necessary whether SIP trunking was being run through them or not. Long distance, local inbound, and termination services can be included, providing another opportunity to save costs. Plus, SIP trunking delivers cost savings as great as 60% over traditional methods.
• Direct-to-provider control: By leveraging SIP trunks over dedicated data circuits, you actually gain more control over your business phone system. As you expand to new domestic or international locations, you can manage and control your own resources.