What is SIP Calling?
SIP (Session Initiation Protocol) trunking refers to phone calls that are routed over the Internet rather than traditional phone lines. SIP calling, therefore, refers to the act of placing calls via a SIP trunk. Because SIP calls take place across the Internet, they tend to be cheaper and more efficient than calls placed through traditional phone systems.
Physical connections to a phone company are eliminated with the use of a SIP trunk. Using SIP trunks, a SIP provider can connect multiple channels to your private branch exchange (PBX) system, allowing you to instantly provision global voice connectivity for your Voice-over-IP (VoIP) infrastructure.
SIP trunking allows you to extend VoIP beyond your organization’s firewall and bypasses the need for an IP-PSTN gateway by carrying many signals at once to connect nodes in a communications system.
While typically used for voice calls, SIP trunks can also carry instant messages, multimedia conferences, user presence information, E-911 emergency calls, and other SIP-based, real-time communications services.
The basis of SIP trunking is the Session Initiation Protocol (SIP), usually pronounced ‘sip’, not ‘ess-eye-pee’. SIP is an application layer protocol for setting up real-time sessions of audio or video between two endpoints, and is leveraged to produce a VoIP call. You can learn more about SIP and how to leverage SIP for your business.
The “trunk” in SIP trunking derives from circuit-switched telecommunications and refers to a dedicated physical line that connects switching equipment. A SIP trunk accomplishes a similar task as its circuit-switched predecessor but works over a virtual connection on the Internet.
- Scalability: SIP trunks allow you to scale down or up and increase capacity whenever you want since SIP trunking uses a virtual connection.
- Flexibility: With SIP you can set up and manage unlimited non-geographic and geographic numbers.
- Cost Savings: SIP trunks are more cost-effective than paying line rental costs for ISDN.
- Disaster Recovery: SIP trunks allow you to redirect calls instantly in the event of any disaster.
- Streamlined Multi-Site Telephony: SIP trunking can help rationalize your telephony and the number of PBXs across multiple sites.
Twilio’s Elastic SIP Trunking makes SIP trunking configuration easy, and grants you the freedom to manage your SIP connectivity however you like. Check out some video tutorials to get started with trunking termination (placing outbound calls), trunking origination (receiving incoming calls), and international trunking.
With Twilio and SIP trunking, you can instantly provision global voice connectivity for your VoIP infrastructure. Whatever your current company’s scale and needs, Twilio offers a SIP trunking service that’s right for you.
With Twilio’s Elastic SIP Trunking, you can instantly provision a SIP network worldwide. Connect to a SIP URI that’s local to your company, and we’ll do the rest. Check out some of the possible SIP Trunking setups and our SIP Trunking Overview to see how you can leverage SIP trunking for your business. We can’t wait to help you build and scale!