Why Use SIP Trunking?
Topic Last Modified: 2011-08-03
Deploying SIP trunking can be a big step toward simplifying your organization’s telecommunications and preparing for the latest enhancements to real-time communications. One of the primary advantages of SIP trunking is that you can consolidate your organization’s connections to the PSTN at a central site, as opposed to legacy TDM trunking, which typically requires a separate trunk from each branch site.
SIP Trunking in Lync Server 2010
The Microsoft Lync Server 2010 SIP trunking capabilities enable the following:
An enterprise user, whether inside or outside the corporate firewall, can make a local or long-distance call specified by an E.164-compliant number that is terminated on the PSTN as a service of the corresponding service provider.
Any PSTN subscriber can contact an enterprise user inside or outside the corporate firewall by dialing a Direct Inward Dialing (DID) number associated with that enterprise user.
The cost savings associated with SIP trunking can be substantial:
Long distance calls typically cost much less through a SIP trunk.
You can cut manageability costs and reduce the complexity of deployment.
Basic rate interface (BRI) and primary rate interface (PRI) fees can be eliminated if you connect a SIP trunk directly to your ITSP at significantly lower cost. In legacy TDM trunking, service providers charge for calls by the minute. The cost of SIP trunking may be based on bandwidth usage, which you can buy in smaller, more economical increments. (The actual cost depends on the service model of the ITSP you choose.)
SIP Trunking vs. Hosting a PSTN Gateway or IP-PBX
Because SIP trunks connect directly to your service provider, you can eliminate your PSTN gateways and their management cost and complexity. Using a SIP trunk can lead to substantial cost savings through reduced maintenance and administration.
Expanded VoIP Services
Voice features are often the primary motivation for deploying SIP trunking, but voice support alone is just the first step. With SIP trunking, you can extend VoIP capabilities and enable Lync Server 2010 to deliver a richer set of services than you can get with previous technology. For example, the same SIP trunk that delivers your telephone service and other VoIP communications services may now provide the following:
Enhanced presence detection for devices that are not running Microsoft Lync Server 2010 can provide better integration with mobile phones, allowing you to see when a user is on a mobile phone call.
E9-1-1 emergency calling enables the authorities who answer 911 calls to determine the caller’s location from his or her telephone number.
Follow up with your ITSP for a list of services that they support and can enable for your organization.