Many voice service providers at one point or another turn to trunking as a technique for sending multiple phone conversations over a single line. Trunking broadly means the use of multiple, parallel ports to increase transmission speed beyond the capabilities of individual ports.

 

There are different methods for performing trunking. One is PRI trunking, in which “PRI” refers to “primary rate interface,” a telecom standard for multiple voice and data transmissions between physical locations. Another, more modern technique is SIP trunking, which makes use of the Session Initiation Protocol (News - Alert), an application-layer protocol for managing communications sessions.

 

Since SIP has become a widely accepted standard for Voice over IP (VoIP) services, many providers are looking to SIP trunking as a more modern and flexible alternative to PRI trunking. The benefits of VoIP are best achieved by using SIP trunking rather than PRI trunking.

 

The motivation for changing from PRI to SIP is mostly associated with the change from traditional, circuit-switched telephony to “packet switching” (i.e. VoIP). As traditional PBXs are replaced with IP BPXs, the benefits of SIP trunking—like the ability to use virtual channels—become more apparent.

 

SIP trunking works best in a pure IP environment, which in some cases may take time to realize. It’s true that many hybrid deployments exist and are still being created (e.g. using T1 lines in conjunction with VoIP), but the trend is toward all-IP and part of the reason for this shift is the flexibility of SIP trunking.

 

The problems associated with VoIP connections that involve both IP and TDM networks are being eliminated as the world moves toward all-IP. Looking long-term, it makes sense to go all-IP and adopt SIP trunking, resulting in a much cleaner and more sophisticated telephony environment.

 

In essence, a SIP trunk consists of a call routed over a carrier’s IP backbone, in conjunction with an IP PBX. SIP trunking is a modern replacement for PRI circuits, and one that, when properly deployed, offers significant cost savings and increase reliability.

 

To learn more about the topics discussed in this article, please visit the SIP Trunking channel on TMCnet.com, brought to you by Excel Telecommunications (News - Alert).