Making the move from PSTN to SIP trunk: SIP trunking explained

Session Initiation Protocol (SIP) trunking is a direct connection between the organization and the Internet Telephony Service Provider(ITSP). It ensures extension of voice over IP telephony beyond the company’s firewall without the requirement of an IP-PSTN gateway. SIP trunk offers several features like for example it carries instant messages, has enhanced 911 emergency call facility, user presence information, multimedia conferences, other real time communication services etc. Microsoft Office Communications Server 2007 R2 can facilitate long distance as well as local calls with caller ID and call hold over SIP trunks.

SIP is a new growing technology and requires trained personnel to deploy, monitor and maintain it. Since, SIP features are still on the process of development, many vendors have proprietary implementations of the protocol. SIP is more flexible than Public Switched Telephone Network (PSTN) as it works independent of media or any session type. Applications can be written to customize the SIP features, hence making it of open standard. It has the potentiality to accommodate multiple users with differing capability. Although PSTN is an older technology, it has built-in reliability, security and emergency location services.

How is SIP trunking beneficial?

Deploying SIP trunk is the best step an organization can take for simplifying its telecommunications network and preparing for the latest real time communications enhancements. It is not only productive but cost savings too.

•  SIP trunking saves money on long distance service.

• It eliminates IP-PSTN gateways. The SIP trunk connects automatically to ITSP without traversing the publicly switched telephone network. Hence, you can get rid of IP-PSTN gateways, its cost and complexities.

• Elimination of a redundant network. Deploying a SIP trunk is a means of a single IP based network rather than other redundant telephone networks.

• It eliminates PRI and BRI subscription fees. The organization can do away with the BRI and PRI cost if it switches to SIP trunking which is directly connected to the Internet telephony service provider.

• SIP trunk is cost effective. You can buy bandwidth rather than in lines of blocks of 24 or 32 in smaller increments and better prices.

• Extending the capabilities of Office Communications Server with new services from ITSP. With SIP trunk, one can extend its existing functions with additional features such as 911 emergency calling etc.

The key to a successful migration is selecting a good team. An extensive research should be done so as to make sure whether the organization has chosen the right provider. The provider should be cost effective, secured, design and deploy all solutions. SIP trunk is a new technology with a brighter prospect for simplifying every organization’s telecommunications network.