Opportunities and Obstacles Facing SIP Trunking Migration

As the enterprise communications market continues to expand, an increasing number of companies are deploying SIP trunking services. According to a recent Webtorials report, around one-third of the 300 businesses surveyed have already moved over to SIP trunking, saving an average of 33 percent in costs. Lower expenditure is not the only incentive; SIP trunking also offers benefits such as rapid disaster recovery, a fortified unified communications platform and centralization of lines. Nevertheless, there are still a number of obstacles to be surmounted, one of which is compatibility with legacy systems.

The motivation behind SIP migration is the "move to an IP environment – both wired and wireless," said Michael Finneran, principal at dBrn Associates. "Now, we are seeing SIP trunking on the wired front. But with the move to LTE, the whole idea is to have an all wireless IP network, referred to as the enhanced packet core."  

Enterprises are eager to grasp the advantages of unified communications. Migrating to SIP empowers businesses with the signaling tools necessary for establishing the varied connections associated with unified communications. 

Finneran also pointed out that SIP is a strong advantage for companies that have several sites. "You might have 10 SIMS in three different locations in three different time zones. But if you are not using a SIM in your Los Angeles office, it is available to make calls in your New York office," he explained.

Dave Michels, an independent analyst and creator of the Talking Pointz blog, explained that SIP trunking also has disaster recovery benefits. "If you have a TDM [time-division multiplexing] trunk coming into a router or phone system, if that phone system fails, you can't easily move those T-1s to a different location… With SIP all you have to do is bring up another server and configure that for the SIP trunk and the SIP trunk moves dynamically.”

One of the biggest advantages of SIP trunking is that it allows a business to buy the specific capacity it needs, enabling them to spend less money now and expand in the future as required. 

SIP has not been without its problems. In 2011, the SIP School conducted a survey of over 400 professionals within the industry. Businesses were quick to point out a number of issues with SIP trunking including intermittent dropping, poor quality due to delay, one-way audio, codec mismatch and packet loss.

Voice quality continues to be an issue with VoIP over Sip trunks and legacy systems because some integrity is lost each time a packet is converted to a circuit. If the network is unable to cope with it, the result is dropped packets and poor quality voice.

Because SIP is not standardized this poses a challenge in getting it to function adequately across multiple systems. Many carriers are reluctant to offer customers SIP trunking because they are unable to guarantee interoperability.

The SIP Forum, formed by IP communications companies to promote the SIP-based products and services, is facing up to the challenge. The forum has developed a task group to analyze interoperability issues and create resolutions.

Finneran predicts that the future of enterprise communications lies in the "end of the public telephone network – the entire legacy of circuit switching and TDM access, and all that stuff that grew out of the old Bell system. It is going to be an all-IP environment," He added that SIP trunking will make up a significant part of this new IP environment, and migration will continue because of lower costs and increased flexibility. (CU) Link