SIP Trunking Transformation for Flexibility and Cost Savings

  • Enterprises are migrating to SIP trunking for voice, contact center, and integrated capabilities.
  • SIP results in better insights, improved disaster recovery, and asset centralization.

Many enterprises are migrating from traditional TDM and ISDN services to SIP trunking for voice, contact center, and integrated capabilities. SIP trunking involves connecting corporate voice traffic to a service provider’s network over a data circuit rather than over multiple TDM lines. The primary reason for this shift is cost savings. Analysts report that costs for PSTN trunking services can be reduced by up to 50 percent, depending upon the specific network configuration and current spend.

SIP adds flexibility and reduces costs

Traditional TDM T1s and ISDN PRIs provide voice circuits in bundles of 23, so businesses often wind up paying for more lines than they actually need. On the other hand, SIP enables purchasing only the required number of concurrent calls with the flexibility to add more capacity during heavy call periods. SIP trunking can also reduce intra-company long distance fees by transporting voice calls over the corporate data network, resulting in potentially significant cost savings. Other benefits of SIP trunking include:

  • Better visibility into call patterns
  • Improved disaster recovery
  • Centralized management
  • Hardware consolidation
  • Service provider standardization
Enterprises prepare for SIP

Enterprises must prepare to shoulder a number of key responsibilities in their SIP transformation – particularly when moving from distributed, site-based trunking to centralized SIP — or risk implementation delays, as well as problems during test and turn-up of SIP services. Deployment challenges include the following:

  • A lack of expertise in configuring and managing voice platforms, including PBXs, Contact Centers, and Unified Communications (UC) solutions.
  • A lack of understanding about how to take advantage of the new capabilities.
  • A complex array of SIP standards. For example, AT&T’s SIP implementation includes support for six Requests for Comment (RFCs) including how call transfers, DTMF handling, codec negotiation, error recovery, and other features are addressed.
  • The addition of new network elements called Session Border Controllers (SBCs) that terminate the SIP trunks and provide security, enhanced call routing, and other critical functions.
  • A range of interoperability and integration concerns due to multiple equipment vendors implementing SIP in different ways.
Moving forward with SIP

To be successful, companies need to understand how moving to SIP will impact their voice and data environments. To do that effectively, they need to:

  • Evaluate the existing infrastructure’s capability to support SIP services.
  • Ensure that technical and project management expertise is available in house or partner with a trusted advisor.
  • Understand how SIP will impact costs for delivering communications services.
  • Develop a comprehensive solution architecture that encompasses the network and SIP trunking services, as well as the systems deployed in the data center and possibly remote sites.
  • Incorporate SIP into the existing operations framework and manage it long term.
Start with a pilot project

To minimize the risk of service disruption, a non-production proof-of-concept or production pilot should be performed that includes extensive testing of integration, interoperability, functionality, and management capabilities. testing of the new solution is recommended before shifting voice traffic to SIP trunking. Finally, the enterprise must plan the migration and SIP service transformation prior to execution and then deliver on that plan to the full production environment.

Are you planning an SIP service transformation and migration project? What challenges and benefits have you experienced?

Eric Sineath Consulting Chief Architect AT&T About Eric