VoIP/SIP Trunking ArchitectureVoIP/SIP Trunking Architecture

Enterprises should consider centralizing all their voice trunks into their data centers as they move to VoIP/SIP.

Enterprises should consider centralizing all their voice trunks into their data centers as they move to VoIP/SIP.One school of IT architecture is for all technology and information to reside within the enterprise's data centers. Cloud computing is an example of this architecture. Following this model, an enterprise office should consist of a very robust IP network and simple client devices that access all the technology services and information that live within the cloud/data centers. Most IPT deployments are following this model by putting the call control, messaging, and conferencing servers in the data center. The next step in this evolution is to move all voice trunking out of business offices and into the data centers.

* Reduce Costs: - While there is an increase in WAN costs to handle the "second leg" of a call between the office site and the data center, this cost can be more than offset by:

---Economies of Scale: To provide P.01 of voice service to a site, most office locations have twice the number of trunks that are used regularly. By aggregating the total number of trunks needed throughout the enterprise, the total number of voice trunks can be cut in half

---Bulk Purchasing: With all voice services delivered to just a few locations, voice circuit rates can be significantly discounted due to competition and aggregated volume. Changing carrier contracts is critical to success.

---Audio Conferencing: Eliminating access & toll fees

* Reporting: Being able to log and report all calls in and out of the organization. For example, customers call in and talk to employees outside of the contact center. In order to enhance CRM, these interactions can be tracked.

* Security: IP/SIP trunking has an associated risk. By treating IP/SIP trunks like an external Internet connection, an organization can enforce and monitor its security policies.

* Mobility: The ability to get the same voice services anywhere--home, office, on the road.

* Management & Support: Most MACD work is software based as the number of users and their voice needs change. This improves the speed of changes, the ease of adding advanced features, and lowers cost.

* Unified Communications: UC integrates people, information, process, and technology to enable more efficient and effective communication. This integration is easier and more cost-effective in a centralized model.

Opponents of a centralized architecture model argue:

* Availability: Dial tone is critical. But with cell phones everywhere, is dial tone any more critical than other corporate applications? The primary cause for loss of network connectivity to a data center is in the local loop, which usually disrupts local voice trunks also.

* Capacity Planning: Sizing a WAN to meet voice needs can be a challenge. At 8:00am, everyone is checking voicemail, at 10:00am, audio conf volume peaks while the 9-10 conf call goes a little long and the 10-11 conf call is starting up. As long as there is high speed local data network access, the WAN bandwidth can be tuned to meet business demand.

The centralized VoIP/SIP trunking model is similar to the Virtual Contact Center (VCC) (pdf) model used in call centers. In the VCC model, all calls come into the data center, and are then forwarded to wherever the agents are.

While the ROI for centralizing all voice trunks may only be 10-20%, the biggest advantage is the flexibility, reporting, and advanced features in treating voice as another application that needs to be integrated with other services and information.Enterprises should consider centralizing all their voice trunks into their data centers as they move to VoIP/SIP.