In a hybrid SIP trunk deployment model (Figure 1), some business sites (different regions) conform to a distributed SIP trunk deployment model. In this model each site has direct SIP session connectivity to IP PSTN and other sites conform to a centralized SIP trunk deployment accessing the IP PSTN through a regional headquarters site, which has SIP session connectivity to the IP PSTN .

The hybrid SIP trunk deployment model has multiple regional sites in different geographic regions, or for specific business functions such as call centers.

Figure 1: Hybrid SIP Trunk Model

Identifying which remote sites should conform to a centralized SIP deployment model, and which should conform to the distributed model, will depend on various factors for each site. These factors include the number of employees, total inbound call volume, total outbound call volume, and overall bandwidth usage.

The hybrid SIP trunk model presents the following advantages:

  • Networks that are linked to a regional sites, QoS and CAC are managed at those regional hubs.
  • Bandwidth is more adaptable to regional site-specific requirements.