The following case study (see Figure 17-3) demonstrates how switched and dedicated access to (one or more) voice networks can be used simultaneously in supporting a call center environment.
BrownCo has deployed dedicated voice network access to two IXC. Both dedicated lines support inbound and outbound calls, with IXC #2 designated the secondary carrier to IXC #1. In the event that BrownCo loses all dedicated access (for example access cable cut) then switched access to the serving LEC is in place to support the inbound/outbound calls. The LEC has trunks to IXC #1 and IXC #3. Which trunk to use (IXC #1 or IXC #3) is determined by the PIC/CIC. In the event that IXC #1 fails (such as switch or database outage), then IXC #2 will be used for dedicated inbound/outbound service and the switched access to the LEC can handle any overflow (calls the dedicated access do not have enough bandwidth to support, one call = one DS0 = 64 Kbps) by directing these switched calls to IXC #3.