300 call treatment cause - code busy call treatment on Distributed SIP Trunking to Connect PSTN In this case study, we cover the SIP trunking solution of one of the largest banks in the United States. This is a financially strong and well-capitalized bank that customers have entrusted with their money for more than 130 years. Its current position is as one of the top 25 commercial banks in the nation with assets of $66.2 billion. The bank now serves more than 4 million business and household accounts in hundreds of communities in 19 western and midwest states. Chapter 12: Case Studies 275 This bank selected Cisco to provide the communications infrastructure to ensure that the SIP trunking service would meet its security, compliance, and architectural requirements. The bank's existing Unified Communication Setup includes Two CUCM clusters Unity cluster IP Contact Center Express (IPCCX) More than 700 commercial and retail banking locations Approximately 10,400 employees The bank wanted to move its legacy PRI/Analog voice traffic onto a SIP trunking SP SO that it could achieve the following goals: Reduce telephony operating expenses Make the transition without ripping and replacing the existing telephony infrastructure Ensure interoperability with its existing CUCM clusters Provide a single, integrated management view of voice services and enable the use of existing IT systems and staff to administer voice across the enterprise Enable the rapid deployment of SIP trunk on its remote gateways by using the UCSPT tool The results were Moving remote sites from traditional PRI/Analog trunks to SIP trunks enabled the bank to reduce its monthly telephony costs. These savings came from a reduction in access charges, the elimination of local call- ing fees, and a significant reduction in long distance fees. Approximately $1 million/year saving due to SIP trunk migration. Enterprise Architecture The distributed SIP trunking solution was deployed with CUBE at each site, SIP trunk IP address per site, and call flow directly from