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A Cisco Telephony Architecture Evolution

Chapter Description

This chapter introduces the concept of ROI, and provides the background and reasoning behind Cisco's decision to migrate to an all-IP network.

Cisco Architecture Evolution

Figures 1-2 and 1-3 represent the evolution of the Cisco architecture and the migration of the technology. Figure 1-2 provides a view of how the network architecture looked in 2001 at the beginning of the migration. Figure 1-3 demonstrates how calls come in to the network, how they tandem through the PBX, and how voice mail and intercluster calling are performed.

Figure 2Figure 1-2 Traffic Flow Example of Voice Mail and Intercluster Calling