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Cisco Networking Simplified by Jim Doherty, Paul Della Maggiora

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Chapter . IP Telephony

Making Calls Over the Net

Traditionally, voice traffic traveled across circuit-switched networks using private branch exchange (PBX) networks or networks of private lines and time-division multiplexers (TDMs). These traditional networks tended to be proprietary, closed systems that were expensive to maintain, upgrade, or scale.

Internet Protocol (IP) telephony integrates traditional voice services with today’s IP networks. With this convergence, both data and voice traffic traverse the same physical network, which eliminates the need for two separate networks and two separate sets of networking skills.

Migrating to an IP-based telephony network reduces the total cost of ownership for voice services in the following ways:

  • Toll ...

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