In this chapter, you learned how voice can be transported along with other data within your network; the following topics were presented:
The benefits of including voice within your data network.
How voice is transported across the network, including how it is digitized and then packetized.
The two ways that the packetization of voice is implemented:
- Using traditional phones and a PBX (or digital phones attached to a PBX) to digitize the voice, and then connecting the PBX to a voice-enabled router to perform the packetization.
- Using IP phones to digitize and packetize the voice. The call-processing function previously performed by the PBX is now handled by a call-processing manager such as CCM.
The two categories of voice traffic: conversation traffic (the audio, also called bearer traffic) and control (or signaling) traffic.
The components of an IP telephony system, including an underlying functioning and robust IP infrastructure and QoS support.
The hardware and software IP phones available from Cisco, the features of CCM, and the voice applications that can be supported.
The voice compression and coding techniques, including the recommended G.729 codec that compresses a call to 8 kbps while still maintaining voice quality.
Calculating the bandwidth requirements for voice traffic and understanding the associated terminology.
Examples of single-site and multisite IP telephony designs.