58 Chapter 2: Understanding Echo Analysis
This chapter explained what echo is and where it occurs in a voice network. This chapter
examined the basics of echo analysis and described the effects of various network elements
on echo. It also explained how echo is measured and how echo cancellers work to estimate
and eliminate echo.
It also looked at customer and service provider expectations about echo, and explained how
to conﬁgure routers and gateways to minimize echo. You saw that the normal characteristics
of packet-based networks can unmask pre-existing problems in the TDM-based voice
Finally, the chapter outlined a process for locating and eliminating loud echoes and long
echoes, and concluded with a real-life case study involving PBX-based echo in an
international voice network.
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