Switching to VoIP

This is the Title of the Book, eMatter Edition

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Chapter 15

CHAPTER 15

What Can Go Wrong?

As system designers, integrators, and geeks, we do our homework to become mas-

ters in a subject fully before we go headfirst, implementing it in a production envi-

ronment, right? Well, we aspire to, anyway. But experience says you can never know

a hundred percent of what there is to know about a subject… particularly with Voice

over IP, which is still changing and evolving. So, once you’ve equipped yourself with

the book knowledge, you hit the field. It’s only then that you’ll get a chance to dis-

cover whether your VoIP project plan has any remaining flaws. But, before you take

that leap of faith, there are a few things you should know about: What can go wrong

when implementing VoIP in the enterprise?

Common Problem Situations

The people you call complain about echo

Generally, echo is at its worst when end-to-end latency is high. If end-to-end latency

is below 150 ms, echo should be nearly imperceptible. Remove echo by removing

latency. Remember that using bigger packet sizes, which are often used with low-

bandwidth codecs, can increase latency. If capacity is stopping you from removing

latency, increase the capacity on the links that are causing the latency. Steer away

from frame-relay and VPN if the link is critical—these technologies