686 Appendix A: Answers to Review Questions
2
What are three different types of voice interfaces used on a Cisco router?
Foreign Exchange System (FXS).
Foreign Exchange Office (FXO).
Ear and Mouth (E&M).
3
What two types of digital signaling are available?
Channel Associated Signaling (CAS).
Common Channel Signaling (CCS).
4
What is a dial plan?
A dial plan is a set of rules for routing incoming and outgoing calls and accessing voice
features from one system to another.
5
List three benefits of a dial plan.
Enables reliability and security.
Enables cost savings.
Controls the behavior of the voice system.
6
What must a successful QoS voice over data network design ensure?
A QoS design must ensure that voice is prioritized over data and will always be delivered
ahead of data.
7
List four factors that have a significant impact on voice quality in a network.
Delay.
Delay variation.
Packet loss.
Echo.
8
List three types of delay that, by design, are inherent in voice networks.
Propagation delay.
Handling delay.
Queuing delay.
9
For good voice quality, what does Cisco recommend as the maximum amount of delay
(one-way) from end to end?
150 ms.
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