Configuration Guide

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IP Telephony Configuration Guide
Appendix E
Quality of Service
The users of corporate voice and data services expect these services to meet a level of quality of
service (QoS). This, in turn, affects network design. The purpose of planning is to design and
allocate enough resources in the network to meet user needs. QoS metrics or parameters help in
meeting the needs required by the user of the service.
This section provides information about:
• “Setting QoS” on page 193
• “Measuring Intranet QoS” on page 195
• “Implementing QoS in IP networks” on page 200
• “Network Quality of Service” on page 202
Setting QoS
There are two interfaces that must be considered when you set up QoS on the network, as shown in
the figure below:
• IP telephony interfaces with the end users: voice services made available need to meet user
QoS objectives.
• The gateways interface with the intranet: the service provided by the intranet is “best-effort
delivery of IP packets,” not guaranteed QoS for real-time voice transport. IP telephony
translates the QoS objectives set by the end users into IP adjusted QoS objectives. The
guidelines call these objectives the intranet QoS objectives.