Cisco Networking Simplified, Second Edition

Chapter . Quality of Service and Network Availability

Quality of Service as Network Protection?

Quality of Service (QoS) is commonly used in networks to provide prioritization of critical network traffic or traffic with special requirements. For example, in a converged network with data and other types of traffic such as voice over IP (VoIP) and video over IP (see Part VII, “Unified Communications”), QoS is used to manage the special requirements of voice and video communications, providing low delay (typically less than 250 milliseconds end-to-end), low jitter (typically less than 10 or 20 milliseconds), and low packet loss (typically less than 0.5 percent of packets). Exceeding these values can cause poor-quality VoIP calls and frustrate users. ...