Quality of Service. Policy-enabled QoS is a network service that provides the ability to prioritize different types of traffic and to manage bandwidth over a network. QoS uses various methods to prioritize traffic, including IEEE 802.1p values and IP DiffServ values. QoS features provide better network service by supporting dedicated bandwidth, improving loss characteristics, avoiding and managing network congestion, shaping network traffic, and setting traffic priorities across the network. (RFC 2386)