End-to-End QoS Network Design: Quality of Service for Rich-Media & Cloud Networks, Second Edition

Chapter 22. Data Center QoS Design Considerations and Recommendations

The primary role of quality of service (QoS) in data center networks is—first and foremost—to manage packet loss. In a Gigabit Ethernet (GE)/10GE/40GE/100GE data center network, it takes only a few milliseconds of congestion to cause instantaneous buffer overruns resulting in severe packet drops. Furthermore, hardware buffering and queuing alone cannot meet the needs of specific data center protocols—such as Remote Direct Memory Access over Converged Ethernet (RoCE) or Fibre Channel over Ethernet (FCoE)—which demand zero-drop/lossless service. To meet such requirements, additional data center bridging (DCB) technologies must also be worked into the data center QoS designs. ...