Chapter 12. Quality Of Service; Qos Overview - Lenovo ThinkSystem NE2552E Application Manual

Chapter 12. Quality of Service

QoS Overview

Ingress Ports
© Copyright Lenovo 2018
Quality of Service (QoS) features allow you to allocate network resources to
mission‐critical applications at the expense of applications that are less sensitive to
such factors as time delays or network congestion. You can configure your network
to prioritize specific types of traffic, ensuring that each type receives the
appropriate QoS level.
The following topics are discussed in this section:
 "QoS Overview" on page 219
 "Using ACL Filters" on page 221
 "Using DSCP Values to Provide QoS" on page 223
 "Using 802.1p Priorities to Provide QoS" on page 228
 "Queuing and Scheduling" on page 229
 "Control Plane Protection" on page 230
 "Packet Drop Logging" on page 231
 "Microburst Detection" on page 232
QoS helps you allocate guaranteed bandwidth to critical applications, and limit
bandwidth for less critical applications. Applications such as video and voice must
have a certain amount of bandwidth to work correctly; using QoS, you can provide
that bandwidth when necessary. Also, you can put a high priority on applications
that are sensitive to timing out or those that cannot tolerate delay, assigning that
traffic to a high‐priority queue.
By assigning QoS levels to traffic flows on your network, you can ensure that
network resources are allocated where they are needed most. QoS features allow
you to prioritize network traffic, thereby providing better service for selected
applications.
Figure 22 on page 219 shows the basic QoS model used by the NE2552E Flex
Switch.
Figure 22. QoS Model
Classify
Packets
ACL
Filter
The NE2552E uses the Differentiated Services (DiffServ) architecture to provide
QoS functions. DiffServ is described in IETF RFC 2474 and RFC 2475.
Meter Perform
Actions
Traffic
ACL Drop/Pass/
Meter Re-Mark
Queue and Egress
Schedule
COS
Queue
219