Qos Overview - Lenovo RackSwitch G8264 Application Manual

QoS Overview

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G8264 Application Guide for ENOS 8.4
QoS helps you allocate guaranteed bandwidth to the 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 that cannot tolerate delay, by assigning their
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 shows the basic QoS model used by the switch.
Figure 22. QoS Model
Ingress Ports Classify
Packets
The basic QoS model works as follows:
Classify traffic:

Read DSCP value.

Read 802.1p priority value.

Match ACL filter parameters.

 Perform actions:
Define bandwidth and burst parameters

Select actions to perform on in‐profile and out‐of‐profile traffic

Deny packets

Permit packets

Mark DSCP or 802.1p Priority

Set COS queue (with or without re‐marking)

Queue and schedule traffic:

Place packets in one of the COS queues.

Schedule transmission based on the COS queue.

Perform
Actions
ACL
Permit/Deny
Filter
Queue and Egress
Schedule
COS
Queue