Configuring Qos; Default Qos Configuration - Cisco Catalyst 2950 Software Manual

Chapter 13

Configuring QoS

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Configuring QoS
Before configuring QoS, you must have a thorough understanding of these items:
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This section describes how to configure QoS on your switch:
Note If your switch is running the standard software image, only the
"Displaying QoS
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Default QoS Configuration

Table 13-2
Table 13-2 Default QoS Configuration
The default port CoS value is 0.
The default port trust state is untrusted.
No policy maps are configured.
No policers are configured.
No policers are configured.
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Weighted round-robin (WRR) scheduling
WRR scheduling requires you to specify a number that indicates the importance (weight) of the
queue relative to the other CoS queues. WRR scheduling prevents the low-priority queues from
being completely neglected during periods of high-priority traffic. The WRR scheduler transmits
some packets from each queue in turn. The number of packets it transmits corresponds to the relative
importance of the queue. For example, if one queue has a weight of 3 and another has a weight of
4, three packets are transmitted from the first queue for every four that are transmitted from the
second queue. By using this scheduling, low-priority queues have the opportunity to transmit
packets even though the high-priority queues are not empty.
The types of applications used and the traffic patterns on your network.
Traffic characteristics and needs of your network. Is the traffic bursty? Do you need to reserve
bandwidth for voice and video streams?
Bandwidth requirements and speed of the network.
Location of congestion points in the network.
Information" sections are applicable.
Default QoS Configuration, page 13-9
Configuration Guidelines, page 13-10
Configuring Classification Using Port Trust States, page 13-10
Configuring a QoS Policy, page 13-13
Configuring CoS Maps, page 13-21
Configuring CoS and WRR, page 13-23
Displaying QoS Information, page 13-25
shows the default QoS configuration.
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Catalyst 2950 Desktop Switch Software Configuration Guide
Configuring QoS
"Configuring CoS and WRR" and
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