Quality of Service (QoS): Managing Bandwidth More Effectively 
Introduction 
Introduction 
QoS Feature  Default  Menu  CLI  Web 
UDP/TCP Priority  Disabled  —  page 8-24  Refer to the Online Help. 
IP-Device Priority  Disabled  —  page 8-30  “ 
IP Type-of-Service Priority  Disabled  —  page 8-36  “ 
LAN Protocol Priority  Disabled  —  page 8-49  “ 
VLAN-ID Priority  Disabled  —  page 8-51  “ 
Source-Port Priority  Disabled  —  page 8-57  “ 
DSCP Policy Table  Various  —  page 8-62  “ 
As the term suggests, network policy refers to the network-wide controls you 
can implement to: 
■  Ensure uniform and efficient traffic handling throughout your network, 
while keeping the most important traffic moving at an acceptable speed, 
regardless of current bandwidth usage. 
■  Exercise control over the priority settings of inbound traffic arriving in 
and travelling through your network. 
Adding bandwidth is often  a good idea, but it is not always feasible and does 
not completely eliminate the potential for network congestion. There will 
always be points in the network where multiple traffic streams merge or where 
network links will change speed and capacity. The impact and number of these 
congestion points will increase over time as more applications and devices 
are added to the network. 
When (not if) network congestion occurs, it is important to move traffic on 
the basis of relative importance. However, without Quality of Service (QoS) 
prioritization, less important traffic can consume network bandwidth and 
slow down or halt the delivery of more important traffic. That is, without QoS, 
most traffic received by the switch is forwarded with the same priority it had 
upon entering the switch. In many cases, such traffic is “normal” priority and 
competes for bandwidth with all other normal-priority traffic, regardless of 
its relative importance to your organization’s mission. 
This section gives an overview of QoS operation and benefits, and describes 
how to configure QoS in the console interface. 
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