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Cisco AVVID Network Infrastructure Enterprise Quality of Service Design
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Chapter 3 QoS in an AVVID-Enabled Campus Network
Summary
Summary
The following general guidelines and recommendations apply when configuring a Cisco AVVID
network in a campus environment:
·
Multiple queues are required on all interfaces to guarantee that loss, delay, and delay variation will
not affect voice, video, mission-critical data.
·
Use service policies to set the ToS and CoS classification marking for those devices that cannot set
the classification and for those devices that you cannot trust.
·
Never allow PC applications to send traffic at a CoS or ToS value of 3-7. Use the ability of the
access-layer switches to manipulate the IP phone's classification and marking ability and set the
appropriate trust for access-layer ports that directly support PCs.
·
Remember that QoS in the campus is not a bandwidth management issue as much as it is a buffer
management issue. TX queue congestion can cause packet loss, which can adversely affect
performance of applications that are sensitive to loss, delay, and delay variation.