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Chapter 3 QoS in an AVVID-Enabled Campus Network
Server Farm Switch Selection
Server Farm Switch Selection
shows a typical server farm design, with a Catalyst 6500 (Layer 3 aware using the Policy
Feature Card [PFC]) at the access layer. A Catalyst 6500 with the PFC is able to classify traffic using
ACLs and Services Policies to apply CoS, IP Precedence, or DSCP markings to traffic on ingress to the
network. Both can be used to ensure admission of traffic into the appropriate queue. The Catalyst 4006
with Supervisor III, and the Catalyst 3550 are also excellent server farm switches with advanced QoS
features. The tradeoffs between a Catalyst 6500, a Catalyst 4000 Supervisor III, and a Catalyst 3500 are
primarily switching capacity and modularity.
Tip
For a comparison of the features of each of the Catalyst switches, see the Cisco Products Quick
Reference Guide: February 2002.
The example configurations for policy-based classification in this section leverage each of these types
of switches for a portion of the configuration.
Figure 3-5
Server Farm Switch Selection
Tip
For more information about designing server farms, see the Designing Small Scale Server Farms white
paper (internal).
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Si
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Core
Distribution
Access
Catalyst 6500
Layer 3 aware
server farm
switch
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conference
CallManager
(TFTP)
H.323
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MGCP
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