Руководство По Проектированию для Cisco Cisco Nexus 5010 Switch
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If you want to increase the buffer space available to a user-created QoS group, you can do so from a network QoS
policy map by using the command queue-limit.
Note: Every new class requires an additional 18.880 KB, so the exact amount of buffer space that is left in
class-default equals 243.2 KB - Buffer space used by other QoS groups - 18.880 KB x Number of QoS groups.
class-default equals 243.2 KB - Buffer space used by other QoS groups - 18.880 KB x Number of QoS groups.
Classification
You need to classify the traffic to perform any QoS operation on it. To do so, you need to put each traffic type in a
QoS group.
You can configure the classification in two ways:
●
At the global level
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At the per-interface level
You can match several fields in the incoming frame to decide how to classify the traffic; for instance:
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You can match the CoS
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You can match the IP precedence or DSCP field
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You can match the packet with an access control list (ACL)
Note: For releases prior to Cisco NX-OS 5.0(2)N1(1), the default matching criterion was the equivalent of
“match any.” Starting from Cisco NX-OS 5.0(2)N1(1), this criterion is user configurable as either match-any or
“match any.” Starting from Cisco NX-OS 5.0(2)N1(1), this criterion is user configurable as either match-any or
match-all; the default is match-all.
You can assign traffic to a QoS group as follows:
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You can assign traffic to any QoS group, from QoS group 2 through QoS group 5.
●
Starting from Cisco NX-OS 5.0(2)N1(1), you can assign traffic to QoS group 1.
●
Although you can use and modify class-default (QoS group 0), you cannot explicitly assign a traffic class to
Qos group 0. QoS group 0 is a catch-all for whatever does not match any of the other traffic classes.
●
The classification entries are looked up in the order that they appear in the configuration. Rules are
evaluated in the order of definition, and traffic is classified based on the first rule that matches.
The following configuration is an example of a possible classification policy (you can customize this configuration to
use ACL matching for instance):
class-map type qos CriticalData
match dscp 18
class-map type qos Scavenger
match dscp 8
class-map type qos Signaling
match dscp 24,26
class-map type qos Video
match dscp 34
policy-map type qos interface-classification
class CriticalData
set qos-group 3
class Scavenger