Cisco Catalyst 3750 Metro Command Reference Manual page 64

class
priority: enables the priority queue (low-latency queueing [LLQ]) for a class of traffic. For more
•
information, see the
attached to an ES port.
queue-limit: configures the maximum packet threshold for tail drop for a class configured in a
•
policy map attached to an ES port. For more information, see the
command is effective only in a hierarchical policy map attached to an ES port.
random-detect: configures Weighted Random Early Detection (WRED) as a drop policy. For more
•
information, see the
policy map attached to an ES port.
service-policy: creates a service policy as a quality of service (QoS) policy within a policy map
•
(called a hierarchical service policy). For more information, see the
class)
• set: classifies IP traffic by setting a class of service (CoS), a Differentiated Services Code Point
(DSCP), an IP-precedence, or the multiprotocol label switching (MPLS) experimental (EXP) bits in
the packet. For more information, see the
hierarchical policy map attached to an ES port.
shape: sets the token bucket committed information rate (CIR) in a policy map. For more
•
information, see the
attached to an ES port.
trust: defines a trust state for a traffic class. For more information, see the
•
The switch supports up to eight classes, including the default class, in a policy map. Packets that fail to
meet any of the matching criteria are classified as members of the default traffic class. You configure the
default traffic class by specifying class-default as the class name in the class policy-map class
configuration command. You can manipulate the default traffic class (for example, set policies to police
or to shape it) just like any other traffic class, but you cannot delete it.
Within a policy map, the class-default applies to all traffic that is not explicitly matched within the policy
map but that does match the parent policy. If no parent policy is configured, the parent policy represents
the physical port. In the physical-level policy map, class-default is the only class that can be configured.
In a hierarchical policy map attached to an ES port, you define a class policy to use either tail drop or
WRED packet drop by using either the queue-limit policy-map class configuration command or the
random-detect policy-map class configuration command, respectively. You cannot use the queue-limit
and random-detect commands in the same class policy, but they can be used in two class policies in the
same policy map.
In a hierarchical policy map attached to an ES port, you must configure the bandwidth or the shape
policy-map class configuration command before you configure either the queue-limit or the
random-detect policy-map class configuration command in a class policy.
When you configure a policy for a class, specify its bandwidth, and attach the policy map to an ES port,
class-based weighted fair queueing (CBWFQ) determines if the bandwidth requirement of the class can
be satisfied. If so, CBWFQ creates the necessary internal data structures to maintain the state for the
class and allocates a queue for it. If CBWFQ decides that the bandwidth requirement for the class cannot
be satisfied, an error message appears, and the policy is not attached. When a class is removed, available
bandwidth for the port is incremented by the amount previously allocated to the class.
To return to policy-map configuration mode, use the exit command. To return to privileged EXEC mode,
use the end command.
You can configure a default class by using the class class-default policy-map configuration command.
Unclassified traffic (traffic that does not meet the match criteria specified in the traffic classes) is treated
as default traffic.
Catalyst 3750 Metro Switch Command Reference
2-36
priority command. This command is effective only in a hierarchical policy map
random-detect
command. This command is effective only in a hierarchical policy map attached to an ES port.
shape command. This command is effective only in a hierarchical policy map
Chapter 2 Catalyst 3750 Metro Switch Cisco IOS Commands
command. This command is effective only in a hierarchical
set command. Some keywords are effective only in a
queue-limit command. This
service-policy (policy-map
trust command.
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