Platform Hardware Capabilities - Cisco Catalyst 4500 Series Configuration Manual

Configuring QoS
Supported classification actions
set cos
set dscp
set precedence
set qos-group
table map support
priority
shape
bandwidth
dbl
queue-limit

Platform Hardware Capabilities

Qos Actions
Classification
Policing
Marking
Queuing
DBL
Prerequisites for Applying a QoS Service Policy
Unlike the Switch QoS model, there is no prerequisite for enabling QoS on various targets. Just the
attachment of a service policy enables QoS and detachment of that policy disables QoS on that target.
Restrictions for Applying a QoS Service Policy
Traffic marking can be configured on an interface, a VLAN, or a port and VLAN. An interface can be a
Layer 2 access port, a Layer 2 switch trunk, a Layer 3 routed port, or an EtherChannel. A policy is
attached to a VLAN using vlan configuration mode.
Attaching QoS service policy to VLANs and EtherChannel is described in the
section on page
Software Configuration Guide—Release IOS XE 3.3.0SG and IOS 15.1(1)SG
40-14
Descriptions
Sets the Layer 2 class of service (CoS) value of an outgoing packet.
Marks a packet by setting the differentiated services code point (DSCP) value in the
type of service (ToS) byte of IPv4 or traffic class byte of IPv6 packet.
Sets the precedence value in the packet header.
Sets a QoS group identifier (ID) that can be used later to classify packets.
Unconditional marking of one packet field based on another packet field.
Gives priority to a class of traffic belonging to a policy map.
Shapes traffic to the indicated bit rate according to the algorithm specified.
Provides a guaranteed minimum bandwidth to each of the eight queues.
Dynamic buffer limit.
Specifies the maximum number of packets a transmit queue can hold.
Numbers of entries supported
64k input and 64k output classification entries are supported.
A given policy can use at most 24k ACLs
16K policers are supported. Policers are allocated to given direction in blocks of 2k.
For example, 2k policers can be used in for input and 14k policers can be used for
output. Single rate policers uses one policer entry. Single Rate Three Color Marker
(srTCM) (RFC 2697) and Two Rate Three Color Marker (trTCM) (RFC 2698) uses
two policer entries
Marking of Cos and DSCP/Precedence is supported through two marking tables, each
capable of supporting 512 entries. There are separate tables for each direction.
The queue size is Configurable with the maximum number of entries configurable per
port depending on the chassis and line card type.
You can enable DBL action on all configured class-maps.
40-38.
Chapter 40 Configuring Quality of Service
"Policy Associations"
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