Specifications

Data Sheet
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Feature Benefit
Overview
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The switches support the aggregate QoS model by enabling classification,
policing/metering, and marking functions on a per-port basis at ingress and
queuing/scheduling functions at egress.
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The switches support configuring QoS ACPs on all ports, using ACPs to help
ensure proper policing and marking on a per-packet basis. Up to four ACPs
per switch are supported in configuring either QoS ACPs or security filters.
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Automatic QoS (Auto-QoS) greatly simplifies the configuration of QoS in
voice-over-IP (VoIP) networks by issuing interface and global switch
commands that allow the detection of Cisco IP phones, the classification of
traffic, and egress queue configuration.
QoS Classification
Support at Ingress
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The switches support QoS classification of incoming packets for QoS flows
based on Layer 2, Layer 3, and Layer 4 fields.
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The following Layer 2 fields (or a combination) can be used for classifying
incoming packets to define QoS flows: source/destination MAC address or 16-
bit Ethertype.
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The switches support identification of traffic based on Layer 3 type of service
(ToS) field DSCP values.
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The following Layer 3 and Layer 4 fields (or a combination) can be used to
classify incoming packets to define QoS flows: source/destination IP address,
TCP source/destination port number, or UDP source/destination port number.
QoS metering/policing at ingress
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Support for metering/policing of incoming packets restricts incoming traffic
flows to a certain rate.
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The switches support up to six policers per Fast Ethernet port, and 60 policers
on a Gigabit Ethernet port.
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The switches offer granularity of traffic flows at 1 Mbps on Fast Ethernet ports,
and 8 Mbps on Gigabit Ethernet ports.
QoS marking at ingress
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The switches support marking and remarking packets based on the state of
policers/meters.
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The switches support marking and remarking based on the following
mappings: from DSCP to 802.1p, and from 802.1p to DSCP.
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The switches support 14 well-known and widely used DSCP values.
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The switches support classifying or reclassifying packets based on the default
DSCP per port, and support classification based on DSCP values in the ACL.
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The switches support classifying or reclassifying frames based on the default
802.1p value per port.
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The switches support 802.1p override at ingress.
QoS scheduling support at egress
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Four queues per egress port are supported in hardware.
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The WRR queuing algorithm helps ensure that low-priority queues are not
starved.
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Strict Priority Scheduling helps ensure that time-sensitive applications such as
voice always follow an expedited path through the switch fabric.
Sophisticated traffic management
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The switch offers the ability to limit data flows based on MAC source or
destination address, IP source or destination address, TCP/UDP port
numbers, or any combination of these fields.
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The switch offers the ability to manage data flows asynchronously upstream
and downstream from the end station or on the uplink.
Management