Ingress Queuing Policies; Ingress Classification Policies; Egress Queuing Policies - Cisco Nexus 5000 Series Configuration Manual

Ingress Queuing Policies

• Any packet that is not tagged with an 802.1p CoS value is classified into the default drop system class.
• You can override the default untagged CoS value for an Ethernet interface or port channel.
After the system applies the untagged CoS value, QoS functions the same as for a packet that entered the
system tagged with the CoS value.
Ingress Queuing Policies
You can associate an ingress policy map with an Ethernet interface to guarantee bandwidth for the specified
traffic class or to specify a priority queue.
The ingress policy is applied in the adapter to all outgoing traffic that matches the specified CoS value.
When you configure an ingress policy for an interface, the switch sends the configuration data to the adapter.
If the adapter does not support the DCBX protocol or the ingress policy type-length-value (TLV), the ingress
policy configuration is ignored.

Ingress Classification Policies

You use classification to partition traffic into classes. You classify the traffic based on the port characteristics
(CoS field) or the packet header fields that include IP precedence, Differentiated Services Code Point (DSCP),
and Layer 2 to Layer 4 parameters. The values used to classify traffic are called match criteria. When you
define a traffic class, you can specify multiple match criteria, you can choose to not match on a particular
criterion, or you can determine traffic class by matching any or all criteria.
Traffic that fails to match any class is assigned to a default class of traffic called class-default.

Egress Queuing Policies

You can associate an egress policy map with an Ethernet interface to guarantee the bandwidth for the specified
traffic class or to configure the egress queues.
The bandwidth allocation limit applies to all traffic on the interface including any FCoE traffic.
Each Ethernet interface supports up to six queues, one for each system class. The queues have the following
default configuration:
• In addition to the six queues, control traffic that is destined for the CPU uses strict priority queues. These
• FCoE traffic (traffic that maps to the FCoE system class) is assigned a queue. This queue uses weighted
• Standard Ethernet traffic in the default drop system class is assigned a queue. This queue uses WRR
If you add a system class, a queue is assigned to the class. You must reconfigure the bandwidth allocation on
all affected interfaces. Bandwidth is not dedicated automatically to user-defined system classes.
Cisco Nexus 5000 Series NX-OS Quality of Service Configuration Guide
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If the untagged packet is sent over a trunk, it is tagged with the default untagged CoS value, which is
zero.
queues are not accessible for user configuration.
round-robin (WRR) scheduling with 50 percent of the bandwidth.
scheduling with 50 percent of the bandwidth.
Configuring QoS
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