Cisco Nexus 5000 Series NX-OS Software Configuration Guide
Configuring QoS
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Configuring QoS

Table Of Contents

Configuring QoS

Information About QoS

MQC

System Classes

Default System Classes

Link-Level Flow Control

Priority Flow Control

MTU

Trust Boundaries

Ingress Policies

Egress Policies

QoS for Multicast Traffic

Policy for Fibre Channel Interfaces

QoS for Traffic Directed to the CPU

Configuration Guidelines and Limitations

Configuring PFC and LLC

Configuring Priority Flow Control

Configuring IEEE 802.3x Link-Level Flow Control

Configuring System Classes

Configuring Class Maps

Configuring Policy Maps

Creating the System Service Policy

System Class Example

Enabling Jumbo MTU

Verifying Jumbo MTU

Configuring QoS on Interfaces

Configuring Untagged CoS

Configuring Ingress Policies

Configuring Egress Policies


Configuring QoS


This chapter describes how to configure the quality of service (QoS) features on the Cisco Nexus 5000 Series switch.

This chapter includes the following sections:

Information About QoS

Configuration Guidelines and Limitations

Configuring PFC and LLC

Configuring System Classes

Configuring QoS on Interfaces

Information About QoS

The Cisco Nexus 5000 Series switch provides QoS capabilities such as traffic prioritization and egress bandwidth allocation.

The default QoS configuration on the switch provides lossless service for Fibre Channel and Fibre Channel Over Ethernet (FCoE) traffic and best-effort service for Ethernet traffic. QoS can be configured to provide additional classes of service for Ethernet traffic. Cisco Nexus 5000 Series QoS features are configured using Cisco Modular QoS CLI (MQC).

This section includes the following topics:

MQC

System Classes

Default System Classes

Link-Level Flow Control

Priority Flow Control

MTU

Trust Boundaries

Ingress Policies

Egress Policies

QoS for Multicast Traffic

Policy for Fibre Channel Interfaces

QoS for Traffic Directed to the CPU

MQC

The Cisco Modular QoS CLI (MQC) provides a standard set of commands for configuring QoS.

You can use MQC to define additional traffic classes and to configure QoS policies for the whole system and for individual Ethernet interfaces. Configuring a QoS policy with MQC consists of the following steps:

1. Define traffic classes using the class-map command.

The class map classifies incoming or outgoing packets based on matching criteria, such as the IEEE 802.1p CoS value. Unicast and multicast packets are classified.

2. Associate policies or actions with each class of traffic using the policy-map command.

The policy map defines a set of actions to take on the associated traffic class, such as limiting the bandwidth or dropping packets.

3. Attach policies to MQC targets using the service-policy command.

An MQC target is an entity (such as an Ethernet interface) that represents a flow of packets. A service policy associates a policy map with an MQC target, and specifies whether to apply the policy on incoming or outgoing packets. This enables the configuration of interface-specific QoS policies such as policing and bandwidth allocation.

System Classes

The system class is a new type of MQC target. A service policy can associate a policy map with a system class, which enables application of a QoS policy across the whole switch.

Parameters in system classes need to be configured consistently across the switch and the whole network to ensure that packets in a specific traffic class receive consistent treatment as they are transported across the network.

To ensure QoS consistency (and for ease of configuration), the switch distributes the system class parameter values to all its attached network adapters using the DCBX protocol. For additional information about communication between the switch and adapters, see the "DCE Bridging Capability Exchange Protocol" section on page 29-3.

If service policies are configured at the interface level, the interface-level policy always takes precedence over system class configuration or defaults.

The following QoS parameters can be specified for a system class:

Drop

No drop specifies lossless service for the system class. Drop specifies that tail drop is used when a queue for this system class is full.

MTU

The system class MTU defines the maximum packet size for any packet classified into the system class. Each system class has a default MTU and the system class MTU is configurable.

Match CoS value

The match CoS value specifies the IEEE 802.1p CoS value to associate with this system class.

Bandwidth and priority

Sets the bandwidth and priority configuration values for this system class. The system class values are used as the default values for all interfaces.

Default System Classes

The Cisco Nexus 5000 Series switch provides the following default system classes:

FCoE system class

All Fibre Channel and FCoE control and data traffic is automatically classified into the FCoE system class, which provides no-drop service.

This class is created automatically when the system starts up (the class is named class-fcoe in the CLI). You cannot delete this class, and you can only modify the IEEE 802.1p CoS value to associate with this class.

The switch classifies packets into the FCoE system class as follows:

FCoE traffic is classified based on EtherType.

Native Fibre Channel traffic is classified based on the physical interface type.

Drop system class

By default, all unicast and multicast Ethernet traffic is classified into the default drop system class.

This class is created automatically when the system starts up (the class is named class-default in the CLI). You cannot delete this class and you cannot change the CoS value associated with the default class.

There are two reserved system classes for internal system use.

Link-Level Flow Control

The IEEE 802.3x link-level flow control capability allows a congested receiver to communicate the far end to pause its data transmission for a short period of time. The link-level flow control feature applies to all the traffic on the link.

The transmit and receive directions are separately configurable. By default, link-level flow control is disabled for both directions.

On the Cisco Nexus 5000 Series switch, Ethernet interfaces do not auto-detect the link-level flow control capability. You must configure the capability explicitly on the Ethernet interfaces.

On each Ethernet interface, the switch can enable either priority flow control or link-level flow control (but not both).

Priority Flow Control

The priority flow control (PFC) capability allows you to apply pause functionality to specific classes of traffic on a link (instead of all the traffic on the link). PFC applies pause functionality based on the IEEE 802.1p CoS value. When the switch enables PFC, it communicates to the adapter which CoS values to apply the pause.

Ethernet interfaces use PFC to provide lossless service to no-drop system classes. PFC implements Pause frames on a per-class basis and uses the IEEE 802.1p CoS value to identify the classes that require lossless service.

In the switch, each system class has an associated IEEE 802.1p CoS value (assigned by default or configured on the system class). If PFC is enabled, the switch sends the no-drop CoS values to the adapter, which then applies PFC to these CoS values.

The default CoS value for the FCoE system class is 3 and this value is configurable.

If PFC is not enabled on an interface, you can enable IEEE 802.3X link-level pause. By default, link-level pause is disabled.

MTU

The Cisco Nexus 5000 Series switch is a Layer 2 switch, and it does not support packet fragmentation. MTU configuration mismatch between ingress and egress interfaces may result in packets being truncated.

When configuring MTU, follow these guidelines:

MTU is specified per system class. You cannot configure MTU on the interfaces.

Fibre Channel and FCoE payload MTU is 2112 bytes across the switch. As a result, the rxbufsize for Fibre Channel interfaces is fixed at 2112 bytes. If the Cisco Nexus 5000 Series switch receives an rxbufsize from a peer different than 2112 bytes, it will fail ELP negotiation and not bring the link up.

The system jumbomtu command defines the upper bound of any MTU in the system. System jumbo MTU has a default value of 9216 bytes. The minimum MTU is 2240 bytes and the maximum MTU is 9216 bytes.

The system class MTU sets the MTU for all packets in the class. The system class MTU cannot be configured larger than the global jumbo MTU.

The FCoE system class (for Fibre Channel and FCoE traffic) has a default MTU of 2240 bytes. This value cannot be modified.

The default drop system class has a default MTU of 1538 bytes. You can configure this value.

The switch sends the MTU configuration to network adapters that support DCBXP.

Trust Boundaries

The trust boundary is enforced by the incoming interface as follows:

All Fibre Channel and virtual Fibre Channel interfaces are automatically classified into the FCoE system class.

By default, all Ethernet interfaces are trusted interfaces. A packet tagged with a 802.1p CoS value is classified into a system class using the value in the packet.

Any packet not tagged with an 802.1p CoS value is classified into the default drop system class. If the untagged packet is sent over a trunk, it is tagged with the default untagged CoS value, which is zero.

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 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 DCBX protocol (or the ingress policy TLVs), the ingress policy configuration is ignored.

Egress 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 eight queues (one for each system class). The queues have the following default configuration:

Queue zero is configured as a strict priority queue. Control traffic destined for the CPU uses this queue.

FCoE traffic (traffic that maps to the FCoE system class) is assigned a queue. This queue uses WRR scheduling with 50 percent of the bandwidth.

Standard Ethernet traffic (in the default drop system class) is assigned a queue. This queue uses WRR scheduling with 50 percent of the bandwidth.

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.

You can configure an additional strict priority queue. This queue is serviced before all other queues except queue zero (which carries control traffic, not data traffic).

QoS for Multicast Traffic

The system provides six multicast queues per interface and allocates one queue for each system class. By default, all multicast Ethernet traffic is classified into the default drop system class. This traffic is serviced by one multicast queue.

The optimized multicast feature allows use of the unused multicast queues, to achieve better throughput for multicast frames. If optimized multicast is enabled for the default drop system class, the system will use all six queues to service the multicast traffic (all six queues are given equal priority).

If you define a new system class. a dedicated multicast queue is assigned for this class. This queue is removed from the set of queues available for optimized multicast.

The optimized multicast feature achieves better throughput for multicast frames and improves performance for multicast frames.


Note Optimized multicast is supported on the BF and later versions of the Cisco Nexus 5020 switch. To verify the model version, enter the show module 1 command. The model version is the last two characters of the model number. Optimized multicast is supported on all versions of the Cisco Nexus 5010 switch.


The system provides two predefined class maps for matching broadcast or multicast traffic. These class maps are convenient for creating separate policy maps for unicast and multicast traffic. The predefined class maps are as follows:

class-all-flood

The class-all-flood class map matches all broadcast, multicast and unknown unicast traffic (across all CoS values). If you configure a policy map with the class-all-flood class map, the system automatically utilizes all available multicast queues for this traffic.

class-ip-multicast

The class-ip-multicast class map matches all IP multicast traffic. Policy options configured in this class map apply to traffic across all Ethernet CoS values. For example, if you enable optimized multicast for this class, the IP multicast traffic for all CoS values is optimized.

If you configure this class as a no-drop class, the priority flow control capability is applied across all Ethernet CoS values. In this configuration, pause will be applied to unicast and multicast traffic.


Note Only one of these predefined classes can be configured in the system QoS policy.


Policy for Fibre Channel Interfaces

The egress queues are not configurable for native Fibre Channel interfaces. Two queues are available as follows:

A strict priority queue to serve high-priority control traffic.

A queue to serve all data traffic and low-priority control traffic.

QoS for Traffic Directed to the CPU

The switch automatically applies QoS policies to traffic that is directed to the CPU to ensure that the CPU is not flooded with packets. Control traffic, such as BPDU frames, is given higher priority to ensure delivery.

Configuration Guidelines and Limitations

Switch resources (such as buffers, virtual output queues, and egress queues) are partitioned based on the default and user-defined system classes. The switch software automatically adjusts the resource allocation to accommodate the configured system classes.

To maintain optimal switch performance, follow these guidelines when configuring system classes and policies:

If less than four Ethernet classes are defined, up to two of these classes can be configured as no-drop classes. If more than three Ethernet classes are defined, only one of these classes can be configured as a no-drop class. The default drop class is counted as an Ethernet class.

If priority flow control is enabled on an Ethernet interface, pause will never be applied to traffic with a drop system class. PFC does not apply pause to drop classes and the link-level pause feature is never enabled on an interface with PFC.

All FCoE traffic on an Ethernet interface is mapped to one no-drop system class. By default, this class is associated with CoS value 3, although you can configure a different value. If you configure standard Ethernet traffic to use the same CoS value as FCoE, this traffic is still mapped to the FCoE system class and the switch will apply priority flow control on the FCoE CoS value.

When configuring Ethernet port channels, note the following guidelines:

The service policy configured on a port channel applies to all member interfaces.

The priority flow control configured on a port channel applies to all member interfaces.

Configuring PFC and LLC

Cisco Nexus 5000 Series switches support PFC and LLC on Ethernet interfaces. The Ethernet interface can operate in two different modes: FCoE mode or standard Ethernet mode.

If the interface is operating in FCoE mode, the Ethernet link is connected at the server port using a converged network adapter (CNA). Refer to Chapter 29, "Configuring FCoE" for information about configuring PFC and LLC when the interface is operating in FCoE mode.

If the interface is operating in standard Ethernet mode, the Ethernet link is connected at the server port with a standard Ethernet network adapter (NIC). The network adapter must support DCBX protocol for PFC or ingress policing to be supported on the interface.


Note You must configure a no-drop Ethernet system class for PFC to operate on Ethernet traffic (PFC will be applied to traffic that matches the CoS value configured for this class).


Configuring PFC and LLC for standard Ethernet is covered in the following topics:

Configuring Priority Flow Control

Configuring IEEE 802.3x Link-Level Flow Control

Configuring Priority Flow Control

By default, Ethernet interfaces negotiate PFC capability with the network adapter using DCBX protocol. When PFC is enabled, PFC is applied to traffic that matches the CoS value configured for the no-drop Ethernet class.

You can override the negotiation result by force-enabling the PFC capability. To force-enable the PFC capability, perform this task:

 
Command
Purpose

Step 1 

switch# configure terminal

Enters configuration mode.

Step 2 

switch(config)# interface type slot/port 

Specifies the interface to be changed.

Step 3 

switch(config-if)# priority-flow-control 
mode {auto|on} 

Sets PFC mode for the selected interface.

Specify on to force-enable PFC.

Specify auto to negotiate PFC capability.

The following example shows how to force-enable PFC on an interface:

switch# configure terminal  
switch(config)# interface ethernet 1/2  
switch(config-if)# priority-flow-control mode on  

To disable PFC capability for an interface, perform this task:

Command
Purpose
switch(config-if)# no 
priority-flow-control mode 

Disables the PFC setting for the selected interface.


Configuring IEEE 802.3x Link-Level Flow Control

By default, link-level flow control capability on Ethernet interfaces is disabled. You can enable link-level flow-control capability for the transmit and receive directions.

To enable link-level flow control capability, perform this task:

 
Command
Purpose

Step 1 

switch# configure terminal

Enters configuration mode.

Step 2 

switch(config)# interface type slot/port 

Specifies the interface to be changed.

Step 3 

switch(config-if)# flowcontrol [receive 
{on|off}] [transmit {on|off}] 

Enables IEEE 802.3x link-level flow control for the selected interface. Set receive and/or transmit on or off.

The following example enables link-level flow control frames on an interface:

switch# configure terminal  
switch(config)# interface ethernet 1/2  
switch(config-if)# flowcontrol receive on transmit on  

To disable link-level flow control, perform this task:

Command
Purpose
switch(config-if)# no flowcontrol 
[receive {on|off}] [transmit {on|off}] 

Disables 802.3x link-level flow control for the selected interface.


Configuring System Classes

This section describes how to configure system classes on the switch. The steps to configure a system class are described in the following topics:

Configuring Class Maps

Configuring Policy Maps

Creating the System Service Policy

System Class Example

Enabling Jumbo MTU

Verifying Jumbo MTU

Configuring Class Maps

The class-map command creates a named object that represents a class of traffic. In the class map, you specify a set of match criteria for classifying the packets. For system classes, the only match criteria supported is match cos.

If a system class is configured with no-drop function, the match cos command serves an additional purpose. The switch sends the CoS value to the adapter, so that the adapter will apply PFC Pause for this CoS value.

The FCoE system class has a default CoS value of 3. You can add a match cos configuration to the FCoE system class to set a different CoS value. PFC Pause will be applied to traffic that matches the new value.

To configure a class map for a system class, perform this task:

 
Command
Purpose

Step 1 

switch# configure terminal

Enters configuration mode.

Step 2 

switch(config)# class-map name

Creates a named object that represents a class of traffic. Class map names can contain alphabetic, hyphen, or underscore characters, are case sensitive, and can be up to 40 characters.

Step 3 

switch(config-cmap)# match cos cos-value

Specifies the CoS value to match for classifying packets into this class. You can configure a CoS value in the range of 0 to 7.

Configuring Policy Maps

The policy-map command is used to create a named object representing a set of policies that are to be applied to a set of traffic classes.

The switch provides two default system classes: a no-drop class for lossless service and a drop class for best-effort service. You can define up to four additional system classes for Ethernet traffic.

You need to create a policy map to specify the policies for any user-defined class. In the policy-map, you can configure the QoS parameters for each class. You can use the same policy map to modify the configuration of the default classes.


Note Before creating the policy map, define a class map for each new system class.


To configure a policy map, perform this task:

 
Command
Purpose

Step 1 

switch# configure terminal

Enters configuration mode.

Step 2 

switch(config)# policy-map name

Creates a named object representing a set of policies that are to be applied to a set of traffic classes. Policy-map names can contain alphabetic, hyphen, or underscore characters, are case sensitive, and can be up to 40 characters.

Step 3 

switch(config-pmap)# class class-name

Associates a class map with the policy map, and enters configuration mode for the specified system class.

Step 4 

switch(config-pmap-c)# pause no-drop

(Optional) Configures a no-drop class. If you do not specify this subcommand, the default policy is drop.

Note The operation for drop policy is simple tail drop, where arriving packets will be dropped if the queue increases to its allocated size

Step 5 

switch(config-pmap-c)# mtu value

(Optional) Specifies the MTU value in bytes.

Step 6 

switch(config-pmap-c) bandwidth percent percentage

(Optional) Specifies the guaranteed percentage of interface bandwidth allocated to this class.

Step 7 

switch(config-pmap-c) priority

(Optional) Specifies that traffic in this class is mapped to a strict priority queue.

Step 8 

switch(config-pmap-c) multicast-optimize

(Optional) Enables multicast optimization. Multicast traffic in this class will be served by all available multicast queues.

Note Only one class in a policy map can be configured for multicast optimization.


Note The switch distributes all the policy map configuration values to the attached network adapters.



Note Policy maps can also be configured for interface service policies. However, different parameters are supported in these policy maps. See the "Configuring QoS on Interfaces" section.


The following example shows how to enable optimized multicast for the default Ethernet class:

switch(config)# policy-map s1 
switch(config-pmap)# class class-default  
switch(config-pmap-c)# multicast-optimize 

The following example shows how to create a policy map with a no-drop Ethernet class:

switch(config)# class-map ethCoS4 
switch(config-cmap)# match cos 4 
switch(config-cmap)# exit 
switch(config)# policy-map ethNoDrop  
switch(config-pmap)# class ethCoS4  
switch(config-pmap-c)# pause no-drop 

Creating the System Service Policy

The service-policy command is used to associate the system class policy-map as the service policy for the system.

 
Command
Purpose

Step 1 

switch# configure terminal

Enters configuration mode.

Step 2 

switch(config)# system qos

Enters system class configuration mode.

Step 3 

switch(config-sys-qos)# service-policy name

Specifies the policy-map to use as the service policy for the system.

The following example sets a no-drop Ethernet policy map as the system class:

switch(config)# class-map ethCoS4 
switch(config-cmap)# match cos 4 
switch(config-cmap)# exit 
switch(config)# policy-map ethNoDrop  
switch(config-pmap)# class ethCoS4  
switch(config-pmap-c)# pause no-drop 
switch(config)# system qos 
switch(config-system)# service-policy ethNoDrop  

System Class Example

In the following example, a new Ethernet no-drop system class is created, and the CoS values of the default system classes are changed from their default values:

switch(config)# class-map trading-data-no-drop 
switch(config-cmap)# match cos 5 
switch(config)# class-map class-fcoe 
switch(config-cmap)# match cos 2 
switch(config)# policy-map system-policy 
switch(config-pmap)# class trading-data-no-drop 
switch(config-pmap-c)# pause no-drop 
switch(config-pmap-c)# mtu 2000 
switch(config)# system qos 
switch(config-system)# service-policy system-policy 

In this example, the first class-map command defines a new Ethernet system class. Packets from all over the system with 802.1p CoS value of 5 will be classified into this new system class.

The second class-map command changes the match value of the default no-drop system class.

The policy-map command defines a QoS policy for each traffic class. The new Ethernet class is configured as a no-drop class, with an MTU of 2000 bytes. The pause no-drop command causes PFC to apply pause functionality for packets with IEEE 802.1p priority value 5.

The service-policy command sets the specified policy as the system class.

Enabling Jumbo MTU

To enable jumbo MTU for the whole switch, set the MTU to its maximum size (9216 bytes) in the policy map for the default Ethernet system class (class-default).

In the following example, the default Ethernet system class is configured to support the jumbo MTU:

switch(config)# policy-map jumbo  
switch(config-pmap)# class class-default  
switch(config-pmap-c)# mtu 9216 
switch(config)# system qos 
switch(config-system)# service-policy jumbo  


Note The system jumbomtu command defines the maximum MTU size for the switch. However, jumbo MTU is only supported for system classes that have mtu configured.


Verifying Jumbo MTU

To verify that jumbo MTU is enabled, enter the show interface ethernet slot/port command for an Ethernet interface that carries traffic with jumbo MTU.

The following example shows how to display summary jumbo MTU information for Ethernet 2/1 (the relevant part of the output is shown in bold font):

switch# show interface ethernet 2/1 
Ethernet2/1 is up 
... 
    Rx 
    1547805598 Input Packets 1547805596 Unicast Packets 0 Multicast Packets 
    0 Broadcast Packets 1301767362 Jumbo Packets 33690 Storm Suppression Packets 
    7181776513802 Bytes 
    Tx 
    1186564478 Output Packets 7060 Multicast Packets 
    0 Broadcast Packets 997813205 Jumbo Packets 
    4813632103603 Bytes 
... 

The following example shows how to display detailed jumbo MTU information for Ethernet 2/1 (the relevant part of the output is shown in bold font):

switch# show interface ethernet 2/1 counters detailed 
Rx Packets: 1547805598 
Rx Unicast Packets: 1547805596 
Rx Jumbo Packets: 1301767362 
Rx Bytes: 7181776513802 
Rx Storm Suppression: 33690 
Rx Packets from 0 to 64 bytes: 169219 
Rx Packets from 65 to 127 bytes: 10657133 
Rx Packets from 128 to 255 bytes: 21644488 
Rx Packets from 256 to 511 bytes: 43290596 
Rx Packets from 512 to 1023 bytes: 86583071 
Rx Packets from 1024 to 1518 bytes: 83693729 
Rx Trunk Packets: 1547805596 
Tx Packets: 1186564481 
Tx Unicast Packets: 1005445334 
Tx Multicast Packets: 7063 
Tx Jumbo Packets: 997813205 
Tx Bytes: 4813632103819 
Tx Packets from 0 to 64 bytes: 137912 
Tx Packets from 65 to 127 bytes: 8288443 
Tx Packets from 128 to 255 bytes: 16596457 
Tx Packets from 256 to 511 bytes: 33177999 
Tx Packets from 512 to 1023 bytes: 66363944 
Tx Packets from 1024 to 1518 bytes: 64186521 
Tx Trunk Packets: 1005451729 

Configuring QoS on Interfaces

QoS parameters that can be configured on Ethernet and port channel interfaces are described in the following topics:

Configuring Untagged CoS

Configuring Ingress Policies

Configuring Egress Policies

Configuring Untagged CoS

Any incoming packet not tagged with an 802.1p CoS value is assigned the default untagged CoS value of zero (which maps to the default Ethernet drop system class). You can override the default untagged CoS value for an Ethernet interface or port channel.

To configure the untagged CoS value, perform this task:

 
Command
Purpose

Step 1 

switch# configure terminal

Enters configuration mode.

Step 2 

switch(config)# interface {ethernet slot/port | port-channel channel-number}

Enters configuration mode for the specified interface or port channel.

Step 3 

switch(config-if)# untagged cos cos-value

Configures the untagged CoS value.

Configuring Ingress Policies

An ingress policy is a service policy applied to incoming traffic on an Ethernet interface. The ingress policy is applied in the adapter to all outgoing traffic that matches the specified class. When you configure an ingress policy on an interface or port channel, the switch sends the configuration data to the adapter.

To configure an ingress policy, perform this task:

 
Command
Purpose

Step 1 

switch# configure terminal

Enters configuration mode.

Step 2 

switch(config)# class-map class-name

Creates a class for the ingress policy.

Step 3 

switch(config)# policy-map policy1-name

Creates a policy map to specify the QoS parameters for the ingress policy.

Step 4 

switch(config-pmap)# class class-name

Associates the ingress class with this policy and enters configuration mode for the class.

Step 5 

switch(config-pmap-c) bandwidth percent percentage

(Optional) Specifies the guaranteed percentage of bandwidth allocated to incoming traffic of this class.

Step 6 

switch(config-pmap-c) priority

(Optional) Specifies that ingress traffic in this class is mapped to a strict priority queue.

Step 7 

switch(config)# interface {ethernet slot/port | port-channel channel-number}

Enters configuration mode for the specified interface.

Note The service policy on a port channel applies to all member interfaces.

Step 8 

switch(config-if)# service-policy input policy-name

Applies the policy map to the interface.

The following example shows that the system class best-effort-drop-class is guaranteed 20 percent of the bandwidth on interface ethernet 1/1:

switch(config)# class-map best-effort-drop-class 
switch(config-cmap)# match cos 5 
switch(config)# policy-map policy1 
switch(config-pmap)# class best-effort-drop-class 
switch(config-pmap-c)# bandwidth percent 20 
switch(config)# interface ethernet 1/1 
switch(config-if)# service-policy input policy1 

Configuring Egress Policies

An egress policy is a service policy applied to the outgoing traffic on an Ethernet interface. You can configure an egress policy to guarantee the bandwidth for the specified traffic class or to configure the egress queues.

To configure an egress policy, perform this task:

 
Command
Purpose

Step 1 

switch# configure terminal

Enters configuration mode.

Step 2 

switch(config)# class-map class-name

Defines a class name for the egress policy.

Step 3 

switch(config)# policy-map policy-name

Creates a policy map to specify the QoS parameters for the egress policy.

Step 4 

switch(config-pmap)# class class-name

Associates the egress class with this policy and enters configuration mode for the class.

Step 5 

switch(config-pmap-c) bandwidth percent percentage

Specifies the guaranteed percentage of bandwidth allocated to this class.

Step 6 

switch(config-pmap-c) priority

Specifies that egress traffic in this class is mapped to a strict priority queue.

Step 7 

switch(config)# interface {ethernet slot/port | port-channel channel-number}

Enters configuration mode for the specified interface.

Note The service policy on a port channel applies to all member interfaces.

Step 8 

switch(config-if)# service-policy output policy-name

Applies the policy map to the interface.

The following example shows that the system class best-effort drop class is guaranteed 20 percent of the bandwidth on interface eth1/1:

switch(config)# class-map best-effort-drop-class 
switch(config-cmap)# match cos 5 
switch(config)# policy-map policy1-egress 
switch(config-pmap)# class best-effort-drop-class 
switch(config-pmap-c)# bandwidth percent 20 
switch(config)# interface ethernet 1/1 
switch(config-if)# service-policy output policy1-egress