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This chapter contains the following sections:
The configurable Cisco NX-OS quality of service (QoS) features allow you to classify the network traffic, prioritize the traffic flow, and provide congestion avoidance.
The default QoS configuration on the device 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 NX-OS QoS features are configured using Cisco Modular QoS CLI (MQC).
Standard Ethernet is a best-effort medium which means that it lacks any form of flow control. In the event of congestion or collisions, Ethernet will drop packets. The higher level protocols detect the missing data and retransmit the dropped packets.
Fibre Channel requires a reliable transport system that guarantees the delivery of every packet. To properly support FCoE, Ethernet has been enhanced with a priority flow control (PFC) mechanism to prevent congestion.
The FCoE QoS must be configured either if native FC or FCoE or FC and FCoE are in use. The FCoE QoS must be added even if Ethernet is not configured on the switch.
switch(config)# system qos switch(config-sys-qos)# service-policy type queuing input fcoe-default-in-policy switch(config-sys-qos)# service-policy type queuing output fcoe-default-out-policy switch(config-sys-qos)# service-policy type qos input fcoe-default-in-policy switch(config-sys-qos)# service-policy type network-qos fcoe-default-nq-policy
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 interfaces. Configuring a QoS policy with MQC consists of the following steps:
MQC provides two command types to define traffic classes and policies:
Defines a class map that represents a class of traffic based on packet-matching criteria. Class maps are referenced in policy maps.
The class map classifies incoming packets based on matching criteria, such as the IEEE 802.1p class of service (CoS) value. Unicast and multicast packets are classified.
Defines a policy map that represents a set of policies to be applied on a class-by-class basis to class maps.
The policy map defines a set of actions to take on the associated traffic class, such as limiting the bandwidth or dropping packets.
You define the following class-map and policy-map object types when you create them:
Defines MQC objects that you can use for system level related actions.
Defines MQC objects that you can use for classification.
Defines MQC objects that you can use for queuing and scheduling.
![]() Note | The qos type is the default for the class-map and policy-map commands, but not for the service-policy which requires that you specify an explicit type. |
You can attach policies to interfaces or EtherChannels as well as at the global system level by using the service-policy command.
You can view all or individual values for MQC objects by using the show class-map and show policy-map commands.
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 mapping enables the configuration of QoS policies such as marking, bandwidth allocation, buffer allocation, and so on.
The system qos is a type of MQC target. You use a service policy to associate a policy map with the system qos target. A system qos policy applies to all interfaces on the switch unless a specific interface has an overriding service-policy configuration. The system qos policies are used to define system classes, the classes of traffic across the entire switch, and their attributes. To ensure QoS consistency (and for ease of configuration), the device distributes the system class parameter values to all its attached network adapters using the Data Center Bridging Exchange (DCBX) protocol.
If service policies are configured at the interface level, the interface-level policy always takes precedence over system class configuration or defaults.
On the Cisco Nexus device, a system class is uniquely identified by a qos-group value. A total of six system classes are supported. Two of the six system classes are defaults and are always present on the device. Up to four additional system classes can be created by the administrator.
The device provides the following system classes:
Drop system class
By default, the software classifies all unicast and multicast Ethernet traffic into the default drop system class. This class is identified by qos-group 0.
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 match criteria associated with the default class.
![]() Note | If congestion occurs when data traffic (class-default) and FCoE traffic (class-fcoe) is flowing at the same time, then the queuing percentage configuration starts up. The FCoE traffic is a no-drop class and does not get policed to the bandwidth assigned as per the queuing class. FCoE traffic cannot be dropped as it expects a lossless medium. When congestion occurs PFC frames are generated at FCoE ingress interfaces and dropping only occurs on the data traffic, even if data traffic is below the assigned bandwidth. For optimizing the throughput you can spread the data traffic load for a longer duration. |
FCoE system class (For the Cisco Nexus 5500 Series device)
For the Cisco Nexus 5500 Series device, the class-fcoe is not automatically created. Before you enable FCoE on the Cisco Nexus 5500 Series device running Cisco NX-OS Release 5.0(2)N1(1), you must enable class-fcoe in the three types of qos policies:
type qos policy maps
type network-qos policy map (attached to system qos)
type queuing policy map (class-fcoe must be configured with a non-zero bandwidth percentage for input queuing policy maps.
When class-fcoe is not included in the qos policies, vFC interfaces do not come up and increased drops occur.
![]() Note | The Cisco Nexus 5500 Series device supports five user-defined classes and one default drop system class. |
The device supports a number of policy types. You create class maps in the policy types.
Before you enable FCoE on the Cisco Nexus device, you must enable class-fcoe in the three types of qos policies (network QoS, queuing, and QoS) by entering the type qos policy maps command and applying at least one FCoE QoS policy under system QoS.
The following QoS parameters can be specified for each type of class:
Type network-qos—A network-qos policy is used to instantiate system classes and associate parameters with those classes that are of system-wide scope.
Classification—The traffic that matches this class are as follows:
Policy—The actions that are performed on the matching traffic are as follows:
![]() Note | A network-qos policy can only be attached to the system QoS target. |
MTU—The MTU that needs to be enforced for the traffic that is mapped to a system class. Each system class has a default MTU and the system class MTU is configurable.
Multicast optimization—This configuration specifies if the performance of multicast traffic mapped to this class will be optimized.
Pause no-drop—No drop specifies lossless service for the system class. Drop specifies that tail drop is used (arriving packets are dropped when the queue reaches its allocated size) when a queue for this system class is full.
An additional parameter pfc-cos can be configured. This parameter identifies the class of service (CoS) values to assert priority flow control (PFC) when traffic for a no-drop system class is not mapped based purely on CoS experiences congestion.
You can change the buffer for the no-drop class.
Queue Limit—This configuration specifies the number of buffers that need to be reserved to the queues of this system class. This option is not configurable for no-drop system classes.
Type queuing—A type queuing policy is used to define the scheduling characteristics of the queues associated with system classes.
![]() Note | Some configuration parameters when applied to an EtherChannel are not reflected on the configuration of the member ports. |
Classification—The traffic that matches this class are as follows:
Policy—The actions that are performed on the matching traffic are as follows:
![]() Note | These policies can be attached to the system qos target or to any interface. The output queuing policy is used to configure output queues on the device associated with system classes. The input queuing policy is used to configure scheduling for queues in the CNA. The input queuing policy parameters are signaled to the CNA over the DCBX protocol. |
Type qos—A type QoS policy is used to classify traffic that is based on various Layer 2, Layer 3, and Layer 4 fields in the frame and to map it to system classes.
![]() Note | Some configuration parameters when applied to an EtherChannel are not reflected on the configuration of the member ports. |
Classification—The traffic that matches this class are as follows:
Access Control Lists—Classifies traffic based on the criteria in existing ACLs.
Class of Service—Matches traffic based on the CoS field in the frame header.
DSCP—Classifies traffic based on the Differentiated Services Code Point (DSCP) value in the DiffServ field of the IP header.
IP Real Time Protocol—Classifies traffic on the port numbers used by real-time applications.
Precedence—Classifies traffic based on the precedence value in the type of service (ToS) field of the IP header.
Protocol—Classifies traffic based on the IPv4 Protocol field or the IPv6 Next Header field of the IP header.
Policy—The actions that are performed on the matching traffic are as follows:
![]() Note | This policy can be attached to the system or to any interface. It applies to input traffic only. |
IEEE 802.3x link-level flow control allows a congested receiver to communicate a transmitter at the other end of the link 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 device, Ethernet interfaces do not automatically 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 (PFC) 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 that is assigned by default or configured on the system class. If you enable PFC, 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. This value is configurable.
By default, the switch negotiates to enable the PFC capability. If the negotiation succeeds, PFC is enabled and link-level flow control remains disabled regardless of its configuration settings. If the PFC negotiation fails, you can either force PFC to be enabled on the interface or you can enable IEEE 802.x link-level flow control.
If you do not enable PFC on an interface, you can enable IEEE 802.3X link-level pause.
![]() Note | Ensure that pause no-drop is configured on a class map for link-level pause. |
By default, link-level pause is disabled.
The Cisco Nexus device is a Layer 2 switch, and it does not support packet fragmentation. A maximum transmission unit (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. The system class allows a different MTU for each class of traffic but they must be consistent on all ports across the entire switch. You cannot configure MTU on the interfaces.
Fibre Channel and FCoE payload MTU is 2158 bytes across the switch. As a result, the rxbufsize for Fibre Channel interfaces is fixed at 2158 bytes. If the Cisco Nexus device receives an rxbufsize from a peer that is different than 2158 bytes, it will fail the exchange of link parameters (ELP) negotiation and not bring the link up.
Enter the system jumbomtu command to define the upper bound of any MTU in the system. The system jumbo MTU has a default value of 9216 bytes. The minimum MTU is 2158 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 2158 bytes. This value cannot be modified.
The switch sends the MTU configuration to network adapters that support DCBX.
![]() Note | MTU is not supported in Converged Enhanced Ethernet (CEE) mode for DCBX. |
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.The 802.1p CoS and DSCP are preserved unless the marking is configured. There is no default CoS to queue and DSCP to queue mapping. You can define and apply a policy to create these mappings. By default, without a user defined policy, all traffic is assigned to the default queue.
Any packet that is 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.
You can override the default untagged CoS value for an Ethernet interface or a port channel interface using the untagged cos cos-value command.
You can override the default untagged Cos value for an Ethernet or a Layer 3 interface or a port channel interface using the untagged cos cos-value command.
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.
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.
You use classification to partition traffic into classes. You classify the traffic based on the packet property (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.
Traffic that fails to match any class is assigned to a default class of traffic called class-default.
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:
In addition to these queues, control traffic that is destined for the CPU uses strict priority queues. These queues are not accessible for user configuration.
FCoE traffic (traffic that maps to the FCoE system class) is assigned a queue. This queue uses weighted round-robin (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 100 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 one strict priority queue. This queue is serviced before all other queues except the control traffic queue (which carries control rather than data traffic).
On the Nexus 5500 platform, the packet buffer per port is 640KB. The Nexus 5548P, Nexus 5548UP, and the Nexus 5596UP switch share the same buffer architecture. The Nexus 5500 platform implements Virtual Output Queueing (VOQ) and ingress buffer architecture with the majority of the buffer allocated at ingress. The architecture allows the switch to store packets at multiple ingress ports when there are multiple ports sending traffic to one egress port which causes congestion.
The following default buffer allocations per port exist for the Cisco Nexus 5500 Platform:
Traffic Class | Ingress Buffer (KB) |
---|---|
Class-fcoe | 79.360 |
User-defined no-drop with an MTU less than 2240 | 79.360 |
User-defined no-drop class with an MTU greater than 2240 | 90.204 |
Tail drop traffic class | 22.720 |
Class-default | All of the remaining buffer (470 with default QoS configuration) |
The default buffer allocation varies depending on the type of class. For example, if you create a regular tail drop traffic class the default allocation is 22.7KB, unless you specify a larger size using the queue-limit command.
To increase the ingress buffer space available to a user-created qos-group, from a network-qos policy-map, use the queue-limit command.
In addition to ingress buffer allocated for each user-created qos-group there is an additional 29.76KB buffer required at egress for each qos-group.
With the default QoS configuration, all of the available buffer (470KB) is allocated to the class-default. When you create a new qos-group, the buffer required for the new qos-group will be taken away from class-default. The amount of buffer that is left for class-default equals 470 minus the ingress buffer used by other qos-groups minus 29.76KB and times the number of qos-groups.
![]() Note | Each new class requires an additional 29.76KB, so the exact amount of buffer that is left in the class default equals 470 minus the buffer used by other qos-groups minus 29.76KB times the number of qos-groups. |
The default QoS policy for the Cisco Nexus device does not create class-fcoe and does not reserve buffer and qos-group for FCoE traffic.
The show queuing interface command can display the amount of ingress buffer allocated for each qos-group
The following buffering limits exist for the Cisco Nexus 5000 Platform:
The following default buffer allocations per port exist for the Cisco Nexus 5000 Platform:
Traffic Class | Ingress Buffer (KB) |
---|---|
Class-fcoe | 76.8 |
User-defined no-drop class of service with an MTU less than 2240 | 76.8 |
User-defined no-drop class of service with an MTU greater than 2240 | 81.9 |
Tail drop class of service | 20.48 |
Class-default | All of the remaining buffer (243.2KB with the default QoS configuration) |
The default buffer allocation varies depending on the type of class. For example, if you create a regular tail drop traffic class the default allocation is 20.48KB, unless you specify a larger size using the queue-limit command.
To increase the buffer space available to a user-created qos-group, from a network-qos policy-map, use the queue-limit command.
All of the available buffer is allocated to the class-default. When you define a new qos-group, the required buffer for the new qos-group is taken from the class-default buffer.
![]() Note | Each new class requires an additional 18.880KB, so the exact amount of buffer that is left in the class default is 243.2KB minus the buffer used by other qos-groups minus 18.880KB times the number of qos-groups. |
The default QoS configuration for the Nexus 5000 platform creates the class-fcoe and class-default.
The show queuing interface command displays the configured qos-group and the ingress buffer allocated for each qos-group.
By default, all multicast Ethernet traffic is classified into the default drop system class. This traffic is serviced by one multicast queue.
Optimized multicasting 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 128 queues to service the multicast traffic. When optimized multicast is enabled for the default drop system class, all 128 queues are given equal priority.
If you define a new system class, a dedicated multicast queue is assigned to that class. This queue is removed from the set of queues available for the optimized multicast class.
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:
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 uses all available multicast queues for this traffic.
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.
![]() Note | If you configure either of these predefined class maps 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. |
The egress queues are not configurable for native Fibre Channel interfaces. Two queues are available as follows:
The device 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 bridge protocol data units (BPDU) frames, is given higher priority to ensure delivery.
To maintain optimal switch performance, follow these guidelines when configuring system classes and policies:
Switch resources (such as buffers, virtual output queues, and egress queues) are partitioned based on the default and user-defined system classes. Cisco NX-OS automatically adjusts the resource allocation to accommodate the configured system classes.
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 a Cisco Nexus 2148T Fabric Extender is connected and in use, data traffic should never be marked with a CoS value of 7. CoS 7 is reserved for control traffic transiting the Fabric Extender.
On the Cisco Nexus 5548 Switch, the FCoE class-fcoe system class is not enabled by default in the QoS configuration. Before enabling FCoE, you must include class-fcoe in each of the three policy types (network-qos, queuing, and qos).
![]() Note | Type qos policies can be activated only on Cisco Nexus 5000 Series interfaces and Cisco Nexus 2000 Series Fabric Extender interfaces. Type qos policies on Fabric Extender fabric interfaces or Fabric Extender fabric EtherChannel interfaces are ineffective, though the Cisco NX-OS CLI does not reject the configuration. We recommend that you do not configure type qos policy-maps on Fabric Extender fabric interfaces or Fabric Extender fabric EtherChannel interfaces to avoid wasting hardware resources. |
When configuring EtherChannels, note the following guidelines:
Configuring System Classes
You can create or modify a class map with the class-map command. The class map is a named object that represents a class of traffic. In the class map, you specify a set of match criteria for classifying the packets. You can then reference class maps in policy maps.
![]() Note | The class map type default is type qos and its match criteria default is match-all. |
You can classify traffic by matching packets based on an existing access control list (ACL). Traffic is classified by the criteria defined in the ACL. The permit and deny ACL keywords are ignored in the matching; even if a match criteria in the access-list has a deny action, it is still used for matching for this class.
Command or Action | Purpose | |||
---|---|---|---|---|
Step 1 |
switch#
configure terminal
|
Enters global configuration mode. | ||
Step 2 |
switch(config)#
class-map type qos
class-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-qos)#
match access-group
name
acl-name
|
Configures a traffic class by matching packets based on the acl-name. The permit and deny ACL keywords are ignored in the matching.
| ||
Step 4 |
switch(config-cmap-qos)#
no match access-group
name
acl-name
| (Optional)
Removes the match from the traffic class. |
This example shows how to classify traffic by matching packets based on existing ACLs:
switch# configure terminal
switch(config)# class-map type qos class_acl
switch(config-cmap-qos)# match access-group name acl-01
Use the show class-map command to display the ACL class-map configuration:
switch# show class-map class_acl
You can classify traffic based on the class of service (CoS) in the IEEE 802.1Q header. This 3-bit field is defined in IEEE 802.1p to support QoS traffic classes. CoS is encoded in the high order 3 bits of the VLAN ID Tag field and is referred to as user_priority.
![]() Note | The Cisco Nexus 2148 Fabric Extender does not support frames with the dot1p vlan 0 tag. |
If a system class is configured with a 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 a 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. A PFC pause will be applied to traffic that matches the new value.
Command or Action | Purpose | |||
---|---|---|---|---|
Step 1 |
switch#
configure terminal
|
Enters global configuration mode. | ||
Step 2 |
switch(config)#
class-map type qos
class-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-qos)#
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.
| ||
Step 4 |
switch(config-cmap-qos)#
no match cos
cos-value
| (Optional)
Removes the match from the traffic class. |
This example shows how to classify traffic by matching packets based on a defined CoS value:
switch# configure terminal switch(config)# class-map type qos match-any class_cos switch(config-cmap-qos)# match cos 4, 5-6
Use the show class-map command to display the CoS value class-map configuration:
switch# show class-map class_cos
Value |
List of DSCP Values |
---|---|
af11 |
AF11 dscp (001010)—decimal value 10 |
af12 |
AF12 dscp (001100)—decimal value 12 |
af13 |
AF13 dscp (001110)—decimal value 14 |
af21 |
AF21 dscp (010010)—decimal value 18 |
af22 |
AF22 dscp (010100)—decimal value 20 |
af23 |
AF23 dscp (010110)—decimal value 22 |
af31 |
AF31 dscp (011010)—decimal value 26 |
af32 |
AF32 dscp (011100)—decimal value 28 |
af33 |
AF33 dscp (011110)—decimal value 30 |
af41 |
AF41 dscp (100010)—decimal value 34 |
af42 |
AF42 dscp (100100)—decimal value 36 |
af43 |
AF43 dscp (100110)—decimal value 38 |
cs1 |
CS1 (precedence 1) dscp (001000)—decimal value 8 |
cs2 |
CS2 (precedence 2) dscp (010000)—decimal value 16 |
cs3 |
CS3 (precedence 3) dscp (011000)—decimal value 24 |
cs4 |
CS4 (precedence 4) dscp (100000)—decimal value 32 |
cs5 |
CS5 (precedence 5) dscp (101000)—decimal value 40 |
cs6 |
CS6 (precedence 6) dscp (110000)—decimal value 48 |
cs7 |
CS7 (precedence 7) dscp (111000)—decimal value 56 |
default |
Default dscp (000000)—decimal value 0 |
ef |
EF dscp (101110)—decimal value 46 |
Command or Action | Purpose | |
---|---|---|
Step 1 | switch# configure terminal |
Enters global configuration mode. |
Step 2 |
switch(config)#
class-map type qos
class-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-qos)#
match dscp
dscp-list
|
Configures the traffic class by matching packets based on the values in the dscp-list variable. For a list of DSCP values, see the Standard DSCP Values table. |
Step 4 |
switch(config-cmap-qos)#
no match dscp
dscp-list
| (Optional)
Removes the match from the traffic class. For a list of DSCP values, see the Standard DSCP Values table. |
This example shows how to classify traffic by matching packets based on the DSCP value in the DiffServ field of the IP header:
switch# configure terminal switch(config)# class-map type qos match-any class_dscp switch(config-cmap-qos)# match dscp af21, af32Use the show class-map command to display the DSCP class-map configuration:
switch# show class-map class_dscp
The IP Real-time Transport Protocol (RTP) is a transport protocol for real-time applications that transmits data such as audio or video and is defined by RFC 3550. Although RTP does not use a common TCP or UDP port, you typically configure RTP to use ports 16384 to 32767. UDP communications use an even port and the next higher odd port is used for RTP Control Protocol (RTCP) communications.
You can classify based on UDP port ranges, which are likely to target applications using RTP.
Command or Action | Purpose | |
---|---|---|
Step 1 |
switch#
configure terminal
|
Enters global configuration mode. |
Step 2 |
switch(config)#
class-map type qos
class-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-qos)#
match ip rtp
port-number
|
Configures the traffic class by matching packets based on a range of lower and upper UDP port numbers, which is likely to target applications using RTP. Values can range from 2000 to 65535. |
Step 4 |
switch(config-cmap-qos)#
no match ip rtp
port-number
| (Optional)
Removes the match from the traffic class. |
switch# configure terminal switch(config)# class-map type qos match-any class_rtp switch(config-cmap-qos)# match ip rtp 2000-2100, 4000-4100
Use the show class-map command to display the RTP class-map configuration:
switch# show class-map class_rtp
You can classify traffic based on the precedence value in the type of service (ToS) byte field of the IP header (either IPv4 or IPv6). The following table shows the precedence values:
Value |
List of Precedence Values |
---|---|
<0-7> |
IP precedence value |
critical |
Critical precedence (5) |
flash |
Flash precedence (3) |
flash-override |
Flash override precedence (4) |
immediate |
Immediate precedence (2) |
internet |
Internetwork control precedence (6) |
network |
Network control precedence (7) |
priority |
Priority precedence (1) |
routine |
Routine precedence (0) |
Command or Action | Purpose | |
---|---|---|
Step 1 | switch# configure terminal |
Enters global configuration mode. |
Step 2 | switch(config)# class-map type qos match-any class-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-qos)#match precedence precedence-values |
Configures the traffic class by matching packets based on precedence values. For a list of precedence values, see the Precedence Values table. |
Step 4 | switch((config-cmap-qos)# no match precedence precedence-values | (Optional)
Removes the match from the traffic class. For a list of precedence values, see the Precedence Values table. |
This example shows how to classify traffic by matching packets based on the precedence value in the ToS byte field of the IP header:
switch# configure terminal switch(config)# class-map type qos match-any class_precedence switch(config-cmap-qos)# match precedence 1-2, critical
Use the show class-map command to display the IP precedence value class-map configuration:
switch# show class-map class_precedence
You can classify traffic based on the IPv4 Protocol field or the IPv6 Next Header field in the IP header. The following table shows the protocol arguments:
Argument |
Description |
---|---|
arp |
Address Resolution Protocol (ARP) |
clns_es |
CLNS End Systems |
clns_is |
CLNS Intermediate System |
dhcp |
Dynamic Host Configuration (DHCP) |
ldp |
Label Distribution Protocol (LDP) |
netbios |
NetBIOS Extended User Interface (NetBEUI) |
Command or Action | Purpose | |
---|---|---|
Step 1 |
switch#
configure terminal
|
Enters configuration mode. |
Step 2 |
switch(config)#
class-map type qos
class-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-qos)#
match protocol {arp |
clns_es |
clns_is |
dhcp |
ldp |
netbios}
|
Configures the traffic class by matching packets based on the specified protocol. |
Step 4 |
switch(config-cmap-qos)#
no match protocol
{arp |
clns_es |
clns_is |
dhcp |
ldp |
netbios}
| (Optional)
Removes the match from the traffic class. |
This example shows how to classify traffic by matching packets based on the protocol field:
switch# configure terminal
switch(config)# class-map type qos class_protocol
switch(config-cmap-qos)# match protocol arp
Use the show class-map command to display the protocol class-map configuration:
switch# show class-map class_protocol
You can classify traffic based on the value of the QoS group internal label, that represents a system class. You can set the value of the QoS group within a policy map using the set qos-group command.
Command or Action | Purpose | |||
---|---|---|---|---|
Step 1 |
switch#
configure terminal
|
Enters configuration mode. | ||
Step 2 |
switch(config)#
class-map type {network-qos |
queuing}
class-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-que)#
match qos-group
qos-group-value
|
Configures the traffic class by matching packets based on a list of QoS group values. Values can range from 0 to 5. QoS group 0 is equivalent to class-default and QoS group 1 is equivalent to class-fcoe.
| ||
Step 4 |
switch(config-cmap-que)#
no match qos-group
qos-group-value
| (Optional)
Removes the match from the traffic class. |
This example shows how to classify traffic based on the value of the QoS group:
switch# configure terminal
switch(config)# class-map type queuing class_qos_group
switch(config-cmap-que)# match qos-group 4
Use the show class-map command to display the QoS group class-map configuration:
switch# show class-map class_qos_group
The policy-map command is used to create a named object that represents a set of policies that are to be applied to a set of traffic classes.
The device provides two default system classes: a no-drop class for lossless service (class-fcoe) and a drop class for best-effort service (class-default). You can define up to four additional system classes for Ethernet traffic.
The following predefined policy maps are used as default service policies:
network-qos: default-nq-policy
Input qos: default-in-policy
Input queuing: default-in-policy
Output queuing: default-out-policy
service-policy type qos input fcoe-default-in-policy
service-policy type queuing input fcoe-default-in-policy
service-policy type queuing output fcoe-default-out-policy
service-policy type network-qos fcoe-default-nq-policy
When class-fcoe is not included in the qos policies, vFC interfaces do not come up and increased drops occur.
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.
The device distributes all the policy-map configuration values to the attached network adapters.
Before creating the policy map, define a class map for each new system class.
Command or Action | Purpose | |||
---|---|---|---|---|
Step 1 |
switch#
configure
terminal
|
Enters global configuration mode. | ||
Step 2 |
switch(config)#
policy-map [type {network-qos |
qos |
queuing}]
policy-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. The three policy-map configuration modes are as follows: | ||
Step 3 |
switch(config)#
no
policy-map [type {network-qos |
qos |
queuing}]
policy-name
| (Optional)
Deletes the specified policy map. | ||
Step 4 |
switch(config-pmap)#
class
[type {network-qos |
qos |
queuing}]
class-name
|
Associates a class map with the policy map, and enters configuration mode for the specified system class. The three class-map configuration modes are as follows:
| ||
Step 5 |
switch(config-pmap)#
no
class [type {network-qos |
qos
|
queuing}]
class-name
| (Optional)
Deletes the class map association. |
Type qos policies are used for classifying the traffic of a specific system class identified by a unique qos-group value. A type qos policy can be attached to the system or to individual interfaces (including Fabric Extender host interfaces) for ingress traffic only.
You can set a maximum of five QoS groups for ingress traffic.
Command or Action | Purpose | |||
---|---|---|---|---|
Step 1 | switch# configure terminal |
Enters global configuration mode. | ||
Step 2 | switch(config)# policy-map type qos policy-name |
Creates a named object that represents 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-qos)# [class | class-default] type qos 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-qos)# set qos-group qos-group-value |
Configures one or more qos-group values to match on for classification of traffic into this class map. The list below identifies the ranges of the qos-group-value . There is no default value. |
This example shows how to define a type qos policy map:
switch# configure terminal switch(config)# policy-map type qos policy-s1 switch(config-pmap-qos)# class type qos class-s1 switch(config-pmap-c-qos)# set qos-group 2
Type network qos policies can only be configured on the system qos attachment point. They are applied to the entire switch for a particular class.
Command or Action | Purpose | |||||
---|---|---|---|---|---|---|
Step 1 | switch# configure terminal |
Enters global configuration mode. | ||||
Step 2 |
switch(config)#
policy-map
type network-qos
policy-name
|
Creates a named object that represents 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-nq)#
class type
network-qos
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-nq)#
mtu
mtu-value
|
Specifies the MTU value in bytes.
| ||||
Step 5 |
switch(config-pmap-c-nq)#
no mtu
| (Optional)
Resets the MTU value in this class. | ||||
Step 6 | switch(config-pmap-c-nq)#
pause no-drop
| Configures a no-drop class. | ||||
Step 7 |
switch(config-pmap-c-nq)#
multicast-optimize
|
Enables multicast optimization. Multicast traffic in this class will be served by all available multicast queues.
| ||||
Step 8 |
switch(config-pmap-c-nq)#
no
multicast-optimize
| (Optional)
Disables multicast optimization. | ||||
Step 9 |
switch(config-pmap-c)#
pause
no-drop [pfc-cos
pfc-cos-value]
|
Configures a no-drop class. If you do not specify this command, the default policy is drop.
The pfc-cos-value range is from 0 to 7. This option is supported only for for a ACL-based system class (which filters traffic using criteria other than cos-based matches).
| ||||
Step 10 |
switch(config-pmap-c-nq)#
no pause
no-drop
| (Optional)
Removes the no-drop option from this class. | ||||
Step 11 |
switch(config-pmap-c-nq)#
queue-limit
number-bytes
bytes
|
Specifies the tail drop threshold on this interface. The threshold range is from 20480 to 204800 bytes.
Use the pause no-drop buffer size option to change the buffer size and pause threshold for the no-drop class. | ||||
Step 12 |
switch(config-pmap-c-nq)#
no
queue-limit
number-bytes
bytes
| (Optional)
Disables the queue limit specification in this class. | ||||
Step 13 |
switch(config-pmap-c-nq)#
set
cos
cos-value
|
Specifies a 802.1Q CoS value which is used to mark packets on this interface. The value range is from 0 to 7. | ||||
Step 14 |
switch(config-pmap-c-nq)#
no set
cos
cos-value
| (Optional)
Disables the marking operation in this class. |
This example shows how to define a type network-qos policy map:
switch# configure terminal switch(config)# policy-map type network-qos policy-que1 switch(config-pmap-nq)# class type network-qos class-que1 switch(config-pmap-c-nq)# mtu 5000 switch(config-pmap-c-nq)# set cos 4
Type queuing policies are used for scheduling and buffering the traffic of a specific system class. A type queuing policy is identified by its QoS group and can be attached to the system or to individual interfaces (except for Fabric Extender host interfaces) for input or output traffic.
Command or Action | Purpose | |||
---|---|---|---|---|
Step 1 | switch# configure terminal |
Enters global configuration mode. | ||
Step 2 |
switch(config)#
policy-map
type queuing
policy-name
|
Creates a named object that represents 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-que)#
class type
queuing
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-que)#
priority
|
Specifies that traffic in this class is mapped to a strict priority queue.
| ||
Step 5 |
switch(config-pmap-c-que)#
no
priority
| (Optional)
Removes the strict priority queuing from the traffic in this class. | ||
Step 6 |
switch(config-pmap-c-que)#
bandwidth
percent
percentage
|
Specifies the guaranteed percentage of interface bandwidth allocated to this class. By default, no bandwidth is specified for a class.
| ||
Step 7 |
switch(config-pmap-c-que)#
no bandwidth
percent
percentage
| (Optional)
Removes the bandwidth specification from this class. |
Marking is a method that you use to modify the QoS fields of the incoming and outgoing packets.
You can use marking commands in traffic classes that are referenced in a policy map. The marking features that you can configure are listed below:
The value of the CoS field is recorded in the high-order three bits of the VLAN ID Tag field in the IEEE 802.1Q header.
Command or Action | Purpose | |||
---|---|---|---|---|
Step 1 | switch# configure terminal |
Enters global configuration mode. | ||
Step 2 |
switch(config) # policy-map [type network-qos] policy-map name
|
Creates or accesses the policy map named policy-map-name and enters policy-map mode. The policy-map name can contain alphabetic, hyphen, or underscore characters, is case sensitive, and can be up to 40 characters. | ||
Step 3 |
switch(config-pmap-nq) # class [type network-qos] {class-map name |class-default}
|
Creates a reference to the class-map-name and enters policy-map class configuration mode. Use the class-default keyword to select all traffic that is not currently matched by classes in the policy map. | ||
Step 4 |
switch(config-pmap-c-nq) # set cos cos-value
|
Specifies the CoS value to cos-value. The cos-value can range from 0 to 7.
|
For Cisco Nexus devices, you can set the DSCP value in the six most significant bits of the DiffServ field of the IP header to a specified value. You can enter numeric values from 0 to 63, in addition to the standard DSCP values shown in the table below:
![]() Note | You can set DSCP or IP Precedence but you can not set both values because they modify the same field in the IP packet. |
Value |
List of DSCP Values |
---|---|
af11 |
AF11 dscp (001010)—decimal value 10 |
af12 |
AF12 dscp (001100)—decimal value 12 |
af13 |
AF13 dscp (001110)—decimal value 14 |
af21 |
AF21 dscp (010010)—decimal value 18 |
af22 |
AF22 dscp (010100)—decimal value 20 |
af23 |
AF23 dscp (010110)—decimal value 22 |
af31 |
AF31 dscp (011010)—decimal value 26 |
af32 |
AF40 dscp (011100)—decimal value 28 |
af33 |
AF33 dscp (011110)—decimal value 30 |
af41 |
AF41 dscp (100010)—decimal value 34 |
af42 |
AF42 dscp (100100)—decimal value 36 |
af43 |
AF43 dscp (100110)—decimal value 38 |
cs1 |
CS1 (precedence 1) dscp (001000)—decimal value 8 |
cs2 |
CS2 (precedence 2) dscp (010000)—decimal value 16 |
cs3 |
CS3 (precedence 3) dscp (011000)—decimal value 24 |
cs4 |
CS4 (precedence 4) dscp (100000)—decimal value 32 |
cs5 |
CS5 (precedence 5) dscp (101000)—decimal value 40 |
cs6 |
CS6 (precedence 6) dscp (110000)—decimal value 48 |
cs7 |
CS7 (precedence 7) dscp (111000)—decimal value 56 |
default |
Default dscp (000000)—decimal value 0 |
ef |
EF dscp (101110)—decimal value 46 |
Command or Action | Purpose | |
---|---|---|
Step 1 | config t
|
Enters configuration mode. |
Step 2 |
policy-map
type
qos
qos-policy-map-name
|
Creates or accesses the policy map named policy-map-name, and then enters policy-map mode. The policy-map name can contain alphabetic, hyphen, or underscore characters, is case sensitive, and can be up to 40 characters. |
Step 3 |
class [type qos] {class-map-name |
class-default}
|
Creates a reference to class-map-name, and enters policy-map class configuration mode. Use the class-default keyword to select all traffic that is not currently matched by classes in the policy map. |
Step 4 |
set dscp
dscp-value
|
Sets the DSCP value to dscp-value. See the Standards DSCP Values table. |
Step 5 |
set qos-group
y
|
Specifies the qos-group. The group value can be from 1 to 5. |
This example shows how to set the DSCP value to 10 and specify the qos-group to 2.
policy-map type qos test-bulkdata class type qos bulkdata set dscp 10 set qos-group 2
You can set the value of the IP precedence field in bits 0 to 2 of the IPv4 type of service (ToS) field or the equivalent Traffic Class field for IPv6 of the IP header. The following table shows the precedence values:
![]() Note | You can set IP Precedence or DSCP but you can not set both values because they modify the same field in the IP packet. |
Value |
List of Precedence Values |
---|---|
<0-7> |
IP precedence value |
critical |
Critical precedence (5) |
flash |
Flash precedence (3) |
flash-override |
Flash override precedence (4) |
immediate |
Immediate precedence (2) |
internet |
Internetwork control precedence (6) |
network |
Network control precedence (7) |
priority |
Priority precedence (1) |
routine |
Routine precedence (0) |
Command or Action | Purpose | |
---|---|---|
Step 1 | config t |
Enters configuration mode. |
Step 2 |
policy-map [type qos] qos-policy-map-name |
Creates or accesses the policy map named policy-map-name, and then enters policy-map mode. The policy-map name can contain alphabetic, hyphen, or underscore characters, is case sensitive, and can be up to 40 characters. |
Step 3 |
class [type qos] {class-map-name | class-default}
|
Creates a reference to class-map-name, and enters policy-map class configuration mode. Use the class-default keyword to select all traffic that is not currently matched by classes in the policy map. |
Step 4 |
set precedence precedence-value
|
Sets the IP precedence value to precedence-value. You can enter one of the values shown in the Precedence Values table. |
switch(config)# policy-map type qos my_policy switch(config-pmap-qos)# class type qos my_class switch(config-pmap-c-qos)# set precedence 5 switch(config-pmap-c-qos)#
QoS Configurations for Layer 3 Routing
In Layer 3 topologies, you must configure each QoS group in the network-qos policy with a unique cos value.
Command or Action | Purpose | |||
---|---|---|---|---|
Step 1 | switch# show policy-map system |
Displays the already configured policy maps and CoS values. In Layer 3 topologies, each qosgroup must have a unique CoS value. Use the show policy-map system command to view CoS values that have been used and that are unavailable for QoS groups. | ||
Step 2 | switch# configure terminal |
Enters global configuration mode. | ||
Step 3 | switch(config) # policy-map [type network-qos] policy-map name |
Creates or accesses the policy map named policy-map-name and enters policy-map mode. The policy-map name can contain alphabetic, hyphen, or underscore characters, is case sensitive, and can be up to 40 characters. | ||
Step 4 | switch(config-pmap-nq) # class [type network-qos] {class-map name |class-default} |
Creates a reference to the class-map-name and enters policy-map class configuration mode. Use the class-default keyword to select all traffic that is not currently matched by classes in the policy map. | ||
Step 5 | switch(config-pmap-nq-c) # set cos cos-value |
Specifies the CoS value. The value can range from 0 to 7.
|
This example shows how to set the CoS value to 4 in a Layer 3 topology:
switch# show policy-map system Type network-qos policy-maps =============================== policy-map type network-qos pn-01 class type network-qos cn-01 match qos-group 1 mtu 8500 pause no-drop set cos 2 class type network-qos cn-02 match qos-group 2 set cos 4 mtu 9216 class type network-qos cn-03 match qos-group 3 mtu 8000 set cos 6 class type network-qos cn-04 match qos-group 4 mtu 8750 set cos 7 class type network-qos cn-ip-multicast match qos-group 5 set cos 5 mtu 7500 class type network-qos class-default match qos-group 0 mtu 1500 set cos 1 ... switch# configure terminal switch(config)# policy-map type network-qos pn-01 switch(config-pmap-nq)# class type network-qos cn-05 switch(config-pmap-c-nq)# set cos 3
Beginning with NX-OS Release 5.0(3)N1(1), on Cisco Nexus 5000 Platform switches, you can map CoS values to an egress queue. You can have a maximum of 4 multicast queues for Layer 3 multicast traffic.
You can use this procedure to distribute traffic into different queues, where each queue is configured with different weighted round robin (WRR) parameters.
Command or Action | Purpose | |
---|---|---|
Step 1 |
switch#
configure
terminal
|
Enters global configuration mode. |
Step 2 |
switch(config)#
wrr-queue
cos-map
queue-id
cos1 ...cos8
|
Maps the assigned CoS values to an egress queue. The egress queue range is from 1 to 4, where 4 can be configured as the expedite queue. You can enter up to eight CoS values. Separate each value with a space. The range is from 0 to 7. |
This example shows how to configure a Layer 3 interface:
switch# configure terminal switch(config)# wrr-queue cos-map 1 0 1 switch(config)#
You can configure a service policy for a Layer 3 interface.
Command or Action | Purpose | |||
---|---|---|---|---|
Step 1 | switch# configure terminal |
Enters global configuration mode. | ||
Step 2 |
switch(config)#
interface
ethernet
slot/port
|
Enters the configuration mode for the specified interface. | ||
Step 3 |
switch(config-if)#
no
switchport
|
Selects the Layer 3 interface. | ||
Step 4 |
switch(config-if)#
service-policy [type {qos |
queuing} [input |
output]policy-name
|
Specifies the policy map to use as the service policy for the Layer 3 interface. There are two policy-map configuration modes:
|
The following example shows how to attach a queuing policy map to a Layer 3 interface:
switch# configure terminal switch(config)# interface ethernet 1/5 switch(config-if)# no switchport switch(config-if)# service-policy type queuing output my_output_q_policy switch(config-if)#
The following example shows how to attach an input qos policy map to a Layer 3 interface:
switch# configure terminal switch(config)# interface ethernet 1/5 switch(config-if)# no switchport switch(config-if)# service-policy type qos input my_input_qos_policy switch(config-if)#
The service-policy command specifies the system class policy map as the service policy for the system.
Command or Action | Purpose | |||
---|---|---|---|---|
Step 1 | switch# configure terminal |
Enters global configuration mode. | ||
Step 2 |
switch(config)#
system
qos
|
Enters system class configuration mode. | ||
Step 3 |
switch(config-sys-qos)#
service-policy
type
{network-qos |
qos |
queuing} [input |
output]
policy-name
|
Specifies the policy map to use as the service policy for the system. There are three policy-map configuration modes:
| ||
Step 4 |
switch(config-sys-qos)#
service-policy
type
{network-qos |
qos |
queuing} [input |
output]
fcoe default
policy-name
| (Optional)
Specifies the default FCoE policy map to use as the service policy for the system. There are four pre-defined policy-maps for FCoE:
|
This example shows how to set a no-drop Ethernet policy map as the system class:
switch(config)# class-map type network-qos ethCoS4 switch(config-cmap-nq)# match qos-group switch(config-cmap-nq)# exit switch(config)# policy-map type network-qos ethNoDrop switch(config-pmap-nq)# class type network-qos ethCoS4 switch(config-pmap-c-nq)# pause no-drop switch(config-pmap-c-nq)# exit switch(config-pmap-nq)# exit switch(config)# system qos switch(config-sys-qos)# service-policy type network-qos ethNoDrop
If you have created and attached new policies to the system QoS configuration, enter the no form of the command to reapply the default policies.
Command or Action | Purpose | |
---|---|---|
Step 1 | switch# configure terminal |
Enters global configuration mode. |
Step 2 |
switch(config)#
system
qos
|
Enters system class configuration mode. |
Step 3 |
switch(config-sys-qos)#
no
service-policy type qos input
policy-map
name
|
Resets the classification mode policy map. This policy-map configuration is for system QoS input or interface input only: |
Step 4 |
switch(config-sys-qos)#
no
service-policy type network-qos
policy-map
name
|
Resets the network-wide policy map. |
Step 5 |
switch(config-sys-qos)#
no
service-policy type queuing output
policy-map
name
|
Resets the output queuing mode policy map. |
Step 6 |
switch(config-sys-qos)#
no
service-policy type queuing input
policy-map
name
|
Resets the input queuing mode policy map. |
The following example shows how to reset the system QoS configuration:
switch# configure terminal switch(config)# system qos switch(config-sys-qos)# no service-policy type qos input my-in-policy switch(config-sys-qos)# no service-policy type network-qos my-nq-policy switch(config-sys-qos)# no service-policy type queuing output my-out-policy switch(config-sys-qos)# no service-policy type queuing input my-in-policy
At the system level, you can enable or disable tail drop for Fabric Extenders for egress direction (from the network to the host).
By default, the tail drop threshold applies to each Fabric Extender port to limit the amount of buffer allocated to each port. To restore the default queue limit, use the fex queue-limit command. To disable the tail drop threshold and to allow Fabric Extender ports to use all available buffer space, use the no form of this command.
![]() Note | You can also set the queue limit for a specified Fabric Extender by using the hardware fex-card-type queue-limit command. Configuring specific Fabric Extenders overrides the queue limit configuration set at the global system level for that Fabric Extender. |
Command or Action | Purpose | |
---|---|---|
Step 1 | switch# configure terminal |
Enters global configuration mode. |
Step 2 |
switch(config)#
system qos
|
Enters system class configuration mode. |
Step 3 |
switch(config-sys-qos)#
fex queue-limit
|
Limits the amount of input buffer space allocated to each Fabric Extender port. |
Step 4 |
switch(config-sys-qos)#
no fex queue-limit
|
Allows a Fabric Extender port to use all available buffer space. |
This example shows how to set the queue limit for the input buffer for each Fabric Extender port:
switch# configure terminal switch(config)# system qos switch(config-sys-qos)# fex queue-limit
This example shows how to remove the queue limit that is enabled by default:
switch# configure terminal switch(config)# system qos switch(config-sys-qos)# no fex queue-limit
You can enable the jumbo Maximum Transmission Unit (MTU) for the whole switch by setting the MTU to its maximum size (9216 bytes) in the policy map for the default Ethernet system class (class-default).
When you configure jumbo MTU on a port-channel subinterface you must first enable MTU 9216 on the base interface and then configure it again on the subinterface. If you enable the jumbo MTU on the subinterface before you enable it on the base interface then the following error will be displayed on the console:
switch(config)# int po 502.4 switch(config-subif)# mtu 9216 ERROR: Incompatible MTU values
For Layer 3 routing on Cisco Nexus devices, you need to configure the MTU on the Layer 3 interfaces (SVIs and physical interfaces with IP addresses) in addition to the global QoS configuration below.
To use FCoE on switch, add class-fcoe in the custom network-qos policy. If already using FCoE, make sure to add the below lines in the config so that the FCoE does not go down on the switch after enabling the jumbo qos policy.
switch# conf t switch(config)# policy-map type network-qos jumbo switch(config-pmap-nq)# class type network-qos class-fcoe switch(config-pmap-nq-c)# end
This example shows how to change qos to enable the jumbo MTU:
switch# conf t switch(config)# policy-map type network-qos jumbo switch(config-pmap-nq)# class type network-qos class-default switch(config-pmap-c-nq)# mtu 9216
![]() Note | The system jumbomtu command defines the maximum MTU size for the switch. However, jumbo MTU is supported only for system classes that have MTU configured. |
On the Cisco Nexus device, traffic is classified into one of eight QoS groups. The MTU is configured at the QoS group level. By default, all Ethernet traffic is in QoS group 0. To verify the jumbo MTU for Ethernet traffic, use the show queueing interface ethernet slot/chassis_number command and find "HW MTU" in the command output to check the MTU for QoS group 0. The value should be 9216.
The show interface command always displays 1500 as the MTU. Because the Cisco Nexus device supports different MTUs for different QoS groups, it is not possible to represent the MTU as one value on a per interface level.
![]() Note |
|
switch# show queuing interface ethernet1/19 Ethernet1/19 queuing information: TX Queuing qos-group sched-type oper-bandwidth 0 WRR 50 1 WRR 50 RX Queuing qos-group 0 q-size: 243200, HW MTU: 9280 (9216 configured) drop-type: drop, xon: 0, xoff: 1520 Statistics: Pkts received over the port : 2119963420 Ucast pkts sent to the cross-bar : 2115648336 Mcast pkts sent to the cross-bar : 4315084 Ucast pkts received from the cross-bar : 2592447431 Pkts sent to the port : 2672878113 Pkts discarded on ingress : 0 Per-priority-pause status : Rx (Inactive), Tx (Inactive) qos-group 1 q-size: 76800, HW MTU: 2240 (2158 configured) drop-type: no-drop, xon: 128, xoff: 240 Statistics: Pkts received over the port : 0 Ucast pkts sent to the cross-bar : 0 Mcast pkts sent to the cross-bar : 0 Ucast pkts received from the cross-bar : 0 Pkts sent to the port : 0 Pkts discarded on ingress : 0 Per-priority-pause status : Rx (Inactive), Tx (Inactive) Total Multicast crossbar statistics: Mcast pkts received from the cross-bar : 80430744
Configuring QoS on Interfaces
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 or EtherChannel interface.
You can configure flow control on a Layer 2 or Layer 3 interface. Use the no switchport command to configure a Layer 3 interface
On a Cisco Nexus device, you can configure a type qos policy map and untagged CoS on the same interface.
Command or Action | Purpose | |
---|---|---|
Step 1 | switch# configure terminal |
Enters global configuration mode. |
Step 2 |
switch(config)#
interface {ethernet [chassis/]slot/port |
port-channel
channel-number}
|
Enters the configuration mode for the specified interface or port channel. |
Step 3 |
switch(config-if)#
no switchport
| (Optional)
Selects a Layer 3 interface. |
Step 4 |
switch(config-if)#
untagged cos
cos-value
|
Configures the untagged CoS value. Values can be from 1 to 7. |
The following example shows how to set the CoS value to 4 for untagged frames received on an interface:
switch# configure terminal switch(config)# interface ethernet 1/2 switch(config-if)# untagged cos 4
The following example shows how to set the CoS value to 3 for untagged frames received on a Layer 3 interface:
switch# configure terminal switch(config)# interface ethernet 1/5 switch(config-if) no switchport switch(config-if)# untagged cos 3 switch(config-if)#
An input qos policy is a service policy applied to incoming traffic on an Ethernet interface for classification. For type queuing, the output policy is applied to all outgoing traffic that matches the specified class. When you configure an input queuing policy on an interface or EtherChannel, the switch sends the configuration data to the adapter using the DCBX protocol.
![]() Note | Type qos policies can be activated only on Cisco Nexus device interfaces and Cisco Nexus Fabric Extender interfaces. Type qos policies on Fabric Extender fabric interfaces or Fabric Extender fabric EtherChannel interfaces are ineffective, though the Cisco NX-OS CLI does not reject the configuration. We recommend that you do not configure type qos policy-maps on Fabric Extender fabric interfaces or Fabric Extender fabric EtherChannel interfaces to avoid wasting hardware resources. |
Command or Action | Purpose | |||
---|---|---|---|---|
Step 1 |
switch#
configure
terminal
|
Enters global configuration mode. | ||
Step 2 |
switch(config)#
interface {ethernet [chassis/]slot/port |
port-channel
channel-number}
|
Enters the configuration mode for the specified interface.
| ||
Step 3 |
switch(config-if)#
service-policy [type {qos |
queuing}] [input |
output]policy-name
|
Specifies the policy map to use as the service policy for the system. There are two policy-map configuration modes:
| ||
Step 4 |
switch(config-if)#
service-policy input
policy-name
|
Applies the policy map to the interface.
|
This example shows how to apply a policy to an Ethernet interface:
switch# configure terminal
switch(config)# interface ethernet 1/1
switch(config-if)# service-policy type qos input policy1
At the Fabric Extender configuration level, you can control the queue limit for a specified Fabric Extender for egress direction (from the network to the host). You can use a lower queue limit value on the Fabric Extender to prevent one blocked receiver from affecting traffic that is sent to other noncongested receivers ("head-of-line blocking"). A higher queue limit provides better burst absorption and less head-of-line blocking protection. You can use the no form of this command to allow the Fabric Extender to use all available hardware space.
![]() Note | At the system level, you can set the queue limit for Fabric Extenders by using the fex queue-limit command. However, configuring the queue limit for a specific Fabric Extender will override the queue limit configuration set at the system level for that Fabric Extender. |
You can specify the queue limit for the following Fabric Extenders:
Cisco Nexus 2148T Fabric Extender (48x1G 4x10G SFP+ Module)
Cisco Nexus 2224TP Fabric Extender (24x1G 2x10G SFP+ Module)
Cisco Nexus 2232P Fabric Extender (32x10G SFP+ 8x10G SFP+ Module)
Cisco Nexus 2248T Fabric Extender (48x1G 4x10G SFP+ Module)
Cisco Nexus N2248TP-E Fabric Extender (48x1G 4x10G Module)
Cisco Nexus N2348UPQ Fabric Extender (48x10G SFP+ 6x40G QSFP Module)
Command or Action | Purpose | |
---|---|---|
Step 1 | switch# configure terminal |
Enters global configuration mode. |
Step 2 |
switch(config)#
fex
fex-id
|
Specifies the Fabric Extender and enters the Fabric Extender mode. |
Step 3 |
switch(config-fex)#
hardware
fex_card_type
queue-limit
queue-limit
|
Configures the queue limit for the specified Fabric Extender. The queue limit is specified in bytes. The range is from 81920 to 652800 for a Cisco Nexus 2148T Fabric Extender and from 2560 to 652800 for all other supported Fabric Extenders. |
This example shows how to restore the default queue limit on a Cisco Nexus 2248T Fabric Extender:
switch# configure terminal switch(config-if)# fex 101 switch(config-fex)# hardware N2248T queue-limit 327680
This example shows how to remove the queue limit that is set by default on a Cisco Nexus 2248T Fabric Extender:
switch# configure terminal switch(config)# fex 101 switch(config-fex)# no hardware N2248T queue-limit 327680
You can configure the no-drop buffer threshold settings for 3000m lossless Ethernet.
![]() Note | To achieve lossless Ethernet for both directions, the devices connected to the Cisco Nexus device must have the similar capability. The default buffer and threshold value for the no-drop can ensure lossless Ethernet for up to 300 meters. |
Command or Action | Purpose | |||||||
---|---|---|---|---|---|---|---|---|
Step 1 | switch# configure terminal |
Enters global configuration mode. | ||||||
Step 2 |
switch(config)#
policy-map type network-qos policy-map name
|
Enters policy-map network-qos class mode and identifies the policy map assigned to the type network-qos policy map. | ||||||
Step 3 |
switch(config-pmap-nq)# class type network-qos class-map name
|
References an existing network QoS class map in a policy map and enters class mode. | ||||||
Step 4 |
switch(config-pmap-nq-c)#
pause no-drop buffer-size
buffer-size pause-threshold xoff-size resume-threshold xon-size
|
Specifies the buffer threshold settings for pause and resume for 3000m lossless Ethernet:
| ||||||
Step 5 |
switch(config-pmap-nq-c)#
no pause no-drop buffer-size
buffer-size pause-threshold xoff-size resume-threshold xon-size
| (Optional)
Removes the buffer threshold settings for pause and resume for 3000m lossless Ethernet. | ||||||
Step 6 |
switch(config-pmap-nq-c)#
exit
|
Exits class mode. | ||||||
Step 7 |
switch(config-pmap-nq)#
exit
|
Exits policy-map network-qos mode. |
This example shows how to configure the no-drop buffer threshold for the Cisco Nexus device for 3000 meters.
switch(config-pmap-nq)# policy-map type network-qos nqos_policy switch(config-pmap-nq)# class type network-qos nqos_class switch(config-pmap-nq-c)# pause no-drop buffer-size 152000 pause-threshold 103360 resume-threshold 83520 switch(config-pmap-nq-c)# exit switch(config-pmap-nq)# exit switch(config)# exit switch#
In the Fabric Extender configuration mode, you can configure the buffer threshold for the Cisco Nexus 2148T Fabric Extender. The buffer threshold sets the consumption level of input buffers before an indication is sent to the egress queue to start observing the tail drop threshold. If the buffer usage is lower than the configured buffer threshold, the tail drop threshold is ignored.
Command or Action | Purpose | |
---|---|---|
Step 1 | switch# configure terminal |
Enters global configuration mode. |
Step 2 |
switch(config)#
fex
fex-id
|
Specifies the Fabric Extender and enters the Fabric Extender mode. |
Step 3 |
switch(config-fex)#
hardware N2148T buffer-threshold
buffer limit
|
Configures the buffer threshold for the Cisco Nexus 2148T Fabric Extender. The buffer threshold is specified in bytes. The range is from 81920 to 316160 for the Cisco Nexus 2148T Fabric Extender. |
This example shows how to restore the default buffer threshold on the Cisco Nexus 2148T Fabric Extender:
switch# configure terminal switch(config)# fex 101 switch(config-fex)# hardware N2148T buffer-threshold 163840
This example shows how to remove the default buffer threshold on the Cisco Nexus 2148T Fabric Extender:
switch# configure terminal switch(config)# fex 101 switch(config-fex)# no hardware N2148T buffer-threshold
Cisco Nexus 5000 Series switches support priority flow control (PFC) and Link-Level Flow Control (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).
If the interface is operating in a standard Ethernet mode, the Ethernet link is connected at the server port with a standard Ethernet network adapter (NIC). The network adapter must support the Data Center Bridging Exchange protocol (DCBX) for PFC or ingress policing to be supported on the interface.
![]() Note | You must configure a system class with the pause no-drop parameter for PFC to operate on Ethernet traffic (PFC will be applied to traffic that matches the CoS value configured for this class). |
By default, Ethernet interfaces negotiate PFC with the network adapter using the DCBX protocol. When PFC is enabled, PFC is applied to traffic that matches the CoS value configured for the no-drop class.
You can override the negotiation result by forcing the interface to enable PFC.
Beginning in Cisco NX-OS Release 5.0(3)N1(1), you can configure priority flow control on a Layer 2 or Layer 3 interface.
![]() Note | Use the no switchport command to configure an interface as a Layer 3 interface |
Command or Action | Purpose | |
---|---|---|
Step 1 | switch# configure terminal |
Enters global configuration mode. |
Step 2 |
switch(config)#
interface
type
slot/port
|
Specifies the interface to be changed. |
Step 3 |
switch(config-if)#
no switchport
| (Optional)
Selects a Layer 3 interface. |
Step 4 |
switch(config-if)#
priority-flow-control
mode {auto | on}
|
Sets PFC mode for the selected interface. Specifies auto to negotiate PFC capability. This is the default. Specifies on to force-enable PFC. |
Step 5 |
switch(config-if)#
no priority-flow-control
mode on
| (Optional)
Disables the PFC setting for the selected interface. |
This 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
This example shows how to force-enable PFC on a Layer 3 interface:
switch# configure terminal switch(config)# interface ethernet 1/5 switch(config-if)# no switchport switch(config-if)# priority-flow-control mode on
By default, LLC on Ethernet interfaces is disabled. You can enable LLC for the transmit and receive directions.
You can configure flow control on a Layer 2 or Layer 3 interface.
![]() Note | Use the no switchport command to configure an interface as a Layer 3 interface. |
Command or Action | Purpose | |
---|---|---|
Step 1 | switch# configure terminal |
Enters global configuration mode. |
Step 2 |
switch(config)#
interface
type
slot/port
|
Specifies the interface to be changed. |
Step 3 |
switch(config-if)#
no switchport
| (Optional)
Selects a Layer 3 interface. |
Step 4 |
switch(config-if)# flowcontrol
[receive
{on | off}] [send {on | off}]
|
Enables LLC for the selected interface. Set receive and/or send on or off. |
Step 5 |
switch(config-if)# no flowcontrol
[receive
{on | off}] [send {on | off}]
| (Optional)
Disables LLC for the selected interface. |
This example shows how to enable LLC on an interface:
switch# configure terminal Enter configuration commands, one per line. End with CNTL/Z. switch(config)# interface e1/48 switch(config-if)# flowcontrol receive on switch(config-if)# flowcontrol send on
This example shows how to enable LLC on a Layer 3 interface:
switch# configure terminal Enter configuration commands, one per line. End with CNTL/Z. switch(config)# interface e1/48 switch(config-if)# no switchport switch(config-if)# flowcontrol receive on switch(config-if)# flowcontrol send on
You can disable slow port pruning on multicast packets.
An interface on the Cisco Nexus 5500 Series device can become congested when it receives excessive multicast traffic or when the mixed unicast and multicast traffic rate exceeds the port bandwidth. When multiple interfaces receive the same multicast flow and one or more ports experience congestion, the slow port prunning feature allows the switch to drop only the multicast packets for the congested port. This feature is turned on by default. To turn the slow port pruning feature off, enter the hardware multicast disable-slow-port-pruning command.
Command or Action | Purpose | |
---|---|---|
Step 1 | switch# configure terminal |
Enters configuration mode. |
Step 2 | switch(config)# hardware multicast disable-slow-port-pruning |
Disables slow port pruning on multicast packets. The default is enabled. |
Step 3 | switch(config)# no hardware multicast disable-slow-port-pruning |
Enables the slow port pruning feature. |
switch(config)# hardware multicast disable-slow-port-pruning switch(config)#
You can enable the Virtual Output Queuing (VOQ) limit for unicast traffic. To alleviate congestion and blocking, use VOQ to prevent one blocked receiver from affecting traffic that is sent to other noncongested blocking receivers.
Command or Action | Purpose |
---|
switch(config)# hardware unicast voq-limit switch(config)#
To verify QoS configuration information, perform one of these tasks:
Command |
Purpose |
---|---|
switch# show class-map |
Displays the class maps defined on the switch. |
switch# show policy-map [name] |
Displays the policy maps defined on the switch. Optionally, you can display the named policy only. |
switch# show policy-map interface [interface number] |
Displays the policy map settings for an interface or all interfaces. |
switch# show policy-map system |
Displays the policy map settings attached to the system qos. |
switch# show policy-map type {network-qos | qos | queuing} [name] | Displays the policy map settings for a specific policy type. Optionally, you can display the named policy only. |
switch# show queuing interface [interface slot/port] |
Displays the queue configuration and statistics. |
switch# show interface flowcontrol [ module number] | Displays the detailed listing of the flow control settings on all interfaces. |
switch# show interface [interface slot/port] priority-flow-control [ module number] | Displays the priority flowcontrol details for a specified interface. |
switch# show interface untagged-cos [ module number] | Displays the untagged CoS values for all interfaces. |
switch# show wrr-queue cos-map [var] | Displays the mapped CoS values to egress queues. |
switch# running-config ipqos | Displays information about the running configuration for QoS. |
switch# startup-config ipqos | Displays information about the startup configuration for QoS. |
This example shows how to display all type queuing class maps:
switch# show class-map type queuing Type queuing class-maps ======================= class-map type queuing class-fcoe match qos-group 1 class-map type queuing class-default match qos-group 0 class-map type queuing class-all-flood match qos-group 2 class-map type queuing class-ip-multicast match qos-group 2 switch#
This example shows how to display the flow control settings on Layer 3 interfaces where Ethernet 1/5 is configured as a routed interface:
switch# show interface flowcontrol Port Send FlowControl Receive FlowControl RxPause TxPause admin oper admin oper -------------------------------------------------------------------------------- Eth1/1 off off off off 0 0 Eth1/2 off off off off 0 0 Eth1/3 off off off off 0 0 Eth1/4 off off off off 0 0 Eth1/5 off off on on 0 0 Eth1/6 off off off off 0 0 Eth1/7 off off off off 0 0 Eth1/8 off off off off 0 0 Eth1/9 off off off off 0 0 Eth1/10 off off off off 0 0 Eth1/11 off off off off 0 0 Eth1/12 off off off off 0 0 Eth1/13 off off off off 0 0 Eth1/14 off off off off 0 0 <--Output truncated--> switch# --------------------------------------------------------------------------------
This example shows how to display the priority flow control information for a specified Layer 3 interface:
switch# show interface ethernet 1/5 priority-flow-control ============================================================ Port Mode Oper(VL bmap) RxPPP TxPPP ============================================================ Ethernet1/5 On On (0) 0 0 switch#
This example shows how to display the untagged CoS values for all interfaces (Layer 2, Layer 3):
switch# show interface untagged-cos S3(config-if)# show int untagged-cos ================================= Interface Untagged-CoS ================================= port-channel100 port-channel127 port-channel128 Ethernet1/1 Ethernet1/2 Ethernet1/3 Ethernet1/4 Ethernet1/5 3 Ethernet1/6 Ethernet1/7 Ethernet1/8 Ethernet1/9 Ethernet1/10 Ethernet1/11 Ethernet1/12 : <--snip--> Ethernet3/31 Ethernet3/32 Ethernet100/1/1 Ethernet100/1/2 <--Output truncated--> switch#
This example shows how to display QoS information:
switch# show running-config ipqos !Command: show running-config ipqos !Time: Sun Apr 20 07:22:36 2008 version 5.0(3)N1(1) class-map type qos class-fcoe class-map type qos match-all c1 match cos 3-5 class-map type queuing class-fcoe match qos-group 1 class-map type queuing class-all-flood match qos-group 2 class-map type queuing class-ip-multicast match qos-group 2 policy-map type qos p1 class c1 set qos-group 3 class-map type network-qos n1 match qos-group 1 class-map type network-qos class-fcoe match qos-group 1 class-map type network-qos class-all-flood match qos-group 2 class-map type network-qos class-ip-multicast match qos-group 2 policy-map type network-qos n2 class type network-qos n1 class type network-qos class-default multicast-optimize interface Ethernet1/5 priority-flow-control mode on untagged cos 3 switch# The above display shows the QoS information for Layer 3 interfaces (Ethernet 1/5 configured as a Layer 3 interface).
This example shows how to display the CoS values that are mapped to the egress queue:
switch# show wrr-queue cos-map MCAST Queue ID Cos Map 0 0 1 1 2 2 3 4 5 3 6 7 switch#
This example shows how to display the class maps defined on the switch:
switch# show class-map Type qos class-maps =================== class-map type qos c1 match cos 0,7 class-map type qos c2 match protocol ldp match ip rtp 2000-65535 match dscp 10,12 match precedence 6-7 match protocol dhcp match protocol arp class-map type qos c3 match cos 2,4-6 class-map type qos c4 match access-group name ipv4 class-map type qos class-fcoe match cos 3 class-map type qos class-default match any class-map type qos class-ip-multicast match ip multicast Type queuing class-maps ======================= class-map type queuing c1 match qos-group 2 class-map type queuing c2 match qos-group 3 class-map type queuing c3 match qos-group 4 class-map type queuing class-fcoe match qos-group 1 class-map type queuing class-default
match qos-group 0
Type network-qos class-maps
==============================
class-map type network-qos c1
match qos-group 2
class-map type network-qos c2
match qos-group 3
class-map type network-qos c3
match qos-group 4
class-map type network-qos c4
match qos-group 5
class-map type network-qos class-fcoe
match qos-group 1
class-map type network-qos class-default
match qos-group 0
This example shows how to display the policy maps defined on the switch:
switch# show policy-map
Type qos policy-maps
====================
policy-map type qos p1
class type qos c1
set qos-group 2
class type qos c3
set qos-group 4
class type qos c4
set qos-group 5
class type qos c2
set qos-group 3
class type qos c22
set qos-group 3
class type qos class-fcoe
set qos-group 1
class type qos class-default
set qos-group 0
Type queuing policy-maps
========================
policy-map type queuing p1
class type queuing c2
bandwidth percent 10
class type queuing c4
bandwidth percent 25
class type queuing c1
bandwidth percent 20
class type queuing c3
bandwidth percent 5
class type queuing class-fcoe
bandwidth percent 30
class type queuing class-default
bandwidth percent 10
Type network-qos policy-maps
===============================
policy-map type network-qos p1
class type network-qos c1
mtu 5000
class type network-qos c2
mtu 9216
queue-limit 30000 bytes
class type network-qos c3
mtu 8000
class type network-qos c4
pause no-drop
class type network-qos class-fcoe
pause no-drop
mtu 2240
class type network-qos class-default
mtu 1538
This example shows how to display the policy maps attached on the system qos:
switch# show policy-map system
Type network-qos policy-maps
===============================
policy-map type network-qos p1
class type network-qos c1 match qos-group 2
mtu 5000
class type network-qos c2 match qos-group 3
mtu 9216
queue-limit 30000 bytes
class type network-qos c3 match qos-group 4
mtu 8000
class type network-qos c4 match qos-group 5
pause no-drop
class type network-qos class-fcoe match qos-group 1
pause no-drop
mtu 2240
class type network-qos class-default match qos-group 0
mtu 1538
Service-policy (queuing) input: p1
policy statistics status: disabled
Class-map (queuing): c2 (match-any)
Match: qos-group 3
bandwidth percent 10
Class-map (queuing): c4 (match-any)
Match: qos-group 5
bandwidth percent 25
Class-map (queuing): c1 (match-any)
Match: qos-group 2
bandwidth percent 20
Class-map (queuing): c3 (match-any)
Match: qos-group 4
bandwidth percent 5
Class-map (queuing): class-fcoe (match-any)
Match: qos-group 1
bandwidth percent 30
Class-map (queuing): class-default (match-any)
Match: qos-group 0
bandwidth percent 10
Service-policy (queuing) output: default-out-policy
policy statistics status: disabled
Class-map (queuing): class-fcoe (match-any)
Match: qos-group 1
bandwidth percent 50
Class-map (queuing): class-default (match-any)
Match: qos-group 0
bandwidth percent 50
This example shows how to display the policy maps attached to an interface:
switch# show policy-map interface ethernet 1/1
Global statistics status : disabled
Ethernet1/1
Service-policy (qos) input: p2
policy statistics status: disabled
Class-map (qos): c1 (match-any)
Match: cos 0,7
set qos-group 2
Class-map (qos): c2 (match-any)
Match: protocol ldp
Match: ip rtp 2000-65535
Match: dscp 10,12
Match: precedence 6-7
Match: protocol dhcp
Match: protocol arp
set qos-group 3
Class-map (qos): c3 (match-any)
Match: cos 2,4-6
set qos-group 4
Class-map (qos): class-ip-multicast (match-any)
Match: ip multicast
set qos-group 5
Class-map (qos): class-fcoe (match-any)
Match: cos 3
set qos-group 1
Class-map (qos): class-default (match-any)
Match: any
set qos-group 0
Service-policy (queuing) input: p1
policy statistics status: disabled
Class-map (queuing): c2 (match-any)
Match: qos-group 3
bandwidth percent 10
Class-map (queuing): c4 (match-any)
Match: qos-group 5
bandwidth percent 25
Class-map (queuing): c1 (match-any)
Match: qos-group 2
bandwidth percent 20
Class-map (queuing): c3 (match-any)
Match: qos-group 4
bandwidth percent 5
Class-map (queuing): class-fcoe (match-any)
Match: qos-group 1
bandwidth percent 30
Class-map (queuing): class-default (match-any)
Match: qos-group 0
bandwidth percent 10
Service-policy (queuing) output: p2
policy statistics status: disabled
Class-map (queuing): c1 (match-any)
Match: qos-group 2
bandwidth percent 5
priority
Class-map (queuing): c2 (match-any)
Match: qos-group 3
bandwidth percent 20
Class-map (queuing): c3 (match-any)
Match: qos-group 4
bandwidth percent 20
Class-map (queuing): c4 (match-any)
Match: qos-group 5
bandwidth percent 40
Class-map (queuing): class-fcoe (match-any)
Match: qos-group 1
bandwidth percent 10
Class-map (queuing): class-default (match-any)
Match: qos-group 0
bandwidth percent 5
This example shows how to display the queue configuration and counter information:
switch# show interface ethernet101/1/1
Ethernet101/1/1 is up Hardware: 100/1000 Ethernet, address: e8b7.4855.6e02 (bia e8b7.4855.6e02) MTU 1500 bytes, BW 1000000 Kbit, DLY 10 usec reliability 255/255, txload 1/255, rxload 1/255 Encapsulation ARPA Port mode is trunk full-duplex, 1000 Mb/s Beacon is turned off Input flow-control is off, output flow-control is on Switchport monitor is off EtherType is 0x8100 Last link flapped 23:45:12 Last clearing of "show interface" counters never 30 seconds input rate 0 bits/sec, 0 packets/sec 30 seconds output rate 144 bits/sec, 0 packets/sec Load-Interval #2: 5 minute (300 seconds) input rate 0 bps, 0 pps; output rate 112 bps, 0 pps RX 0 unicast packets 0 multicast packets 0 broadcast packets 0 input packets 0 bytes 0 jumbo packets 0 storm suppression bytes 0 runts 0 giants 0 CRC 0 no buffer 0 input error 0 short frame 0 overrun 0 underrun 0 ignored 0 watchdog 0 bad etype drop 0 bad proto drop 0 if down drop 0 input with dribble 0 input discard 0 Rx pause TX 0 unicast packets 9452 multicast packets 0 broadcast packets 9452 output packets 1591946 bytes 0 jumbo packets 0 output errors 0 collision 0 deferred 0 late collision 0 lost carrier 0 no carrier 0 babble 0 output discard 0 Tx pause 1 interface resets
This example shows how to display the queue configuration and statistics:
switch# show queuing interface ethernet101/1/1
Ethernet101/1/1 queuing information: Input buffer allocation: Qos-group: 0 2 3 4 5 (shared) frh: 2 drop-type: no-drop cos: 0 1 2 3 4 5 6 xon xoff buffer-size ---------+---------+----------- 81920 114688 286720 Queueing: queue qos-group cos priority bandwidth mtu --------+------------+--------------+---------+---------+---- 2 0 0 2 3 WRR 73 2048 4 2 1 WRR 1 5120 5 3 6 WRR 6 8192 6 4 4 WRR 20 6144 7 5 5 PRI 0 9728 Queue Limit Tx: 30015488 bytes Queue Limit Rx: 30007296 bytes Queue Statistics: ---+----------------+-----------+------------+----------+-----------+ Que|Received / |Tail Drop |No Buffer |MAC Error |Multicast | No |Transmitted | | | |Tail Drop | ---+----------------+-----------+------------+----------+-----------+ 2rx| 0| 0| 0| - | 2tx| 0| 0| 0| 0| 0| ---+----------------+-----------+------------+----------+-----------+ 4rx| 0| 0| 0| - | 4tx| 0| 0| 0| 0| 0| ---+----------------+-----------+------------+----------+-----------+ 5rx| 0| 0| 0| - | 5tx| 0| 0| 0| 0| 0| ---+----------------+-----------+------------+----------+-----------+ 6rx| 0| 0| 0| - | 6tx| 0| 0| 0| 0| 0| ---+----------------+-----------+------------+----------+-----------+ 7rx| 0| 0| 0| - | 7tx| 0| 0| 0| 0| 0| ---+----------------+-----------+------------+----------+-----------+ Priority-flow-control enabled: no Flow-control status: cos qos-group rx pause tx pause masked rx pause -------+-----------+---------+---------+--------------- 0 0 xon xon xon 1 2 xon xon xon 2 0 xon xon xon 3 0 xon xon xon 4 4 xon xon xon 5 5 xon xon xon 6 3 xon xon xon 7 n/a xon xon xon
Example QoS Configurations
This example shows how to configure traffic in the entire system matching an access control list to have the frame CoS fields rewritten to the value 5.
Command or Action | Purpose | |
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Step 1 | Set up the ingress classification policy (the access control list was defined previously). |
(config)# class-map type qos cmap-qos-acl (config-cmap-qos)# match access-group ACL-CoS (config-cmap-qos)# exit (config)# policy-map type qos pmap-qos-acl (config-pmap-qos)# class cmap-qos-acl (config-pmap-c-qos)# set qos-group 4 (config-pmap-c-qos)# exit (config-pmap-qos)# exit |
Step 2 | Attach the classification policy to the system. | (config)# system qos (config-sys-qos)# service-policy type qos input pmap-qos-acl (config-sys-qos)# exit |
Step 3 | Set up the system class allocation and rewrite policy. Allocate the system class for qos-group 4 and define the rewrite action. | (config)# class-map type network-qos cmap-nq-acl (config-cmap-nq)# match qos-group 4 (config-cmap-nq)# exit (config)# policy-map type network-qos pmap-nq-acl (config-pmap-nq)# class type network-qos cmap-nq-acl (config-pmap-c-nq)# set cos 5 (config-pmap-c-nq)# exit (config-pmap-nq)# exit |
Step 4 | Attach the allocation and rewrite policy to the system. | (config)# system qos (config-sys-qos)# service-policy type network-qos pmap-nq-acl (config-sys-qos)# exit |
This example shows how to use an access control list to apply 50% bandwidth to traffic on Ethernet interface 1/3 that matches traffic on Ethernet interface 1/1.
Command or Action | Purpose | |||
---|---|---|---|---|
Step 1 | Set up the ingress classification policy. |
(config)# class-map type qos cmap-qos-bandwidth (config-cmap-qos)# match access-group ACL-bandwidth (config-cmap-qos)# exit (config)# policy-map type qos pmap-qos-eth1-1 (config-pmap-qos)# class cmap-qos-bandwidth (config-pmap-c-qos)# set qos-group 2 (config-pmap-c-qos)# exit (config-pmap-qos)# exit | ||
Step 2 | Attach the classification policy to the interface Ethernet 1/1. | (config)# interface ethernet 1/1 (config-if)# service-policy type qos input pmap-qos-eth1-1 (config-if)# exit | ||
Step 3 | Set up the system-wide definition of the qos-group first. | (config)# class-map type queuing cmap-que-bandwidth (config-cmap-que)# match qos-group 2 (config-cmap-que)# exit | ||
Step 4 | Set up the egress bandwidth policy. |
(config)# policy-map type queuing pmap-que-eth1-2 (config-pmap-que)# class type queuing class-default (config-pmap-c-que)# bandwidth percent 10 (config-pmap-c-que)# exit (config-pmap-que)# class type queuing class-fcoe (config-pmap-c-que)# bandwidth percent 40 (config-pmap-c-que)# exit (config-pmap-que)# class type queuing cmap-que-bandwidth (config-pmap-c-que)# bandwidth percent 50 (config-pmap-c-que)# exit (config-pmap-que)# exit | ||
Step 5 | Attach the bandwidth policy to the egress interface. | (config)# interface ethernet 1/3 (config-if)# service-policy type queuing output pmap-que-eth1-2 (config-if)# exit | ||
Step 6 | Allocate the system class for qos-group 2. | (config)# class-map type network-qos cmap-nq-bandwidth (config-cmap-nq)# match qos-group 2 (config-cmap-nq)# exit | ||
Step 7 | Set up the network-qos policy. | (config)# policy-map type network-qos pmap-nq-bandwidth (config-pmap-nq)# class type network-qos cmap-nq-bandwidth (config-pmap-c-nq)# exit (config-pmap-nq)# exit | ||
Step 8 | Attach the network-qos policy to the system. | (config)# system qos (config-sys-qos)# service-policy type network-qos pmap-nq-bandwidth (config-sys-qos)# exit |
This example shows how to attach a 802.1p tag with a CoS value of 3 to incoming untagged packets, and force priority-flow-control negotiation on Ethernet interface 1/15.
Command or Action | Purpose |
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