Queue management policies
This chapter is only applicable to the 7210 SAS-Mxp, 7210 SAS-R6, and 7210 SAS-R12.
This chapter provides information to configure queue management policies using the command line interface.
Overview
The 7210 SAS-R6 and 7210 SAS-R12 equipped with an IMM-c card do not use the configured CBS and MBS parameter values in the queue management policy. The CBS and MBS values are system-defined for each queue. That is, CBS and MBS parameters are not user-configurable. In this section, references to modifying the CBS and MBS values in the queue management policies applies only to the 7210 SAS-R6 and 7210 SAS-R12 equipped with an IMM-b card.
A set of profiles or templates are available in hardware for configuring the queue parameters such as CBS, MBS, and WRED slopes. These profiles are available for use with multiple queues in the system. Queue management policies allow the user to define the queue parameters and allow sharing among the queues.
A single system buffer pool is available for use by all the queues in the system. Users can allocate the amount of buffers that each queue can use by specifying the CBS and MBS parameters in the queue management policy.
Weighted Random Early Detection (WRED) is available to manage buffers during periods of congestion. WRED slopes are supported for each queue in the system. Queue management policies allow the user to configure slope parameters that dictate a WRED profile for each queue. Each queue supports the following slopes:
slope for in-profile or high priority traffic
slope for out-of-profile or low priority traffic
Each slope allows specifying the start-average, the max-average, the drop-probability and the Time Average Factor (TAF). Each queue has a default slope policy. Multiple queues in the system can share a single policy. If a policy is shared the system computes the WRED drop probabilities for each of the queues separately based on their average queue length.
Basic configurations
A basic queue management policy must conform to the following restrictions:
Each slope policy must have a unique policy ID.
High slope and low slope are shut down by default.
Default values can be modified but parameters cannot be deleted.
Service management tasks
Creating a queue management policy
To create a new queue management policy, define the following:
a queue management policy name
a brief description of the policy features
CBS and MBS values
high slope for the high priority WRED slope graph
low slope for the low priority WRED slope graph
time average factor (TAF)
slope parameters, such as max-avg, start-avg, max-prob, time-average-factor
Use the following CLI syntax to configure a queue management policy.
config>qos
queue-mgmt name
description description-string
cbs kbytes
mbs kbytes
high-slope
start-avg percent
max-avg percent
max-prob percent
no shutdown
low-slope
start-avg percent
max-avg percent
max-prob percent
no shutdown
time-average-factor taf
The following is a sample queue management policy configuration output:
A:7210>config>qos>queue-mgmt# info
----------------------------------------------
high-slope
shutdown
start-avg 40
max-avg 50
exit
low-slope
shutdown
start-avg 40
max-avg 80
exit
cbs 5000
mbs 800000
time-average-factor 7
----------------------------------------------
Editing QoS policies
Existing policies and entries can be edited through the CLI or NMS. The changes are applied immediately to all services where the policy is applicable.
To prevent configuration errors, perform the following:
- Copy the policy to a work area.
- Edit the policy.
- Overwrite the original policy.
Queue management policy command reference
Command hierarchies
Configuration commands for 7210 SAS-Mxp, 7210 SAS-R6, and 7210 SAS-R12
config
- qos
- queue-mgmt name [create]
- no queue-mgmt name
- description description-string
- no description
- cbs size-in-kbytes
- no cbs
- mbs size-in-kbytes
- no mbs
- [no] high-slope
- max-avg percent
- no max-avg
- max-prob percent
- no max-prob
- [no] shutdown
- start-avg percent
- no start-avg
- [no] low-slope
- max-avg percent
- no max-avg
- max-prob percent
- no max-prob
- [no] shutdown
- start-avg percent
- no start-avg
- time-average-factor value
- no time-average-factor
- scope {exclusive | template}
- no scope
Operational commands
config
- qos
- copy queue-mgmt src-name dst-name [overwrite]
Show commands
show
- qos
- queue-mgmt [name] [detail]
Command descriptions
Configuration commands
Generic commands
description
Syntax
description description-string
no description
Context
config>qos>queue-mgmt
Platforms
7210 SAS-Mxp, 7210 SAS-R6, and 7210 SAS-R12
Description
This command creates a text description stored in the configuration file for a configuration context.
The description command associates a text string with a configuration context to help identify the context in the configuration file.
The no form of this command removes any description string from the context.
Parameters
- description-string
Specifies a text string describing the entity. Allowed values are any string up to 80 characters composed of printable, 7-bit ASCII characters. If the string contains special characters (#, $, spaces, and so on), the entire string must be enclosed within double quotes.
Queue management policy QoS commands
cbs
Syntax
cbs size-in-kbytes
no cbs
Context
config>qos>queue-mgmt
Platforms
7210 SAS-Mxp, 7210 SAS-R6, and 7210 SAS-R12
Description
This command specifies the CBS value. The CBS is the minimum depth of the queue.
The 7210 SAS-R6 and 7210 SAS-R12 equipped with an IMM-c card ignore the CBS parameters configured in the queue management policy. The CBS value is system-defined for each queue and is not user-configurable.
The no form of this command reverts to the default value.
Parameters
- size-in-kbytes
Specifies the minimum depth of the queue, in kilobytes.
high-slope
Syntax
[no] high-slope
Context
config>qos>queue-mgmt
Platforms
7210 SAS-Mxp, 7210 SAS-R6, and 7210 SAS-R12
Description
This command configures the in-profile WRED slope parameters.
The no form of this command reverts the high-slope configuration commands to the default values.
low-slope
Syntax
[no] low-slope
Context
config>qos>queue-mgmt
Platforms
7210 SAS-Mxp, 7210 SAS-R6, and 7210 SAS-R12
Description
This command configures the out-of-profile WRED slope parameters.
The no form of this command reverts the low-slope configuration commands to the default values.
mbs
Syntax
mbs size-in-kbytes
no mbs
Context
config>qos>queue-mgmt
Platforms
7210 SAS-Mxp, 7210 SAS-R6, and 7210 SAS-R12
Description
This command specifies the MBS value. The MBS is the maximum depth of the queue.
The 7210 SAS-R6 and 7210 SAS-R12 equipped with an IMM-c card ignore the MBS parameters configured in the queue management policy. The MBS value is system-defined for each queue and is not user-configurable.
The no form of this command reverts to the default value.
Parameters
- size-in-kbytes
Specifies the maximum depth of the queue, in kilobytes.
queue-mgmt
Syntax
queue-mgmt name [create]
no queue-mgmt name
Context
config>qos
Platforms
7210 SAS-Mxp, 7210 SAS-R6, and 7210 SAS-R12
Description
This command configures a QoS queue management policy. A set of profiles and templates are available in hardware for configuring the queue parameters such as CBS, MBS, and WRED slopes parameters per queue. These profiles are available for use with multiple queues in the system. Queue management policy allows the user to define the queue parameters and allow for sharing among the queues.
The no form of this command reverts to the default value.
Parameters
- name
Specifies the name of the queue management policy. Valid names consist of any string up to 32 characters composed of printable, 7-bit ASCII characters. If the string contains special characters (#, $, spaces, and so on), the entire string must be enclosed within double quotes.
- create
Keyword used to create a QoS queue management policy.
time-average-factor
Syntax
time-average-factor value
no time-average-factor
Context
config>qos>queue-mgmt
Platforms
7210 SAS-Mxp, 7210 SAS-R6, and 7210 SAS-R12
Description
This command configures the time-average factor (TAF).
The value specified for the TAF affects the speed at which the shared buffer average utilization tracks the instantaneous shared buffer utilization. A low value weights the new shared buffer average utilization calculation more to the shared buffer instantaneous utilization, where a value of zero means the shared buffer instantaneous utilization is used exclusively. A high value weights the new shared buffer average utilization calculation more to the previous shared buffer average utilization value.
The no form of the command reverts to the default value.
Default
7
Parameters
- value
Specifies the TAF, expressed as a decimal integer.
scope
Syntax
scope {exclusive | template}
no scope
Context
config>qos>queue-mgmt
Platforms
7210 SAS-Mxp, 7210 SAS-R6, and 7210 SAS-R12
Description
This command configures the scope as exclusive or template. The policy’s scope cannot be changed if the policy is applied to an interface multiple ports.
The no form of this command reverts the scope of the policy to the default.
Default
template
Parameters
- exclusive
Specifies that the policy can only be applied to one interface. If a policy with an exclusive scope is assigned to a second interface an error message is generated. If the policy is removed from the exclusive interface, it will become available for assignment to another exclusive interface.
- template
Specifies that the policy can be applied to multiple interface ports on the router. Default QoS policies are configured with template scope. An error is generated if you try to modify the scope parameter from template to exclusive scope on default policies.
WRED slope commands
max-avg
Syntax
max-avg percent
no max-avg
Context
config>qos>queue-mgmt>high-slope
config>qos>queue-mgmt>low-slope
Platforms
7210 SAS-Mxp, 7210 SAS-R6, and 7210 SAS-R12
Description
This command configures the maximum average value.
The no form of this command reverts to the default value.
Default
max-avg 90 — high slope default is 90% buffer utilization
max-avg 75 — low slope default is 75% buffer utilization
Parameters
- percent
Specifies the maximum average for the high or low slopes.
max-prob
Syntax
max-prob percent
no max-prob
Context
config>qos>queue-mgmt>high-slope
config>qos>queue-mgmt>low-slope
Platforms
7210 SAS-Mxp, 7210 SAS-R6, and 7210 SAS-R12
Description
This command configures the maximum probability value.
The no form of this command reverts to the default value.
Default
max-avg 75 — high slope default is 75% maximum drop probability corresponding to max-avg
max-avg 75 — low slope default is 75% maximum drop probability corresponding to max-avg
Parameters
- percent
Specifies the maximum probability for the high or low slopes.
shutdown
Syntax
[no] shutdown
Context
config>qos>queue-mgmt>high-slope
config>qos>queue-mgmt>low-slope
Platforms
7210 SAS-Mxp, 7210 SAS-R6, and 7210 SAS-R12
Description
This command enables or disables the administrative status of the WRED slope.
By default, all slopes are shutdown and have to be explicitly enabled (no shutdown), which implies a zero drop probability.
The no form of this command administratively enables the WRED slope.
Default
shutdown
start-avg
Syntax
start-avg percent
no start-avg
Context
config>qos>queue-mgmt>high-slope
config>qos>queue-mgmt>low-slope
Platforms
7210 SAS-Mxp, 7210 SAS-R6, and 7210 SAS-R12
Description
This command is used to configure the starting average value.
The no form of this command reverts to the default value.
Default
max-avg 70 — high slope default is 70% buffer utilization
max-avg 50 — low slope default is 50% buffer utilization
Parameters
- percent
Specifies the starting average for the high or low slopes.
Operational commands
copy
Syntax
copy queue-mgmt src-name dst-name [overwrite]
Context
config>qos
Platforms
7210 SAS-Mxp, 7210 SAS-R6, and 7210 SAS-R12
Description
This command copies the existing queue management policy entries to another queue management policy.
The copy command is a configuration level maintenance tool used to create new policies using existing policies. It also allows bulk modifications to an existing policy with the use of the overwrite keyword.
Parameters
- src-name
Specifies the name of the source policy, up to 32 characters.
- dst-name
Specifies the name of the destination policy, up to 32 characters.
- overwrite
Keyword to overwrite the information in the destination policy by the information in the source policy.
Show commands
queue-mgmt
Syntax
queue-mgmt [name] [detail]
Context
show>qos
Platforms
7210 SAS-Mxp, 7210 SAS-R6, and 7210 SAS-R12
Description
This command displays queue management policy information.
Parameters
- name
Specifies the name of the queue management policy.
- detail
Displays detailed information about the queue management policy.
Output
The following output is an example of queue management policy information, and Output fields: queue management policy describes the output fields.
Sample output for 7210 SAS-R6 IMM-b, 7210 SAS-R12 IMM-b, and 7210 SAS-Mxp*A:Dut-A>config# /show qos queue-mgmt 100 detail
===============================================================================
QoS Queue Management Policy
===============================================================================
Policy : 100
Description : (Not Specified)
CBS : 100 MBS : 200
Time Avg : 7
High Slope Parameters
-------------------------------------------------------------------------------
Start Avg : 70 Admin State : Enabled
Max Avg : 90 Max Prob. : 75
Low Slope Parameters
-------------------------------------------------------------------------------
Start Avg : 50 Admin State : Enabled
Max Avg : 75 Max Prob. : 75
Associations
SAP Egress
-------------------------------------------------------------------------------
No SAP Egress Associations found.
-------------------------------------------------------------------------------
Network Queues
-------------------------------------------------------------------------------
No Network Queue Policy Associations found.
-------------------------------------------------------------------------------
Access Egress
-------------------------------------------------------------------------------
Access Egress Policy Id : 199
Queue Ids : 1, 2, 3, 4, 5, 6, 7, 8
-------------------------------------------------------------------------------
Access-Port Associations
-------------------------------------------------------------------------------
Port-id : 1/1/6
-------------------------------------------------------------------------------
Access Egress Queue Override
-------------------------------------------------------------------------------
No Access Egress queue override Associations found.
-------------------------------------------------------------------------------
===============================================================================
*A:Dut-A>config# /show qos queue-mgmt 200 detail
===============================================================================
QoS Queue Management Policy
===============================================================================
Policy : 200
Description : (Not Specified)
CBS : 125 MBS : 500
Time Avg : 7
High Slope Parameters
-------------------------------------------------------------------------------
Start Avg : 70 Admin State : Enabled
Max Avg : 90 Max Prob. : 75
Low Slope Parameters
-------------------------------------------------------------------------------
Start Avg : 50 Admin State : Disabled
Max Avg : 75 Max Prob. : 75
Associations
SAP Egress
-------------------------------------------------------------------------------
No SAP Egress Associations found.
-------------------------------------------------------------------------------
Network Queues
-------------------------------------------------------------------------------
Network Queue Policy Name : 200
Queue Ids : 1, 2, 3, 4, 5, 6, 7, 8
-------------------------------------------------------------------------------
Network-Port Associations
-------------------------------------------------------------------------------
Port-id : 1/1/26
-------------------------------------------------------------------------------
Access Egress
-------------------------------------------------------------------------------
No Access Egress Associations found.
-------------------------------------------------------------------------------
Access Egress Queue Override
-------------------------------------------------------------------------------
Port-id : 1/1/6 Queue Ids : 1
-------------------------------------------------------------------------------
===============================================================================
| Label | Description |
|---|---|
Policy |
Displays the ID that uniquely identifies the policy |
Description |
Displays a string that identifies the policy’s context in the configuration file |
Time Avg |
Displays the weighting between the previous shared buffer average utilization result and the new shared buffer utilization |
CBS |
Displays the committed burst size |
MBS |
Displays the maximum burst size |
Slope Parameters |
|
Start Avg |
Displays, in percentage, the low priority or high priority RED slope position for the shared buffer average utilization value where the packet discard probability starts to increase above zero |
Max Avg |
Displays the percentage of the shared buffer space for the buffer pool at which point the drop probability becomes 1, expressed as a decimal integer |
Admin State |
Up — The administrative status of the RED slope is enabled Down — The administrative status of the RED slope is disabled |
Max Prob. |
Specifies the high priority RED slope position for the maximum non-one packet discard probability value before the packet discard probability rises directly to one |
Service Associations |
|
SAP Egress Policy Id |
Displays the SAP egress policy ID |
Queue Ids |
Displays the queue IDs |
Access Egress Associations |
|
Access Egress Policy Id |
Displays the access-egress policy ID |
Queue Ids |
Displays the queue IDs |
Access-Port Associations |
|
Port-id |
Displays the port ID |