Slope QoS policies
This chapter provides information to configure slope QoS policies using the command line interface.
This chapter is applicable to the 7210 SAS-Sx/S 1/10GE (standalone and standalone-VC mode), 7210 SAS-Sx 10/100GE (standalone mode), and 7210 SAS-T (network mode and access-uplink mode).
See Queue management policies for more information about configuring slope policies on the 7210 SAS-Mxp, 7210 SAS-R6, and 7210 SAS-R12.
Overview
Slope policies define WRED parameters used to manage congestion at queuing points in the network.
Configuration guidelines
This section provides configuration guidelines for slope QoS policies.
WRED support on 7210 SAS-T access-uplink and network mode, 7210 SAS-Sx/S 1/10GE, and 7210 SAS-Sx 10/100GE
Two WRED slopes are supported per queue, one each for in-profile or high-priority traffic and out-of-profile or low-priority traffic.
The hardware supports a limited amount of profiles, out of which some are reserved for system internal use and the rest is available for user configuration. It is not possible to allocate a unique profile for each and every queue available on platform. Multiple queues will need to share the same WRED profile. Software manages the allocation of hardware WRED profiles based on user configuration. It automatically allocates a single WRED hardware profile if multiple queues use the same slope parameters (that is, max-average, start-average, drop probability and time average factor). Only if these parameters differ, it allocates a different hardware WRED profile for use by the queue. A WRED profile (that is, each high-slope and low-slope) allows the user to specify the slope parameters, such as maximum average, start average, drop probability, and time average factor (TAF).
Though the WRED profile is shared among queues, the WRED state (for example, average queue size) is maintained independently for each queue in the hardware.
Basic configurations
A basic slope QoS policy must conform to the following:
Each slope policy must have a unique policy ID.
High slope, low slope and non-TCP slope are shut down (default).
Default values can be modified but parameters cannot be deleted.
Create a slope QoS policy
Configuring and applying slope policies is optional. If no slope policy is explicitly applied to a port, a default slope policy is applied.
To create a new slope policy, define the following:
a slope policy ID value
The system will not dynamically assign a value.
include a description
The description provides a brief overview of policy features.
The high slope for the high priority Random Early Detection (RED) slope graph.
The low slope for the low priority Random Early Detection (RED) slope graph.
The time average factor (TAF), a weighting exponent used to determine the portion of the shared buffer instantaneous utilization and shared buffer average utilization used to calculate the new shared buffer average utilization.
Use the following CLI syntax to configure a slope policy for 7210 SAS-T, 7210 SAS-Sx/S 1/10GE and 7210 SAS-Sx 10/100GE:
config>qos
slope-policy name
description description-string
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 displays the slope policy configuration for 7210 SAS-T, 7210 SAS-Sx/S 1/10GE and 7210 SAS-Sx 10/100GE:
*A:hw_sass_duth>config>qos>slope-policy# info detail
----------------------------------------------
no description
queue "1"
high-slope
shutdown
start-avg 70
max-avg 90
max-prob 75
exit
low-slope
shutdown
start-avg 50
max-avg 75
max-prob 75
exit
time-average-factor 7
exit
#
Applying slope policies
Apply slope policies to the egress buffer pool on the access and network ports.
Ports
The following CLI syntax examples may be used to apply slope policies to ports:
config>port>access>egress>pool>slope-policy name
config>port>network>egress>pool>slope-policy name
Default slope policy values
The default access egress and network egress policies are identified as policy-id ‟default”. The default policies cannot be edited or deleted. The following example displays default policy parameters.
A:ALA>config>qos# slope-policy default
A:ALA>config>qos>slope-policy# info detail
----------------------------------------------
description "Default slope policy."
queue "1"
high-slope
shutdown
start-avg 70
max-avg 90
max-prob 75
exit
low-slope
shutdown
start-avg 50
max-avg 75
max-prob 75
exit
time-average-factor 7
exit
queue "2"
high-slope
shutdown
start-avg 70
max-avg 90
max-prob 75
exit
low-slope
shutdown
start-avg 50
max-avg 75
max-prob 75
exit
time-average-factor 7
exit
queue "3"
high-slope
shutdown
start-avg 70
max-avg 90
max-prob 75
exit
low-slope
shutdown
start-avg 50
max-avg 75
max-prob 75
exit
time-average-factor 7
exit
queue "4"
high-slope
shutdown
start-avg 70
max-avg 90
max-prob 75
exit
low-slope
shutdown
start-avg 50
max-avg 75
max-prob 75
exit
time-average-factor 7
exit
queue "5"
high-slope
shutdown
start-avg 70
max-avg 90
max-prob 75
exit
low-slope
shutdown
start-avg 50
max-avg 75
max-prob 75
exit
time-average-factor 7
exit
queue "6"
high-slope
shutdown
start-avg 70
max-avg 90
max-prob 75
exit
low-slope
shutdown
start-avg 50
max-avg 75
max-prob 75
exit
time-average-factor 7
exit
queue "7"
high-slope
shutdown
start-avg 70
max-avg 90
max-prob 75
exit
low-slope
shutdown
start-avg 50
max-avg 75
max-prob 75
exit
time-average-factor 7
exit
queue "8"
high-slope
shutdown
start-avg 70
max-avg 90
max-prob 75
exit
low-slope
shutdown
start-avg 50
max-avg 75
max-prob 75
exit
time-average-factor 7
exit
----------------------------------------------
A:ALA>config>qos>slope-policy#
Service management tasks
Deleting QoS policies
A slope policy is associated by default with access and network egress pools. A default policy may be replaced with a non-default policy, but a policy cannot be entirely removed from the configuration. When a non-default policy is removed, the policy association reverts to the default slope policy policy-id default. A QoS policy cannot be deleted until it is removed from all ports where it is applied or if the policies are using the slope-policy.
ALA-7>config>qos# no slope-policy slopePolicy1
MINOR: QOS #1902 Slope policy has references
ALA-7>config>qos#
Ports
The following CLI syntax examples can be used to remove slope policies from ports:
config>port>access>egress>pool# no slope-policy name
config>port>network>egress>pool# no slope-policy name
Remove a policy from the QoS configuration
To delete a slope policy, enter the following command:
config>qos# no slope-policy policy-id
config>qos# no slope-policy slopePolicy1
Copying and overwriting QoS policies
You can copy an existing slope policy, rename it with a new policy ID value, or overwrite an existing policy ID. The overwrite option must be specified or an error occurs if the destination policy ID exists.
config>qos> copy {slope-policy} source-policy-id dest-policy-id [overwrite]
The following output displays the copied policies.
A:ALA-7210M>config>qos#
----------------------------------------------
...
description "Default slope policy."
queue "1"
high-slope
shutdown
start-avg 70
max-avg 90
max-prob 75
exit
low-slope
shutdown
start-avg 50
max-avg 75
max-prob 75
exit
time-average-factor 7
exit
queue "2"
high-slope
shutdown
start-avg 70
max-avg 90
max-prob 75
exit
low-slope
shutdown
start-avg 50
max-avg 75
max-prob 75
exit
time-average-factor 7
exit
queue "3"
high-slope
shutdown
start-avg 70
max-avg 90
max-prob 75
exit
low-slope
shutdown
start-avg 50
max-avg 75
max-prob 75
exit
time-average-factor 7
exit
queue "4"
high-slope
shutdown
start-avg 70
max-avg 90
max-prob 75
exit
low-slope
shutdown
start-avg 50
max-avg 75
max-prob 75
exit
time-average-factor 7
exit
queue "5"
high-slope
shutdown
start-avg 70
max-avg 90
max-prob 75
exit
low-slope
shutdown
start-avg 50
max-avg 75
max-prob 75
exit
time-average-factor 7
exit
...
----------------------------------------------
A:ALA-7210M>config>qos#
Editing QoS policies
You can change existing policies and entries in the CLI or NMS. The changes are applied immediately to all services where this policy is applied. To prevent configuration errors, copy the policy to a work area, make the edits, and then write over the original policy.
Slope QoS policy command reference
Command hierarchies
Configuration commands
config
- qos
- [no] slope-policy name
- description description-string
- no description
- queue queue-id
- [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
Operational commands
config
- qos
- copy slope-policy src-name dst-name [overwrite]
Show commands
show
- qos
- slope-policy [slope-policy-name] [detail]
Command descriptions
Configuration commands
Generic commands
description
Syntax
description description-string
no description
Context
config>qos>slope-policy
Platforms
7210 SAS-T (in access-uplink mode and Network), 7210 SAS-Sx 1/10GE: standalone and standalone-VC, and 7210 SAS-Sx 10/100GE
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.
Slope policy QoS commands
slope-policy
Syntax
[no] slope-policy name
Context
config>qos
Platforms
7210 SAS-T (in access-uplink mode and Network), 7210 SAS-Sx 1/10GE: standalone and standalone-VC, and 7210 SAS-Sx 10/100GE
Description
This command configures a QoS slope policy.
Default
slope-policy ‟default”
Parameters
- name
Specifies the name of the slope 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.
Slope policy QoS policy commands
queue
Syntax
queue queue-id
Context
config>qos>slope-policy
Platforms
7210 SAS-T (in access-uplink mode and Network), 7210 SAS-Sx 1/10GE: standalone and standalone-VC, and 7210 SAS-Sx 10/100GE
Description
Commands in this context configure the high-priority, low-priority, and non-tcp slope parameters per queue.
Parameters
- queue-id
Specifies the ID of the queue for which the drop-rate is to be configured.
high-slope
Syntax
[no] high-slope
Context
config>qos>slope-policy>queue
Platforms
7210 SAS-T (in access-uplink mode and Network), 7210 SAS-Sx 1/10GE: standalone and standalone-VC, and 7210 SAS-Sx 10/100GE
Description
This command defines the high priority Random Early Detection (RED) slope graph. Each buffer pool supports a high priority RED slope for managing access to the shared portion of the buffer pool for high priority or in-profile packets.
The high-slope parameters can be changed at any time and the affected buffer pool high priority RED slopes will be adjusted appropriately.
The no form of this command reverts the high slope configuration commands to the default values. If the commands within high-slope are set to the default parameters, the high-slope node will not appear in save config and show config output unless the detail parameter is present.
low-slope
Syntax
[no] low-slope
Context
config>qos>slope-policy
config>qos>slope-policy>queue
Platforms
7210 SAS-T (in access-uplink mode and Network), 7210 SAS-Sx 1/10GE: standalone and standalone-VC, and 7210 SAS-Sx 10/100GE
Description
This command defines the low priority Random Early Detection (RED) slope graph. Each buffer pool supports a low priority RED slope for managing access to the shared portion of the buffer pool for low priority or out-of-profile packets.
The low-slope parameters can be changed at any time and the affected buffer pool low priority RED slopes must be adjusted appropriately.
The no form of this command reverts the low slope configuration commands to the default values. If the leaf commands within low-slope are set to the default parameters, the low-slope node will not appear in save config and show config output unless the detail parameter is present.
time-average-factor
Syntax
time-average-factor value
no time-average-factor
Context
config>qos>slope-policy>queue
Platforms
7210 SAS-T (in access-uplink mode and Network), 7210 SAS-Sx 1/10GE: standalone and standalone-VC, and 7210 SAS-Sx 10/100GE
Description
This command configures a weighting factor to calculate the new shared buffer average utilization after assigning buffers for a packet entering a queue. To derive the new shared buffer average utilization, the buffer pool takes a portion of the previous shared buffer average and adds it to the inverse portion of the instantaneous shared buffer utilization. The time-average-factor command sets the weighting factor between the old shared buffer average utilization and the current shared buffer instantaneous utilization when calculating the new shared buffer average utilization.
The Time Average Factor (TAF) value applies to all high, low priority, and non-tcp packets WRED slopes for egress access and network buffer pools controlled by the slope policy.
The no form of this command reverts to the default value.
Default
7
Parameters
- value
Specifies the TAF, expressed as a decimal integer. The value specified for 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, zero using it exclusively. A high value weights the new shared buffer average utilization calculation more to the previous shared buffer average utilization value.
RED slope commands
max-avg
Syntax
max-avg percent
no max-avg
Context
config>qos>slope-policy>queue>high-slope
config>qos>slope-policy>queue>low-slope
Platforms
7210 SAS-T (in access-uplink mode and Network), 7210 SAS-Sx 1/10GE: standalone and standalone-VC, and 7210 SAS-Sx 10/100GE
Description
This command configures the low priority or high priority or non-tcp Weighted Random Early Detection (WRED) slope position for the reserved and shared buffer average utilization value where the packet discard probability rises directly to one. The percent parameter is expressed as a percentage of the shared buffer size.
The no form of this command reverts the max-avg value to the default. If the current start-avg setting is larger than the default, an error will occur and the max-avg value will not be changed to the default.
Default
max-avg 90 — High slope default is 90% buffer utilization before discard probability is 1
max-avg 75 — Low slope default is 75% buffer utilization before discard probability is 1
Parameters
- percent
Specifies the percentage of the reserved and shared buffer space for the buffer pool at which point the drop probability becomes 1. The value entered must be greater or equal to the current setting of start-avg. If the entered value is smaller than the current value of start-avg, an error will occur and no change will take place.
max-prob
Syntax
max-prob percent
no max-prob
Context
config>qos>slope-policy>queue>high-slope
config>qos>slope-policy>queue>low-slope
Platforms
7210 SAS-T (in access-uplink mode and Network), 7210 SAS-Sx 1/10GE: standalone and standalone-VC, and 7210 SAS-Sx 10/100GE
Description
This command configures the low priority or high priority Random Early Detection (RED) slope position for the maximum non-one packet discard probability value before the packet discard probability rises directly to one. The percent parameter is expressed as a percentage of packet discard probability where always discard is a probability of 1. A max-prob value of 80 represents 80% of 1, or a packet discard probability of 0.8.
The no form of this command reverts the value to the default.
Default
max-prob 80
Parameters
- percent
Specifies the maximum drop probability percentage corresponding to the max-avg, expressed as a decimal integer.
shutdown
Syntax
[no] shutdown
Context
config>qos>slope-policy>high-slope
config>qos>slope-policy>low-slope
Platforms
7210 SAS-T (in access-uplink mode and Network), 7210 SAS-Sx 1/10GE: standalone and standalone-VC, and 7210 SAS-Sx 10/100GE
Description
This command enables or disables the administrative status of the Random Early Detection slope.
By default, all slopes are shutdown and have to be explicitly enabled (no shutdown).
The no form of this command administratively enables the RED slope.
Default
shutdown
start-avg
Syntax
start-avg percent
no start-avg
Context
config>qos>slope-policy>queue>high-slope
config>qos>slope-policy>queue>low-slope
Platforms
7210 SAS-T (in access-uplink mode and Network), 7210 SAS-Sx 1/10GE: standalone and standalone-VC, and 7210 SAS-Sx 10/100GE
Description
This command configures the low priority or high priority Random Early Detection (RED) slope position for the shared buffer average utilization value where the packet discard probability starts to increase above zero. The percent parameter is expressed as a percentage of the shared buffer size.
The no form of this command reverts the start-avg value to the default. If the max-avg value is smaller than the default, an error will occur and the start-avg value will not be changed to the default.
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 percentage of reserved and shared buffer space for the buffer pool at which the drop starts. The value entered must be lesser or equal to the current setting of max-avg. If the entered value is greater than the current value of max-avg, an error will occur and no change will take place.
Slope policy QoS policy commands
time-average-factor
Syntax
time-average-factor value
no time-average-factor
Context
config>qos>slope-policy>queue
Platforms
7210 SAS-T (in access-uplink mode and Network), 7210 SAS-Sx 1/10GE: standalone and standalone-VC, and 7210 SAS-Sx 10/100GE
Description
This command sets a weighting factor to calculate the new shared buffer average utilization after assigning buffers for a packet entering a queue. To derive the new shared buffer average utilization, the buffer pool takes a portion of the previous shared buffer average and adds it to the inverse portion of the instantaneous shared buffer utilization. The time-average-factor command sets the weighting factor between the old shared buffer average utilization and the current shared buffer instantaneous utilization when calculating the new shared buffer average utilization.
The TAF value applies to all high, low priority, and non-tcp packets WRED slopes for egress access and network buffer pools controlled by the slope policy.
Operational commands
copy
Syntax
copy slope-policy src-name dst-name [overwrite]
Context
config>qos
Platforms
7210 SAS-T (in access-uplink mode and Network), 7210 SAS-Sx 1/10GE: standalone and standalone-VC, and 7210 SAS-Sx 10/100GE
Description
This command copies existing QoS policy entries for a QoS policy ID to another QoS policy ID.
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
- slope-policy
Specifies the source policy ID that the copy command will attempt to copy from and specifies the destination policy ID to which the command will copy a duplicate of the policy. Indicates that the source policy ID and the destination policy ID are slope policy IDs.
- overwrite
Keyword to overwrite the existing destination policy. Everything in the existing destination policy will be overwritten with the contents of the source policy.
Show commands
slope-policy
Syntax
slope-policy [slope-policy-name] [detail]
Context
show>qos
Platforms
7210 SAS-T (in access-uplink mode and Network), 7210 SAS-Sx 1/10GE: standalone and standalone-VC, and 7210 SAS-Sx 10/100GE
Description
This command displays slope policy information.
Parameters
- slope-policy-name
Specifies the name of the slope policy.
- detail
Displays detailed information about the slope policy.
Output
The following output is an example of QoS slope policy information, and Output fields: QoS slope policy describes the output fields.
Sample output*A:SN12345678# show qos slope-policy 100
===============================================================================
QoS Slope Policy
===============================================================================
Policy : 100
Description : Slope policy 100
-------------------------------------------------------------------------------
Utilization State Start-Threshold
-------------------------------------------------------------------------------
High Slope
-------------------------------------------------------------------------------
QueueId State Start-Avg(%) Max-Avg(%) Max-Prob(%)
-------------------------------------------------------------------------------
Queue1 Down 70 90 75
Queue2 Down 70 90 75
Queue3 Down 70 90 75
Queue4 Down 70 90 75
Queue5 Down 70 90 75
Queue6 Down 70 90 75
Queue7 Down 70 90 75
Queue8 Down 70 90 75
-------------------------------------------------------------------------------
Low Slope
-------------------------------------------------------------------------------
QueueId State Start-Avg(%) Max-Avg(%) Max-Prob(%)
-------------------------------------------------------------------------------
Queue1 Down 50 75 75
Queue2 Down 50 75 75
Queue3 Down 50 75 75
Queue4 Down 50 75 75
Queue5 Down 50 75 75
Queue6 Down 50 75 75
Queue7 Down 50 75 75
Queue8 Down 50 75 75
-------------------------------------------------------------------------------
Time Avg Factor
-------------------------------------------------------------------------------
Queue Id Time Avg Factor
-------------------------------------------------------------------------------
Queue1 7
Queue2 7
Queue3 7
Queue4 7
Queue5 7
Queue6 7
Queue7 7
Queue8 7
===============================================================================
*A:SN12345678# show qos slope-policy 100 detail
*A:SN12345678#
===============================================================================
QoS Slope Policy
===============================================================================
Policy : 100
Description : Slope policy 100
-------------------------------------------------------------------------------
High Slope
-------------------------------------------------------------------------------
QueueId State Start-Avg(%) Max-Avg(%) Max-Prob(%)
-------------------------------------------------------------------------------
Queue1 Down 70 90 75
Queue2 Down 70 90 75
Queue3 Down 70 90 75
Queue4 Down 70 90 75
Queue5 Down 70 90 75
Queue6 Down 70 90 75
Queue7 Down 70 90 75
Queue8 Down 70 90 75
-------------------------------------------------------------------------------
Low Slope
-------------------------------------------------------------------------------
QueueId State Start-Avg(%) Max-Avg(%) Max-Prob(%)
-------------------------------------------------------------------------------
Queue1 Down 50 75 75
Queue2 Down 50 75 75
Queue3 Down 50 75 75
Queue4 Down 50 75 75
Queue5 Down 50 75 75
Queue6 Down 50 75 75
Queue7 Down 50 75 75
Queue8 Down 50 75 75
-------------------------------------------------------------------------------
Time Avg Factor
-------------------------------------------------------------------------------
Queue Id Time Avg Factor
-------------------------------------------------------------------------------
Queue1 7
Queue2 7
Queue3 7
Queue4 7
Queue5 7
Queue6 7
Queue7 7
Queue8 7
-------------------------------------------------------------------------------
Associations
-------------------------------------------------------------------------------
Object Type Object Id Application Pool
-------------------------------------------------------------------------------
Port 1/1/13 Acc-Egr default
===============================================================================
*A:SN12345678#
| Label | Description |
|---|---|
Policy |
The ID that uniquely identifies the policy |
Description |
A string that identifies the policy’s context in the configuration file |
Time Avg |
The weighting between the previous shared buffer average utilization result and the new shared buffer utilization |
Slope Parameters |
|
Start Avg |
Specifies 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 |
Specifies 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 |