12. Slope QoS Policies

This chapter provides information to configure slope QoS policies using the command line interface.

12.1. Overview of Buffer Pools and Slope Policies

For an overview of buffer pools supported on the 7210 SAS-K 2F1C2T, 7210 SAS-K 2F6C4T and 7210 SAS-K 3SFP+ 8C, see Buffer Pools.

On the 7210 SAS-K 2F1C2T, slope policies are applied to service ingress queues, service egress queues, access-uplink port ingress queues, and access-uplink port egress queues.

On the 7210 SAS-K 2F6C4T and 7210 SAS-K 3SFP+ 8C, slope policies are applied to service ingress and egress queues; network port ingress and egress queues; hybrid port ingress and egress queues; and access-uplink port ingress and egress queues.

Each of these queuing points allocates buffers from the buffer pool and implements WRED for congestion management. During congestion WRED is used to evaluate how buffers from the pool are allocated to different FCs and to in-profile and out-of-profile traffic within a given FC. The slope policies define the WRED parameters to use for in-profile/high-priority packets and for out-of-profile/low-priority packets. The high-slope and low-slope define the parameters for in-profile/high-priority packets and for out-of-profile/low-priority packets respectively. In addition, on ring ports the option is available to use separate slopes for ring traffic (that is, traffic coming in on one ring port and going out of another ring port) and non-ring traffic (that is, traffic coming in on access port and going out of another access port or access-uplink port). For more information about ring and non-ring ports, see Buffer Pools.

12.2. Basic Configurations

A basic slope QoS policy must conform to the following.

  1. Each slope policy must have a unique policy ID.
  2. High slope and low slope (both ring and non-ring slopes) are shut down by default.
  3. Default values can be modified but parameters cannot be deleted.

12.2.1. Creating 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:

  1. A slope policy ID value. The system will not dynamically assign a value.
  2. Include a description. The description provides a brief overview of policy features.
  3. The high slope for the high priority Random Early Detection (RED) slope graph.
  4. The low slope for the low priority Random Early Detection (RED) slope graph.

Use the following syntax to configure a slope policy.

CLI Syntax:
slope-policy "default" create
description "Default slope policy."
high-slope
shutdown
start-avg percent
max-avg percent
max-prob percent
exit
low-slope
shutdown
start-avg percent
max-avg percent
max-prob percent
exit
high-slope-ring
shutdown
start-avg percent
max-avg percent
max-prob percent
exit
low-slope-ring
shutdown
start-avg percent
max-avg percent
max-prob percent
exit

12.2.1.1. Default Slope Policy Values for the 7210 SAS-K 2F1C2T, 7210 SAS-K 2F6C4T, and 7210 SAS-K 3SFP+ 8C

The following is a sample default slope policy configuration output, and Table 46 lists the default values.

*A:SAH01-051>config>qos>slope-policy$ info detail
----------------------------------------------
            no description
            high-slope
                shutdown
                start-avg 70
                max-avg 90
                max-prob 80
            exit
            low-slope
                shutdown
                start-avg 50
                max-avg 75
                max-prob 80
            exit
            high-slope-ring
                shutdown
                start-avg 70
                max-avg 90
                max-prob 80
            exit
            low-slope-ring
                shutdown
                start-avg 50
                max-avg 75
                max-prob 80
            exit
----------------------------------------------
*A:SAH01-051>config>qos>slope-policy$
Table 46:  Default Slope Policy Values 

Description

Default Slope Policy

high-slope

Administrative state

shutdown

start-avg

70% utilization

max-avg

90% utilization

max-prob

80%

low slope

Administrative state

shutdown

start-threshold

50% utilization

max-avg

75% utilization

max-prob

80%

high-slope-ring

Administrative state

shutdown

start-threshold

70% utilization

max-avg

90% utilization

max-prob

80%

low-slope-ring

Administrative state

shutdown

start-threshold

50% utilization

max-avg

75% utilization

max-prob

80%

12.3. Applying Slope Policies

On the 7210 SAS-K 2F1C2T, slope policies are associated with service ingress queues, service egress queues, access-uplink port egress queues, and access-uplink port ingress queues.

On the 7210 SAS-K 2F6C4T and 7210 SAS-K 3SFP+ 8C, slope policies are associated with service ingress and egress queues; network port ingress and egress queues; hybrid port ingress and egress queues; and access-uplink port ingress and egress queues.

The following syntax examples may be used to apply slope policies to service ingress queues, service egress queues, access-uplink port ingress queues, and access-uplink port egress queues on the 7210 SAS-K 2F1C2T.

CLI Syntax:
config>qos>sap-ingress> queue id slope-policy name
config>qos>sap-egress> queue id slope-policy name
config>qos>network>ingress> queue id slope-policy name
config>qos>network-queue> queue id slope-policy name

The following syntax examples may be used to apply slope policies to service ingress and egress queues; network port ingress and egress queues; hybrid port ingress and egress queues; and access-uplink port ingress and egress queues on the 7210 SAS-K 2F6C4T or 7210 SAS-K 3SFP+ 8C.

CLI Syntax:
config>qos>sap-ingress> queue id slope-policy name
config>qos>sap-egress> queue id slope-policy name
config>qos>network>ingress> queue id slope-policy name
config>qos>network-queue> queue id slope-policy name

12.4. Deleting QoS Policies

A slope policy is associated by default with access and access uplink 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. 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#
 

The following syntax removes slope policies from ports.

CLI Syntax:
config>qos>sap-ingress> queue id no slope-policy name
config>qos>sap-egress> queue id no slope-policy name
config>qos>network>ingress> queue id no slope-policy name
config>qos>network-queue> queue id no slope-policy name

12.4.1. Removing a Policy from the QoS Configuration

The following shows the command usage to delete a slope policy.

CLI Syntax:
config>qos# no slope-policy policy-id
Example:
config>qos# no slope-policy slopePolicy1

12.5. 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.

CLI Syntax:
config>qos> copy {slope-policy} source-policy-id dest-policy id [overwrite]

The following is a sample output of copied policies.

 
*A:SAH01-051>config>qos>slope-policy# info detail
----------------------------------------------
            description "Default slope policy."
            high-slope
                shutdown
                start-avg 70
                max-avg 90
                max-prob 80
            exit
            low-slope
                shutdown
                start-avg 50
                max-avg 75
                max-prob 80
            exit
            high-slope-ring
                shutdown
                start-avg 70
                max-avg 90
                max-prob 80
            exit
            low-slope-ring
                shutdown
                start-avg 50
                max-avg 75
                max-prob 80
            exit
----------------------------------------------
*A:SAH01-051>config>qos>slope-policy#
 

12.6. 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.