Service egress QoS policies
This chapter provides information to configure service egress QoS policies using the CLI.
Overview
The service-egress policy defines the Service Level Agreement (SLA) for service packets as they egress on a SAP configured on either an access port or a hybrid port. Service-egress QoS policies allow the definition of queue parameters along with a remark policy.
With the default service egress policy, the system allocates one queue. The eight FCs are mapped to use the same queue. The user has the option to define up to eight queues per policy and define the FC-to-queue mapping. In addition, the policy allows the user to define the queue parameters. The hardware does not support a linear range of values for the rate parameters (CIR and PIR). The user can specify the computation method of rates to match the rates supported by the hardware, through the configuration of adaptation rules.
The SAP egress policy for access SAPs supports the following:
per-SAP egress queuing and shaping, hierarchical shaping on SAP egress (with three levels of shaping) with a per-FC/queue shaper, per-SAP aggregate shaper and per-port egress rate shaper
SAP egress queues, shaping, and scheduling
On the 7210 SAS-K 2F1C2T and 7210 SAS-K 2F6C4T, hardware queues are allocated in groups of two, and on the 7210 SAS-K 3SFP+ 8C, hardware queues are allocated in groups of four; these grouped queues are reserved for use by the SAP even if the user specifies an odd value. The 7210 SAS-K 2F1C2T and 7210 SAS-K 2F6C4T support two, four, six, or eight queues per SAP. The 7210 SAS-K 3SFP+ 8C supports four or eight queues per SAP.
Provides an option to configure the FC-to-queue map, allowing the user to assign the packets classified into a particular FC to any of the queues configured for the SAP.
On SAP egress, only a single queue can be configured per FC and all traffic (unicast and BUM) share the single queue.
Allows configuration of queue shaper rate (CIR/PIR), CBS and MBS, queue priority and weight. The assigned priority and weight is used to determine the priority and weight of the queue in both the CIR and PIR scheduling loop.
Allows configuration of WRED slopes (per queue) – high-slope and low-slope. One of the configured WRED slopes is used to allocate buffer to the packet. In-profile packets use the high-slope and out-of-profile packets use the low-slope. The profile of the packet is determined at the ingress (access uplink port ingress or Access SAP ingress) and carried through to be used at SAP egress to determine the WRED slope to apply and also to determine the egress marking value to use (if remarking/marking is enabled).
Supports Strict Priority (SP) scheduling and Weighted-Fair Queuing (WFQ) scheduling for SAP egress queues.
SAP egress remarking/marking
Dot1p and/or IP DSCP marking must be supported on access SAP egress. Configuration of per FC dot1p and/or IP DSCP marking is supported, with the capability to assign different dot1p and/or IP DSCP values for in-profile and out-of-profile packets. In addition, support for marking DEI value is available.
The following is a sample configuration output showing the default access SAP egress QoS.
*A:SAH01-071>config>qos>sap-egress# info detail
----------------------------------------------
description "Default SAP egress QoS policy."
scope template
no remarking
remark 1
queue 1 create
adaptation-rule cir closest pir closest
rate cir 0 pir max
mbs 60
cbs 10
slope-policy "default"
priority 1
weight 1
exit
fc af create
queue 1
exit
fc be create
queue 1
exit
fc ef create
queue 1
exit
fc h1 create
queue 1
exit
fc h2 create
queue 1
exit
fc l1 create
queue 1
exit
fc l2 create
queue 1
exit
fc nc create
queue 1
exit
Egress SAP FC and profile overrides
The FC of an access egress packet can be changed to redirect the packet to an alternate queue than the ingress FC determination would have used. The profile of an access egress packet can also be changed to modify the congestion behavior within the egress queue. In both cases, egress marking decisions are based on the new FC and profile, instead of the FC or profile determined at ingress.
The SAP egress QoS policy supports the use of reclassification rules to override the ingress FC and profile of packets that egress a SAP where the QoS policy is applied.
dot1p, IP precedence, and DSCP entries can be defined, each with an explicit FC or profile override parameters. The reclassification logic for each entry follows the same basic hierarchical behavior as the classification rules within the SAP ingress QoS policy. IP DSCP entries have the highest match priority, followed by IP precedence and dot1p.
If the IP precedence values overlap with DSCP values by matching the same IP header TOC field, the DSCP entry parameters override or remove the IP precedence parameters. When none of the matched entries override a parameter, the ingress classification is preserved; that is, the FC and profile assigned by SAP/network ingress classification rules is carried over and used at egress.
The egress queue shaper does not reassign the profile for the packet. By default, the profile is assigned a value of undefined at access SAP egress when the profile is not defined explicitly by the user in the service egress policy reclassification entry. A value of undefined specifies that the profile assigned at ingress is carried over. Therefore, the user can use egress reclassification to assign only an FC without specifying a profile. The profile assigned at ingress by either the ingress classification entry or the ingress shaper is carried over. The egress classification entry modifies the profile only if the user explicitly configures the profile as in or out.
This capability is supported on access SAP egress for all services.
Configuration guidelines for access SAP egress policies
This section provides a list of configuration guidelines for access SAP egress policies.
This section applies to SAPs configured on access ports and hybrid ports.
The configuration guidelines for access SAP egress policies are the following:
On the 7210 SAS-K 2F1C2T and 7210 SAS-K 2F6C4T, hardware queues are allocated in groups of two, and on the 7210 SAS-K 3SFP+ 8C, hardware queues are allocated in groups of four; these grouped queues are reserved for use by the SAP even if the user specifies an odd value. The 7210 SAS-K 2F1C2T and 7210 SAS-K 2F6C4T support two, four, six, or eight queues per SAP. The 7210 SAS-K 3SFP+ 8C supports four or eight queues per SAP.
FC-to-queue map can be defined; this allows the user to assign the packets classified into a particular FC to any one of the queues configured for the SAP.
Both unicast traffic and BUM traffic share a single queue per FC. In other words, unlike service ingress policy, it is not possible to assign different queues for BUM traffic and unicast traffic.
The queue parameters such as queue shaper rate (CIR/PIR), CBS and MBS, queue priority and weight can be defined. The assigned priority and weight is used to determine the priority and weight of the queue in both the CIR and PIR scheduling loop.
WRED slopes (per queue) can be configured: high-slope and low-slope. Depending on the queue mode and the profile assigned to the packet on SAP ingress classification, one of the configured WRED slopes is used to evaluate if a buffer can be allocated to the packet. In-profile packets use the high-slope and out-of-profile packets use the low-slope.
SP scheduling and WFQ scheduling for SAP ingress queues are supported.
Basic configurations
A basic service egress QoS policy must conform to the following:
have a unique service egress QoS policy ID
have a QoS policy scope of template or exclusive
have at least one FC queue
Creating an access SAP egress policy
To create an access SAP egress policy, define the following:
a SAP egress policy name
a brief description of the policy features
the queue parameters for all the queues
Use the following syntax to configure a SAP egress policy.
*A:SAH01-051>config>qos# sap-egress
- no sap-egress <policy-id>
- sap-egress <policy-id> [create]
<policy-id> : [1..65535]|<name:64 char max>
<create> : keyword - mandatory while creating an entry.
[no] description - Description for this sap-egress policy
[no] fc + Configure forwarding-class mappings
[no] queue + Configure a queue
[no] remark - Specify Remarking policy for this policy
[no] remarking - Enable/disable remarking
[no] scope - Specify scope of the policy
*A:SAH01-051>config>qos# info detail
sap-egress 1 create
description "Default SAP egress QoS policy."
scope template
no remarking
remark 1
queue 1 create
adaptation-rule cir closest pir closest
rate cir 0 pir max
mbs 60
cbs 10
slope-policy "default"
priority 1
weight 1
exit
fc af create
queue 1
exit
fc be create
queue 1
exit
fc ef create
queue 1
exit
fc h1 create
queue 1
exit
fc h2 create
queue 1
exit
fc l1 create
queue 1
exit
fc l2 create
queue 1
exit
fc nc create
queue 1
exit
exitEditing 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.
Service egress policy command reference
Command hierarchies
Configuration commands
- config
- qos
- sap-egress policy-id [create]
- [no] description description-string
- dot1p-classification policy-id
- no dot1p-classification
- dscp-classification policy-id
- no dscp-classification
- fc fc-name [create]
- no fc fc-name
- ip-prec-classification policy-id
- no ip-prec-classification
- queue queue-id [create]
- no queue queue-id
- adaptation-rule [pir adaptation-rule] [cir adaptation-rule]
- no adaptation-rule
- cbs size-in-kbyte
- no cbs
- mbs size in kbytes
- no mbs
- prioritylevel
- no priority
- slope-policy name
- no slope-policy
- rate cir cir-rate-in-kbps [pir pir-rate-in-kbps]
- no rate
- weight weight
- no weight
- scope {exclusive | template}
- remark policy-id
- no remark
- [no] remarking
Copy commands
- config
- qos
- copy sap-egress src-pol dst-pol [overwrite]
Show commands
- show
- qos
- sap-egress [policy-id] [detail | association]
Command description
Configuration commands
Generic commands
description
Syntax
description description-string
no description
Context
config>qos>sap-egress
Platforms
Supported on all 7210 SAS platforms as described in this document
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.
SAP egress queue QoS policy commands
sap-egress
Syntax
sap-egress policy-id [create]
Context
config>qos
Platforms
Supported on all 7210 SAS platforms as described in this document
Description
This command configures a SAP egress policy. The SAP egress policy determines the QoS treatment to packets at service egress.
When the policy is created, by default only one queue is created. The user can create up to 8 queues and associate it to different FCs on the SAPs to which this SAP egress policy is attached. The SAP egress policy allows the user to define the queue parameters for the eight queues.
Default
sap-egress 1
Parameters
- policy-id
Specifies the SAP egress policy.
dot1p-classification
Syntax
dot1p-classification policy-id
no dot1p-classification
Context
config>qos>sap-egress
Platforms
7210 SAS-K 2F6C4T and 7210 SAS-K 3SFP+ 8C
Description
This command associates a dot1p classification policy, which contains entries used to map traffic sent on an access SAP to an FC and profile state, based on the dot1p bits in the packet.
When the dot1p classification policy is defined in a service egress QoS policy and associated with an access SAP egress, a packet sent out of the SAP is used to match with the dot1p values defined in this policy. If a match is found, the corresponding FC and profile are assigned to the packet.
The FC and profile assigned by the dot1p entry match can be overridden by an IP precedence match or IP DSCP match. See Egress SAP FC and profile overrides for more information about the match hierarchy.
The no form of this command disables the use of the dot1p classification policy.
Default
no dot1p-classification
Parameters
- policy-id
Specifies the policy ID.
dscp-classification
Syntax
dscp-classification
no dscp-classification
Context
config>qos>sap-egress
Platforms
7210 SAS-K 2F6C4T and 7210 SAS-K 3SFP+ 8C
Description
This command associates an IP DSCP classification policy, which contains entries used to map traffic sent on a SAP to an FC and profile state, based on the IP DSCP bits in the packet.
When the DSCP classification policy is defined in a service egress QoS policy and associated with an access SAP egress, a packet sent out of the SAP is used to match with the IP DSCP values defined in this policy. If a match is found, the corresponding FC and profile are assigned to the packet.
The FC and profile assigned by the dot1p entry match or IP precedence entry match can be overridden by an IP DSCP match. See Egress SAP FC and profile overrides for more information about the match hierarchy.
The no form of this command disables the use of the DSCP classification policy.
Default
no dscp-classification
Parameters
- policy-id
Specifies the policy ID.
fc
Syntax
fc fc-name [create]
no fc fc-name
Context
config>qos>sap-egress
Platforms
Supported on all 7210 SAS platforms as described in this document
Description
This command creates a class instance of the forwarding class name. When the fc-name is created, classification actions can be applied and can be used in match classification criteria.
The no form of this command removes all the explicit queue mappings for fc-name forwarding types. The queue mappings revert to the default meters for fc-name.
Parameters
- fc-name
Specifies the forwarding class name for the queue.
- create
Creates a forwarding class.
ip-prec-classification
Syntax
ip-prec-classification policy-id
no ip-prec-classification
Context
config>qos>sap-egress
Platforms
7210 SAS-K 2F6C4T and 7210 SAS-K 3SFP+ 8C
Description
This command associates an IP DSCP classification policy with IP precedence entries used to map traffic sent out of a SAP to an FC and profile state based on the IP precedence bits in the packet.
When it is defined in a service egress QoS policy and associated with an access SAP egress, a packet sent out of the SAP is used to match with the IP precedence values defined in this policy. If a match is found, the corresponding FC and profile are assigned to the packet.
The FC and profile assigned by the dot1p entry match can be overridden by an IP precedence match, and the FC and profile assigned by the IP precedence match can be overridden by an IP DSCP match. See Egress SAP FC and profile overrides for more information about the match hierarchy.
The no form of this command disables the use of the DSCP classification policy and IP precedence values.
Default
no ip-prec-classification
Parameters
- policy-id
Specifies the policy ID.
queue
Syntax
queue queue-id [create]
no queue queue-id
Context
config>qos>sap-egress
Platforms
Supported on all 7210 SAS platforms as described in this document
Description
This command creates a queue and modifies queue parameters associated with a particular queue. The queue ID to FC map is user-defined.
The 7210 SAS-K 2F1C2T and 7210 SAS-K 2F6C4T support two, four, six, or eight queues per SAP.
The 7210 SAS-K 3SFP+ 8C supports four or eight queues per SAP.
The no form of this command deletes the queue.
Parameters
- queue-id
Specifies the ID of the queue.
- create
Creates a network queue policy.
adaptation-rule
Syntax
adaptation-rule [cir adaptation-rule] [pir adaptation-rule]
no adaptation-rule
Context
config>qos>sap-egress>queue
Platforms
Supported on all 7210 SAS platforms as described in this document
Description
This command defines the method used by the system to derive the operational CIR and PIR rates when the queue is provisioned in hardware. For the cir and pir parameters, the system attempts to find the best operational rate depending on the defined constraint.
The no form of this command removes any explicitly defined constraints used to derive the operational CIR and PIR created by the application of the policy. When a specific adaptation-rule is removed, the default constraints for cir and pir apply.
Default
adaptation-rule pir closest cir closest
Parameters
- cir adaptation-rule
Specifies the adaptation rule and defines the constraints enforced when adapting the CIR rate defined using the queue queue-id rate command. The cir parameter requires a qualifier that defines the constraint used to derive the operational CIR rate for the queue. When the cir parameter is not specified, the default constraint applies. The max (maximum), min (minimum), and closest qualifiers are mutually exclusive.
- pir adaptation-rule
Specifies the adaptation rule and defines the constraints enforced when adapting the PIR rate defined using the queue queue-id rate command. The pir parameter requires a qualifier that defines the constraint used when deriving the operational PIR rate for the queue. When the pir command is not specified, the default constraint applies. The max (maximum), min (minimum), and closest qualifiers are mutually exclusive.
cbs
Syntax
[no] cbs size-in-kbytes
Context
config>qos>sap-egress>queue
Platforms
Supported on all 7210 SAS platforms as described in this document
Description
This command specifies the CBS value (minimum depth of the queue).
The no form of this command reverts to the default value.
Default
32
Parameters
- size-in-kbytes
Specifies the CBS value, in kilobytes
mbs
Syntax
[no] mbs size-in-kbytes
Context
config>qos>sap-egress>queue
Platforms
Supported on all 7210 SAS platforms as described in this document
Description
This command specifies the MBS value (maximum depth of the queue).
The no form of this command reverts to the default value.
Default
512
Parameters
- size-in-kbytes
Specifies the MBS value, in kilobytes.
priority
Syntax
priority level
no priority
Context
config>qos>sap-egress>queue
Platforms
Supported on all 7210 SAS platforms as described in this document
Description
This command defines the queue priority. The queue priority is used by the scheduler to determine the order of service in both the within-cir loop and within-pir loop. Higher priority queues are serviced before lower priority queues.
The no form of this command reverts the level to the default.
Default
1
Parameters
- level
Specifies the priority of the queue.
slope-policy
Syntax
slope-policy name
no slope-policy
Context
config>qos>sap-egress>queue
Platforms
Supported on all 7210 SAS platforms as described in this document
Description
This command is used to override the default slope policy configuration for the queue. The specified slope policy name must exist as a current slope policy name. If the slope policy does not exist, the slope-policy command fails. If a slope policy is currently associated with a queue, the slope policy cannot be removed from the system.
The slope policy contains the ring and non-ring high and low WRED slope definitions that are used by the queue. See Buffer pools for more information about ring and non-ring buffer pools and slope usage.
If the slope-policy command is not executed or the no slope-policy command is executed, the default slope policy will be associated with the queue.
The no form of this command reverts the queue to the default slope policy.
Parameters
- name
Specifies an existing slope policy name, up to 32 characters.
rate
Syntax
rate cir cir-rate-in-kbps [pir pir-rate-in-kbps]
no rate
Context
config>qos>sap-egress>queue
Platforms
Supported on all 7210 SAS platforms as described in this document
Description
This command defines the administrative PIR and the administrative CIR parameters for the queue. The PIR defines the maximum rate that the queue can transmit packets through the port. Defining a PIR does not necessarily guarantee that the queue can transmit at the intended rate. The actual rate sustained by the queue can be limited by oversubscription factors or available egress bandwidth. The CIR defines the rate at which the system prioritizes the queue over other queues competing for the same bandwidth.
The rate command can be executed at anytime, altering the PIR and CIR rates for all queues created on the access ports.
The max default specifies the amount of bandwidth in kilobits per second. The max value is mutually exclusive to the pir-rate-in-kbps value.
The no form of this command reverts all queues created with the queue ID by association with the QoS policy to the default PIR(max) and CIR(0) parameters.
Default
rate cir 0 pir max
Parameters
- cir cir-rate-in-kbps
Specifies the administrative CIR rate, in kilobits per second. The cir parameter overrides the default administrative CIR used by the queue.
- pir pir-rate-in-kbps
Specifies the administrative PIR rate, in kilobits per second. When the rate command is executed, a PIR setting is optional.
weight
Syntax
weight weight
no weight
Context
config>qos>sap-egress>queue
Platforms
Supported on all 7210 SAS platforms as described in this document
Description
This command configures the weight of the queue.
The configured weight determines the proportion of available bandwidth that is given to this queue in comparison to other queues contending for bandwidth at the same priority level.
The no form of this command reverts the weight to the default.
Default
1
Parameters
- weight
Specifies the weight of the queue.
scope
Syntax
scope {exclusive | template}
no scope
Context
config>qos>sap-egress
Platforms
Supported on all 7210 SAS platforms as described in this document
Description
This command configures the scope as exclusive or template. The scope of the policy cannot be changed if the policy is applied to multiple interface 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 port. 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. The system default policies cannot be put into the exclusive scope. An error is generated if scope exclusive is executed in any policies with a policy ID equal to 1.
- template
Specifies that the policy can be applied to multiple interface ports on the router. Default QoS policies are configured with a template scope. An error is generated when scope template is changed to scope exclusive for default policies.
Operational commands
copy
Syntax
copy sap-egress src-pol dst-pol [overwrite]
Context
config>qos
Platforms
Supported on all 7210 SAS platforms as described in this document
Description
This command copies the existing SAP egress QoS policy entries to another SAP egress QoS 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.
If the destination policy already exists, the overwrite keyword must be specified.
Parameters
- src-pol
Specifies the source policy.
- src-pol
Specifies the destination policy.
- overwrite
Specifies to replace the existing destination policy. Everything in the existing destination policy is overwritten with the contents of the source policy. If overwrite is not specified, an error occurs if the destination policy ID exists.
remark
Syntax
remark policy-id
no remark
Context
config>qos>sap-egress
Platforms
Supported on all 7210 SAS platforms as described in this document
Description
This command specifies the remarking policy ID to use for marking packets on service egress (also known as Access SAP egress).
The remarking policy ID must be associated with the appropriate SAP egress policy and remarking must be enabled in the service egress policy to enable marking of packets sent out of service (SAP) egress. Only a remarking policy of type dot1p, dscp, or dot1p-dscp is allowed when the remark policy is associated with service egress. See Remark policies for more information about remark policy types and their usage.
The no form of this command removes the explicit association of the remark policy and associates the default remark policy. In other words, if remarking is enabled and no remark policy is executed, then the default remark policy is used to mark packets sent out. If no remark policy is executed and remarking is disabled, then packets are not remarked at all.
Parameters
- policy-id
Specifies the remark policy.
remarking
Syntax
[no] remarking
Context
config>qos>sap-egress
Platforms
Supported on all 7210 SAS platforms as described in this document
Description
This command enables the system to remark egress packets sent out of service egress (also known as, access SAP egress).
When remarking is enabled, the remark policy configured in the QoS policy context is used to determine the FC to QoS bit mapping. For example, when remarking is enabled in the sap-egress QoS policy, the remark policy associated with sap-egress QoS policy is used to determine the FC to dot1p mapping to use for marking packets sent out of access SAPs.
See Remark policies for more information about configuring remark policies.
The no form of this command disables remarking.
Default
no remarking
Show commands
sap-egress
Syntax
sap-egress [policy-id] [association | detail]
Context
show>qos
Platforms
Supported on all 7210 SAS platforms as described in this document
Description
This command displays SAP egress QoS policy information.
Parameters
- policy-id
Displays the policy ID of the SAP egress policy.
- association
Displays associations related to the specified SAP egress policy.
- detail
Displays detailed policy information including the policy associations.
Output
The following output is an example of SAP egress QoS policy information, and Output fields: show SAP egress describes the output fields.
Sample output*A:Dut-A# show qos sap-egress 10 detail
===============================================================================
QoS Sap Egress
===============================================================================
-------------------------------------------------------------------------------
Sap Egress Policy (10)
-------------------------------------------------------------------------------
Scope : Template
Remark : False Remark Pol Id : 1
DSCP Class Policy : 20 IP Prec Class Policy : 10
Dot1p Class Policy : 10
Name : (Not Specified)
Description : (Not Specified)
Label |
Description |
|---|---|
SAP Egress Policy |
Displays the ID that uniquely identifies the policy |
Scope |
Exclusive — Implies that this policy can be applied only to a single access egress port Template — Implies that this policy can be applied to multiple access ports on the router |
Remark |
True — Remarking is enabled for all the dot1q-tagged packets that egress the ports on which the SAP egress QoS policy is applied and remarking is enabled False — Remarking is disabled for the policy |
Remark Pol Id |
Displays the policy ID of the remarking policy |
DSCP Class Policy |
Displays the ID that uniquely identifies the DSCP classification policy |
IP Prec Class Policy |
Displays the ID that uniquely identifies the DSCP classification policy with IP precedence This field applies only to the 7210 SAS-K 2F6C4T and 7210 SAS-K 3SFP+ 8C |
Dot1p Class Policy |
Displays the ID that uniquely identifies the dot1p classification policy |
Description |
A text string that helps identify the policy context in the configuration file |