10. Access Egress QoS Policies for 7210 SAS-Mxp
This section provides information to configure Access Egress QoS policies using the command line interface.
10.1. Overview
On 7210 SAS-Mxp, the users have an option to use either port-based egress queuing and shaping or SAP-based egress queuing and shaping for SAPs configured on access ports or hybrid ports. The configure system resource-profile qos port-scheduler-mode command lets you select the mode to be used for SAPs configured on all the ports of the node (in other words, this is a per node setting).
On 7210 SAS-Mxp platforms, an access egress policy allows user to define the marking values for the traffic sent out of the access ports towards the customer. Access egress QoS policies map forwarding class flows to marking values to use. In addition, based on the queuing mode used on access egress, it also defines the per port queue parameters.
10.1.1. Access Egress QoS Policy for SAP-based Queuing Mode on 7210 SAS-Mxp
7210 SAS-Mxp supports SAP-based marking for access SAPs and port-based egress marking on access ports. SAP-based marking is only supported for Layer 2 SAPs, that is, SAPs configured in Epipe and VPLS service. If user enables remarking in the SAP egress policy attached to the SAP, the remark policy configured is used to mark the packets sent out of the SAP. If remarking is disabled in the SAP egress policy attached to the SAP, remark policy configured under the access-egress policy associated with the egress access port is used to mark all packets sent out of the Layer 2 SAP configured on the access port. This is known as port-based marking.
Port-based marking is supported primarily for Layer 3 SAPs (that is, SAPs configured in VPRN services and IES services). In other words, SAP-based marking is not supported for Layer 3 SAPs.
In 7210 SAS-Mxp, no explicit CLI command is provided to choose between port-based marking and SAP-based marking for Layer 2 SAPs. The user can choose SAP-based marking by enabling remarking in the SAP egress policy attached to the Layer 2 SAP or choose port-based marking by disabling remarking in the SAP egress policy attached to the SAP and enabling remarking in the access-egress policy associated with the access port on which the Layer 2 SAP is configured.
A remarking policy can be defined for each access egress policy and remarking is disabled by default. Only remarking policy of type dot1p, dot1p-lsp-exp-shared, dscp or dot1p-dscp can be used with access-egress policy. The following is the marking behavior with different remark policy types (when SAP-based marking is disabled and port-based marking is enabled, see the note below):
- If remark policy type is dot1p or dot1p-lsp-exp-shared, then all traffic sent out of Layer 2 SAPs and Layer 3 SAPs configured on that port will have its Dot1p bits marked.
- If remark policy type is dscp, then all traffic sent out of Layer 2 SAPs and Layer 3 SAPs configured on that port will have its IP DSCP bits marked (assuming Layer 2 SAPs are carrying IP traffic).
- If remark policy type is of type dot1p-dscp, then all traffic sent out of Layer 2 SAPs and Layer 3 SAPs configured on that port will have its IP DSCP bits (assuming Layer 2 SAPs are carrying IP traffic) and Dot1p bits marked.
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10.1.2. Access Egress QoS Policy for Port-based Queuing Mode on 7210 SAS-Mxp
On 7210 SAS-Mxp, in addition to marking values, the access egress QoS policy provides an option to define port-based queues and scheduling when per port queues are used for SAPs configured on access ports.
On 7210 SAS-Mxp, the users have an option to use either port-based egress queuing and shaping or SAP-based egress queuing and shaping for SAPs configured on access ports or hybrid ports. The configure system resource-profile qos port-scheduler-mode command lets you select the mode to be used for SAPs configured on all the ports of the node. When port-scheduler-mode is enabled, software uses 8 egress queues per access port and all the SAPs configured on the port will share the 8 egress queues for traffic sent out of that port. In this mode, SAPs configured on hybrid port shares the egress queues with network port traffic. Enabling port-scheduler-mode affects the behavior for all the SAPs configured on either access or hybrid port. That is, port-based egress queues is mutually exclusive to use of SAP-based egress queues. When port-scheduler-mode is enabled, per port egress queues are defined using the access egress policies.
Additionally, the marking values used to mark traffic from different forwarding classes is defined by the remark policy in the access egress policy. In other words, per SAP marking cannot be used when Port-based queuing mode is used. A remarking policy can be defined for each access egress policy and remarking is disabled by default. Only remarking policy of type dot1p, dot1p-lsp-exp-shared, dscp or dot1p-dscp can be used with access-egress policy. The following is the marking behavior with different remark policy types:
- If remark policy type is dot1p or dot1p-lsp-exp-shared, all traffic sent out of Layer 2 SAPs and Layer 3 SAPs configured on that port will have its Dot1p bits marked.
- If remark policy type is dscp, all traffic sent out of Layer 2 SAPs and Layer 3 SAPs configured on that port will have its IP DSCP bits marked (assuming Layer 2 SAPs are carrying IP traffic).
- If remark policy type is of type dot1p-dscp, all traffic sent out of Layer 2 SAPs and Layer 3 SAPs configured on that port will have its IP DSCP bits (assuming Layer 2 SAPs are carrying IP traffic) and Dot1p bits marked.
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On 7210 SAS-Mxp, access egress QoS policies define egress queues and map forwarding class flows to queues, if port-scheduler-mode is enabled. In port-scheduler-mode, the system allocates 8 queues to access port egress by default. To define a basic access egress QoS policy, the following are required:
- A unique access egress QoS policy ID.
- A QoS policy scope of template or exclusive.
- The parameters that can be configured for a queue are discussed in Queue Parameters.
Optional service egress QoS policy elements include:
- Specify remark policy that defines IEEE 802.1p priority value remarking based on forwarding class.
On 7210 SAS-Mxp, when port-based queuing is used, the FC to queue map is fixed and the queue's priority is determined by the queue number, with higher queue number having the higher priority. The user can configure a queue to be a strict queue to change the scheduling behavior for that queue.
The following is a sample default access-egress policy for 7210 SAS-Mxp.
10.1.3. Access Egress QoS Policy Queue Override
The following QoS policy queue parameters can be overridden using the configure>port>ethernet>access>egress>queue-override command. For command description details, refer to the Port Ethernet QoS Commands section in the 7210 SAS-M, T, R6, R12, Mxp, Sx, S Interface Configuration Guide.
- adaptation rule (specifies the criteria used to compute the operational PIR and CIR values for this queue (min, max, or closest))
- percent rate (enables configuration of a queue’s PIR and CIR as a percentage of the egress port’s line rate rather that the values set by rate parameter)
- queue management (associates a queue management policy with the queue)
- queue mode (sets strict or weighted mode for the queue)
- rate (defines the administrative PIR and CIR for the queue)
- weight (determines the proportion of available bandwidth that is given to this queue)
10.1.4. Basic Configurations
A basic access egress QoS policy must conform to the following:
- Have a unique access egress QoS policy ID.
- Have a QoS policy scope of template or exclusive.
10.1.4.1. 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
- Over write the original policy
10.1.4.2. Deleting QoS Policies
Every access Ethernet port is associated, by default, with the default access egress policy (policy-id 1). You can replace the default policy with a customer-configured policy, but you cannot entirely remove the policy from the port configuration. When you remove a non-default access egress policy, the association reverts to the default policy-id 1.
A QoS policy cannot be deleted until it is removed from all access ports where they are applied.