Service ingress, service egress, and network QoS policies are defined with a scope of either template or exclusive. Template policies can be applied to multiple SAPs or IP interfaces; exclusive policies can only be applied to a single entity.
On most systems, the number of configurable SAP ingress and egress QoS policies per system is larger than the maximum number that can be applied per FP. The tools>dump>resource-usage>card>fp output displays the number of policies applied on an FP (the default SAP ingress policy is always applied once for internal use). The tools>dump>resource-usage>system output displays the usage of the policies at a system level. The show>qos>sap-ingress and show>qos>sap-egress commands can be used to show the number of policies configured.
One service ingress QoS policy and one service egress QoS policy can be applied to a specific SAP. One network QoS policy can be applied to a specific IP interface. A network QoS policy defines both ingress and egress behavior.
Router QoS policies are applied on service ingress, service egress, and network interfaces and define classification rules for how traffic is mapped to queues:
the number of forwarding class queues
the queue parameters used for policing, shaping, and buffer allocation
QoS marking/interpretation
The router supports thousands of queues. The exact numbers depend on the hardware being deployed.
There are several types of QoS policies:
service ingress
service egress
network (for ingress and egress)
network queue (for ingress and egress)
scheduler
shared queue
slope
Service ingress QoS policies are applied to the customer-facing SAPs and map traffic to forwarding class queues on ingress. The mapping of traffic to queues can be based on combinations of customer QoS marking (IEEE 802.1p bits, DSCP, and ToS precedence), IP criteria, and MAC criteria.
The characteristics of the forwarding class queues are defined within the policy as to the number of forwarding class queues for unicast traffic and the queue characteristics. There can be up to eight unicast forwarding class queues in the policy; one for each forwarding class. A service ingress QoS policy also defines up to three queues per forwarding class to be used for multipoint traffic for multipoint services.
In the case of VPLS, four types of forwarding are supported (that is not to be confused with forwarding classes): unicast, multicast, broadcast, and unknown. Multicast, broadcast, and unknown types are flooded to all destinations within the service while the unicast forwarding type is handled in a point-to-point manner within the service.
Service egress QoS policies are applied to SAPs and map forwarding classes to service egress queues for a service. Up to eight queues per service can be defined for the eight forwarding classes. A service egress QoS policy also defines how to remark the forwarding class to IEEE 802.1p bits in the customer traffic.
Network QoS policies are applied to IP interfaces. On ingress, the policy applied to an IP interface maps incoming DSCP and EXP values to forwarding class and profile state for the traffic received from the core network. On egress, the policy maps forwarding class and profile state to DSCP and EXP values for traffic to be transmitted into the core network.
Network queue policies are applied on egress to network ports and channels and on ingress to FPs. The policies define the forwarding class queue characteristics for these entities.
Service ingress, service egress, and network QoS policies are defined with a scope of either template or exclusive. Template policies can be applied to multiple SAPs or IP interfaces whereas exclusive policies can only be applied to a single entity.
One service ingress QoS policy and one service egress QoS policy can be applied to a specific SAP. One network QoS policy can be applied to a specific IP interface. A network QoS policy defines both ingress and egress behavior.
If no QoS policy is explicitly applied to a SAP or IP interface, a default QoS policy is applied.
A summary of the major functions performed by the QoS policies is listed in Table: QoS policy types and descriptions .
Policy type |
Applied at… |
Description |
See |
|---|---|---|---|
Service Ingress |
SAP ingress |
Defines up to 32 forwarding class queues and queue parameters for traffic classification Defines up to 31 multipoint service queues for broadcast, multicast, and destination unknown traffic in multipoint services Defines match criteria to map flows to the queues based on combinations of customer QoS (IEEE 802.1p/DE bits, DSCP, TOS precedence), IP criteria, or MAC criteria |
|
Service Egress |
SAP egress |
Defines up to eight forwarding class queues and queue parameters for traffic classification Maps one or more forwarding classes to the queues |
|
Network |
Router interface |
Used for classification/marking of IP and MPLS packets At ingress, defines DSCP, dot1p MPLS LSP-EXP, and IP criteria classification to FC mapping At ingress, defines FC to policer/queue-group queue mapping At egress, defines DSCP or precedence FC mapping At egress, defines FC to policer/queue-group queue mapping At egress, defines DSCP, MPLS LSP-EXP, and dot1p/DE marking |
|
Network Queue |
Network ingress FP and egress port |
Defines forwarding class mappings to network queues and queue characteristics for the queues |
|
Slope |
Ports |
Enables or disables the WRED slope parameters within an egress queue, an ingress pool, or an egress megapool |
|
Scheduler |
Customer multiservice site Service SAP |
Defines the hierarchy and parameters for each scheduler Defined in the context of a tier that is used to place the scheduler within the hierarchy Three tiers of virtual schedulers are supported |
|
Shared Queue |
SAP ingress |
Shared queues can be implemented to mitigate the queue consumption on an MDA |