On the 7210 SAS-D and 7210 SAS-Dxp, an access-egress policy defines the queue and marking characteristics for the traffic egressing toward the customer on the access ports. There are eight queues always available at the access port, and FCs are mapped to these eight queues. By configuring queue shaper rates, the individual FC traffic can be managed so that the traffic for each FC is well within SLA limits and does not impact the traffic of other FCs. The access-egress policy also provides an option for marking packets sent out of access ports, allowing the FC to be mapped to packet header priority bits (for example, IEEE dot1p bits).
The FCs are mapped to eight queues by the software, as per Table: FC-to-queue ID map, and this mapping is not user configurable. The queue ID determines the priority of the queue, with a higher queue-ID denoting a higher priority.
To define a basic access egress QoS policy, the following are required:
a unique service access QoS policy ID
a QoS policy scope of template or exclusive
IEEE 802.1p priority value remarking based on FC
on 7210 SAS-D and 7210 SAS-Dxp, an option is available to use IP DSCP values for marking based on FC
See Queues and queue parameters for information about the parameters that can be configured for a queue.
The FC determination per service egress packet is determined at ingress. If the packet ingressed the service on the same router, the service ingress classification rules determine the FC of the packet. If the packet was received over a service transport tunnel on an access-uplink port, the FC is marked in the outer tag of the QinQ encapsulation.