This section contains overview information as well as information on the following topics:
This section provides information on per-SAP aggregate shapers for Gen-2 adapter cards and platforms. For information on Gen-3 adapter cards and platforms, see QoS for Gen-3 Adapter Cards and Platforms.
Hierarchical QoS (H-QoS) provides the 7705 SAR with the ability to shape traffic on a per-SAP basis for traffic from up to eight CoS queues associated with that SAP.
On Gen-2 hardware, the per-SAP aggregate shapers apply to access ingress and access egress traffic and operate in addition to the 16-priority scheduler, which must be used for per-SAP aggregate shaping.
The 16-priority scheduler acts as a soft policer, servicing the SAP queues in strict priority order, with conforming traffic (less than CIR) serviced prior to non-conforming traffic (between CIR and PIR). The 16-priority scheduler on its own cannot enforce a traffic limit on a per-SAP basis; to do this, per-SAP aggregate shapers are required (see H-QoS Example).
The per-SAP shapers are considered aggregate shapers because they shape traffic from the aggregate of one or more CoS queues assigned to the SAP.
Figure: Access Ingress Scheduling for 4-Priority and 16-Priority SAPs (with Per-SAP Aggregate Shapers) and Figure: Access Egress Scheduling for 4-Priority and 16-Priority SAPs (with Per-SAP Aggregate Shapers) (per Port) illustrate per-SAP aggregate shapers for access ingress and access egress, respectively. They indicate how shaped and unshaped SAPs are treated.
H-QoS is not supported on the 4-port SAR-H Fast Ethernet module.