This section provides information on per-customer 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.
A per-customer aggregate shaper is an aggregate shaper into which multiple SAP aggregate shapers can feed. The SAPs can be shaped at a desired rate called the Multiservice Site (MSS) aggregate rate. At ingress, SAPs that are bound to a per-customer aggregate shaper can span a whole Ethernet MDA meaning that SAPs mapped to the same MSS can reside on any port on a given Ethernet MDA.
At egress, SAPs that are bound to a per-customer aggregate shaper can only span a port. Towards the fabric at ingress and towards the port at egress, multiple per-customer aggregate shapers are shaped at their respective configured rates to ensure fair sharing of available bandwidth among different per-customer aggregate shapers. Deep ingress queuing capability ensures that traffic bursts are absorbed rather than dropped. Multi-tier shapers are based on an end-to-end backpressure mechanism that uses the following order (egress is given as an example):
per-port egress rate (if configured), backpressures to
per-customer aggregate shapers, backpressures to
per-SAP aggregate shapers, backpressures to
per-CoS queues (in the scheduling priority order)
To configure per-customer aggregate shaping, a shaper policy must be created and shaper groups must be created within that shaper policy. For access ingress per-customer aggregate shaping, a shaper policy must be assigned to an Ethernet MDA and SAPs on that Ethernet MDA must be bound to a shaper group within the shaper policy bound to that Ethernet MDA. For access egress per-customer aggregate shaping, a shaper policy must be assigned to a port and SAPs on that port must be bound to a shaper group within the shaper policy bound to that port. The unshaped SAP shaper group within the policy provides the shaper rate for all the unshaped SAPs (4-priority scheduled SAPs). For each shaped SAP, however, an ingress or egress shaper group can be specified. For more information on shaper policies, see Applying a Shaper QoS Policy and Shaper Groups.
The access ingress shaper policy is configured at the MDA level for fixed platforms. The default value for an access ingress shaper policy for each MDA and module is blank, as configured using the no shaper-policy command. On all 7705 SAR fixed platforms (with the exception of the 7705 SAR-X), when no MSS is configured, the existing access ingress aggregate rate is used as the shaper rate for the bulk of access ingress traffic. In order to use MSS, a shaper policy must be assigned to the access ingress interface of one MDA, and the shaper policy change is cascaded to all MDAs and modules in the chassis.
Before the access ingress shaper policy is assigned, the config system qos access-ingress-aggregate-rate 10000000 unshaped-sap-cir max command must be configured. Once a shaper policy is assigned to an access ingress MDA, the values configured using the access-ingress-aggregate-rate command cannot be changed.
On all 7705 SAR fixed platforms (with the exception of the 7705 SAR-X), when a shaper policy is assigned to an Ethernet MDA for access ingress aggregate shaping, it is automatically assigned to all the Ethernet MDAs in that chassis. The shaper group members contained in the shaper policy span all the Ethernet MDAs. SAPs on different Ethernet MDAs configured with the same ingress shaper group will share the shaper group rate.
Once the first MSS is configured, traffic from the designated SAPs is mapped to the MSS and shaped at the configured rate. The remainder of the traffic is then shaped according to the configured unshaped SAP rate. When a second MSS is added, SAPs that are mapped to the second MSS are shaped at the configured rate and traffic is arbitrated between the first MSS, the second MSS and unshaped SAP traffic.
In the access egress direction, the default shaper policy is assigned to each MSS-capable port. Ports that cannot support MSS are assigned a blank value, as configured using the no shaper-policy command. The default egress shaper group is assigned to each egress SAP that supports MSS. If the SAP does not support MSS, the egress SAP is assigned a blank value, as configured using the no shaper-group command.