Quality of Service Guide QoS and QoS Policies
Edition: 01 3HE 11014 AAAC TQZZA 47
3.1.9 Per-Customer Aggregate Shapers (Multiservice
Site) on Gen-2 Hardware
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.
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