Quality of Service Guide QoS and QoS Policies
Edition: 01 3HE 11014 AAAC TQZZA 87
3.2.5.1.1 Aggregate Mode BMU Support
An aggregate mode shaper provides a single aggregate shaping rate. The rate
defines the maximum bandwidth that an adapter card can switch through its fabric
interface at any given time. The rate is a bulk value and is independent of the
destination or the type of traffic. For example, in aggregate mode, an ingress adapter
card might use the full rate to communicate with a single destination adapter card, or
it might use the same rate to communicate with multiple egress adapter cards.
Aggregate mode and the aggregate rate apply to fabric shapers that handle
combined unicast/BMU traffic, unicast-only traffic, or BMU-only traffic. One
aggregate rate sets the rate on all adapter cards. The proportional distribution
between unicast and BMU traffic can be fine-tuned using queue-level schedulers,
while the to-fabric shaper imposes a maximum rate that ensures fairness on the
fabric for traffic from all adapter cards.
When services (IES, VPRN, and VPLS) are enabled, the fabric profile mode for
access ingress should be set to aggregate mode.
3.2.5.1.2 Destination Mode BMU Support
Destination mode offers granular to-fabric shaping rates on a per-destination adapter
card basis. While destination mode offers more flexibility and gives more control than
aggregate mode, it also requires a greater understanding of network topology and
flow characteristics under conditions such as node failures and link, adapter card, or
port failures.
In a destination mode fabric profile, the unicast traffic and BMU traffic are always
shaped separately.
For unicast traffic, individual destination rates can be configured on each adapter
card. For BMU traffic, one multipoint rate sets the rate on all adapter cards. Fairness
among different BMU flows is ensured by tuning the QoS queues associated with the
port.
3.2.5.2 LAG SAP Support (Access Only)
Fabric shapers support access ingress traffic being switched from a SAP to another
SAP residing on a port that is part of a Link Aggregation Group (LAG). Either the
aggregate mode or destination mode can be used for fabric shaping.
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