Ccag Sap Qos; Link Level Ccag Sap Qos Adaptation; Distributed Ccag Sap Qos Adaptation - Alcatel-Lucent 7750 SR OS Service Manual

CCAG SAP QoS

When a SAP is created on a CCAG, the service queues defined by the ingress and egress QoS
policy are created on each CCA member in the CCAG. Packets are forwarded to the egress queues
based on the hashing or service mapping enforced by the LAG functions internal to the system.
Packets are received on a CCA ingress queue based on which CCA handled the egress processing.
Each ingress and egress hardware queue buffering and rate parameters are managed by the system
based on one of two models governed by the state of the LAG QoS adaptation setting. The
adaptation state also governs the application of hierarchical virtual schedulers associated with the
SAP queues.

Link Level CCAG SAP QoS Adaptation

Link level QoS adaptation is set when the CCA access QoS adaptation flag is set to link. Link-
level distribution informs the system that a service queue's buffering and rate parameters should
be applied directly to each hardware queue representing the service queue. For example, when a
service queue is configured with a rate equal to 10Mbps, each corresponding CCA hardware
queue will be configured with a rate of 10Mbps. Given many flows conversation hashing to
different CCAs, the maximum forwarded rate will be the 10Mbps multiplied by the number of
active CCAs.
When a link-level adaptation service queue is a child to a parent virtual scheduler, the parent
scheduler and the rest of the scheduler hierarchy is implemented per CCA. An instance of the
scheduler policy is maintained per CCA.
When a CCAG SAP is a member of a Multi-Service Site (MSS), all SAPs in the MSS must be
CCAG SAPs created on the same CCAG-ID.

Distributed CCAG SAP QoS Adaptation

Distributed QoS adaptation is set when the CCA access QoS adaptation flag is set to distribute.
The distribute QoS parameter setting informs the system that a service queue's buffering and rate
parameters should be distributed between the active CCAs in the CCAG. For example, when a
service queue is configured with a rate equal to 10Mbps and two CCAs are active in the CCAG,
each corresponding CCA hardware queue will be configured with a rate of 5Mbps (1/2 of the
provisioned service queue parameters). Given many flows conversation hashing to different
CCAs, the maximum forwarded rate will be limited to 10Mbps.
When a distributed adaptation service queue is a child to a parent virtual scheduler, the parent
scheduler and the rest of the scheduler hierarchy is implemented on each IOM with an active
member CCA from the CCAG. The scheduler parameters are divided amongst the IOMs with
active CCAs based on the total number of active CCAs. If there are three active CCAs in the
7750 SR OS Services Guide
Versatile Service Module
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