Queue Parameters - Alcatel-Lucent 7210 SAS E OS Quality Of Service Manual

QoS Overview

Queue Parameters

This section describes the queue parameters provisioned on access ports and access uplink port's
queues for QoS.
The queue parameters are:
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Queue ID
The queue ID is used to uniquely identify the queue. The queue ID is only unique within the
context of the QoS policy within which the queue is defined. On 7210 SAS E, the queue ID is not
a user configurable entity but the queue ID is statically assigned to the 8 Queues on the port
according to FC-QiD map table shown in Table 21.
Committed Information Rate
The committed information rate (CIR) for a queue performs two distinct functions:
1. Minimum bandwidth guarantees — Egress queues CIR setting provides the bandwidth which
will be given to this queue as compared to other queues on the port competing for a share of
the available link bandwidth. The queue CIR does not necessarily guarantee bandwidth in all
scenarios and also depends on factors such as CIR oversubscription and link port bandwidth
capacity. For each packet in an egress queue, the CIR is checked with the current transmis-
sion rate of the queue. If the current rate is at or below the CIR threshold, the queue is consid-
ered in-profile. If the current rate is above the threshold, the queue is considered out-of-
profile. This in and out profile state of queue is linked to scheduler prioritizing behavior as
discussed below.
2. Scheduler queue priority metric — The scheduler serving a group of egress queues prioritizes
individual queues based on their current CIR and PIR states. Queues operating below their
CIR are always served before those queues operating at or above their CIR.
Queues at the egress never marks the packets as in-profile or out-profile based on the queue CIR,
PIR values. The in-profile and out-profile state of the queue interacts with the scheduler
mechanism and provides the minimum and maximum bandwidth guarantees.
Page 30
Queue ID on page 30
Committed Information Rate on page 30
Peak Information Rate on page 32
Adaptation Rule on page 33
Committed Burst Size on page 34
7210 SAS-E OS Quality of Service Guide