Alcatel-Lucent 7450 - Weighted Scheduler Group in a Port Scheduler Policy

Overview
536 Quality of Service Guide
Weighted Scheduler Group in a Port Scheduler Policy
The existing port scheduler policy defines a set of eight priority levels with no ability of
grouping levels within a single priority. In order to allow for the application of a scheduling
weight to groups of queues competing at the same priority level of the port scheduler policy
applied to the vport, or to the Ethernet port, a new group object is defined under the port
scheduler policy:
CLI Syntax: configure>qos>port-scheduler-policy>group group-name
rate pir-rate[cir cir-rate]
Up to eight groups can be defined within each port scheduler policy. One or more levels can
map to the same group. A group has a rate and optionally a cir-rate and inherits the highest
scheduling priority of its member levels. For example, the scheduler group for the 7450 ESS
and 7750 SR shown in the vport in Figure 35 consists of level priority 3 and level priority 4.
It thus inherits priority 4 when competing for bandwidth with the standalone priority levels
8, 7, and 5.
In essence, a group receives bandwidth from the port or from the vport and distributes it
within the member levels of the group according to the weight of each level within the group.
Each priority level will compete for bandwidth within the group based on its weight under
congestion situation. If there is no congestion, a priority level can achieve up to its rate (cir-
rate) worth of bandwidth.
The mapping of a level to a group is performed as follows:
CLI Syntax: configure>qos>port-scheduler-policy>level priority-
level rate pir-rate [cir cir-rate] group group-name
[weight weight-in-group]
CLI will enforce that mapping of levels to a group are contiguous. In other words, a user
would not be able to add priority level to group unless the resulting set of priority levels is
contiguous.
When a level is not explicitly mapped to any group, it maps directly to the root of the port
scheduler at its own priority like in existing behavior.
Basic Configurations
A basic QoS scheduler policy must conform to the following:
• Each QoS scheduler policy must have a unique policy ID.
• A tier level 1 parent scheduler name cannot be configured.