Slope Policies - Alcatel-Lucent 7450 Quality Of Service Manual

QoS Policies
After the IOM has been placed into named pool mode, a named pool policy must be
associated with the ingress and egress contexts of the MDA or individual ports on the MDA
for named pools to be created. There are no named pools that exist by default.
Each time the default pool reserve, aggregate MDA pool limit or individual pool sizes is
changed, buffer pool allocation must be re-evaluated.
Pools may be deleted from the named pool policy at anytime. Queues associated with
removed or non-existent pools are mapped to one of the default pools based on whether the
queue is access or ingress. The queue is flagged as 'pool-orphaned' until either the pool
comes into existence, or the pool name association is changed on the pool.
An ingress or egress port managed buffer space is derived from the port's active bandwidth.
Based on this bandwidth value compared to the other port's bandwidth value, the available
buffer space is given to each port to manage. It may be desirable to artificially increase or
decrease this bandwidth value to compensate for how many buffers are actually needed on
each port. If one port has very few queues associated with it and another has many queues
associated, the commands in the port's "modify-buffer-allocation-rate" CLI context may be
used to move one port's bandwidth up, and another port's bandwidth down. As provisioning
levels change between ports, the rate modification commands may be used to adapt the buffer
allocations per port.
Buffer allocation rate modification is supported for both standard and named pool mode
buffer allocation methods.
The system allocates buffers based on the following criteria:

Slope Policies

For network ingress, a buffer pool is created for the XMA or MDA and is used for all network
ingress queues for ports on the XMA or MDA.
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• "named-pool-mode" setting on the IOM
• Amount of path bandwidth on channelized ports
• Existence of queues provisioned on the port or channel
• Current speed of each port
• Each ports "ing-percentage-of-rate" and "egr-percentage-of-rate" command setting
• The port-allocation-weights setting for default, MDA and port
• The ports division between network and access bandwidth
• Each individual named pool's network-allocation-weight and access-allocation-
weight
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