Alcatel-Lucent 7450 Quality Of Service Manual page 643

Ethernet service switch; service router; extensible routing system

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When multiple hardware queues represent a single logical service queue, the system

automatically monitors the offered load and forwarding rate of each hardware queue. Based

on the monitored state of each hardware queue, the system imposes an individual CIR and

PIR rate for each queue that provides an overall aggregate CIR and PIR reflective of what is

provisioned on the service queue.

Figure 36: Unicast Service Queue Mapping to Multiple Destination Based Hardware Queues

Ingress Shared Queuing

To avoid the hardware queue expansion issues associated with normal service based queuing,

the system allows an ingress logical service queue to map to a single hardware queue when

shared queuing is enabled. Shared queuing uses two passes through the ingress forwarding

plane to separate ingress per service queuing from the destination switch fabric queuing. In

the case of shared queuing, ingress unicast service queues are created one-for-one relative to

hardware queues. Each hardware queue representing a service queue is mapped to a special

destination in the traffic manager that 'forwards' the packet back to the ingress forwarding

plane allowing a second pass through the traffic manager. In the second pass, the packet is

placed into a 'shared' queue for the destination forwarding plane. The shared queues are used

by all services configured for shared queuing.

Quality of Service Guide

Multipoint Service Queue is

representated by a single

Hardware Queue (Single Pass)

Unicast Service Queue is

representated by Multiple SF

Destination Hardware Queues

IOM monitors individual destination

Hardware Queues based on offered

Load and Forwarded Rate determine

each Queues Operating Parameters

(CIR, PIR...) relative to the Service Queue

Switch Fabric

Backpressure through

Switch Fabric based

Shared-Queue QoS Policies