Alcatel-Lucent 7750 SR - Figure 1: Unicast Service Queue Mapping to Multiple Destination Based Hardware Queues; Services Overview

Page 34 7750 SR OS Services Guide
that provides an overall aggregate CIR and PIR reflective of what is provisioned on the service
queue.
Figure 1: 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’
OSSG225
Multicast
Queue
Multipoint Service Queue is
Represented by a Single
Hardware Queue (Single Pass)
IOM Monitors Individual Destination
Hardware Queues Based on Offered
Load and Forwarded rate to Determine
Each Queues Operating Parameters
(CIR, PIR...) Relative to the Service Queue
Unicast
Queue
Unicast Service Queue is
Represented by Multiple SF
Destination Hardware Queues
Backpressure Through
Switch Fabric Based on Class
Hardware
Queue
Switch Fabric
Unicast
SFEgress
MDA 1
SFEgress
MDA 2
SFEgress
MDA 3
SFEgress
MDA n
Multicast
Hardware
Queue
Hardware
Queue
Hardware
Queue
Hardware
Queue