Hierarchical Queuing Framework - Cisco 10000 Series Configuration Manual

Quality of service configuration guide

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Hierarchical Scheduling and Queuing

The performance routing engine (PRE3 and PRE4) supports a hierarchical queuing framework (HQF)

for scheduling and queuing. This HQF architecture enables service providers to manage their QoS

services at three or four layers of hierarchy. The scheduler uses the HQF to allocate excess bandwidth

among the subscriber queues and logical interfaces. The scheduler services queues based on the

maximum rate and bandwidth-remaining ratio you specify.

This chapter describes hierarchical scheduling and queuing, and includes the following topics:

Hierarchical Queuing Framework

The hierarchical queuing framework (HQF) defines a QoS architecture for implementing hierarchical

packet scheduling and queuing on the PRE3 and PRE4. The HQF enables service providers to manage

their QoS at three or four levels of hierarchy. The 3-level HQF scheduler uses the following hierarchy:

The 4-level HQF scheduler uses the same hierarchy as above, except that it splits the logical layer into

an upper logical layer for sessions and a lower logical layer for subinterfaces. For more information, see

The parallel express forwarding (PXF) engine performs all packet-level scheduling using the HQF.

Hierarchical Queuing Framework, page 22-1

MQC Hierarchical Queuing with 3-Level Scheduler, page 22-5

4-Level Scheduler, page 22-10

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