Feature History For Mqc Hierarchical Queuing With 3-Level Scheduler; Prerequisites For Mqc Hierarchical Queuing With 3-Level Scheduler; Restrictions For Mqc Hierarchical Queuing With 3-Level Scheduler; Scheduling Hierarchy - Cisco 10000 Series Configuration Manual

MQC Hierarchical Queuing with 3-Level Scheduler
For more information about the 4 level scheduler, see the

Feature History for MQC Hierarchical Queuing with 3-Level Scheduler

Cisco IOS Release
Release 12.2(31)SB2
Release 12.2(33)SB

Prerequisites for MQC Hierarchical Queuing with 3-Level Scheduler

Traffic classes must be configured on the router using the class-map command.

Restrictions for MQC Hierarchical Queuing with 3-Level Scheduler

•
•
•
•

Scheduling Hierarchy

As shown in
bandwidth for subscriber traffic:
•
•
•
By using VP and VC scheduling with existing Cisco 10000 ATM line cards, the scheduler supports
priority propagation: cell-based VP shaping in the segmentation and reassembly (SAR) mechanism with
frame-based VC scheduling in the performance routing engine 3 (PRE3).
Cisco 10000 Series Router Quality of Service Configuration Guide
22-6
Description
This feature was introduced and implemented on the
Cisco 10000 series router for the PRE3.
This feature was introduced on the PRE4 for the
Cisco 10000 series router.
We recommend that the sum of all priority traffic on a given interface not exceed 90 percent of the
physical bandwidth of that interface.
The 3-level scheduler does not support bandwidth propagation. Therefore, you cannot configure a
bandwidth guarantee for any queue other than a priority queue.
To allow oversubscription provisioning, the admission control check is not performed.
The sum of all priority traffic running on a given port must be less than or equal to 90 percent of the
port bandwidth.
Figure 22-1, the 3-level scheduler uses the following scheduling hierarchy to allocate
Class layer—The 3-level scheduler uses virtual-time calendars to schedule class queues.
Logical layer (subinterface, session, or ATM VC)—Virtual-time calendars perform weighted round
robin based on the weight of the logical interface and the number of bytes dequeued.
Physical layer (interface or ATM virtual path)—A real-time calendar ensures that the maximum rate
for the class and the logical interface are not exceeded.
Chapter 22 Hierarchical Scheduling and Queuing
"4-Level Scheduler" section on page 22-10
PRE Required
PRE3
PRE4
OL-7433-09