Queuing Mechanisms Objectives

Queuing Mechanisms

Objectives

• Upon completing this module, you will be able to:
• Describe and configure FIFO queuing
• Describe and configure priority queuing (PQ)
• Describe and configure custom queuing (CQ)
• Describe and configure basic weighted fair queuing (WFQ), distributed WFQ, ToS-based distributed WFQ, and QoS-group-based distributed WFQ
• Describe and configure modified deficit round robin (MDRR) queuing
• Describe and configure IP RTP Prioritization

Queuing Overview

• © 2001, Cisco Systems, Inc.

• QOS v1.0—3-

Objectives

• Upon completing this lesson, you will be able to:
• Understand how queuing works on Cisco routers
• List the most used queuing mechanisms

Queuing in Cisco IOS

• Cisco routers running Cisco IOS have a number of different queuing mechanisms
• This module focuses on the following:
• First In First Out (FIFO)
• Priority Queuing (PQ)
• Custom Queuing (CQ)
• Weighted Fair Queuing (WFQ) with the different distributed versions
• Modified Deficit Round Robin (MDRR)
• IP RTP Prioritization
• These mechnisms are implemented as software queues

Output Interface Queue Structure

• Each interface has its hardware and software queuing system.
• The hardware queuing system (transmit queue, or TxQ) always uses FIFO queuing.
• The software queuing system can be selected and configured depending on the platform and Cisco IOS version.

• Hardware
• Queue
• (TxQ)

• Software
• Queuing
• System

• Output
• Interface

• Forwarder

• Any supported queuing mechanism

• Always FIFO