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RCA THOMSON SpeedTouchTM (Wireless) Business DSL Router 3.2 Differentiated Services

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Chapter 3

Basic QoS Concepts

E-NIT-CTC-20041213-0013v0.5

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3.2 Differentiated Services

Introduction Differentiated Services (DiffServ) is an architecture which allows service providers to

offer different kinds of services to different customers and their traffic streams.

Differentiated Services is a framework for scalable service discrimination and allows

an approach to modular IPQoS objectives for the needs of various types of

applications.

The premise to DiffServ networks is that routers within the core of the network are

capable to forward the packets of different traffic streams in different Per-Hop

Behaviours (PHB). The PHB for the packets is indicated by a Differentiated Services

Codepoint (DSCP) in the IP header. The DiffServ architecture does not use any

signalling between the routers but all the forwarding behaviour is defined by using

the DSCP.

Terminology Before we continue we will explain the abbreviations used in this section.

Behaviour Aggregate (BA):

Is a collection of packets with the same Differentiated Services codepoint, thus

receiving the same PHB, crossing a DiffServ node in a particular direction.

Differentiated Services CodePoint (DSCP):

Is the value in the IP header in the DS field, used to select the PHB.

Per-Hop Behaviour (PHB):

Is the forwarding behaviour for the packet applied at DiffServ compliant nodes

to a DiffServ BA.

Service Level Specification (SLS):

Is a set of parameters and their values which together define the service offered

to a traffic stream by a DiffServ domain.

Traffic Conditioning Specification (TCS):

Is a set of parameters and their values which together specify a set of classifier

rules.

Contents

Main Page Page Page Contents Contents 4 6 Meters, queues and IPQoS......................................... 59 7 Scenario 1: Residential user.......................................85 Page Page About this IPQoS Configuration Guide About this IPQoS Configuration Guide ! Page Chapter 1 1 Document scope Page 2Introduction 2.1 What is Quality of Service? Definition Misunderstandings ! Page 2.2 Relative versus Guaranteed QoS Types of QoS 3 Basic QoS Concepts 3.1 Precedence and TOS Introduction First generation Precedence values Second generation 3.2 Differentiated Services Differentiated Services domain 3.3 Classification and conditioning principles Introduction classifier Traffic classification Traffic conditioning Page 3.4 Differentiated Services Code Point (DSCP) Introduction Per Hop Behaviour Standardized PHBs Page Assured Forwarding (AF) PHB Group: 4 IP QoS Framework Overview 4.1 Main Framework Components Graphical overview QoS Components 4.2 Resource Management Mapping to internal class 5 Packet Classification and Labelling 5.1 Classification Introduction Terminology 5.1.1 Order of classification rules Introduction Routing classification Sub-chains ! Page 5.2 Labels Introduction CLI Command groups ! Label command group Adding a label Label parameters Debug command group 5.2.1 Label parameters explained Introduction Classification Defclass Page Page 5.2.2 Using TOS, DSCP or Precedence Introduction Precedence TOSmarking TOS DSCP 5.2.3 Forwarding parameters. Introduction TTLoverwrite TTL Modify the label parameters Page 5.3 Rules 5.3.1 Rules parameters explained Introduction Srcintf Chain Index Srcip Dstip Serv Page The flush command 5.3.2 Rule debug commands Introduction Traceconfig Traceconfig result Stats 5.4 Chains Page 5.4.1 Define a relation between chains 5.5 Expressions Page Bridgeport Addr Precedence Tos Dscp ! Srcportend Dstport Icmptype Dstportend Page Page 6 Meters, queues and IPQoS 6.1 Meters and queues 6.2 The IPQoS command group Overview IPQoS command group EF command group meter command group Page Page Page MTU explained. EF stats command EF list command Line Speed 6.4 Meter command group Introduction Adding a meter 6.4.1 Meter config command Meter parameters meter config Label Meter config parameters explained Name Intf Droprate Markrate Burst Page Dscp Precedence Class Classification Meter delete command Meter list command Meter start command Meter stop command Meter flush command Meter stats command 6.4.2 Packet flow Illustration Classification Metering 6.5 Queue command group Introduction Queue config command 6.5.1 Queue config parameters explained Dest Ecnmarking Queue Propagate Data ACK1Data DataACK2 Example Maxpackets Respackets Maxbytes Resbytes Hold Markprob Queue list command Queue stats command Queue clear command 6.6 IPQoS Command group Introduction ipqos config command 6.6.1 Ipqos config parameters explained Introduction Dest Discard State ! Priority Realtimerate Burstsize Weight Maxpackets Maxbytes Ipqos list command 7 Scenario 1: Residential user. 7.1 Configuring labels and rules for VoIP. Introduction The web interface Labels Rules Expressions Page 7.2 Configuring labels and rules for DSCP. Introduction Labels Rules Expressions 7.3 Configuring labels and rules for Interactive traffic. Introduction Labels Page Expressions Page Page 8 Scenario 2: Business user with TOS marking. ! 8.1 Labels Page Page Page 8.2 Rules. Page Page Page Page Page Page Page Page 8.3 IPQoS per PVC Page Page Chapter 9 9 Scenario 3: Metering Page Reference List Reference List Page Abreviation List Abreviation List