book

Cisco IOS™ 12.0 Quality of Service

by Cisco Systems, Inc.

April 1999

Intermediate to advanced

288 pages

5h 33m

English

Cisco Press

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Acknowledgments
What Is QoS?About QoS ArchitectureWho Could Benefit from Using Cisco IOS QoS?Why Deploy Cisco IOS QoS?End-to-End QoS ModelsBest-Effort ServiceIntegrated ServiceDifferentiated ServiceCisco's QoS FeaturesClassificationIP PrecedencePBRCAR (Packet Classification)BGP Policy PropagationCongestion ManagementWhat Is Congestion in Networks?FIFO QueuingPQCQWFQ and VIP-Distributed WFQCongestion AvoidanceWREDVIP-Distributed WREDPolicing and ShapingCAR Rate LimitingShapingSignalingLink Efficiency MechanismsCompressed Real-Time ProtocolLink Fragmentation and InterleavingAbout the Cisco IOS 12.0 Reference LibraryCisco IOS Reference Library OrganizationBooks Available in the Cisco IOS 12.0 Reference LibraryBook ConventionsCommand Syntax ConventionsCisco Connection OnlineUsing Cisco IOS SoftwareGetting HelpExample: How to Find Command OptionsUnderstanding Command ModesSummary of Main Command ModesUsing the No and Default Forms of CommandsSaving Configuration Changes
About IP PrecedenceHow the IP Precedence Bits Are Used to Classify PacketsSetting or Changing the IP Precedence ValuePolicy-Based RoutingHow It WorksWhen Should You Use PBR?QoS Policy Propagation via Border Gateway ProtocolCommitted Access Rate
PBR Configuration Task ListEnable PBREnable Fast-Switched PBREnable Local PBRPBR Configuration ExamplesEqual Access ExampleDiffering Next Hops Example
QoS Policy Propagation via BGP Configuration Task ListOverview of TasksConfiguration Task ListConfigure Policy Propagation Based on Community ListsConfigure Policy Propagation Based on the AS Path AttributeConfigure Policy Propagation Based on an Access ListMonitor QoS Policy Propagation via BGPQoS Policy Propagation via BGP Configuration ExamplesRouter A's ConfigurationRouter B's Configuration
CAR Configuration Task ListConfigure CAR and DCAR for All IP TrafficConfigure CAR and DCAR PoliciesIP Precedence or MAC AddressIP Access ListConfigure a Class-Based DCAR PolicyMonitor CAR and DCARCAR and DCAR Configuration ExamplesSubrate IP Services ExampleInput and Output Rate Limiting on an Interface ExampleRate Limiting in an IXP ExampleRate Limiting by Access List ExampleConfiguration Commands for Router LEFT
Why Use Congestion Management?Deciding Which Queuing Policy to UseFirst-In, First-Out QueuingWeighted Fair QueuingAbout WFQWFQ and IP PrecedenceWFQ and Resource Reservation ProtocolWFQ and Frame RelayConsiderationsVIP-Distributed WFQFlow-Based VIP-Distributed WFQRestrictionsDrop PolicyCustom QueuingHow It WorksDetermining Byte Count Values for QueuesHow the Byte Count Is UsedDetermining the Byte CountWindow SizeWhy Use CQ?ConsiderationsPriority QueuingHow It WorksHow Packets Are Classified for PQWhy Use PQ?ConsiderationsRestrictions

WFQ Configuration Task ListConfigure WFQ and DWFQMonitor Fair QueuingFair Queuing Configuration ExamplesWFQ ExampleDWFQ Example
Custom Queuing Configuration Task ListDefine the Custom Queue ListSpecify the Maximum Size of the Custom QueuesAssign Packets to Custom QueuesMonitor Custom Queue ListsCustom Queuing Configuration ExamplesDefine the Custom Queue List ExampleSpecify Maximum Number of Packets Allowed in Each Custom Queue ExampleSpecify Maximum Queue Size in Bytes ExampleAssign by Protocol Type ExamplesAssign by Interface Type ExampleAssign by Default Queue Example
Priority Queuing Configuration Task ListDefine the Priority ListAssign Packets to Priority QueuesSpecify the Maximum Size of the Priority QueuesAssign the Priority List to an InterfaceMonitor Priority Queuing ListsPriority Queuing Configuration ExamplesPriority Queuing Based on Protocol Type ExamplePriority Queuing Based on Interface ExampleSpecify the Maximum Size of the Priority Queue ExampleAssign Priority List to an Interface ExamplePriority Queuing Using Multiple Rules Example
Tail DropWeighted Random Early DetectionAbout REDHow It WorksPacket Drop ProbabilityHow TCP Handles Traffic LossHow the Router Interacts with TCPAbout WREDWhy Use WRED?How It WorksAverage Queue SizeVIP-Distributed WREDWhy Use VIP-Distributed WRED?Restrictions
WRED Configuration Task ListEnable WREDChange WRED ParametersMonitor WRED and DWREDWRED and DWRED Configuration ExamplesWRED and DWRED Configuration ExampleParameter-Setting DWRED ExampleParameter-Setting WRED Example
What Is a Token Bucket?Policing with CARHow It WorksMatching CriteriaRate LimitsConform and Exceed ActionsMultiple Rate PoliciesRestrictionsTraffic ShapingAbout Traffic ShapingWhy Use Traffic Shaping?Traffic Shaping and Rate of TransferDE BitDifferences Between GTS and FRTSTraffic Shaping and QueuingGTSFRTSDerived RatesRestrictions
GTS Configuration Task ListConfigure GTSConfigure GTS for an Access ListConfigure Adaptive GTS for Frame Relay NetworksMonitor the GTS ConfigurationGTS Configuration ExamplesEnable GTS on the Interface ExampleConstrained Access Rate ExampleDiffering Controlled Rates through an IP Internet ExampleFrame Relay Adaptability to Congestion ExampleAccommodating Differing Access Speeds Example
FRTS Configuration Task ListConfigure a Map ClassConfigure FRTSVirtual Circuits for Different Types of TrafficTraffic Shaping TasksEnable FRTS on the InterfaceUnderstand the Frame Relay ForeSight FeatureCongestion Notification MethodsForeSight PrerequisitesEnable Enhanced Local Management InterfaceSpecify a Traffic Shaping Map Class for the InterfaceDefine a Map Class with Queuing and Traffic Shaping ParametersDefine Access ListsDefine Priority Queue Lists for the Map ClassDefine Custom Queue Lists for the Map ClassCreate a Broadcast Queue for an InterfaceConfigure Discard EligibilityConfigure DLCI Priority LevelsMonitor the Frame Relay ConnectionsFRTS Configuration ExamplesSVC Interface ExampleSVC Subinterface ExampleTraffic Shaping with Three Point-to-Point Subinterfaces ExampleTraffic Shaping with Router ForeSight ExampleELMI Example
IP PrecedenceRSVPHow It Works
RSVP Reservation TypesDistinct ReservationShared ReservationPlanning for RSVP ConfigurationRSVP Implementation ConsiderationsFrame Relay Internetwork ConsiderationsATM Internetwork ConsiderationsResource Reservation Protocol Configuration Task ListEnable RSVPEnter Senders in the RSVP DatabaseEnter Receivers in the RSVP DatabaseEnter Multicast AddressesControl Which RSVP Neighbor Can Offer a ReservationMonitor RSVPRSVP Configuration for a Multicast Session ExampleRouter ARouter BRouter C
Link Fragmentation and InterleavingHow It WorksCRTP HeaderHow It WorksWhy Use Compressed Real-Time Protocol Header?
Interleaving for Multilink PPP Configuration Task ListConfigure MLP Interleaving and Queuing for Real-Time TrafficRestrictionsMLP Interleaving Configuration TasksMonitor PPP and MLP InterfacesMLP Interleaving and Link Fragmentation Examples
CRTP Configuration Task ListBefore You Configure CRTPEnable CRTP on a Serial InterfaceEnable CRTP with Frame Relay EncapsulationChange the Number of Header Compression ConnectionsDisplay System and Network StatisticsCRTP Configuration Examples
access-list rate-limitDefaultCommand ModeUsage GuidelinesExamplesRelated Commandsbgp-policyDefaultCommand ModeUsage GuidelinesExamplecustom-queue-listDefaultCommand ModeUsage GuidelinesExampleRelated Commandsfair-queueDefaultCommand ModeUsage GuidelinesExamplesRelated Commandsfair-queue (DWFQ)Syntax DescriptionDefaultCommand ModeUsage GuidelinesExampleRelated Commandsip rsvp bandwidthDefaultCommand ModeUsage GuidelinesExampleRelated Commandsip rsvp neighborsDefaultCommand ModeUsage GuidelinesExampleRelated Commandsip rsvp reservationDefaultCommand ModeUsage GuidelinesExamplesRelated Commandsip rsvp senderDefaultCommand ModeUsage GuidelinesExampleRelated Commandsip rsvp udp-multicastDefaultCommand ModeUsage GuidelinesExampleRelated Commandspriority-groupDefaultCommand ModeUsage GuidelinesExampleRelated Commandspriority-list defaultDefaultCommand ModeUsage GuidelinesExampleRelated Commandspriority-list interfaceDefaultCommand ModeUsage GuidelinesExampleRelated Commandspriority-list protocolDefaultCommand ModeUsage GuidelinesExamplesRelated Commandspriority-list queue-limitDefaultCommand ModeUsage GuidelinesExampleRelated Commandsqueue-list defaultDefaultCommand ModeUsage GuidelinesExampleRelated Commandsqueue-list interfaceDefaultCommand ModeUsage GuidelinesExampleRelated Commandsqueue-list protocolDefaultCommand ModeUsage GuidelinesExamplesRelated Commandsqueue-list queue byte-countDefaultCommand ModeUsage GuidelinesExampleRelated Commandsqueue-list queue limitDefaultCommand ModeUsage GuidelinesExampleRelated Commandsrandom-detectSyntax DescriptionDefaultCommand ModeUsage GuidelinesExampleRelated Commandsrandom-detect exponential-weighting-constantDefaultCommand ModeUsage GuidelinesExampleRelated Commandsrandom-detect precedenceDefaultCommand ModeUsage GuidelinesExampleRelated Commandsrate-limitDefaultCommand ModeUsage GuidelinesExampleRelated Commandsset ip precedenceSyntax DescriptionDefaultCommand ModeUsage GuidelinesExampleRelated Commandsset ip qos-groupDefaultCommand ModeUsage GuidelinesExampleshow access-listsDefaultCommand ModeUsage GuidelinesSample DisplaysRelated Commandsshow access-lists rate-limitCommand ModeUsage GuidelinesSample DisplaysRelated Commandsshow interfacesCommand ModeUsage GuidelinesSample Display for DWFQSample Display for DWREDshow interfaces fair-queueCommand ModeUsage GuidelinesSample Displayshow interfaces random-detectCommand ModeUsage GuidelinesSample DisplayRelated Commandsshow interfaces rate-limitCommand ModeUsage GuidelinesSample DisplayRelated Commandsshow ip cefCommand ModeUsage GuidelinesSample Displayshow ip interfaceCommand ModeUsage GuidelinesSample Displayshow ip rsvp installedCommand ModeUsage GuidelinesSample Displayshow ip rsvp interfaceCommand ModeUsage GuidelinesSample Displayshow ip rsvp neighborCommand ModeUsage GuidelinesSample Displayshow ip rsvp requestCommand ModeUsage GuidelinesSample Displayshow ip rsvp reservationCommand ModeUsage GuidelinesSample Displayshow ip rsvp senderCommand ModeUsage GuidelinesSample Displayshow queueCommand ModeUsage GuidelinesSample Displayshow queuingDefaultCommand ModeUsage GuidelinesSample DisplaysRelated Commandsshow tech-support rsvpSyntax DescriptionDefaultCommand ModeUsage Guidelinesshow traffic-shapeDefaultCommand ModeUsage GuidelinesSample DisplayRelated Commandsshow traffic-shape statisticsDefaultCommand ModeUsage GuidelinesSample DisplayRelated Commandstraffic-shape adaptiveDefaultCommand ModeUsage GuidelinesExampleRelated Commandstraffic-shape fecn-adaptSyntax DescriptionDefaultCommand ModeUsage GuidelinesExampleRelated Commandstraffic-shape groupDefaultCommand ModeUsage GuidelinesExampleRelated Commandstraffic-shape rateDefaultCommand ModeUsage GuidelinesExampleRelated Commands

Content preview from Cisco IOS™ 12.0 Quality of Service

Chapter 5. Congestion Management Overview

Congestion management features allow you to control congestion by determining the order in which packets are transmitted out an interface based on priorities assigned to those packets. Congestion management entails the creation of queues, assignment of packets to those queues based on the packet's classification, and scheduling of the packets in a queue for transmission. The congestion management QoS feature offers four types of queuing protocols, each allowing you to specify creation of a different number of queues, which affords greater or lesser degrees of differentiation of traffic and the order in which that traffic is transmitted.

During periods with light traffic, that is, when no congestion exists, ...