Manuals / Cisco Systems / Computer Equipment / Network Router

Cisco Systems OL-4266-08 manual 42-123

Models: OL-4266-08

1 124

Download 124 pages 34.88 Kb

Page 123

Chapter 42 Configuring PFC QoS

PFC QoS Glossary

•Marking is the process of setting a Layer 3 DSCP value in a packet; in this publication, the definition of marking is extended to include setting Layer 2 CoS values. Marking changes the value of a label.

•Packets carry traffic at Layer 3.

•Policing is limiting bandwidth used by a flow of traffic. Policing is done on the PFC and Distributed Forwarding Cards (DFCs). Policing can mark or drop traffic.

•Queues—Queues are allocations of buffer space used to temporarily store data on a port.

•QoS labels—PFC QoS uses CoS, DSCP, and IP Precedence as QoS labels. QoS labels are prioritization values carried in Layer 3 packets and Layer 2 frames.

•Scheduling is the assignment of Layer 2 frames to a queue. PFC QoS assigns frames to a queue based on Layer 2 CoS values.

•Shaped round robin (SRR) is a dequeuing algorithm.

•Threshold—Percentage of queue capacity above which traffic is dropped.

•Type of Service (ToS) is a one-byte field that exists in an IP version 4 header that is used to specify the priority value applied to the packet. The ToS field consists of eight bits. The first three bits specify the IP precedence value, which can range from zero to seven, with zero being the lowest priority and seven being the highest priority. The ToS field can also be used to specify a DSCP value. DSCP is defined by the six most significant bits of the ToS. DSCP values can range from 0 to 63.

•Weight—ratio of bandwidth allocated to a queue.

		Cisco 7600 Series Router Cisco IOS Software Configuration Guide, Release 12.2SX

	OL-4266-08			42-123
	OL-4266-08			42-123

Image 123

Cisco Systems OL-4266-08 manual 42-123

Contents

42-1 A P T E RPort Types Supported by PFC QoS Overview42-2 42-3 PFC QoS Feature Processing Overview42-4 2shows traffic flow and PFC QoS features with a PFC342-5 3shows traffic flow and PFC QoS features with a PFC2Ingress LAN Port PFC QoS Features Component Overview42-6 42-7 Flowchart of Ingress LAN Port PFC QoS FeaturesThese sections describe PFCs and DFCs as they relate to QoS PFC and DFC QoS FeaturesPort Trust Ingress Congestion AvoidanceSupported Distributed Forwarding Cards Supported Policy Feature CardsPFC and DFC QoS Feature List and Flowchart FeatureIngress PFC QoS 42-1042-11 Internal Dscp ValuesInitial Internal Dscp Value Final Internal Dscp Value42-12 PFC QoS Egress Port FeaturesThese sections describe PFC QoS egress port features Port-Based PFC QoS and VLAN-Based PFC QoSFlowchart of PFC QoS Egress LAN Port Features Egress CoS Values42-13 Egress ACL Support for Remarked Dscp Egress Dscp Mutation with a PFC3Egress ToS Byte Egress PFC QoS Interfaces42-15 Marking on Egress OSM Ports42-16 Understanding Classification and MarkingClassification and Marking at Untrusted Ingress Ports Ingress Classification and Marking at Trusted Ports42-17 Classification and Marking at Ingress OSM PortsIngress Classification and Marking at Trust CoS LAN Ports Ingress Classification and Marking at Trust Dscp Ports42-18 These sections describe policers PolicersClassification and Marking on the Msfc Overview of Policers42-20 Aggregate Policers42-21 Microflow PolicersUnderstanding Port-Based Queue Types Ingress and Egress Buffers and Layer 2 CoS-Based Queues42-22 42-23 42-24 Ingress Queue Types42-25 Egress Queue TypesModule to Queue Type Mappings Ingress Egress Queue Drop42-26 42-27 42-28 = CoS Egress CoS set from final internal Dscp values PFC QoS Global SettingsFollowing global PFC QoS settings apply Feature Default Value42-30 Default Values With PFC QoS EnabledReceive-Queue Limits Transmit-Queue Limit sDefault Drop-Threshold Percentages and CoS Value Mappings Bandwidth Allocation Ratios42-31 1q2t Receive Queues 1q4t Receive Queues42-32 1p1q4t Receive Queues 1p1q0t Receive Queues42-33 42-34 1p1q8t Receive Queues42-35 1q8t Receive Queues42-36 2q8t Receive Queues27, 29, 31, 33, 39, 41-45 8q4t Receive QueuesStandard receive queue Threshold CoS Lowest priority 11, 13, 15-17, 19, 21, 2342-38 42-39 48-6342-40 8q8t Receive Queues 2q2t Transmit Queues42-41 42-42 1p2q2t Transmit Queues42-43 1p3q8t Transmit Queues42-44 1p7q4t Transmit Queues42-45 42-46 48-63Tail-drop 100% nonconfigurable 1p7q8t Transmit Queues42-47 42-48 1p3q1t Transmit QueuesDefault Values With PFC QoS Disabled 1p2q1t Transmit Queues42-49 42-50 General GuidelinesPFC3 Guidelines Wrr-queue bandwidth except Gigabit Ethernet LAN ports42-51 42-52 PFC2 GuidelinesSupported Granularity for CIR and PIR Rate Values Class Map Command RestrictionsPolicy Map Command Restrictions Policy Map Class Command Restrictions42-54 Supported Granularity for CIR and PIR Token Bucket Sizes42-55 IP Precedence and Dscp ValuesCommand Purpose Enabling PFC QoS Globally42-56 Enabling Ignore Port Trust Enables ignore port trust globally on the routerDisables ignore port trust globally on the router DefaultConfiguring Dscp Transparency Enabling Queueing-Only Mode42-58 42-59 Enabling Microflow Policing of Bridged Traffic42-60 Enabling VLAN-Based PFC QoS on Layer 2 LAN PortsEnabling Egress ACL Support for Remarked Dscp Creating Named Aggregate Policers42-61 42-62 42-63 Configuring a PFC QoS Policy These sections describe PFC QoS policy configuration42-64 Yes 800 to Yes 900 to Supported only with PFC2 MAC Layer PFC QoS Policy Configuration OverviewProtocol Numbered ACLs Extended ACLs Named ACLs IPv4 Yes 100 to 1300 to 2000 to IPv6 Yes namedConfiguring MAC ACLs Configuring Protocol-Independent MAC ACL Filtering42-66 42-67 Enabling VLAN-Based MAC QoS Filtering42-68 Configuring MAC ACLs42-69 Configuring ARP ACLs for QoS FilteringConfiguring a Class Map Creating a Class Map42-70 Class Map Filtering Guidelines and Restrictions Configuring Filtering in a Class MapOptional Configures the class map to filter using an ACL Clears the ACL configuration from the class map42-72 Verifying Class Map ConfigurationTo create a policy map, perform this task Configuring a Policy MapPolicy Map Class Configuration Guidelines and Restrictions Creating a Policy MapCreating a Policy Map Class and Configuring Filtering Configuring Policy Map Class Actions42-74 Configuring Policy Map Class Marking Configuring the Policy Map Class Trust State42-75 42-76 Configuring Policy Map Class PolicingUsing a Named Aggregate Policer Configuring a Per-Interface Policer42-77 42-78 Additional classes in the policy map Verifying Policy Map ConfigurationTo verify policy map configuration, perform this task Exits policy map class configuration modeRemoves the policy map from the interface Attaching a Policy Map to an InterfaceTo attach a policy map to an interface, perform this task Attaches a policy map to the interfaceRouter# show policy-map interface fastethernet 5/36 42-8142-82 Configuring Egress Dscp Mutation on a PFC3Configuring Named Dscp Mutation Maps To configure a named Dscp mutation map, perform this task42-83 Attaching an Egress Dscp Mutation Map to an InterfaceAttaches an egress Dscp mutation map to the interface Removes the egress Dscp mutation map from42-84 42-85 Configuring Ingress CoS Mutation MapsConfiguring Dscp Value Maps Mapping Received CoS Values to Internal Dscp Values42-86 Configuring Dscp Markdown Values Configures a Dscp markdown map42-87 42-88 Configures the internal Dscp to egress CoS map Mapping Internal Dscp Values to Egress CoS Values42-89 42-90 Configuring the Trust State of Ethernet LAN and OSM PortsConfigures the trust state of the port Reverts to the default trust state untrusted42-91 Configuring the Ingress LAN Port CoS Value42-92 Configuring Standard-Queue Drop Threshold PercentagesConfigures the ingress LAN port CoS value Reverts to the default port CoS value42-93 Configuring a Tail-Drop Receive QueueConfiguring a WRED-Drop Transmit Queue Configuring a WRED-Drop and Tail-Drop Receive Queue42-94 42-95 Configuring a WRED-Drop and Tail-Drop Transmit Queue42-96 Configuring 1q4t/2q2t Tail-Drop Threshold Percentages42-97 Configures the receive- and transmit-queue tail-dropReverts to the default receive- and transmit-queue Tail-drop thresholdsConfiguring DSCP-Based Queue Mapping Mapping QoS Labels to Queues and Drop Thresholds42-98 42-99 Configuring Ingress DSCP-Based Queue MappingConfiguring the Port to Trust Dscp Enabling DSCP-Based Queue Mapping42-100 Reverts to the default mappingMapping Dscp Values to Standard Receive-Queue Thresholds Maps Dscp values to the standard receive queue42-101 Queueing interface commandMapping Dscp Values to Standard Transmit-Queue Thresholds Maps Dscp values to a standard transmit-queue42-102 42-103 Mapping Dscp Values to the Transmit Strict-Priority Queue42-104 Configuring CoS-Based Queue MappingMapping CoS Values to Standard Receive-Queue Thresholds Maps CoS values to the standard receive queueMapping CoS Values to Standard Transmit-Queue Thresholds Maps CoS values to a standard transmit-queue threshold42-105 Mapping CoS Values to Strict-Priority Queues Maps CoS values to the receive and transmit42-106 42-107 Maps CoS values to a tail-drop threshold42-108 Allocating Bandwidth Between Standard Transmit Queues42-109 42-110 Setting the Receive-Queue Size RatioReverts to the default size ratio Sets the size ratio between the receive queues42-111 Configuring the Transmit-Queue Size RatioConfigures the queue size ratio between transmit queues Configures the strict priority queue size42-112 Access LayerDistribution and Core Interswitch Links Sample Network Design Overview42-113 42-114 Identify the Voice Signaling Traffic from an IP Phone VvlanIdentify the Voice Traffic from an IP Phone Vvlan Identify the SAP Traffic from the PC DvlanSet dscp ef 42-11542-116 Accepting the Traffic Priority Value on Interswitch Links42-117 Prioritizing Traffic on Interswitch Links42-118 42-119 Voice Strict Priority Voice signaling Queue 2, ThresholdTraffic Type CoS from DSCP-to-CoS map Output QueueUsing Policers to Limit the Amount of Traffic from a PC Class map commands42-120 42-121 To monitor the policing operation, use these commands42-122 PFC QoS Glossary42-123 42-124