Using Dscp Values to Provide QoS | Blade ICE G8000 instruction

RackSwitch G8000 Application Guide

Using DSCP Values to Provide QoS

The switch uses the Differentiated Services (DiffServ) architecture to provide QoS functions. DiffServ is described in IETF RFCs 2474 and 2475.

The six most significant bits in the TOS byte of the IP header are defined as DiffServ Code Points (DSCP). Packets are marked with a certain value depending on the type of treatment the packet must receive in the network device. DSCP is a measure of the Quality of Service (QoS) level of the packet.

The switch can classify traffic by reading the DiffServ Code Point (DSCP) or IEEE 802.1p priority value, or by using filters to match specific criteria. When network traffic attributes match those specified in a traffic pattern, the policy instructs the switch to perform specified actions on each packet that passes through it. The packets are assigned to different Class of Service (COS) queues and scheduled for transmission.

Differentiated Services Concepts

To differentiate between traffic flows, packets can be classified by their DSCP value. The Dif- ferentiated Services (DS) field in the IP header is an octet, and the first six bits, called the DS Code Point (DSCP), can provide QoS functions. Each packet carries its own QoS state in the DSCP. There are 64 possible DSCP values (0-63).

	Version	ToS	Length	ID Offset TTL Proto FCS SIP	DIP Data
	Length

Differentiated Services Code Point (DSCP)

unused

7 6 5 4 3

Figure 6-2Layer 3 IPv4 packet

2

1

0

106 Chapter 6: Quality of Service

BMD00041, November 2008

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Blade ICE G8000 manual Using Dscp Values to Provide QoS, Differentiated Services Concepts

Contents

Application Guide RackSwitch G8000 Application Guide Contents Ports and Trunking Quality of Service Appendix a Troubleshooting Figures RackSwitch G8000 Application Guide Tables RackSwitch G8000 Application Guide Preface Who Should Use This Guide What You’ll Find in This Guide Typographic Conventions Typographic Conventions How to Get Help Accessing the Switch Log on to the switch Enter IP interface mode Configuring an IP InterfaceConfigure the default gateway. Enable the gateway Using Telnet Configuring BBI access via Http Using the Browser-Based InterfaceConfiguring BBI access via Https RS G8000 config# access https import-certificate Snmp v1 Using SnmpDefault configuration Snmp User configuration Privacy-password 22 „ Accessing the Switch Configure an entry in the notify table Configuring Snmp Trap HostsSNMPv2 trap host configuration SNMPv1 trap host SNMPv3 trap host configuration Securing Access to the Switch Radius Authentication and Authorization How Radius authentication works Configuring Radius Configure the Radius secret and enable the feature Radius authentication features in Blade OS Switch User Accounts Radius Attributes for G8000 user privileges TACACS+ Authentication How TACACS+ authentication works TACACS+ authentication features in Blade OS Authorization Command authorization and logging Accounting Configuring TACACS+ Authentication Configure the TACACS+ secret and second secret Secure Shell Configuring SSH features on the switchSSH encryption of management messages Generating RSA Host and Server Keys for SSH access SSH Integration with RADIUS/TACACS+ Authentication Considerations for configuring End User Accounts End User Access ControlUser Access Control Listing current Users Logging into an End User account RackSwitch G8000 Application Guide 38 „ Accessing the Switch Port-based Network Access Control Extensible Authentication Protocol over LAN 802.1X authentication process Port Unauthorized EAPoL message exchange „ Authorized 802.1X port states„ Unauthorized „ Force Unauthorized Supported Radius attributes Support for Radius Attributes Configuration guidelines BMD00041, November VLANs Overview Vlan numbers VLANs and Port Vlan ID NumbersViewing VLANs Viewing and Configuring PVIDs Pvid numbers Vlan Tagging 1Default Vlan settings 2Port-based Vlan assignment 4802.1Q tag assignment Vlan configuration rules Vlan Topologies and Design Considerations Multiple VLANs with Tagging Adapters Component Description Vlan Enable tagging on uplink ports that support multiple VLANs Vlan configuration exampleConfigure the VLANs and their member ports Private VLANs Private Vlan ports Configuration example Select a Vlan and define the Private Vlan type as primary Configure a secondary Vlan and map it to the primary Vlan Verify the configuration RackSwitch G8000 Application Guide 62 „ VLANs Ports and Trunking Built-In fault tolerance Statistical load distribution Before you configure static trunks Static trunk group configuration rules 66 „ Ports and Trunking Port Trunking Example Follow these steps on the G8000 Repeat the process on the other switch Examine the trunking information on each switch Configurable Trunk Hash Algorithm „ Source IP SIP + Destination IP DIP Admin key Link Aggregation Control Protocol RS G8000 # show lacp information Configuring Lacp Lacp configuration guidelinesSet the Lacp mode Spanning Tree 1Ports, Trunk Groups, and VLANs Bridge Protocol Data Units BPDUs Determining the Path for Forwarding BPDUs Spanning Tree Group configuration guidelines Changing the Spanning Tree mode Assigning a Vlan to a Spanning Tree Group Rules for Vlan Tagged ports Creating a VlanAdding and removing ports from STGs RackSwitch G8000 Application Guide Rapid Spanning Tree Protocol Port state changes Edge Port Rstp configuration guidelinesPort Type and Link Type Link Type Rstp configuration example Configure Rapid Spanning Tree Default Spanning Tree configuration Per Vlan Rapid Spanning Tree Why do we need multiple Spanning Trees? 1Two VLANs on one Spanning Tree Group Configuring Pvrst Pvrst configuration guidelinesSet the Spanning-tree mode to PVRST+ Mstp Region Multiple Spanning Tree ProtocolCommon Internal Spanning Tree Mstp configuration guidelines Passing Vlan Blocking Vlan Configuring Multiple Spanning Tree Groups Configure Multiple Spanning Tree Protocol 90 „ Spanning Tree Configuring Fast Uplink Convergence Fast Uplink Convergence RackSwitch G8000 Application Guide 92 „ Spanning Tree Quality of Service COS Using ACL Filters MAC Extended ACLs IP Standard ACLs IP Extended ACLs 1Well-known protocol types Understanding ACL priority Assigning ACLs to a port Use the following command to view ACL statistics Viewing ACL statistics Example ACL configuration examplesConfigure an Access Control List Assign the ACL to port 100.10.1.0 Add the ACL to port Add the ACL to a port Configure IP ACLs to deny all other traffic Configure a MAC ACL to deny all other traffic Assign the ACLs to a port Configuring storm control Using Storm Control FiltersBroadcast storms Using Dscp Values to Provide QoS Differentiated Services Concepts RackSwitch G8000 Application Guide Per Hop Behavior Drop Class Precedence Default QoS Service Levels QoS Levels Use the following command to perform DSCP-to-802.1p mapping DSCP-to-802.1p mapping Using 802.1p Priority to Provide QoS 3Layer 2 802.1q/802.1p Vlan tagged packet Configure a port’s default 802.1p priority value to 802.1p configuration exampleQueuing and Scheduling Remote Monitoring Overview Configure the Rmon statistics on a port Configuring Rmon statisticsEnable Rmon on a port Rmon group 1-Statistics Rmon group 2-History History MIB Object ID Configure the Rmon History parameters for a port Rmon group 3-AlarmsConfiguring Rmon History View Rmon History for the port Alarm MIB objects Configuring Rmon Alarms Configure the Rmon event parameters Configure Rmon eventsConfigure the Rmon Alarm parameters to track Icmp messages Rmon group 9-Events Basic IP Routing IP Routing Benefits Routing Between IP Subnets 1The Router Legacy Network 122 „ Basic IP Routing 2Switch-Based Routing Topology Example of Subnet Routing Using VLANs to segregate Broadcast Domains 1Subnet Routing Example IP Address Assignments Add the switch ports to their respective VLANs 3Subnet Routing Example Optional Vlan Ports Enable IP routing Configure the default gateway to the routers’ addressesAssign a Vlan to each IP interface Dynamic Host Configuration Protocol RackSwitch G8000 Application Guide 128 „ Basic IP Routing Igmp Igmp Snooping FastLeave IGMPv3 Snooping Enable IGMPv3 Snooping optional Igmp Snooping configuration exampleConfigure Igmp Snooping Add VLANs to Igmp Snooping View dynamic Igmp information RS G8000# show ip igmp groups Configure a Static Multicast Router Static Multicast Router High Availability Uplink Failure Detection 1Uplink Failure Detection example Spanning Tree Protocol with UFD Configuration guidelines Failure Detection Pair Monitoring UFD Configuring UFDTurn on Uplink Failure Detection UFD Troubleshooting Monitoring Ports Figure A-1Monitoring Ports View the current configuration Configuring Port MirroringEnable port mirroring Port Mirroring behavior BMD00041, November Index Numerics Igmp TACACS+