Extreme Networks Px Series manual Terms, 1Conceptual view of server load balancing

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The Px series application switch can examine actual user requests, rather than simply forwarding the requests to the servers. You can use the powerful array of tools provided by the Px series application switch to scale websites by:

•Creating special purpose servers

•Making better use of web caches

•Allowing movement of web content without extensive re-linking of the site

Terms

The Px series application switch creates a level of abstraction between the real servers and the Internet, by configuring a virtual IP (VIP) address and port on the application switch. The VIP has a globally-reachable public IP address, and corresponds to the DNS entry for the website. All traffic for the website is sent to the application switch, which applies policies to decide how to forward the traffic to a real server.

Figure 1-1 shows several Internet users all connecting to the website www.busy.com.

	Virtual Server
101.1.35.2	www.busy.com

235.19.10.1

193.16.1.36	64.10.10.100
193.16.1.36
64.64.6.4
Internet clients

Real Server 1 10.1.1.3

Real Server 2 10.1.1.4

Real Server 3 10.1.1.5

WS_012

Figure 1-1:Conceptual view of server load balancing

1-2	Px Series Application Switch Installation and Configuration Guide

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Contents Published April Part number 100101-00 Rev Page Contents Installing the PxM Application Switch Module Configuring Servers and Services Index Index of Commands Preface IntroductionConventions Text ConventionsIcon Alerts you to Convention DescriptionRelated Publications Preface Server Load Balancing Concepts Purpose of Server Load BalancingTerms 1Conceptual view of server load balancingLoad Balancing Modes Layer 4 Load BalancingLayer 7 Load Balancing and Content Analysis 2Single client-server transaction using layer3Establishing a layer 7 request Getting Started on Load Balancing Configuration Port RewriteGetting Started on Load Balancing Configuration Page Installing the SummitPx1 Application Switch Overview of the SummitPx1 Application SwitchSummitPx1 Front View 1Px series application switch LEDs Color IndicatesSummitPx1 Application Switch Rear View Signal Description2DB-9 Adapter Pinouts To DB-9Installing the SummitPx1 Application Switch Determining the LocationRack Mounting Powering On the SummitPx1 Free-StandingSetting Up Console Communication Configuring Switch IP Parameters Configuring the 10/100 Ethernet Management Port Installing the PxM Application Switch Module Installing I/O ModulesRemoving I/O Modules Removing I/O Modules Page Managing the Switch Using the Command-Line Interface Abbreviated Syntax and Command CompletionSyntax Symbols 1Command Syntax SymbolsSymbol Description Line-Editing KeysSpecifying Text Values 2Line-Editing KeysConfiguring Management Access Command HistoryPrompt Text Changing the Default Passwords Creating Accounts Modifying AccountsCommand Description Managing the PxMConfiguring VLANs Configuring Snmp 4SNMP Configuration SettingsSetting Description System ContactConfiguring DNS Client Services SettingDescriptionUsing Secure Shell 2 SSH2 5DNS Client Configuration CommandsEnabling SSH2 for Inbound Switch Access Config ssh2 keyUsing SCP2 from an External SSH2 Client SSH2 Client Functions on the Switch Utilities Showing CPU LoadChecking Basic Connectivity Logging Configuring a Startup Banner Message Starting the GlobalPx Content Director AgentExample Configuration Internet DNS serverFollowing commands configure all system-related facilities Page Configuring Servers and Services Configuring Real ServersConfiguring Server Groups Configuring Virtual Services Layer 7 Virtual Services Layer 4 Port-based Load BalancingConfiguring Traffic Tagging Configuration Example 1Tag SpecificationsTag Specification Description Tag Range Configuration Example Page Choosing Policies, Persistence Modes, and NAT Scheduling PoliciesPersistence Modes 1Scheduling PoliciesSpecifier Policy Description Client IP Persistence Mode UDP Flow Persistence1Client IP persistence mode Configuring Client IP Stickiness Cookie Persistence Modes2Self-identifying cookie persistence mode Persistence Modes Hashed Cookie Persistence Session Learned Cookie Persistence Mode 4Learned cookie persistence mode Configuring Cookie Stickiness SSL Session Identifier Persistence Full-NAT Mode NAT ModesServer-only Half-NAT Mode Configuring Full-NAT Mode and Proxy IP AddressesConfiguring Half-NAT Mode Config source-flow name next-hop gateway-mode ip Real Syslog server SummitPx1 Configuration Example Page URL Switching Domain and URL SwitchingDomain Switching 1Typical switching scenario2Domain switching example Configuring URL Switching URL Switching3Simple URL switching example 4More Complicated URL switching example 5Hierarchical approach to pattern rules Creating Domain and URL Switching Rules 1Wildcard CombinationsWildcard Example Definition Modifying Existing URL Rules and Domains Application Servers Management net Configuration Example Page Configuring Redundancy Using Vrrp with the SummitPx1Adding and Configuring VRRPs Give backup systems lower prioritiesUsing Vrrp in Existing Redundant Networks 1Application switch using multiple VLANs Vrrp Automatic SynchronizationFollowing commands can be passed from master to backup Configuring Redundancy for the PxM Using Esrp with the PxMConfiguring the PxM for Multiple VLANs For SW2Configuring a Default Gateway Health Checks OverviewServer Startup Pacing Health Checking Procedure Configuring Health Checks Timers and CountersTypes of Health Checks You can disable health checks for a server group Page Monitoring the Switch 1Statistics Display CommandsShowing Traffic Statistics Displays packet-level counters for Showing Configuration Details 2Configuration Display CommandsConfiguration Displays Status Displays SummitPx128 # show server detailsShow health Information Column DescriptionManaging and Troubleshooting Operation 5Management and Troubleshooting CommandsCommandDescription Index EsrpHttp GET AUX Page Index of Commands