ICP cache hierarchies, Miss | Intel 1520 specs

For information on how to enable parent caching from the Manager UI, see the parent caching section on the Conﬁgure: Routing page (see Setting HTTP parent caching options‚ on page 40). For information on how to enable parent failover using the command-line interface, see Controlling parent proxy caching‚ on page 89.

New York

Intel NetStructure Cache Appliance

3returned document

regionalcache

hit

parent cache

1 request

end user

	Baltimore
Intel NetStructure Cache Appliance
localcache	miss

2forwarded request

Peer, sibling, and parent caches

Figure 7 A cache hierarchy in action

ICP cache hierarchies

Internet Cache Protocol (ICP) is a protocol for proxy caches to exchange information about their content. ICP query messages ask other caches if they are storing a particular URL. ICP response messages reply with a hit or miss answer.

ICP hierarchies employ sibling caches as well as parent caches. Sibling caches exist at the same hierarchical level, while parent caches exist one level up in the hierarchy. A cache exchanges ICP messages only with speciﬁc ICP peers. An ICP peer can be a sibling cache or a parent cache.

If the Intel NetStructure Cache Appliance has ICP enabled, it sends out ICP queries to its sibling caches in the event of a cache miss on an HTTP request. If there are no hits on siblings, the appliance sends ICP queries to ICP parents. If there are no hits on ICP parents, the appliance forwards the request to its HTTP parents. If there are no HTTP parent caches established, the appliance forwards the request to a selected ICP parent cache (which resolves the request by communicating with the origin server).

136Intel NetStructure Cache Appliance Administrator’s Guide

Image 148

Intel 1520 manual ICP cache hierarchies, Miss

Contents

Intel NetStructure 1520 Cache Appliance Copyright 2000, Intel Corporation. All rights reserved Contents Configuring the Appliance Using the Command-Line Interface Troubleshooting Problems 109 Error Messages 151 Changing network address configuration on the NIC Contents 106 Preface Who should read this manual Conventions used in this manualConvention Purpose Bold Chapter Introduction What is an Intel NetStructure Cache Appliance? Why use this caching appliance?Flexible cache architecture Web proxy cache Intel NetStructure Cache Appliance features Secure, single-point administration Multithreading process supportHigh-speed caching Broad protocol support How to use this guide Snmp Network ManagementPerformance reporting To find out about … See …Page Getting Started Controls and physical features on your system Starting the system for the first time Command-line interface‚ on Hhmmss Getting Started Accessing the Manager UI Using Monitor and Configure mode Dashboard Monitor mode frame Configure mode frame Using online help Accessing the command-line interfaceChanging passwords Verifying that caching worksPage Monitoring Appliance Performance Accessing monitor pages Using the Dashboard Resolving alarms Dashboard alert lightsExposing node detail Alert light Condition Description Using the Node Changing the selected node Using the Graphs Using the ProtocolsUsing the Cache Using the ARM Using the Other Using the Mrtg Configuring the Appliance Accessing configure pages Using the Server Basics NetStructure Cache section Setting general optionsOption Description Setting Web management options Setting virtual IP addressing optionsUsing virtual IP addressing for node failover What are virtual IP addresses? Adding entries to the Virtual IP address list Setting throttling of network connections Setting browser auto configuration optionsConfiguring load-shedding Enabling Snmp agents Configuring Http Option Definition Configuring Nntp Name and port see Option Definition Configuring FTP FTP Cache activation Storage Freshness For IMS If Modified Since revalidation requests Variable content Following table describes the variable conﬁguration options Using the Routing Using the SecurityLink displays the Change Administrator’s Password Setting Http parent caching options Setting ICP options Establishing ICP peers Field Description Setting server accelerator options Option Description Checking transparency Using the Host DatabaseChecking Wccp Configuring the host database Another invalid hostname message to the user Configuring DNS Using the Snapshots Reaching the Snapshots Using the Command-Line Interface Using the appliance after initial start-up Starting the command-line interfaceStarting the appliance the first time Navigating the command-line interface To do this Do this Using the setup menu Changing network addresses configuration Changing the DNS address and domain name Changing the controller speed and transmission modeChanging the gateway address Configuring time zone settings Configuring date and time settingsViewing current network address settings Using the main menu Starting the appliance Checking the status of the Server and ManagerStopping the appliance Installing a new version of the appliance software Viewing and maintaining versions of the software Application upgrade OS/Application upgrade Patch upgradeRunning a different version of the appliance software Clearing statistics Deleting a version of the appliance software Rebooting the System Halting the System Using the config menu Resetting to factory settingsPreparing a cache disk Setting general controls Configuring protocol options Configuring Http options Configuring Nntp options Conﬁguring Nntp servers Following table describes the tags you can use in a rule Tag Description Tag Description Examples Conﬁguring Nntp access Following table lists the access directive options If access is Authenticator is User is Pass is Configuring Secure Socket Layer SSL port Configuring FTP options Setting filter rules Primary Destination Allowed Value Secondary Specifier Allowed Value Action Value Setting remap rules Target Configuring the cache Enabling caching for different protocols Setting disk storage options Setting object freshness options Following table shows the options Configuring caching rules Request URL method use one of the following Destip=112.12.12.12 scheme=ftp action=never-cache Configuring security options Controlling client access to the appliance Controlling access to the Manager UI Configuring and maintaining ICP peers Configuring routing optionsViewing and modifying ICP rules Following table describes each ﬁeld Example Mcttl Viewing current ICP settings Enabling and disabling ICP Setting the ICP query timeout Setting the ICP port numberEnabling and disabling multicast in ICP Controlling parent proxy caching Secondary Specifiers Allowed Value Action Tag Allowed Value Action Tag Allowed Value Configuring Wccp options Configuring the Adaptive Redirection Module ARM Enabling and disabling transparent redirection Configuring ARM bypass rules Rule Description Bypass rules have the following format Rule Format Configuring the host database options Configuring load-shedding options Option Description Configuring logging options Using the monitor menu Viewing Node statisticsStatistic Description Cache Progress Viewing Protocol statistics Statistic DescriptionNetwork Statistics Description Statistics Description Client Server Statistics Description Operations Originating Statistics Description QueriesFrom this Node Viewing Cache statistics From ICP Peers Viewing Other statistics Statistic Description Using the expert menu Using the load menu Using the save menuUsing the logoff menu Troubleshooting Problems Rebooting your system Rebooting your system from the CLI Upgrading software Page Caching Solutions and Performance Appendix a Web proxy caching Day in the life of a cache request Ensuring cached object freshness Cache miss Revalidating objects Http object freshness testsExpires header test Last-Modiﬁed / Date header test Deciding whether to serve Http objects Default testRevalidate rules Configuring Http freshness options Configuring Http revalidation Caching Http alternates Configuring Http cachabilityTo cache or not to cache? Transparent proxy caching Directive source Caching directives Serving requests transparently Interception strategies Using a layer 4-aware switch to filter transparency requests Using a WCCP-enabled router for transparency Using policy-based routing to filter transparency requests Using a router to ﬁlter Http requests ARM redirection Appliance adaptive bypass Adaptive interception bypassMore about bypass rules Configuring bypass options Static and dynamic adaptive bypassSource bypass Destination bypass Server acceleration How server acceleration works Advantages of server accelerationRetrieving requested documents Whereas the corresponding proxy request would look like this Web server redirects Understanding server acceleration mapping rules Examples of rules and translations User Request Translated Request User Request Origin Server Header Translated Header Understanding cache hierarchies Http cache hierarchies ICP cache hierarchies Miss Nntp cache hierarchies Bombay News article caching Appliance as a caching proxy news server Appliance as a news serverSupporting several parent news servers Blocking particular groups ClusteringSeveral news servers supplying the same groups Several servers supplying different groups Maintaining the cache updates and feeds TransparencyPosting Pull the overview information for speciﬁed groups Configuring Access control Pull the articles for speciﬁed groupsDynamically subscribe to speciﬁed groups Take a partial feed push for speciﬁed groups Self-tuning DataFlow core Obeying Nntp control messagesClient bandwidth throttling Carrier-class architecture Fine-grained parallelism Raw-disk object storeAlias-free caching Fast space reclamation Alarms Advanced protocol featuresHigh-availability Fast kernel packet engine Virtual IP failover Monitor Dashboard Expansion capabilities Node fault toleranceLoad shedding Centralized administration Client ACL Page Error Messages Appendix B Html messages sent to clients Title Code Description Appendix B Error Messages 153 Standard Http response messages Message Description Appendix B Error Messages 155 Page Glossary DNS ISP POP Wccp Page Index News server features