Emulex 375 manual Cascading Switches, String Cascades, Tree Cascades

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EMULEX MODEL 375 SAN STORAGE SWITCH

CHAPTER 3: SWITCH MANAGEMENT

USER’S GUIDE

Cascading Switches

When multiple switches are connected, the connecting links between the switches are referred to as "cascades". There are two distinct cascade configurations to consider when configuring networks for optimal performance and connectivity: string cascades and tree cascades.

String Cascades

A string cascade connects multiple switches (up to three switches maximum) together in a "daisy- chained" configuration. When one device requests access to another device, the request is sent to each switch in the cascade before device access is granted. This arbitration method promotes fairness between the switches. However, when compared to tree cascades, string cascades offer less performance due to the increased latency between the switches.

Figure 3-20: String Cascade configuration example

When configuring a switch port for a string cascade, use the String Cascade Smart Setting. To enable the string cascade, go to the Automatic Trunking page. From the Automatic Trunking page, select the Single Cascade option, or place the string cascade into a trunk group. See “Automatic Trunking” on page 46 for additional information.

To reduce contention and improve performance between initiator traffic and target traffic when using a string cascade configuration, connect the ports of each switch together using the same String Cascade Smart Settings. For example, in Figure 3-20the three switches are connected through two string cascades using the String Cascade - Trunk 1 and String Cascade - Trunk 2 Smart Settings. This creates two dedicated paths through which initiators and targets can communicate.

Tree Cascades

Tree cascades provide the best performance (lowest latency) configuration. A tree cascade consists of a root switch connected to additional switches (up to 8 switches maximum). When a device on a switch requests access to another device, the request is sent the particular switch for that device. The limitation to the tree cascade configuration is the random nature of devices gaining access to one another, as fairness is not used for tree cascades.

Figure 3-21: Tree Cascade configuration example

When configuring a port for a tree cascade, use the Tree Cascade Smart Setting. To enable the tree cascade, go to the Automatic Trunking page. From the Automatic Trunking page, select the Single Cascade option, or place the tree cascade into a trunk group. See “Automatic Trunking” on page 46 for additional information.

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PART NUMBER 00041392-002 REV. B

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Contents Emulex Model ART N Umber 00041392-002 R EV. B Table of Contents Chapter Introduction OverviewFeatures Inspeed TechnologySwitch Applications Storage Consolidation and Shared Storage Pooling3depicts a sample tape library consolidation configuration Tape Library ConsolidationRich Media Server ClusteringInstallation Preparation To unpack the switchRack Installation Desktop InstallationSwitch Installation To place the switch on a desktopInstalling the Retention Clips optional To install the retention clipTo insert the power cord with the retention clip in place To remove the power cord with the retention clip in placeSwitch Leds Ethernet LEDsEthernet LEDs indicate the network connection status System LEDs Port LEDsPower Supply/Fan Module LED Installing an SFP Attaching a Device to the SwitchRemoving an SFP SFP CompatibilityBooting the Switch and SAN To boot the switch and SANPower SUPPLY/FAN Module Replacement To remove an old power supply/fan moduleTo insert a new power supply/fan module Chapter Switch Management Configuring the Network Interface Getting StartedTo connect through a serial interface Connecting to the Web Manager Command Button Description SubmitWeb Manager Overview To connect to the Web ManagerCommand Button Description Cancel RebootLogin/Logout DocumentationInitial Switch Setup Log in to the SwitchChange the Password To log in to the switchChange the Switch Name To view the current date and time Click Switch Date & TimeTo set the date and time settings To change the switch name Click Switch ConfigurationManaging the Switch Frequent Switch Configuration TasksLogging in to the Switch Configuring the Switch SettingsTo change a switch setting To reset the switchGeneral Switch Settings Switch IdentificationNetwork Location Switch Speed To change the switch speed Click Switch ConfigurationVersion Information Blocking ARBSetting Snmp Traps To configure an Snmp trapConfiguring Date and Time Settings To change the time Click Switch Date & TimeTo synchronize time with the host system Click Host Time Changing the Password Switch Password page appearsOpening a Telnet Session Adjusting the Switch Thresholds Switch Thresholds page appearsTo change switch thresholds or time intervals Configuring the Port Smart Settings To view the Port Smart Settings Click Port Smart SettingsPort Smart Settings page appears Default Smart Settings Creating Custom Smart Settings To assign a Smart Setting to one or more portsTo set all ports to the currently selected Smart Setting To create a custom Smart SettingSmart Setting Assignments To modify a custom Smart SettingTo rename a custom Smart Setting To delete a custom Smart SettingPre-Insertion Testing Following settings are availablePort Information Setting Description Stealth Intelligent Change Change NotificationsManager Change Notification onPort Recovery Diagnostics Setting Description Port ControlBypass on Clock Delta Managing Firmware and Configuration Files Switch Firmware FilesTo load new firmware on the switch To check for new firmwareSwitch Configuration Files Restoring the Factory Default SettingsOne-Step Zoning Color Description Down redUp green Not Active yellowSingle-Switch Zoning Adding Devices to Multiple Zones To add storage devices to multiple zonesMultiple Switch Zoning 16 Ports in Multiple Zones on the One-Step ZoningRecovering a Bad Zone Automatically Alpa ZoningConnecting Ports Through Hard Zoning To set up Hard ZoningCascading Switches String CascadesTree Cascades Automatic Trunking 22 Automatic Trunking exampleLoad Balancing 23 Advanced Functions Automatic TrunkingLoad Indicators To change the load balancing settingsViewing Switch Status Monitoring the SwitchFairness and Prioritization Switch Information Current status is provided for the following itemsPort Utilization and Health Port Color Indication GreenYellow RedTo view the event log Click Switch Event Log Viewing the Event LogEvent Log Messages page appears Last time the event log was polled appears at the topViewing Port Information To view port information Click Port InformationPort Information page appears Viewing Port Utilization Port Utilization page appearsValue Description High AverageViewing Port Diagnostics Port Diagnostics page appearsTo save diagnostic information To reset a port Click Advanced Functions Diagnostics PortManual Port Operation To clear the countersViewing Ordered Sets CRC Error Detection Indication F7 InitializationChange Notification UnknownTroubleshooting Device Connections Troubleshooting Management Connections Port Bypass Conditions and RecoveryDefault Smart Setting Attributes Fibre Channel References Appendixes Switch Specifications Operating ConditionsConnecting to the CLI Logging in and OUTTo connect through a network interface To log in to the CLIUsing the CLI Frequent Switch Configuration TasksCLI Commands Severity Description Level Event Event Message SeverityError during Port Disc Port Ptbi failed due to timeoutLIP Cycle Timeout System config reset to factory defaultArbitrated Loop Physical Addresses Hex DecimalAlpa or Arbitrated Loop Physical AddressArbitration Current Fill WordIndex SFP Part Number 00041392-002 REV. B
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