HP P4459A manual Fibre Loop Switch Initialization

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HP P4459A 8-Port Fibre Loop Switch Installation & Operation Guide

•If node A is free, node C’s data is forwarded directly to node A without interference. That is, the messages do not circulate through each device on the loop and so latency savings on this transaction are also gained. Note that all transactions are directed between the two communicating nodes. No traffic ever circulates the entire network as it would in a loop topology.

•If node A is busy with another loop tenancy, the open message from node C is held until that loop tenancy is completed. Holding the open message until node A is free sounds extreme until one considers the latency around a normal loop operation with a high number of nodes. The time just for one open message to circulate around a large loop (greater than 60 nodes) and get back buffer credit is actually greater than the completion of an entire loop tenancy transferring a single maximum frame across the switch. The relative time difference is on the order of a magnitude (tens of microseconds vs. tens of milliseconds).

•If A is busy and B, C, and D all simultaneously want to send data to A, a first-come, first-serve algorithm is enforced. This enforcement is realized due to the prioritized queueing of open messages at the destination. If the queue is greater than a programmable value, the switch responds with a close message to all subsequent open requests from other nodes.

Fibre Loop Switch Initialization

The initialization behavior of the fibre loop switch is encompassed within an intelligent agent referred to as P4459A Name Server. P4459A Name Server virtualizes the entire initialization process and eliminates the lengthy login procedure found on other switches.

In a hub-based Fibre Channel network, any device generates Loop Initialization Protocol (LIP) messages to notify the other devices on the loop that initialization needs to occur. During the LIP process, each port in turn receives the LIP sequence and retransmits the LIP. This process continues until the LIP sequence returns to the initiating port. Since port addresses are assigned during the LIP process, no “real” work is performed on the loop while it is underway. Therefore, it is wise to have a measure of visibility and control over LIP generation. This is the advantage of P4459A Name Server. It limits the effects of a LIP on other devices in the network.

Generally, a new node requires some period of time to become ready to participate on the network. The switch does nothing until the end node signals

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Contents HP Part Number Audience Assumptions Safety Instructions Symbols Used on EquipmentSymbols in Text Contents Appendix B Regulatory Information Preface Related PublicationsRelated Web Sites Gbic Ports Chapter Introducing the HP P4459A Port Fibre Loop SwitchFibre Loop Switch Features Front View of the Fibre Loop Switch Front Panel LEDs LEDs Switching Operation Switching Using Fibre Channel ProtocolFibre Channel Arbitration in the Fibre Loop Switch Fibre Loop Switch Initialization Introducing the HP P4459A 8-Port Fibre Loop Switch Page Installing the Fibre Loop Switch Unpacking the Fibre Loop SwitchInstalling and Removing GBICs Fibre Loop Switch Installing a GbicRemoving a Gbic Remove any cables attached to the GbicRack Mounting the Fibre Loop Switch Rack InstallationRack Installation Basics Mounting in HP Systems Racks Tools Required Preparation Marking Holes and Attaching Barrel Nuts on HP Systems Racks Mark the Rack Column Holes Place the Barrel Nuts on the Rack ColumnsInstalling the Fibre Loop Switch Attach the Sleeves to the Front Rack Columns Identify the six Torx screws Attaching Sleeves to an HP Systems Rack Installing the Fibre Loop Switch Attach the Switch Rails to the Switch Chassis Securing the Switch Rails to the SwitchInstall the switch Installing the Switch into an HP Systems Rack Complete the Installation Connect the appropriate AC power cord to the switchRetract the anti-tip foot, if desired Powering up a System Cabling for the Fibre Loop SwitchCopper cable requirements for the Fibre Loop Switch Chapter Fibre Loop Switch Troubleshooting General Maintenance ConsiderationsTroubleshooting the Switch Reading the LED IndicatorsReading The Power, Fault, and Initialization LEDs Reset Button ConnectionsFans Temperature ControlFibre Channel Cables Filler PanelPage Physical Specifications Appendix a Fibre Loop Switch Functional SpecificationsSwitching Environmental SpecificationsFibre Channel Communications Electrical SpecificationsLED Specifications Regulatory CertificationVcci V3 1997, Class a Page Electromagnetic Compliance Appendix B Regulatory InformationRegulatory Notices For products labeled as Class a Class a AccessoriesClass a Equipment Class a Warning Radio Frequency Emissions Warning for Accessories Declaration of Conformity US and EU Declaration of ConformityRegulatory Notices Product Safety Laser Safety Germany Class Laser Product Lasser Klasse 1 Produkt Hewlett-Packard Hardware Accessories Appendix C Warranty and SupportHardware Accessories Limited Warranty Canada HP Repair and Telephone SupportThird-Party Hardware Products Other CountriesWorld Wide Web Page Glossary Transmission sent to all NPorts on a network ElectroMagnetic Compatibility FC-PH Fpga Time delay of data traffic through a network or a switch Lilp Lpsm OFC Fibre Channel Arbitrated Loop that is connected to a fabric SAN Physical or logical layout of nodes on a network
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