Sun Microsystems 6U manual Defining an Additional Delay Before Transmitting a Packet

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If your network has systems that use longer IPG (the sum of ipg1 and ipg2), and if those systems seem to be slow when accessing the network, increase the values of ipg1 and ipg2 to match the longer IPGs of the other systems.

Defining an Additional Delay Before Transmitting a Packet

The adapter’s PFEX ASIC supports a programmable mode called local area network controller for Ethernet (LANCE) mode, which is set with the lance_mode parameter.

When a driver receives a packet with lance_mode enabled (the default), it adds an additional time delay before transmitting the packet. This delay, set by the ipg0 parameter, is in addition to the delay set by the ipg1 and ipg2 parameters. The additional ipg0 delay helps to reduce collisions.

If lance_mode is disabled, the value of ipg0 is ignored and no additional delay is set. Only the delays set by ipg1 and ipg2 are used. Disable lance_mode if other systems keep sending a large number of back-to-back packets. Systems that have lance_mode enabled might not have enough time to transmit a large number of back-to-back packets on the network.

You can add an additional delay by setting the ipg0 parameter to a value from 0 to 31, which is the nibble time delay. Note that nibble time is the time it takes to transfer four bits on the link. If the link speed is 10 Mbps, nibble time is equal to 400 ns. If the link speed is 100 Mbps, the nibble time is equal to 40 ns.

For example, if the link speed is 10 Mbps, and you set ipg0 to 20, multiply 20 by 400 ns to get 8000 ns. If the link speed is 100 Mbps, and you set ipg0 to 30, you would multiply 30 by 40 ns to get 1200 ns.

TABLE B-4defines the lance_mode and ipg0 parameters.

TABLE B-4Parameters Defining lance_mode and ipg0

Parameter

Values

Description

 

 

 

 

lance_mode

0

0

= lance_mode disabled

 

1

1

= lance_mode enabled (default)

ipg0

0 to 31

Additional media byte time delay before

 

 

transmitting a packet (after receiving a

 

 

packet)

 

 

 

 

Note The default value of ipg0 is 16, which is 6.4 microseconds for 10 Mbps and 0.64 microseconds for 100 Mbps.

Appendix B Configuring the Sun Quad FastEthernet Device Driver Parameters 61

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Contents Sun Microsystems, Inc San Antonio Road Palo Alto, CA Please Recycle FCC Class a Notice Regulatory Compliance StatementsICES-003 Class a Notice Avis NMB-003, Classe a Bsmi Class a Notice Page Contents Configuring the Network Software Installing the Front-Access AdapterRemoving and Replacing the Adapter SpecificationsIndex Testing the AdapterFigures Figure A-1 Tables Operation SpecificationsPage How This Book Is Organized PrefaceTypographic Conventions Using Unix CommandsTable P-1Typographic Conventions Table P-3Related Documentation Shell PromptsRelated Documentation Table P-2Shell PromptsOrdering Sun Documentation Accessing Sun Documentation OnlineSun Welcomes Your Comments Overview Sun Quad FastEthernet 6U CompactPCI Adapter Front card Product DescriptionFeatures Installation Methods Overview of the Installation ProcedureModels of Hot Swap 1Rear-Access Installation Overview Installing the Rear-Access Adapter2Front-Access Installation Overview Installing the Front-Access AdapterInstalling the Rear-Access Adapter Contents of the Ship Kit Preparing for the InstallationTools and Equipment Needed 1CompactPCI Slot Pairs in a Sun Netra ct 800 Server Top View Selecting a CompactPCI Slot Pair in the SystemDetermining the Installation Type Installing the Rear-Access Adapter in Hot-Swap Mode2Location of the Rear Transition Card’s Ejection Levers To Install the Rear Transition CardLocking mechanism TabsTabs 6Closing the Ejection Levers Two Types of Levers Cutouts Tabs Locate the slot where you plan to install the front card To Install the Rear-Access Front Card9Location of the Front Card’s Ejection Levers Page Remove the wrist strap from the chassis and from your wrist # cfgadm pci Log in to the serverTo Power Off the Server Installing the Rear-Access Adapter in Cold-Swap ModeTo Install the Rear Transition Card To Install the Rear-Access Front Card Remove the wrist strap from the chassis and from your wrist To Power On the Server To Connect the Cables to the Rear Ethernet Ports Connecting the Cables to the Rear Transition CardInstalling the Front-Access Adapter Selecting a CompactPCI Slot in the System To Install the Front-Access Adapter in Hot-Swap Mode Installing the Front-Access Adapter in Hot-Swap ModeTop Adapter Ejection levers in the locked position 2Opening the Ejection Levers Two Types of Levers 4Location of the Ejection Lever Tabs Two Types of Levers 7Location of the Front-Access Adapter’s Hot-Swap LED Refer to the server’s documentation for the procedure Remove the wrist strap from the chassis and from your wrist Installing the Front-Access Adapter in Cold-Swap Mode To Install the Front-Access Adapter in Cold- Swap Mode Remove the wrist strap from the chassis and your wrist Installing the Front-Access Adapter To Connect the Cables to the Front-Access Ethernet Ports Connecting the Cables to Front-Access AdapterConfiguring the Network Software Etc/pathtoinst file for qfe devices At the terminal prompt, use the grep command to searchConfiguring the Network Software # cat /etc/inet/hosts Autonegotiation Protocol Activate the new qfe interfaces using the ifconfig commandLog in to the system as superuser Setting the local-mac-address Property# eeprom local-mac-address\?=true To Boot the System Over the Network Booting the System Over a Sun Quad FastEthernet InterfacePress the Return key to boot the system over the qfe device Select the qfe device that you want to use as a boot devicePage Specifications Figure A-1RJ-45 Ethernet Port Locations Ethernet Port Locations DescriptionsTable A-2Operation Specifications Operation SpecificationsPhysical Dimensions of the Rear-Access Adapter Physical DimensionsTable A-3Physical Dimensions Rear-Access Table A-5Environmental Specifications Environmental SpecificationsPhysical Dimensions of the Front-Access Adapter Table A-4Physical Dimensions Front-AccessTable A-6Power Requirements Power RequirementsConfiguring Sun Quad FastEthernet Device Driver Parameters Hardware Overview Sun Quad FastEthernet Device Driver ParametersTable B-1qfe Driver Parameters, Status, and Descriptions Device Driver Parameter Values and DefinitionsInterpacket Gap Parameters Parameters that Define the Current StatusTable B-2Read-Only Parameters Defining the Current Status Table B-4Parameters Defining lancemode and ipg0 Defining an Additional Delay Before Transmitting a PacketTable B-5Operational Mode Parameters Operational Mode ParametersTable B-7Read-Only Transceiver Capabilities Defining the Number of Back-to-Back Packets to TransmitParameters That Report Transceiver Capabilities Table B-6Back-to-Back Packet Transmission CapabilityTable B-8Read-Only Link Partner Capabilities Parameters That Report the Link Partner CapabilitiesUsing the ndd Utility to Set and Display Parameters Setting the qfe Device Driver ParametersTo Specify the Device Instance for the ndd Utility To modify a parameter value, use the -setoption Using the ndd Utility in Noninteractive Mode# ndd /dev/qfe \? Type q to exit interactive mode Using the ndd Utility in Interactive ModeSetting Forced Mode Using the ndd Utility To Enable Autonegotiation Using the ndd Utility Table B-9qfe.conf File Parameters Setting Parameters Using the qfe.conf FileLog in to the system To Set Driver Parameters By Creating a qfe.conf FileSave the qfe.conf file Removing and Replacing Adapter Use the ifconfig command to disable the qfe interfaces To Disable the Network Interfaces and Remove the AdapterDisabling the Network Interfaces and Removing the Adapter Appendix C Removing and Replacing the Adapter Replacing the Adapter and Activating the Network Interfaces Activate the qfe interfaces using the ifconfig commandTo Replace the Adapter and Activate the Network Interfaces Testing the Adapter Table D-1SunVTS Documentation Using the SunVTS Diagnostic SoftwareTo Run the FCode Self-Test Diagnostic Using the OpenBoot Prom FCode Self-TestReset the system to activate these parameter changes Ok setenv diag-switch? false ok setenv auto-boot? true Reset and reboot the system Index LED Creating, 43 editing, 42 examplesQfe.conf file

6U specifications

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