Sun Microsystems 805-1797-10 manual Table C-4Parameters Defining lancemode and ipg0

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

Defining an Additional Delay Before Transmitting a Packet Using lance_mode and ipg0

The PCI Fast Ethernet and Expansion (PFEX) ASIC supports a programmable mode called lance_mode. The ipg0 parameter is associated with lance_mode.

After a packet is received with lance_mode enabled (default) an additional delay is added by setting the ipg0 parameter 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 delay set by ipg0 helps to reduce collisions. Systems that have lance_mode enabled might not have enough time on the network.

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.

You can add the additional delay by setting the ipg0 parameter 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, nibble time is equal to 40 ns.

For example, if the link speed is 10 Mbps, and you set ipg0 to 20 nibble times, multiply 20 by 400 ns to get 800 ns. If the link speed is 100 Mbps, and you set ipg0 to 30 nibble-times, multiply 30 by 40 ns to get 120 ns.

Table C–4 defines the lance_mode and ipg0 parameters.

TABLE C–4Parameters Defining lance_mode and ipg0

Parameter

Values

Description

 

 

 

lance_mode

0

lance_mode disabled

 

1

lance_mode enabled (default)

 

 

ipg0

0-311

Additional IPG before transmitting

 

 

a packet (after receiving a packet)

 

 

 

1.The default value is 16 nibble-times, which is 6.4 microseconds for 10 Mbps and 0.64 microseconds for 100 Mbps.

Configuring the Quad FastEthernet Device Driver Parameters 29

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Contents Revision A, August USA 650 960-1300 fax 650 Revision A, August Please Recycle Contents Running Diagnostics Tests Index Regulatory Compliance StatementsPage How This Book Is Organized PrefaceRelated Documents Unix CommandsShell Prompts Typographic ConventionsTable P-1SunExpress Contact Information Ordering Sun DocumentsXii Sun Welcomes Your CommentsPage 1Sun Quad FastEthernet PCI adapter Product OverviewHardware and Software Requirements Features1Hardware and Software Requirements Displaying the OpenBoot Prom Revision Level Checking the OpenBoot Prom Revision LevelPage Using a text editor, add the following line to the end Installing the AdapterAdding an Entry to the driveraliases File Installing the Adapter Diagnostic Testing Verifying the InstallationExamining Network Activity Code Example 2-1 watch-net-allCommad Output Perform a reconfiguration boot on the system Rebooting the SystemPage Configuring the Host Files Installing the Driver SoftwareAt the command line, use the grep command to search Configuring the Driver SoftwareEtc/hosts file Reboot your system Booting From the NetworkAt the ok prompt type As superuser root, type Post-Installation Procedures OptionalConfiguring Driver Parameters Increasing TCP/IP PerformanceType Forcing Network Speed Between 10 Mbps and 100 MbpsLocal-mac-address Property Auto-NegotiationOk setenv local-mac-address? true Page Table A-1Physical Dimensions Specifications Physical DimensionsTable A-3Performance Specifications Power RequirementsTable A-2Power Requirements Performance SpecificationsSpecifications Page Figure B-132-Pin RJ-45 Connectors Interface SignalsPage Internal Transceiver Configuring the Quad FastEthernet Device Driver ParametersTable C-1qfe Driver Parameter, Status, and Descriptions Driver Parameter Values and DefinitionsQfe Driver Parameter, Status, and Descriptions Defining the Current StatusTable C-2Read-Only Parameters Defining the Current Status Inter-Packet Gap ParametersPacket after receiving a packet Table C-4Parameters Defining lancemode and ipg0Table C-5Operational Mode Parameters Operational Mode ParametersTable C-7Read-Only Transceiver Capabilities Defining the Number of Back-to-Back Packets to TransmitReporting Transceiver Capabilities Table C-6Back-to-back Packet Transmission CapabilityTable C-8Read-Only Link Partner Capabilities Reporting the Link Partner CapabilitiesSetting Parameters Using the ndd Utility Setting qfe Driver ParametersTo Specify the Device Instance for the ndd Utility To modify a parameter value, use the -setoption Use the instance number to select the deviceUsing the ndd Utility in Interactive Mode Select at least one of the five capabilities adv100fdxcap To Set the Mode to Auto-NegotiationTable C-9Setting Variables in the /etc/system File Setting Parameters in the /etc/system FileSetting Parameters Using the qfe.conf File Unit-address = 2,1 Fourth line in the previous example Setting ipg Driver Parameters Using a qfe.conf FileKernel/drv/qfe.conf file Set the ipg1 and ipg2 parameters for the above four devicesUsing the OpenBoot Prom FCode Selftest Running Diagnostics TestsShut down the system Reset the systemType show-devsto display the list of devices Reset and reboot the system Set the auto-boot?configuration parameter to truePage FCC Class a Notice Regulatory Compliance StatementsFCC Class B Notice DOC Class B Notice Avis DOC, Classe B DOC Class a Notice Avis DOC, Classe aEMC Declaration of ConformitySupplementary Information SafetyPage Index-51 Index
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