PictureTel III ISA manual Fifo Packet Threshold, Concurrent UDP Streams, Low-Priority Ratio

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Advanced Options Tab

B-3

The following advanced values can be modified to regulate PACE traffic on the network.

FIFO Packet Threshold

Controls the number of non-PACE packets that the network driver allows in the FIFO ahead of PACE packets. A smaller number decreases the time between PACE packets, but it can also decrease performance. The recommended setting is 3.

Concurrent UDP Streams

Controls the number of simultaneous multimedia UDP packet streams that the network driver can handle at any given time. For many applications, the number of UDP streams is the same as the number of connections.

For example, a videoconference with three people at three different sites uses three concurrent UDP streams for the video data. The concurrent UDP streams setting must be a power of two (2, 4, 8, 16, etc.), but the optimal value varies depending on your PC and the application that you are running.

Although a video server can support up to 32 connections, a client may only want to conference with four other people at a time. The recommended setting is 16.

Low-Priority Ratio

When PACE support is enabled, high-priority packets are always transmitted before low-priority packets. If a high-priority application sends out a sufficiently high number of high-priority packets, low-priority packets may not be sent.

To prevent this problem, the driver uses a ratio setting to periodically send out a low-priority packet (if one is waiting to be sent). For example, if a value of 1000 is entered, one low-priority packet would be sent for every 1,000 high-priority packets. The recommended setting is 25.

Natural Packet Interval

To communicate packet priority to interconnect devices (repeaters, switches, and the like), the PACE driver slightly modifies the Ethernet packet. Because of this, connection problems may result when these modified packets are sent out for long periods of time during which no low-priority packets are sent. To get around this problem, the driver can be configured to periodically send out an unaltered, natural packet. The recommended setting is 180 seconds.

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Contents EtherLink III ISA Network Interface Card User Guide 3Com Corporation 5400 Bayfront Plaza Santa Clara, California Lifetime Limited Warranty Sweden, Finland, Norway Contents To Obtain an IP Address Automatically To Configure Dynamic Access SoftwareTo Not Save Installation Settings Running the AutoLink Install ProgramChecklist NIC Test Network Test Uninstalling the NICPerforming Automated Installations Installing from a DisketteDisable Receive Packet Buffering Troubleshooting Hubs with Crossover Cable C-1Low-Priority Ratio Natural Packet Interval Update Device Driver Wizard Screen Select Device ScreenDNS Configuration Screen Save Installation Settings Screen Parameters for 3C509B NIC Models Option SettingsDiagnostic Programs TablesPage How to Use This Guide About this GuideIf you are looking for Turn to Convention Description ConventionsList conventions that are used throughout this guide Icon Alerts you toNetwork Interface Card Overview Network Interface Card InstallationMaximum NIC Model Cable Connector Transceiver Network SegmentBefore You Begin 3Com 3C509B EtherDisk diskettes 1Installing the NIC 2Installing the 3C509B NIC Go to Link LED later in this chapter Connecting to the Network4Connecting to the BNC Port on the 3C509B-TPC NIC Describes the LED states If the NIC LED indicates a problem, check the followingLink LED Go to the next sectionPage Setup for Custom Installation Selecting the Type of InstallationExpress Installation Multiple NIC Installations Windows 95 SetupCustom Installation Future installations3Com Installation Wizard Windows 95 SetupPerforming the Preinstallation Procedure Follow these steps to perform the preinstallation procedureClick OK Configuring the NIC in a Plug and Play PC Turn the power on and boot Windows3Com Installation Wizard starts. Go to Chapter Insert EtherDisk diskette 1 in drive a Click NextClick Finish Next step is to configure the NIC Plug and Play is disabled on the NICDisabling Plug and Play on the NIC DOS Pnpdsabl screen appears, as shown in FigureConfiguring the NIC Add New Hardware Wizard starts and displays the first screenSelect No, and then click Next 8Install from Disk Screen 10I/O Range Assigned to the NIC Screen Windows NT SetupWindows NT Setup Select OEM Option screen appears Network screen appearsFollow these steps to perform a Custom installation Custom InstallationConfiguring the NIC To Accept Configuration SettingsTo Modify Configuration Settings Testing the NIC and the Network ConnectionFollow these steps to test the network connection Follow these steps to test the NICMessage confirms that the NIC is functioning correctly Network Connection Test screen appears, as shown in FigureSelect the No radio button Click Next Installing TCP/IP Under WindowsTo Not Install TCP/IP To Install TCP/IPGo to Configuring DNS later in this chapter Configuring TCP/IP Under WindowsTo Obtain an IP Address Automatically Follow these steps to obtain an IP address automaticallyClick Add New Gateway to add the new gateway configuration To Specify an IP Address ManuallyMessage confirms that the DNS connection is functioning Configuring DNSTo Obtain a DNS Address Automatically Follow these steps to obtain a DNS address automaticallyNext step is to identify your PC on the network To Specify a DNS Address ManuallyFollow these steps to specify a DNS address manually New server appears in the Servers list boxType the name of your computer Next step is to configure DynamicAccess softwareIdentifying Your PC on the Network Follow these steps to enter field dataTo Not Configure DynamicAccess Software Configuring DynamicAccess SoftwareTo Configure DynamicAccess Software Pace Support Setup screen appears, as shown in FigureDouble-click the 3Com Pace Config icon shown in Figure To Not Save Installation Settings Repeating a Previous InstallationSelect the Yes radio button, and then click Next To Save Installation SettingsClick Finish Installation Complete screen appears, as shown in FigureCompleting the Installation and Configuration WindowsClick Yes Click Close Windows NT19Microsoft TCP/IP Properties Screen Choose a method to configure TCP/IPSelect the Specify an IP address radio button Page AutoLink Requirements ConfigurationRunning the AutoLink Install Program Under WindowsI N N U AutoLink program menu is displayedNetwork Text File Name Network Driver Name Operating System Installing Other Supported Network DriversObtaining NetWare Loadable Modules NetWare Server NLM NameNIC Configuration screen is displayed, as shown in Figure Removing NIC SoftwareNIC software is removed from your PC Select Configure NIC and press EnterSelect Auto Configure and press Enter Reconfiguring the NICFollow these steps to configure the 3C509B ISA NIC for an Changing NIC Configuration from ISA to EisaChanging NIC Configuration from Eisa to ISA Option Default Setting Supported Settings Changing Configuration SettingsFollow these steps to change the configuration settings Page Windows 95 Windows NT Troubleshooting ChecklistResolving Hardware Conflicts in Windows 95 and Windows NT Close all open windows and restart the PC System Properties window is displayedGeneral tab of the 3Com NIC Diagnostics program appears Double-click the 3Com icon in the taskbar trayRestart the PC 3Com EtherLink III 3C509 ISA Adapter Bus screen appears Installing Multiple NICs in a Windows NT PCInstalling the First NIC Setup program copies files, and the Network screen reappearsFiles are copied, and the Network screen reappears Installing Subsequent NICsSetup program displays a warning message Microsoft TCP/IP Properties screen appearsMessages are displayed, and you are prompted to reboot Windows 95 and Windows NT TroubleshootingDiagnostic Testing Under Windows 95 and Windows NT Starting the 3Com NIC Diagnostics ProgramConfiguration DiagnosticsDynamicAccess Tab Description GeneralRunning Tests Uninstalling the NICClick Remove Click OK Reinstalling NIC SoftwareClick Install Performing Automated InstallationsInstalling from the Hard Disk Installing from a DisketteDiagnostic Testing Under Windows Windows TroubleshootingSelect the NIC you want to test and press Enter Starting the DOS Configuration and Diagnostic ProgramIf multiple NICs are installed, each NIC is listed Running the Group 1 TestsAssembling a Loopback Plug Failure in this test usually indicates a cabling problemRunning the Group 2 Test Follow these steps to run the Group 1 testsStarting the Group 2 Test Setting Up an Echo ServerFollow these steps to set up an echo server Running the Group 3 TestMain window of the diagnostic program is displayed Diagnostic NIC Installed Program Name Echo ServerStarting the Group 3 Test Getting Help If a Test Fails NIC Specifications SpecificationsRJ-45 Connector Pin Assignments AUI Connector Pin AssignmentsPin Function TypeExample Cable SpecificationsPage Additional Ranges tab is shown in Figure B-1 Additional Ranges TabClick Add Advanced Options TabNatural Packet Interval Fifo Packet ThresholdConcurrent UDP Streams Low-Priority RatioDisable Switch Packet Prioritization Disable Receive Packet BufferingThis option disables the receive packet buffer Crossover Cable Troubleshooting Hubs with Crossover CableFigure C-1Straight-Through and Crossover Cable Pinouts To make a crossover cable, connect TD+ to RD+ and TD- to RDOnline Technical Services 3Com Bulletin Board ServiceWorld Wide Web Site 408 654 3ComFacts Automated Fax ServiceAccess by Analog Modem Access by Digital ModemLog on to CompuServe 3ComForum on CompuServe Online ServiceSupport from Your Network Supplier To use 3ComForumRegional Sales Office Telephone Number 3Com Corporation Support from 3Com3Com Ireland Returning Products for Repair To obtain an RMA number, call or faxCountry Telephone Number Fax Number Numbers IndexIndex NIC Page 3Com Corporation Limited Warranty FCC Class B Statement FCC Declaration of Conformity Page Page Page Page Page