Sun Microsystems 1.0 To Tunethe Low Water Mark

28 SunFDDI/P1.0 Adapter User’s Guide—May 1997

4

3. Use ndd —set to modify the current value of the TCP high water marks

(tcp_xmit_hiwat and tcp_recv_hiwat).

For optimum performance over FDDI connections, the TCP high water

marks should both be set to 32 Kbytes.

4. Use ndd —get (the default) to check the current value of the UDP high

water marks (udp_xmit_hiwat and udp_recv_hiwat).

5. Use ndd —set to modify the current value of the UDP high water marks

(udp_xmit_hiwat and udp_recv_hiwat).

For optimum performance over FDDI connections, the UDP high water

marks should both be set to 32 Kbytes.

▼To Tunethe Low Water Mark

By default, the low water mark is set to 2 Kbytes. Provided the high water

mark is also tuned, increasing the low water mark can improve the

performance slightly.The low water mark must never be set higher than the

high water mark. Use ndd(1M) to change the TCP and UDP low water marks:

1. Log in as root or become superuser.

#ndd —set /dev/tcp tcp_xmit_hiwat 32768

#ndd —set /dev/tcp tcp_recv_hiwat 32768

#ndd —get /dev/udp udp_xmit_hiwat

8192

#ndd —get /dev/udp udp_recv_hiwat

8192

#ndd —set /dev/udp udp_xmit_hiwat 32768

#ndd —set /dev/udp udp_recv_hiwat 32768

Contents

Main Page Regulatory Compliance Statements FCCClass A Notice FCCClass B Notice Page Page Declaration of Conformity Contents Part 1 Installing and Configuring SunFDDI/P Page Part 2 Planning and Implementing SunFDDI Networks Page Page Page Page Page Figures Page Page Page Preface How this Book is Organized Part 1 Installing and Conguring SunFDDI/P Part 2 Planning and Implementing SunFDDI Networks UNIX Commands TypographicConventions The following table describes the typographic changes used in this book. Shell Prompts Related Documents Ordering Sun Documents Getting Help Sun Welcomes YourComments Page Page SunFDDI/POverview 1 Feature Summary FDDI Conformance HardwareInstallation 2 Device Instances and Device Names Installation Items Installing SunFDDI/P Adapter Cards Connecting Fiber Optic Cables To Connect the Fiber Optic Cable MIC-to-MIC Coupler Cleaning the Fiber Optic Cable To Clean the Fiber Optic Cable Link Status Indicator (Diagnostic LED) Page InstallingSunFDDI/P Software 3 Installation Requirements Declaring IP Addresses for SunFDDI/P Installing and Conguring SunFDDI/P To Load and Mount the CD-ROM To Install SunFDDI/P Using pkgadd To Install the DeviceDriver (SUNWpfr) Page To Install the Utilities, man Pages,and SNM Agents (SUNWpft) To Finish the Installation To Check the Installation Unloading Drivers Installing SunNet Manager Agents for SunFDDI/P To Use pf_install_agents Page Removing SunFDDI/P To Remove SunFDDI/P ImprovingNetwork Performance 4 High Performance FDDI Networks Ring Latency Improvement Data Throughput Improvement Send and Receive Buffers Performance Across Bridges TargetTokenRotation Time (TTRT) Improving Performance Changing the High and Low WaterMarks To Tunethe High Water Mark To Tunethe Low Water Mark Tuningthe High and Low Water Marks at Boot Time Tuningthe Socket Options MTU Path Discovery To Tunethe Maximum Transfer Unit (MTU) To Disable MTU Path Discovery To Tunethe Target Token Rotation Time (TTRT) Page Troubleshootingand Diagnostics 5 TroubleshootingChecklist To Check the Connection to the Station To Check the Connections Between Stations To Check the Link Status Indicator Page To Check the SunFDDI/P Driver To Check the IP Addresses To Check the IP Routing To Check the Protocol Statistics To Check the SMT Traffic Solving Common Problems Page Page Page <pid> <date&time> <path> Running the Hardware Self-TestProgram To Run the HardwareSelf-Test Loading the Device Driver Manually To Configureand Load the Device Driver Page Page Page FDDINetwork Architecture 6 FDDI Network Model Physical Medium Dependent (PMD) Layer Multi-Mode Fiber (MMF) Physical (PHY) Layer Media Access Control(MAC) Layer Station Management (SMT) Layer Communication Between FDDI Layers Page FDDI Network Architecture FDDI Stations Single-Attached Station (SAS) Dual-Attached Station (DAS) FDDI Concentrators Single-Attached Concentrator (SAC) Dual-Attached Concentrator (DAC) FDDI Failure Recovery Station Wrapping Page Optical Bypass Switches Page Page FDDI Ring Operation UnrestrictedAsynchronous Transmission FDDI Performance Page Page FDDINetwork Topologies 7 Basic Dual-Ring Network Page Standalone Concentrator Page Concentrators with Dual-Homing Treeof Concentrators Page Ring of Trees Page Mixed FDDI/Ethernet Networks FDDI/Ethernet IP Router A Treeof Concentrators in an Ethernet Network A Ring of Treesin an Ethernet Network Routes in Mixed FDDI/Ethernet Networks Page Page Page Page Changing the Default MAC Address (pf_macid) To Change the Default MACAddress with pf_macid Displaying SunFDDI/P Statistics (pf_stat) Displaying Local Interface Statistics Page RMT(Ring Management) PCM(Physical Connection Management) Ring_OP(Ring Operational) XmitP(Transmit Packets) RecvP(Receive Packets) Example Local Statistics Displaying Statistics fromNeighboring Stations InterpretingStatistics from Neighboring Stations Phy(Physical Connection) Frame(Frames Received) Error(Error Frames) Page Example Neighbor Statistics Monitoring SMT Frames (pf_smtmon) Todisplay the SMT frames received by interface pf1 in hexadecimal format, type: SMT Frame Classes and Types NIF(Neighbor Information Frames) SIF(Status Information Frames) ECF(Echo Frames) RDF(Request Denied Frame) Filtering Output frompf_smtmon Page ManagingFDDI Stations UsingSunNet Manager 9 Installing the SunNet Manager Agents To Install the Standard SNM Agents on a Client To Install the FDDI Schemas on a Client Installing the FDDI Schemas on the Console To Share pf_install_agents From a Client Page Managing FDDI Networks with SunNet Manager To Set Up the SunNet Manager Console Using the SunFDDI/P Local Agent (pf_fddi) To Gather Local Station Statistics To Gather Neighbor Station Statistics To Request Information from the Local Agent To Use the SunFDDI/P Proxy Agent (pf_fddismt7_2) To Specify the Target Station To Gather Information from the Proxy Agent InterpretingTraps and Errors Page Page Page Page DevelopingApplications that Runover SunFDDI/P 10 Developing Applications with DLPI Page DLPI Addressing Page Page SettingUp Servers andDiskless Clients 11 Setting Up a Server and Diskless Clients To Set Up a Server To Introduce Diskless Clients to a Server Page Page Page Page To Update the NIS Server Installing the SunFDDI/P Driver for a Diskless Client To Install on a Client Booting a Diskless Client Over SunFDDI/P To Boot a Diskless Client Page FrequentlyAsked QuestionsAbout SunFDDI A Page Page Page Page Page Glossary Page Page Page Page Page Index Symbols Numerics A B D E F G H I J K L M N O P Q R S T U V W X Reader Comment Card