Chapter 4. Configuring a Host for Basic Connections

Configuring an SX.25 host for basic X.25 WAN or LAN connections involves setting global parameters for the SX.25 host, setting parameters on individual ports, and rebuilding the IRIX kernel. All global configuration parameters and some individual port parameters affect the contents of the IRIX kernel. So whenever you change IRIX kernel parameters, the kernel must be rebuilt to put your changes into effect.

This chapter contains the sections listed below to help you configure an SX.25 host for basic X.25 network connections. It might be useful to refer to Figure 3-5 for an illustration of the configuration process as you do these procedures:


Note: Because rebuilding the kernel requires rebooting the host, you might want to delay the kernel rebuild until after you configure the global parameters and the basic connection service for all WAN ports.


The Global Kernel Parameters Option

Kernel parameters specify how to create the streams and memory blocks that support X.25 network connections. Use the ``Kernel Parameters'' option on the Edit menu to specify global kernel parameters for an SX.25 host. These parameters specify the number of virtual circuits and UUCP connections that the host can sustain simultaneously. They also specify the X.29 protocol, which is the interface between PAD users on the host and the X.25 network.

Do not confuse the global Kernel Parameters option (on the Edit menu) with the ``Kernel Parameters'' option on the Setup menu of the WAN port configuration screen. Whereas global kernel parameters pertain to the entire host, port kernel parameters pertain only to the individual WAN port for which they are set (see “Setting WAN Port Kernel Parameters” for details). Whenever you use either Kernel Parameters option, you must reboot the SX.25 host to put your changes into effect.

Procedure to Configure Global Kernel Parameters

Use this procedure to configure global kernel parameters.

  1. Start gx25adm to display the primary window.

    The primary gx25adm menu is displayed when you start the utility (shown in Figure 4-2). See “Starting the gx25adm Utility” in Chapter 3 if you need startup instructions.

  2. Open snetd.options to store the global kernel parameters.

    Use the ``Open'' option from the File menu to open the SX.25 configuration file, which is normally /etc/config/snetd.options (see “The SX.25 Configuration File” for information on this file). If you prefer to create a new configuration file by a different name, use the ``New'' option from the File menu instead (see “The Open Option” or “The New Option” for information on using these options).

  3. Select ``Kernel Parameters'' from the Edit menu.

    After your selection, the Kernel Configuration screen, shown in Figure 4-1, is displayed.

    Figure 4-1. The Kernel Configuration Screen


  4. Specify the maximum number of virtual circuits for this system.

    Use the slider to specify the maximum number of virtual circuits that this system can support simultaneously. The valid range is 0 through 32,768.

  5. Enter the maximum number of UUCP connections for this system.

    Use the slider to specify the maximum number of UUCP connections that this system can support simultaneously. The valid range is 0 through 2048.

  6. Enter the X.29 protocol recommendation to be used on this system.

    The default X.29 protocol recommendation is 88, for 1988. Click the option menu to make a different selection (84 for 1984 or 80 for 1980).

  7. Click the OK button to confirm your kernel parameter settings.

    Clicking OK signals gx25adm that the kernel parameter settings you entered are correct; it does not record the settings permanently. Settings are not recorded until you explicitly save them in a configuration file (step 8, which follows).

  8. Save your selections in the SX.25 configuration file.

    Use the ``Save'' option from the File menu to save your configuration selections in the /etc/config/snetd.options file. If you used the ``New'' option to create a new configuration file in step 2, use the ``Save As'' option to save your selections instead. (See “Using the File Menu” in Chapter 3 if you need instructions for saving files.)

Because the information that you specified affects the IRIX kernel, you must complete the procedures in “Procedure to Rebuild the IRIX Kernel” to put your changes into effect. However, you should plan to complete individual port configuration procedures before rebuilding the kernel, since some WAN port parameters affect kernel contents.

About the Ports List

Before you perform any configuration procedure on a port, you must first select the port from the ports list. This list comprises all ports on the system that SX.25 software determines to be available for configuration: previously configured ports are listed when the Configured tab is selected, and unconfigured ports are listed when the Unconfigured tab is selected. Selecting a port opens the record for the port in the SX.25 configuration file (see “The SX.25 Configuration File” in Chapter 1 for a description of this file). After the port is selected, go on to the instructions in a specific configuration procedure to complete the configuration process.

Two loopback ports, wloop0 and wloop1, are automatically included in the list of ports available for configuration. If you plan to do local testing of the X.25 protocol stack, or if you plan to test an X.25 network application, configure the loopback ports first using the WAN and LAN port configuration procedures in this chapter. Your loopback configuration must include a DTE and a DCE component.

Port Selection Procedure

Use this procedure to select a port from the ports list:

  1. Start the gx25adm utility, if you have not already done so.

    See “Starting the gx25adm Utility” in Chapter 3 if you need startup instructions.

  2. Open the configuration file, if you have not already done so.

    Use the ``Open'' option from the File menu to open an SX.25 configuration file. The default configuration file is /etc/config/snetd.options (see “The SX.25 Configuration File” for information on this file). If you prefer to create a new configuration file by a different name, use the ``New'' option from the File menu instead (see “The Open Option” or “The New Option” for information on using these options).

  3. Select the Configured or Unconfigured tab from the primary window.

    If you are configuring a port that is not yet set up for X.25 operation, select the ``Unconfigured'' tab. A list of unconfigured ports appears in the Ports window after your selection.

    If you are changing the operating parameters of a port that is already configured, select the Configured tab. A list of configured ports appears in the ports window after your selection.

    Figure 4-2 illustrates the primary window with a list of unconfigured ports.

    Figure 4-2. Sample Ports List


  4. Select the port that you want to configure.

    For an unconfigured port, select a port from the Ports list on the Unconfigured tab and click the Configure button. For a previously configured port, select a port from the Ports list on the Configured tab and click the Display button. Figure 4-2 shows that LAN port ec0 is selected from the unconfigured ports list.

Go to the “WAN Port Configuration Procedure,” the “LAN Port Configuration Procedure,” or a procedure in Chapter 5 to complete the configuration process on the port that you selected.

Using Port Configuration Windows

Use the WAN or LAN port configuration window, shown in Figure 4-7 and Figure 4-10, to configure a port for connection to an X.25 network. The information that you enter in this window creates a configuration record for the port in the snetd.options file (or an alternative configuration file, if you choose to use one). The new record is written to snetd.options when you save the file using an option from the File menu (see “Using the File Menu” in Chapter 3 for details). The port configuration record governs how the port will function when snetd.options is put into effect (see “The Network Option” in Chapter 3 for information on putting configuration files into effect).

To configure a port, specify its subnet ID and its DTE address; then, select a factory-shipped parameter file from each scroll list to specify link-level and packet-level parameter settings. Port configuration windows contain two scroll lists: an X.25 files and LAPB files list appears in the WAN window, and an X.25 files and LLC2 files list appears in the LAN window (See “SX.25 Software Components” in Chapter 1 for information on factory shipped files and “Evaluating SX.25 Parameter Files” in Chapter 2 to determine the suitability of factory-shipped files for your network connections.)

Click these topics to view more information about the WAN and LAN port configuration windows:

The Setup Menu

The Setup menu appears only on the WAN port configuration window. Use this menu to set kernel parameters for a WAN port when you configure it. Whenever you set port kernel parameters, you must reboot the SX.25 host to put your settings into effect. (See “Setting WAN Port Kernel Parameters” for more information.)

The Options Menu

The Options menu offers two port configuration options: use the IP/IXE option on this menu to configure ports for connections to IP networks; use the PVC Map option to specify the logical channels that will be dedicated to permanent virtual circuits. (See “The IP/IXE Option” and “The PVC Map Option” in Chapter 5 for more information.)

The Run Time Stacks Menu

The Run-Time Stacks menu offers options to configure an alternative X.25 and LABP protocol stack. Use these options on an operating port to check its performance with modified protocol parameter settings. The alternative stack can be used temporarily to evaluate port performance; it can also be saved as the permanent protocol stack for the port. (See “Run Time Parameters Option” in Chapter 5 for more information.)

The Help Menu

Use the Help menu on the WAN or LAN port configuration window to display a list of the help topics that are available from this window. Select the ``Overview'' option to display general information about the port configuration windows and the features that they offer.

In addition to the Help menu, you can also get help on individual window features by using the F1 key. For example, to request help on the SubnetID field, move the cursor to the entry field and press F1.

Port Configuration Window Buttons

Both port configuration windows contain buttons for selecting a link procedure, buttons for controlling entries in the scroll lists, and buttons for closing the port configuration window. These buttons are described in the subsections that follow.

The Open Button

Use the Open button to open a parameter file in the scroll list and review the file's contents. If you open a factory-shipped file and find that you need to change it, you must create a custom file to save your changes—the settings in a factory-shipped file are permanent (see “The Save As Option” in Chapter 3 for instructions). If you open a custom file and you want to change it, you can save your changes directly to the opened file (see “The Save Option” in Chapter 3 for instructions).

The Delete Button

Use the Delete button to remove a parameter file from the scroll list. You cannot use Delete to remove a factory-shipped parameter file from a scroll list—the original version of each factory-shipped file must always be available for port configurations.

The Assign Button

Use the Assign button after you select a parameter file from a scroll list to specify the file in the configuration record for this port. When you click Assign, the selected filename is displayed in the filename field above the scroll list. When you save the configuration file, the parameter file that you selected is permanently recorded in the port's configuration record (see “The Save Option” in Chapter 3 for instructions).

Link Procedure Buttons

Use these buttons to specify the link procedure for a port. Click LAP or LAPB to select the link procedure for a WAN port. If a WAN port uses extended addressing, click both the LAPB and Extended LAPB buttons. Click LLC1 or LLC2 to select the link procedure for a LAN port. If a local or loop SAP is required for the LAN port, specify the SAP as a hexadecimal number in the Local SAP or Loop SAP entry field.

The OK Button

Use the OK button to close the port configuration window and confirm that your entries are correct. These entries are recorded in the port's configuration record when you save the configuration file using an option from the File menu (see “The Save Option” in Chapter 3 for instructions).

The Cancel Button

Use the Cancel button to close the port configuration window and discard your entries. When you click Cancel, no changes are made to the configuration file; any information that was saved in the port configuration record from previous sessions remains unchanged.

WAN Port Configuration Procedure

The WAN port configuration procedure is described in two parts: the first part, “Setting WAN Port Kernel Parameters,” explains how to set kernel parameters on a WAN port; the second part, “Creating a WAN Port Configuration Record,” explains how to enter information in a port configuration record and save it in the configuration file. Perform both procedures to configure a new port, or perform either procedure separately to change an existing configuration.

Setting WAN Port Kernel Parameters

Use this procedure to configure a port for connection to an X.25 WAN:

  1. Complete the “Port Selection Procedure” if you have not already done so.

    When you select a WAN port using the port selection procedure, the WAN port configuration window is displayed (see Figure 4-7).

  2. Use the Setup menu to specify the kernel parameters for this port.

    Select the ``Kernel Parameters'' option from the Setup menu, shown in Figure 4-3, to specify the parameters for this port that affect the IRIX kernel.

    Figure 4-3. Kernel Parameters Option on the Setup Menu


  3. Specify port kernel parameters listed on the Kernel Configuration window.

    Port kernel parameters vary with the bus architecture of the SX.25 host. Use the information in “Kernel Parameter Settings For GIO Systems,” “Kernel Parameter Settings For ISC Systems,” and “Kernel Parameter Settings For VSC Systems” to specify parameter settings for ports on a particular system mode.

  4. Click the Apply and Close buttons when you finish specifying kernel parameters.

    The port kernel parameters dialog closes after you apply your changes.

Continue the configuration process, using the instructions in “Creating a WAN Port Configuration Record,” which follows. If this port was previously configured and the configuration record is still correct, it is not necessary to create a new configuration record. Go on to additional port configurations or, when all WAN port kernel parameters are configured, go on to “Procedure to Rebuild the IRIX Kernel.”

Kernel Parameter Settings For GIO Systems

Use the parameter descriptions that follow Figure 4-4 to specify kernel level parameters for GIO bus systems.

Figure 4-4. Kernel Parameters for Ports on a GIO Bus


Maximum Frame Size 


Valid range is 0 to 4104 bytes.

Encoding 

Set to ``NRZI'' for SNA; set to ``NRZ'' for all other protocols.

Kernel Parameter Settings For ISC Systems

Use the parameter descriptions that follow Figure 4-5 to specify kernel level parameters for ISC bus systems.

Figure 4-5. Kernel Parameters for Ports on an ISC Bus


Maximum Frame Size 


Valid frame size is 0 to 4096 bytes.

Electrical Interface 


Select the electrical interface standard: CCITT V.35, CCITT X.21, or EIA 232.

Encoding 

Set to ``NRZI'' for SNA; set to ``NRZ'' for all other protocols.

Kernel Parameter Settings For VSC Systems

Use the parameter descriptions that follow Figure 4-6 to specify kernel level parameters for VSC bus systems.

Figure 4-6. Kernel Parameters for Ports on a VME Bus


Maximum Frame Size 


Valid range is 0 to 4104 bytes.

Physical Interface 


Set to ``DTE'' or ``DCE.''

Baud Rate 

If this host will function as a DCE, set a baud rate. The valid range is 0 to 1544000.

No Automatic RTS 


Set to ``Disabled'' to allow automatic request to send packets to be transmitted; set to ``Enabled'' to prevent automatic request to send packets from being transmitted.

Encoding 

Set to ``NRZI'' for SNA; set to ``NRZ'' for all other protocols.

Creating a WAN Port Configuration Record

The procedure in this section explains how to configure a port for connection to an X.25 WAN using factory-shipped SX.25 parameter files to specify packet-level and link-level protocol parameters. However, if you determine that a port requires customized parameter files (see “Evaluating SX.25 Parameter Files” in Chapter 2 for details), you will be instructed to perform additional procedures at step 4 and step 7 to create the necessary files.


Note: If you decide to quit the port configuration procedure before completing it, click the Cancel button to close the port configuration window and discard your entries.


  1. Complete the “Port Selection Procedure” or “Setting WAN Port Kernel Parameters” if you have not already done so.

    If you have not already done so, perform these preliminary procedures to open the port's record in the configuration file and specify its kernel parameters to the IRIX operating system. After you complete either of these procedures, the WAN port configuration window is displayed (shown in Figure 4-7).

    Figure 4-7. The WAN Port Configuration Window


  2. Assign a subnet ID to the WAN port.

    Select a letter from the Subnet ID field to assign the subnet ID. Use the up and down arrows to scroll through the list. Your selection may be any letter from A through Z, but it must be unique to this port; subnet addresses that are already assigned do not appear in the scroll list (see “Subnet IDs and DTE Addresses” in Chapter 1 for more information).

  3. Assign a DTE address to the port.

    Enter a DTE address in the DTE Address field to assign an address to this port. (See “Subnet IDs and DTE Addresses” in Chapter 1 for background information and “X.121 Addresses” in Appendix A for address formatting information.)

  4. Selecting an X.25 parameter file and check its settings.

    Select a file from the X.25 Parameter Files list, based on the port's function as DTE or DCE equipment and on the X.25 recommendation implemented on the network (see “X.25 Parameter Files” in Chapter 1 for background information). To check the settings in the selected file, click the Open button (or double-click on the file) to display its contents. Select the labeled tabs at the bottom of the window to view additional parameter settings. To view an unlabeled tab, move the pointer to the unlabeled area and use the right mouse button to select a tab from a pull down list (see Figure 4-8).

    Figure 4-8. Tabs of X.25 Parameters



    Note: Original X.25 parameter files cannot be modified. If you determine that settings in the factory-shipped file are not suitable for the network to which this port connects, go to “Creating an X.25 Parameter File” in Chapter 7 and complete that procedure to create a customized file. Return to step 5 of this procedure when you finish creating the custom file.


  5. Assign the selected X.25 file as a port configuration specification.

    Click the Assign button to assign a selected X.25 parameter file as a configuration specification for this port. Port configuration specifications are stored in the SX.25 configuration file when you save it using the File menu. If you want to remove a file that you assigned, click the Delete button.

  6. Select a link procedure for the port.

    The link procedure is determined by the link access protocol implemented on the network to which the port will connect. Most X.25 networks use LAPB rather than LAP, since it allows either end to initiate transmissions. Click the check box beside LAP or LAPB to select the link procedure for this port. If the network uses LAPB with extended addressing, select both LAPB and Extended LAPB Addressing.

  7. Select the LAPB parameter file and check its settings.

    Select the LAPB parameter file for this port (see “LAPB Parameter Files” in Chapter 1 for background information). To check the settings in the selected file, click the Open button (or double-click on the file) to display its contents. Select the labeled tabs at the bottom of the window to view additional parameter settings. To view an unlabeled tab, move the pointer to the unlabeled area and use the right mouse button to select a tab from a pulldown list (see Figure 4-9).

    Figure 4-9. Tabs of LAPB Parameters



    Note: The factory-shipped LAPB parameter file cannot be modified. If you determine that settings in the factory-shipped file are not suitable for the network to which this port connects, go to “Creating a LAPB Parameter File” in Chapter 7 and complete that procedure to create a customized file. Return to step 8 of this procedure when you finish creating the custom file.


  8. Assign the LAPB parameter file as a port configuration specification.

    Click the Assign button to assign the LAPB parameter file as a configuration specification for this port. Port configuration specifications are stored in the SX.25 configuration file when you save it using the File menu. If you want to remove a file that you assigned, click the Delete button.

  9. Click OK to confirm this port configuration.

    Clicking OK confirms the configuration specifications that you made during the session, but it does not save your settings to a file. Settings are recorded in an SX.25 configuration file when you explicitly save them using the File menu.

  10. Save your selections in the configuration file.

    Use the ``Save'' option from the File menu to save your configuration selections in the /etc/config/snetd.options file. If you opened a new file in step 2 of this procedure, use the ``Save As'' option instead. (See “Using the File Menu” in Chapter 3 if you need instructions for saving files.)

The WAN port is now configured. To put the configured port into operation, you must rebuild the IRIX kernel and stop and restart the network (see “Procedure to Rebuild the IRIX Kernel” in this chapter and “Using the Action Menu” in Chapter 3 for procedures). If you have other WAN ports to configure, however, complete those configurations before rebuilding the kernel.

LAN Port Configuration Procedure

The procedure in this section explains how to configure a port for connection to an X.25 LAN using factory-shipped SX.25 parameter files to specify packet-level and link-level protocol parameters. However, if you determine that a port requires customized parameter files (see “Evaluating SX.25 Parameter Files” in Chapter 2 for details), you will need to perform an additional procedure at step 4 and step 7 to create the necessary files.


Note: If you decide to quit the port configuration procedure before completing it, click the Cancel button to close the port configuration window and discard your entries.


  1. Complete the “Port Selection Procedure” if you have not already done so.

    When you select a LAN port using the port selection procedure, the LAN port configuration window is displayed (see Figure 4-10).

    Figure 4-10. LAN Port Configuration Window


  2. Assign a subnet ID to the LAN port.

    Select a letter from the list in the Subnet ID field to assign the subnet ID. Use the up and down arrows to scroll through the list. Your selection may be any letter from A through Z, but it must be unique to this port (see “Subnet IDs and DTE Addresses” in Chapter 1 for more information).

  3. Assign a DTE address to the port.

    Enter a DTE address in the DTE Address field to assign a port address. (See “X.121 Addresses” in Appendix A for more information.)

  4. Select an X.25 parameter file to specify the packet-level settings for this port.

    Select a file from the X.25 Parameter Files list, based on the port's function as DTE or DCE equipment and on the X.25 recommendation implemented on the network. If you would like to check the settings in the selected file before you assign it to this port, click the Open button (or double-click on the file) to display file contents. Select the labeled tabs at the bottom of the window to view additional parameter settings. To view an unlabeled tab, move the pointer to the unlabeled area and use the right mouse button to select a tab from a pull down list (see Figure 4-11).

    Figure 4-11. Tabs of X.25 Parameters



    Note: Original X.25 parameter files cannot be modified. If you determine that settings in the factory-shipped file are not suitable for the network to which this port connects, go to “Creating an X.25 Parameter File” in Chapter 7 and complete that procedure to create a customized file. Return to step 5 of this procedure when you finish.


  5. Assign the selected X.25 file as a port configuration specification.

    Click the Assign button to assign the selected X.25 parameter file as a configuration specification for this port. Port configuration specifications are stored in the SX.25 configuration file that you save in step 10 of this procedure.

  6. Select a LAN link procedure.

    Click the checkbox beside LLC1 or LLC2. Enter the service access point, Local SAP or Loop SAP, as a hexadecimal number.

  7. Open an LLC2 parameter file and check its settings.

    SX.25 supports connections to Ethernet LANs, FDDI LANs, and token ring LANs. Select the LLC2 parameter file that corresponds to the physical medium of your LAN. If you would like to check the settings in the selected file before you assign it, click the Open button (or double-click on the file) to display file contents. Select the labeled tabs at the bottom of the window to view additional parameter settings (see Figure 4-12).

    Figure 4-12. Tabs of LLC2 Parameters



    Note: Original LLC2 parameter files cannot be modified. If you determine that settings in the factory-shipped file are not suitable for the network to which this port connects, go to “Creating an LLC2 Parameter File” in Chapter 7 and complete that procedure to create a customized file. Return to step 8 of this procedure when you finish creating the custom file.


  8. Assign the selected LLC2 file as a port configuration specification.

    Click the Assign button to assign the selected LLC2 parameter file as a configuration specification for this port. Port configuration specifications are stored in the SX.25 configuration file that you save in step 10 of this procedure.

  9. Click OK to confirm this port configuration.

    Clicking OK ends the port configuration session, but it does not record parameter settings. Settings are not recorded in an SX.25 configuration file until you explicitly save them (step 10, which follows).

  10. Save your selections in the configuration file.

    Use the ``Save'' option from the File menu to save your configuration selections in the /etc/config/snetd.options file. If you opened a new file in step 2 of this procedure, use the ``Save As'' option instead. (See “Using the File Menu” in Chapter 3 if you need instructions on saving files.)

The LAN port is now configured. The new port goes into operation the next time that you restart the network (see “The Network Option” in Chapter 3 for information on stopping and starting the network).

Procedure to Rebuild the IRIX Kernel

The IRIX kernel must be rebuilt whenever you modify a global kernel parameter (see “Procedure to Configure Global Kernel Parameters”) or a kernel parameter for an individual port (see “Setting WAN Port Kernel Parameters”). Rebuilding the kernel requires a temporary shutdown of the SX.25 host; for this reason, you should complete all changes to kernel parameters before rebuilding the kernel, if possible. To rebuild the kernel, use options on the Action menu of the SX.25 primary window (see “Using the Action Menu” in Chapter 3 if you need information on using these options).

Use the procedure below to rebuild the IRIX kernel.


Note: Be sure to make standard host shutdown preparations before you perform this procedure.


  1. Stop network operations using the ``Network'' option on the Action menu.

  2. Rebuild the kernel using the ``Create Kernel'' option on the Action menu.

  3. Reboot the system.

    You can reboot the system using the ``Restart System'' option on the System tool of your toolchest.

  4. Restart the gx25adm utility, if needed.

    By default, the SX.25 application restarts when your system is restarted. If you disabled this function, you must restart SX.25 before you can perform this step. See “Starting the gx25adm Utility” in Chapter 3 if you need instructions.

The SX.25 host is now operating with the new kernel parameters that you specified.