Back-to-Back WAN Links

This example will work for Solstice X.25 9.x and SunLink X.25 8.x. You can also configure a back-to-back WAN link for SunNet X.25 7.0, but the instructions are slightly different. They have been included in the example.

1. Connect your communications equipment.

   If you are using a modem eliminator, connect the cables from the modem eliminator to the two machines. If you are using a null modem cable, connect the cable to the two machines.

2. Create a link on the local machine.

   Follow the instructions in "Configuring a Single WAN Link".

   In the x25tool windows use the following values:

   • In the Link Editor window, accept ZSH (the default), or specify HSI for the Device item.

   • Choose a speed that is supported by the remote machine for the Tx Clock parameter. If the remote machine is a SunNet X.25 7.0 machine, on that machine enter a command such as:

     % grep syncinit /etc/sunlink/x25/rc /usr/sunlink/sync/syncinit zss0 speed=19200 txc=baud rxc=rxc > /dev/console 2>&1

     In the example output above, the remote machine is running at 19200 bps. In such a case, specify 19200 for Tx Clock for the local machine.

   • In the Link Editor window, set the Interface parameter to DTE (the default) or DCE. The local machine Interface parameter must be the opposite of the remote end. For example, if the remote machine is a SunNet X.25 7.0 machine, on that machine enter a command such as:

     remote_host x25config -d /etc/solstice/x25/x25params0 | grep 198x25 1984 normal dte

     In the example output above, the remote machine is a DTE. In this case, you would, specify DCE for the local machine.

   • Still in the Link Editor window, specify a Local Address. Make a note of this address.

   • Under Logical Channel range in the Link Editor window, specify a two-way range that corresponds to the range used by the remote machine. If the remote machine is a SunNet X.25 7.0 machine, on that machine enter a command such as:

     remote_host% x25config -d /etc/sunlink/x25/x25params0 | grep way lcn_two_way 512-575

     In the example output above, the remote machine has a logical channel range of 512-575, the default for SunNet X.25 7.0. In this case, you would specify the same range for the local machine.

   • Choose an X.25 configuration file that is appropriate for your local DTE/DCE role and for the X.25 recommendation year supported by the remote machine. For example, if the remote machine is a DTE that supports 1984 X.25, select def.dce84.x25.

3. Display the PAD Hosts Database widow.

   In the x25tool base window, select Services => PAD => PAD Host database.

   In the PAD Hosts Database window, click on Add and enter the name of the remote machine in the Host Name field and the DTE or DCE X.121 address of the remote machine in the Remote Address field. If the remote machine is a SunNet X.25 7.0 machine, on that machine enter a command such as:

   remote_host% x25config -d /etc/sunlink/x25/x25params0 | grep ^add address 1000-5555-22

   In the example output above, the remote machine has an address of 1000555522. Enter this value (without the hyphens) in the Remote Address field.

   After entering the name and address of the remote machine, click on Apply in the PAD Hosts Database Window. Click on OK to dismiss the window.

4. Start the X.25 network.

5. Repeat Steps 2, 3 and 4 of this procedure on the remote machine to bring up the X.25 software on that machine.

   If this machine is running Solstice 9.x or SunLink 8.x, perform the steps exactly as described above. If the remote machine is running SunNet X.25 7.0 or another vendor's X.25, create an equivalent configuration.

6. In a terminal window, enter a command such as:

   local_host% /opt/SUNWconn/bin/pad remote host

   where remote host is the name you entered for the remote host. You should receive a message indicating that your call is connected. If you do not, it indicates a configuration problem on the local or remote end.