7.13.1 Network Communications Failure

7.13.1.1 Symptom

The system is unable to communicate over the network.

7.13.1.2 Action

Your system conforms to the Ethernet 10BASE-T/100BASE-TX standard, which states that the Ethernet 10BASE-T link integrity test function should always be enabled on both the host system and the Ethernet hub. The system cannot communicate with a network if this function is not set identically for both the system and the network hub (either enabled for both or disabled for both). This problem applies only to 10BASE-T network hubs, where the Ethernet link integrity test is optional. This is not a problem for 100BASE-TX networks, where the test is enabled by default. Refer to the documentation provided with your Ethernet hub for more information about the link integrity test function.

If you connect the system to a network and the network does not respond, use the OpenBoot PROM command watch-net-all to display conditions for all network connections:

ok watch-net-all

For most PCI Ethernet cards, the link integrity test function can be enabled or disabled with a hardware jumper on the PCI card, which you must set manually. (See the documentation supplied with the card.) For the standard TPE and MII main logic board ports, the link test is enabled or disabled through software.

Remember also that the TPE and MII ports share the same circuitry and as a result, you can use only one port at a time.

Some hub designs permanently enable (or disable) the link integrity test through a hardware jumper. In this case, refer to the hub installation or user manual for details of how the test is implemented.

Determining the Device Name of the Ethernet Interface

To enable or disable the link integrity test for the standard Ethernet interface, or for a PCI-based Ethernet interface, you must first know the device name of the desired Ethernet interface. To list the device name:

1. Shut down the operating system and take the system to the ok prompt.

2. Determine the device name for the desired Ethernet interface, using one of the two solutions that follow.

Solution 1

Use this method while the operating system is running:

1. Become superuser.

2. Type:

   # eeprom nvramrc="probe-all install-console banner apply disable-link-pulse device-name" (Repeat for any additional device names.) # eeprom "use-nvramrc?"=true

3. Reboot the system (when convenient) to make the changes effective.

Solution 2

Use this alternative method when the system is already in OpenBoot:

1. At the ok prompt, type:

   ok nvedit 0: probe-all install-console banner 1: apply disable-link-pulse device-name (Repeat this step for other device names as needed.) (Press CONTROL-C to exit nvedit.) ok nvstore ok setenv use-nvramrc? true

2. Reboot the system to make the changes effective.