Chapter 2 Network Connection Procedure

The Sun HPC ClusterTools 3.0 software may--but need not be--already installed on the nodes before you perform the procedures described in this chapter. The ClusterTools 3.0 software must be installed before you configure the SCI drivers, as described in Chapter 3, Configuring the SCI Network Interface.

Install SCI Adapter Cards

Notes for Scrubber Jumper Settings

If the nodes are not already in a power-off state, turn their power switches off and disconnect their power cables from the power outlet.

Verify that each SCI adapter card's scrubber jumper has the correct setting for the network configuration in which it will be used.

• Switchless two-node network - If you are creating a two-node network in which the nodes will connect directly, not through a switch, set the scrubber jumper at one end of a connection to ON and the scrubber jumper at the other end of the connection to OFF.

• Switched two-node network - If you plan to add one or two nodes to a two-node network at a later time, you may want to connect the nodes through an SCI switch when you first set up the two-node network. See the section "Notes for Switched Two-Node Network" for an explanation.

• Three- and four-node networks - The scrubber jumper on every SCI adapter card must be set to ON.

Notes for Switched Two-Node Network

In a switchless two-node network, one scrubber jumper must be ON and the other must be OFF. In a three- or four-node network, all scrubber jumpers must be ON. This means, if you add a node to a two-node network that was originally set up without a switch, you must:

• add a switch to the network

• change the OFF scrubber jumper to ON and reboot that node

If, however, you configure the two-node network with a switch from the beginning, you will initially set all scrubber jumpers to ON. As a result, the adapter cards will be initialized to communicate through a switch from the beginning and it will not be necessary to change any scrubber jumpers when you add nodes to the network.

If you plan to do this, read the instructions for creating three- and four-node networks instead of the section on two-node networks.

The chief disadvantage to using a switch when it is not required is that the switch adds some latency that would otherwise not be in the network.

Notes Regarding SBus Slots

If the SCI adapter cards are not already installed in the nodes, install them in available SBus slots. Refer to the hardware installation manual that was supplied with your server for installation instructions.

It possible, apply the following guidelines when choosing which SBus slots to use:

• Install the cards in the lowest-numbered available SBus slots.

• If you are installing two adapter cards per node, locate them in adjacent SBus slots.

Adhering to these guidelines will make it easier for you to edit the SCI configuration file, sci_config.hpc, later in the installation process. Chapter 3, Configuring the SCI Network Interface explains how to edit this file.

Connecting SCI Adapter Cards in a Two-Node Network

This section explains how to create a two-node SCI network that does not use an SCI switch.

1. Position the nodes in the desired locations.

2. Use an 80-line SCI station cable to connect the SCI adapter card of one node to the SCI adapter card of the other node.

   If each of your nodes has two SCI adapter cards, use two SCI cables, one for each pair of adapter cards. See Figure 2-1 for examples.

3. Connect the node power cords to the appropriate power outlets.

4. Turn the node power switches on and boot the nodes.

   Figure 2-1 Examples of Two-Node Unswitched SCI Connections

   
   

Connecting SCI Adapter Cards in a Three- or Four-Node Network

Perform the following steps to create a three- or four-node SCI network.

1. Position the nodes in the desired locations.

2. Use a separate 80-line SCI station cable to connect each SCI adapter card to a port on an SCI switch.

   You can connect any SCI adapter card to any switch port, but you should follow a logical order in making your connections. This will simplify network configuration and administration tasks. See Figure 2-2 and Figure 2-3 for connection examples.

3. Connect the node power cords to the appropriate power outlets.

4. Turn the node power switches on and boot the nodes.

   Figure 2-2 Examples of Three-Node Switched SCI Connections

   
   

Figure 2-3 Examples of Four-Node SCI Switched Connections