HP XC System Software Hardware Preparation Guide Version 3.2

NOTE: You can choose a number smaller than the absolute maximum number of interconnect
ports for max-node, but you can not expand the system to a size larger than this number in the
future without completely rediscovering the system, thereby renumbering all nodes in the system.
This restriction does not apply to hardware configurations that contain HP server blades and
enclosures.
Specific considerations for connections to the interconnect based on interconnect type are discussed
in the following sections:
• “QsNet Interconnect Connections” (page 45)
• “Gigabit Ethernet Interconnect Connections” (page 45)
• “Administration Network Interconnect Connections” (page 46)
• “Myrinet Interconnect Connections” (page 46)
• “InfiniBand Interconnect Connections” (page 46)
The method for wiring the administration network and interconnect networks allows expansion
of the system within the system's initial interconnect fabric without recabling of any existing
nodes. If additional switch chassis or ports are added to the system as part of the expansion,
some recabling may be necessary.
3.4.1 QsNet Interconnect Connections
For the QsNet
II
interconnect developed by Quadrics, it is important that nodes are connected to
the Quadrics switch ports in a specific order. The order is affected by the order of the
administration network and console network.
Because the Quadrics port numbers start numbering at 0, the highest port number on the Quadrics
switch is port max-node minus 1, where max-node is the maximum number of nodes possible
in the system. This is the port on the Quadrics switch to which the head node must be connected.
The head node in an HP XC system is always the node connected to the highest port number of
any node on the Root Administration Switch and the Root Console Switch.
NOTE: The head node port is not the highest port number on the Root Administration Switch.
Other higher port numbers are used to connect to other switches. If the Root Administration
Switch is a ProCurve 2848 switch, the head node is connected to port number 42, as discussed
in “Root Administration Switch” (page 40).
If the Root Administration Switch is a ProCurve 2824 switch, the head node is connected to port
number 22 on that switch, as discussed in “Root Administration Switch” (page 40). The head
node should, however, be connected to the highest port number on the interconnect switch.
The next node connected directly to the root switches (Administration and Console) should have
connections to the Quadrics switch at the next highest port number on the Quadrics switch
(max-node minus 2). All nodes connected to the Root Administration Switch will be connected
to the next port in descending order.
Nodes attached to branch switches must be connected starting at the opposite end of the Quadrics
switch. The node attached to the first port of the first Branch Administration Switch should be
attached to the first port on the Quadrics switch (Port 0).
3.4.2 Gigabit Ethernet Interconnect Connections
The HP XC System Software is not concerned with the topology of the Gigabit Ethernet
interconnect, but it makes sense to structure it in parallel with the administration network in
order to make your connections easy to maintain.
3.4 Interconnect Connections 45