Chapter 3. InfiniBand hardware overview and implementation 53
3.8.3 Using the switch: user and passwords
To configure the switch, you can log in through a serial (RS232/TTY) connection
with one of the following predefined user/password combinations shown in
Table 3-7 on page 53.
Table 3-7 User and password combinations
3.9 InfiniBand cables
The currently supported System p servers and the M/T 7048 Topspin switches
use cables in certain lengths to interconnect the servers to the switches. The
length of the cables offered by IBM are 1.5 m, 3 m, and 8 m. Longer cables are
available from other vendors, but they are
NOT SUPPORTED for configurations
offered by IBM with System p servers. Refer to Table 3-8 for currently supported
cable types, length, feature codes, and part numbers.
Table 3-8 InfiniBand cables
The Feature code 1838 is for System p Server 590 and 595 only.
InfiniBand cable type Length Feature code Part number
4x 3 m 1835 42R6244
4x 8 m 1836 42R6245
12x to three 4x cables 8 m 1838 42R6248
4x 1.5 m 1839 42R6243
54 Implementing InfiniBand on IBM System p
Identifying IBM supported cables
IBM supported cables can be identified by the label carrying the part number
(P/N) and also by the connector color. Figure 3-10 shows the 4x cable connector.
Figure 3-10 4x InfiniBand connector
Figure 3-11 shows the 12x cable connector.
Figure 3-11 12x InfiniBand connector
Chapter 3. InfiniBand hardware overview and implementation 55
3.9.1 Cabling with octopus cables
Octopus cables are cables with a 12x connector on one end and three 4x
connectors on the other end of the cable. This enables a 12x device to connect to
a switch using a group of three switch port connectors. The bandwidth of 30
Gbps per adapter port can be achieved with the octopus cable. The three ports
grouped together on the switch side will operate as a single port 12x.
Using static 12x mode
In a group of three ports operating in static 12x mode, one port is assumed to be
the control port of the group. This port is the port you will see as active and
reports a operating speed of 30 Gbps.
The octopus 4x cable ends are labeled with numbers 16, 17, and 18 and they
have a special significance and orientation.
The lowest numbered port in a group is the configuration port that determines
if the group is running in 12x static mode. This is also the only port that can be
enabled/disabled. The other two ports configuration properties are irrelevant.
The controlling port in a group can be different for each group. It is either the
lowest numbered port or the highest numbered port, so it may be different
from the lowest numbered configuration port. It will always be connector 16 of
the octopus cable.
For the cable groups, refer to Table 3-9 on page 56 for details on the SFS 7000P
switch and refer to Table 3-10 on page 56 for details on the SFS 7008P switch.
Important: The 12x groups will only work in 12x speed and will not degrade to
4x or 1x speed. Either the link is up and running at 12x speed or the link will be