Lexmark IBM 9077 - Manual (Page 197)

Single RS/6000 SP and Single SP Switch Router 179
If these ping commands fail, check routing settings and IP address
assignment again. If everything is as it should be, try to ping the GRF
FDDI media card ports or the GRF SP Switch media card to find the failing
part:
ping 10.2.1.15 (on node 12in SP2)
ping 10.3.1.16 (on node 10 in SP2)
ping 10.4.1.17 (on node 11 in SP2)
ping 10.5.1.18 (on node 9 in SP2)
ping 192.168.14.4 (on nodes in SP21)
If any errors occur, check cabling, the configuration of the SP Switch
Router media cards (See Section 3.7, “Step-by-Step Media Card
Configuration” on page 86 and Section 4.4, “FDDI Configuration” on page
121) and also the network adapters in the SP nodes.
Performance:
To get a rough overview of the data transfer rates that can be achieved in
such a scenario, the following test was performed:
We used ftp to transfer several 300 MB large files from different nodes in
SP21 to the four FDDI equipped nodes in SP2 and vice versa. We sent these
files to /dev/null to eliminate any hard disk influence on the receiver side.
The slow internal SCSI disks in two of our four nodes in SP2 would not allow
the transfer rate to exceed 4.5 MB/s. Both remaining nodes in SP2 contain
faster SSA hard disks that allowed a transfer rate of 7.5 MB/s. Nevertheless,
this would not be enough to exceed the FDDI bandwidth. So we decided to
start several ftp programs on nodes in SP2 and SP21 to sum up the transfer
rates.
With this scenario, we measured a cumulative transfer rate of up to 44 MB/s
(observed with the freeware tool monitor) that is close to the maximum
theoretical transfer rate of 4x12.5 MB/s=50 MB/s. Every node FDDI interface
yielded an overall transfer rate of about 11 MB/s (sending and receiving). The
limiting factor once again was the CPU on each of the four nodes that was not
able to handle more data simultaneously (100% busy, as seen with monitor).
5.1.4.2 SP Switch - FDDI Connection with Bridging
This scenario corresponds closely to the one described in Section 5.1.4.1,
“SP Switch - FDDI Connection without Bridging” on page 174. It might be
used to transparently connect four physically separated FDDI backbones to
one large LAN that is connected to the SP Switch.