System information

Planning Considerations

Network Stations, LAN utilization, CPU utilization, and so on. I/T Technical

Support Staff must evaluate each project to produce the optimum network

design. We recommend that, when you are building Network Station

solutions, you phase the customer projects to ensure the design meets

expectations with no surprises.

• Initialization time varies from AS/400 model to AS/400 model. In general,

the larger the model, the better the performance. On larger models, the

bottleneck is the LAN IOP and, on smaller models, the bottleneck is CPU

and LAN IOP. The 2629 LAN IOP provides better performance than the

2619.

• 10Mb Ethernet, 100Mb Ethernet and 16Mb token-ring are about equal in

performance within this environment.

• During initialization, CPU utilization can be quite high, especially on the

smaller AS/400 systems, which will impact other jobs. In addition, TFTP

requires more CPU than RFS.

• Subnet broadcast can significantly reduce LAN traffic and AS/400 CPU

utilization. Subnet broadcast is available with AS/400 V4R2 and Network

Station Release 3. If possible, we highly recommend that subnet

broadcast be used. In general, subnet broadcast is not advisable with

twinax, except as discussed earlier.

• The network administer should configure TCP/IP, LAN frame size and

TFTP block size for best performance. In general, the larger the size, the

better the performance.

• For twinax, the 6180 adapter is significantly faster than the 6050. The

6180 is about equal to a 4Mb token-ring.

• Because TFTP selects the path to use, there is no value to add a second

IOP, with the same network address, to a LAN to get better initialization

performance. All Network Stations, from the same network, use the TFTP

selected path.

• It is best to configure six TFTP jobs per LAN that has attached Network

Stations. However, for systems that have multiple LANs, since there is no

way, at this time, to dedicate a TFTP job to a particular LAN, initialization

may not perform as well as desired.

• In general, V4R2 provides better performance than V4R1, which provides

better performance than V3R7. V4R2 contains TCP/IP and IOP LAN

enhancements. In some cases, customers will see substantial

improvements in kernel/configuration initialization. In general, these

improvements will be visible when a single Network Station is initialized

with a small TFTP block size. V4R2 contains RFS enhancements.