System information

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AS/400 IBM Network Station: Techniques for Deployment in a WAN
subnet the IBM 5500 control unit or to obtain an additional set of addresses
for the twinax workstations attached to the control unit. Should you decide to
obtain a new address space, the routing tables in routers that are upstream
from the IBM 5500 control unit must be manually updated to include the new
address space. You would have to coordinate those addresses with the
Internic (if Internet access is desired) and default router addresses to be
configured in the twinax workstations, which are more complex to determine.
Manual table updates are required because the IBM 5500 control unit does
not run any routing protocols (RIP, RSPF, and so on). IBM recommends that,
when you install the 5500 control unit into an existing network, you should
subnet your existing address space to avoid problems.
C.3.1.1 Subnetting Example
Subnetting is accomplished by partitioning an existing address space and
using each set of addresses for different sets of devices. Partitioning is
accomplished by using a subnet mask that is more restrictive for the twinax
workstations attached to the 5500 control unit than for the LAN to which the
5500 control unit is also attached. The following is a simple example:
Figure 155. 5500 Subnet Example
LAN
Subnet mask: 255.255.255.0
Address range: 100.100.100.0
through 100.100.100.191
Subnet
Subnet mask: 255.255.255.192.
Address range: 100.100.100.192
through 100.100.100.255