IBM 5500-01E, Operational, Installation, And Maintenance Manual

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Consult the documentation provided with your ISDN modem for more details
on the parameters required by your modem and the steps necessary to
configure them.
Understanding TCP/IP Concepts
There are many ways that you can use the IBM 5500 Control Unit in your
network environment. A good general understanding of TCP/IP as well as
network concepts, is necessary to get the most from your 5500 Control Unit.
The following section briefly describes some of these fundamental concepts.
An example of subnetting as it applies to the 5500 Control Unit is included to
help you understand these concepts and show you how you can insert the
5500 Control Unit into an existing TCP/IP network.
The most common configurations for the IBM 5500 Express IP Control Unit
are:
• Connection to AS/400 through WAN interface with LAN connected to
either Ethernet or Token Ring. Workstations on LAN and twinax-attached
workstations (either Network Stations or PCs with 5250 Express
emulation adapters).
• Connection to AS/400 through WAN interface of 2210 router, LAN
connection to 2210 and existing 5494 with twinax workstations initially
connected to the 5494 migrating to the IBM 5500 Unit.
Understanding IP Address Requirements
Obtaining contiguous IP addresses might be difficult, so be prepared and
obtain extra addresses for the future.
Valid Internet protocol (IP) addresses must meet the following criteria:
• 4 decimal numbers (called octets) separated by periods
• The left-most octet must be greater than or equal to 1 and less than or
equal to 223
• The remaining octets must be greater than or equal to zero and less than or
equal to 255
• All IP addresses must be unique
• The IP Address must not equal the Net Address
• The IP Address must not equal the Broadcast Address
Gateways and IP Addresses
TCP/IP LANs share some common characteristics; participating workstations
must each have unique IP addresses. Access to the IP address space outside
the local network requires the use of a router (gateway). The local network is
defined by the value of the IP address logically ANDed with the subnet mask.