42 PCI ESCON Adapter Installation Guide
Subnet 0 207.168.12.1 – 207.168.12.62
Subnet 1 207.168.12.65 – 207.168.12.126
Subnet 2 207.168.12.129 – 207.168.12.190
Subnet 3 207.168.12.193 – 207.168.12.254
As shown, the Ethernet segment makes up subnet 0 and the Token-Ring makes up
subnet 1. Subnets 2 and 3 are currently not used. The router’s Ethernet port is
assigned an IP address in Subnet 0 and the Token-Ring port is assigned an address in
subnet 1.
Workstations on the Ethernet LAN are configured with their Default Gateway set to
207.168.12.1. Workstations and the server on the Token-Ring have their Default
Gateway set to 207.168.12.65.
Adding a TCP/IP link to a mainframe from the server in this environment is easy and
straightforward. Figure 5-25 shows how the network might look after a PCI ESCON
Adapter and TCP/IP Direct Connect have been added to the server.
Figure 5-25. Installing TCP/IP Direct Connect into Network
Notice that a new IP address has been assigned to TCP/IP Direct Connect
(207.168.12.130) and to the Mainframe (207.168.12.129). These addresses are both
part of subnet 2 which was unused before the ESCON adapter was installed. The
addresses must both be in the same subnet in order for Microsoft TCP/IP to send
TCP/IP traffic across to the Mainframe. If the mainframe were in a different subnet
than TCP/IP Direct Connect, TCP/IP would incorrectly attempt to identify an IP
address for a gateway in order to get to the mainframe.
Figure 5-26 shows the TCP/IP Direct Connect Configuration for this example.
207.168.12.67
207.168.12.4
207.168.12.3
207.168.12.2
207.168.12.1
207.168.12.65
207.168.12.66
207.168.12.68
207.168.12.129
207.168.12.130