Table of Contents X.25 Scenario using the IBM 9370

5.11 3745 and Ethernet Adapter

The 3745 when installed with an ESS (3745 Ethernet SubSystem), and running the NCP (Network Control Program) Version 6, support the routing of IP and ARP Ethernet traffic. Both Ethernet V2 and IEEE 802.3 frames are supported by the 3745 ESS. It supports communication from:

• Ethernet IP workstation/host to Ethernet IP workstation/host
• Ethernet IP workstation/host to VM/MVS TCP/IP host.

5.11.1 Principle of Operation

NCP IP routing uses SNA sessions to transport IP datagrams across an SNA backbone network. SNA sessions are established from NCP IP nodes to other NCP IP nodes and SNALINK TCP/IP hosts. IP datagrams are enveloped at an IP node into an SNA RU and sent across an SNA session to a destination NCP IP node or SNALINK TCP/IP host. The routing mechanism is based on static NCP routing tables. The destination NCP IP node or SNALINK TCP/IP host de-envelopes the IP datagrams and sends the frames to an Ethernet/802.3 LAN or a TCP/IP host subsystem respectively. NCP also supports the TCP/IP Address Resolution Protocol (ARP). IP traffic will benefit from NCP routing of IP within the SNA backbone network (error recovery, flow control, etc.).


Figure: 3745 and Ethernet Adapter

5.11.2 Example

All the workstations can access a VTAM application in the host using TELNET.

All the workstations can access a TCP/IP application in the host (for example FTP).

Workstation 1 can communicate with workstation 2 (Ethernet-to-Ethernet in the same 3745).

Workstation 1 can communicate with workstation 3 (Ethernet-to-Ethernet in different 3745s using the SNA backbone).

Table of Contents 3174 Establishment Controller