Scenario: Sharing a modem between logical partitions using L2TP

Situation

You are the system administrator at a medium-sized company. It is time to update your computer equipment, but you want to do more than that; you want to streamline your hardware. You start the process by consolidating the work of three old systems onto one new system. You create three logical partitions on the system. The new system comes with a 2793 internal modem. This is the only input/output processor (IOP) you have that supports Point-to-Point Protocol (PPP). You also have an old 7852–400 electronic customer support modem.

Solution

Multiple systems and partitions can share the same modems for dial-up connections, eliminating the need for each system or partition to have its own modem. This is possible if you use L2TP tunnels and configure L2TP profiles that allow outgoing calls. In your network, the tunnels will run over a virtual Ethernet network and a physical network. The physical line is connected to another system that shares the modems in your network.

Details

The following figure illustrates the network characteristics for this scenario:

Prerequisites and assumptions

System A must meet the following setup requirements:

• IBM® i 5.3 or later, installed on the partition that owns the ASYNC capable modems
• Hardware that allows you to partition.
• IBM Navigator for i
• You have created at least two logical partitions (LPAR) on the system. The partition that owns the modem must have IBM i 5.3, or later, installed. The other partitions can have IBM i, Linux®, or AIX® installed. In this scenario, the partitions are either using the IBM i or the Linux operating system.
• You have virtual Ethernet created to communicate across partitions.