Provide z/OS HiperSockets Layer 2 and converged interface support

There are two related issues described here:
1. System z HiperSockets provides Operating Systems with two modes of access to the HS channel ("internal LAN"): 1. Layer 2 mode (firmware routes frames using MAC address within fully formed IEEE 802.3 frames) and 2. Layer 3 mode (firmware routes frames using IP address within internal QDIO header). Operating System images that must communicate over the same HS channel must use the same access mode (i.e. the firmware does not support L2 to L3 conversion). z/OS does not support HS in L2 mode (for customer networks). Linux supports both L2 and L3 modes. If a Linux image needs to communicate with z/OS it must use L3 mode. Linux images that need to communicate with the z/VM VSwitch bridge support must access HS in L2 mode. This Linux environment (bridge) would then require each Linux instance define multiple network interfaces (HS for z/OS and HS network for connecting with external network (via the bridge). This multi-home approach can become complex for system z users to manage. A single network interface within each Linux image allowing connectivity to internal images (e.g. z/OS) and external hosts would be beneficial.

2. A HS network is logically a unique (internal) LAN segment (with a unique IP subnet). A second (related) HS issue occurs for z/OS administrators who frequently move z/OS instances among different CPCs. Each time they move an instance of z/OS they must reconfigure the IP interface (subnet) for HS (to match the HS LAN within each CPC). This problem is resolved with the z/VM bridge support (for z/VM Linux images) and for z/OS with HS converged interface support (created for the IEDN allowing a single IP interface for both OSA and HS).

Both of the above problems could be resolved by z/OS providing 1. HS L2 support and 2. providing the HS converged interface support. This solution is essentially the HS IEDN support (i.e. making the HS IEDN support available for customer networks).