AF_IUCV address family support

6.10 LPAR mode z/VM guest

The AF_IUCV address family provides an addressing mode for communications between applications that run on IBM® Z.

This addressing mode can be used for connections through real HiperSockets and through the z/VM® Inter-User Communication Vehicle (IUCV).

Support for AF_IUCV based connections through real HiperSockets requires Completion Queue Support.

HiperSockets devices facilitate connections between applications across LPARs within an IBM Z®. In particular, an application that runs on an instance of Linux® on IBM Z can communicate with:
  • Itself
  • Other applications that run on the same Linux instance
  • An application on an instance of Linux on IBM Z in another LPAR
IUCV facilitates connections between applications across z/VM guest virtual machines within a z/VM system. In particular, an application that runs on Linux on z/VM can communicate with:
  • Itself
  • Other applications that run on the same Linux instance
  • Applications running on other instances of Linux on z/VM, within the same z/VM system
  • Applications running on a z/VM guest other than Linux, within the same z/VM system
  • The z/VM control program (CP)

The AF_IUCV address family supports stream-oriented sockets (SOCK_STREAM) and connection-oriented datagram sockets (SOCK_SEQPACKET). Stream-oriented sockets can fragment data over several packets. Sockets of type SOCK_SEQPACKET always map a particular socket write or read operation to a single packet.