VMCI Sockets 5.1 Release Notes

Release date: 10 Sept 2012 | ESXi build number: 799733
Last document update: 12 Aug 2012.



About VMCI Sockets

Virtual Machine Communication Interface (VMCI). ESX/ESXi 4.0 incorporated VMCI, a new virtual device to facilitate high-speed communication between virtual machines and their host. VMCI first appeared in Workstation 6.0, and does not rely on in-guest networking. The VMCI Sockets library offers a convenient interface for programming the VMCI device at the user level.

VMCI Sockets API. First introduced in VMware Workstation 6.5 and ported to ESX/ESXi 4.0, VMCI Sockets is a convenience API for the VMCI device. With minimal IP-socket code modifications, it can provide fast communication between guest virtual machines and their host.

Discontinuation Notice

VMCI support continues for host to guest communications. Guest to guest communications (VM to VM) were deprecated in vSphere 5.0 and Workstation 8.0. Inter-guest functionality has been removed in the vSphere 5.1 release.

Changes and New Features

  • In the vSphere 5.1 release, guest to guest VMCI has been removed.
  • When VMCI was made available in ESX/ESXi 4.0, both datagram and stream sockets were supported.
  • In Workstation 7.0, stream sockets were supported for Linux hosts, Linux guests, and Windows guests, but only datagram sockets were supported for Windows hosts.
  • In Workstation 6.5, stream sockets were not supported between host and guest, so you had to use datagram sockets instead.

Known Issues and Workarounds

  • The VMCI driver is not included in-box in any release of Microsoft Windows. When users power on a Windows virtual machine, the device manager shows a missing driver for the VMCI device until VMware Tools is installed. For details, see Windows device manager shows yellow bang for VMCI device.