Server Virtualization refers to the method of running multiple operating systems and independent applications on a single physical machine. It’s used as a means of enhancing physical resources to maximize the investment in hardware, where the server administrator uses a software application to divide one physical server into multiple isolated virtual environments.
Server virtualization brings the possibility of sharing hardware between multiple server applications, with each application believing it is running on its own computer with no risk of one application causing another to fail. Disk intensive applications can be matched with CPU heavy ones in order to get the maximum out of each piece of server hardware. In a virtualized environment, server applications and their virtualized operating systems access the underlying hardware through a virtualization layer. Communications hardware (such as a fax board) is typically not supported in this virtualized world, and so any server application that needs to use such hardware requires an alternative approach – this obstacle often results in fax servers being maintained separately from an organizations virtualized environment. With Fax Over IP (FoIP) this is no longer necessary. Real-time FoIP is based on the International Telecommunications Union (ITU) standard T.38, which describes the technical features necessary to transfer facsimile documents in real-time between two standard Group 3 facsimile terminals over the Internet or other networks using IP protocols. T.38 is the preferred FoIP protocol as it aligns with the behavior of faxes over the PSTN. As with the T.30 standard (what fax machines use), the IP fax transmission is handled like a traditional fax call and an end-to-end communication is established. A fax server that sends or receives faxes using T.38 looks just like any other non-FoIP fax device to its partner. The two end points establish a session, send and verify the transmission of one or more pages and then complete the session with active confirmations from both sides. The difference with a FoIP-enabled server is that the first part of the communication session from the server to the network traverses an IP network rather than traveling directly over the PSTN. If the partner device is directly addressable on the same network, the session can use T.38 for the entire transmission; however, if the telephone line separates the devices, the IP switch manages the “unwrapping” of T.38 packets into standard T.30 fax transmissions over the PSTN.