PXE-Preboot Execution Environment

What Is PXE?
Almost every corporate PC purchased since 1998 is "Wired for Management" (WfM) compliant. WfM is an industry standard, initiated by Intel to improv the manageability of client PC systems,
and is part of the Intel and Microsoft PC98 specification. The Preboot Execution Environment (PXE) is part of the WfM specification. What exactly is PXE? How does it helreduce cost of ownership and simplify client PC management? PXE is an open industry standard developed by a number of software and hardware vendors. It was initially designed by Intel, with input from
several other vendors including 3Com, HP, Dell, Compaq, and Phoenix Technologies. PXE works with a network interface card (NIC) in the PC, and makes the NIC a boot device.

The PXE vision is to "Make the network interface a standard, industry-accepted PC boot device." 1 This means adding the NIC to the traditional list of standard boot devices, such as floppy drives, hard disks, and CD-ROMs, that load the operating system or set up programs on the PC. It allows the client PC to "network boot." Booting from the network opens up a vast array of management and support features.

PXE boots the client PC from the network by transferring a "boot image file" from a server. This file can be the operating system for the client PC or a pre-OS agent (see the section, "Pre-OS," later in this paper) that performs client management tasks. Since PXE is not operating systemspecific, the image file can load anyOS. It provides support for network booting , of embedded and other operating systems. Because PXE works with the NIC, it requires a PXE-enabled NIC.

Most currently available NICs do support PXE, including those from 3Com, Intel, Digital, RealTek, and SMC.

PXE is available either as a boot ROM chip that you add to the NIC, or as part of
the system BIOS if the network interface is on the motherboard. PXE is specific to a type of NIC; a boot ROM for one type (for example, a3C905C) will not work on another type of NIC.