The Preboot Execution Environment is abbreviated to PXE. It is a method of connecting a computer to a network before its operating system has started up or any other of its devices, such as hard drives, have been initialized. The benefit of this system is to enable network administrators to install software on networked computers, even if they appear to turned off.
A PXE server is configured following two protocols, DHCP, which is the Dynamic Host Configuration Protocol, and TFTP, or Trivial File Transfer Protocol. The DHCP server and the TFTP server programs have to be resident on the same computer. The PXE server does not have to be on the same computer, but for administrative convenience, it usually is. The first stage in the PXE process is the allocation of an Internet Protocol address by the DCHP server. The PXE server then delivers a file to each computer under manipulation, which is called a Network Bootstrap Program, or NBP. This is delivered using TFTP. The NBP then boots the computer and downloads an installation file.
The PXE standard does not specify the contents of the NBP file. This is because PXE is only intended to substitute for the lack of an operating system or boot file on the local computer. Common practice among network administrators already dictates the discovery of installation software on a configuration server. The PXE process only replaces the task of visiting a workstation with a CD to boot it.
The PXE standard was developed by Intel as part of its "Wired for Management" initiative. The system includes programs on a network adapter's operating chip to enable remote management by a network administrator. It also enables PCs to be turned on by sending a "wake up" packet to it over the network. The system enables network administrators to turn on any number of computers on the network and install software on them automatically and remotely.
Intel dominates the computer chip market and adds PXE capabilities on all its network adapter chips. It published the protocol as an open standard to encourage other chip manufacturers to implement PXE capabilities. The procedure cannot be executed if the networked computer does not implement "Wake-on-LAN" capabilities to turn the computer on remotely.
- Intel: Preboot Execution Environment (PXE) Specification; Sept. 20; 1999
- Tech Target: Wired for Management (WfM); David Palmer; February 2002
- Microsoft Tech Net: Dynamic Host Configuration Protocol; May 5, 2011
- "Linux Journal;" PXE Magic: Flexible Network Booting with Menus; Kyle Rankin; April 1, 2008
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